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Sample records for anopheles epiroticus population

  1. Impact of insecticide-treated nets on wild pyrethroid resistant Anopheles epiroticus population from southern Vietnam tested in experimental huts

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    Trung Ho; Speybroeck Niko; Berkvens Dirk; Chinh Vu; Van Bortel Wim; Coosemans Marc

    2009-01-01

    Abstract Background In this study, the efficacy of insecticide-treated nets was evaluated in terms of deterrence, blood-feeding inhibition, induced exophily and mortality on a wild resistant population of Anopheles epiroticus in southern Vietnam, in order to gain insight into the operational consequences of the insecticide resistance observed in this malaria vector in the Mekong delta. Method An experimental station, based on the model of West Africa and adapted to the behaviour of the target...

  2. Pyrethroid susceptibility and behavioral avoidance in Anopheles epiroticus, a malaria vector in Thailand.

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    Ritthison, Wanapa; Titgratog, Rungarun; Tainchum, Krajana; Bangs, Michael J; Manguin, Sylvie; Chareonviriyaphap, Theeraphap

    2014-06-01

    The physiological susceptibility to insecticides and the behavioral responses of four wild-caught populations of female Anopheles epiroticus to synthetic pyrethroids (deltamethrin, permethrin, and alpha-cypermethrin) were assessed. Test populations were collected from different localities along the eastern coast, Trat (TR), Songkhla (SK), and Surat Thani (ST) and one population from the western coast, Phang Nga (PN). Results showed that all four populations of An. epiroticus were susceptible to all three synthetic pyrethroids tested. Behavioral responses to test compounds were characterized for all four populations using an excito-repellency test system. TR displayed the strongest contact excitation ('irritancy') escape response (76.8% exposed to deltamethrin, 74.1% permethrin, and 78.4% alpha-cypermethrin), followed by the PN population (24.4% deltamethrin, 35% permethrin, and 34.4% for alpha-cypermethrin) by rapidly escaping test chambers after direct contact with surfaces treated with each active ingredient compared with match-paired untreated controls. Moderate non-contact repellency responses to all three compounds were observed in the TR population but were comparatively weaker than paired contact tests. Few mosquitoes from the SK and ST populations escaped from test chambers, regardless of insecticide tested or type of trial. We conclude that contact excitation was a major behavioral response in two populations of An. epiroticus, whereas two other populations showed virtually no escape response following exposure to the three pyrethroids. The explanation for these large unexpected differences in avoidance responses between pyrethroid-susceptible populations of the same species is unclear and warrants further investigation.

  3. Biting patterns and host preference of Anopheles epiroticus in Chang Island, Trat Province, Eastern Thailand

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    Ritthison, W.; Tainchum, K.; Manguin, Sylvie; Bangs, M.J.; Chareonviriyaphap, T.

    2014-01-01

    A study of species diversity of Anopheles mosquitoes, biting patterns, and seasonal abundance of important mosquito vectors was conducted in two villages of Chang Island, Trat Province, in eastern Thailand, one located along the coast and the other in the low hills of the central interior of the island. Of 5,399 captured female anophelines, 70.25% belong to the subgenus Cellia and remaining specimens to the subgenus Anopheles. Five important putative malaria vectors were molecularly identifie...

  4. Population genetic structure of Anopheles arabiensis and Anopheles gambiae in a malaria endemic region of southern Tanzania

    NARCIS (Netherlands)

    K.R. Ng'habi; B.G.J. Knols; Y. Lee; H.M. Ferguson; G.C. Lanzaro

    2011-01-01

    Background: Genetic diversity is a key factor that enables adaptation and persistence of natural populations towards environmental conditions. It is influenced by the interaction of a natural population's dynamics and the environment it inhabits. Anopheles gambiae s.s. and Anopheles arabiensis are t

  5. Pyrethroid resistance in an Anopheles funestus population from Uganda.

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    John C Morgan

    Full Text Available BACKGROUND: The susceptibility status of Anopheles funestus to insecticides remains largely unknown in most parts of Africa because of the difficulty in rearing field-caught mosquitoes of this malaria vector. Here we report the susceptibility status of the An. funestus population from Tororo district in Uganda and a preliminary characterisation of the putative resistance mechanisms involved. METHODOLOGY/PRINCIPAL FINDINGS: A new forced egg laying technique used in this study significantly increased the numbers of field-caught females laying eggs and generated more than 4000 F1 adults. WHO bioassays indicated that An. funestus in Tororo is resistant to pyrethroids (62% mortality after 1 h exposure to 0.75% permethrin and 28% mortality to 0.05% deltamethrin. Suspected DDT resistance was also observed with 82% mortality. However this population is fully susceptible to bendiocarb (carbamate, malathion (organophosphate and dieldrin with 100% mortality observed after exposure to each of these insecticides. Sequencing of a fragment of the sodium channel gene containing the 1014 codon conferring pyrethroid/DDT resistance in An. gambiae did not detect the L1014F kdr mutation but a correlation between haplotypes and resistance phenotype was observed indicating that mutations in other exons may be conferring the knockdown resistance in this species. Biochemical assays suggest that resistance in this population is mediated by metabolic resistance with elevated level of GSTs, P450s and pNPA compared to a susceptible strain of Anopheles gambiae. RT-PCR further confirmed the involvement of P450s with a 12-fold over-expression of CYP6P9b in the Tororo population compared to the fully susceptible laboratory colony FANG. CONCLUSION: This study represents the first report of pyrethroid/DDT resistance in An. funestus from East Africa. With resistance already reported in southern and West Africa, this indicates that resistance in An. funestus may be more widespread

  6. Evidence of natural Wolbachia infections in field populations of Anopheles gambiae

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    Baldini, Francesco; Segata, Nicola; Pompon, Julien; Marcenac, Perrine; Robert Shaw, W.; Dabiré, Roch K.; Diabaté, Abdoulaye; Levashina, Elena A.; Catteruccia, Flaminia

    2014-01-01

    Wolbachia are maternally transmitted intracellular bacteria that invade insect populations by manipulating their reproduction and immunity and thus limiting the spread of numerous human pathogens. Experimental Wolbachia infections can reduce Plasmodium numbers in Anopheles mosquitoes in the laboratory, however, natural Wolbachia infections in field anophelines have never been reported. Here we show evidence of Wolbachia infections in Anopheles gambiae in Burkina Faso, West Africa. Sequencing of the 16S rRNA gene identified Wolbachia sequences in both female and male germlines across two seasons, and determined that these sequences are vertically transmitted from mother to offspring. Whole-genome sequencing of positive samples suggests that the genetic material identified in An. gambiae belongs to a novel Wolbachia strain, related to but distinct from strains infecting other arthropods. The evidence of Wolbachia infections in natural Anopheles populations promotes further investigations on the possible use of natural Wolbachia–Anopheles associations to limit malaria transmission. PMID:24905191

  7. Systematics and Population Level Analysis of Anopheles darlingi

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    Conn JE

    1998-01-01

    Full Text Available A new phylogenetic analysis of the Nyssorhynchus subgenus (Danoff-Burg and Conn, unpub. data using six data sets {morphological (all life stages; scanning electron micrographs of eggs; nuclear ITS2 sequences; mitochondrial COII, ND2 and ND6 sequences} revealed different topologies when each data set was analyzed separately but no heterogeneity between the data sets using the arn test. Consequently, the most accurate estimate of the phylogeny was obtained when all the data were combined. This new phylogeny supports a monophyletic Nyssorhynchus subgenus but both previously recognized sections in the subgenus (Albimanus and Argyritarsis were demonstrated to be paraphyletic relative to each other and four of the seven clades included species previously placed in both sections. One of these clades includes both Anopheles darlingi and An. albimanus, suggesting that the ability to vector malaria effectively may have originated once in this subgenus. Both a conserved (315 bp and a variable (425 bp region of the mitochondrial COI gene from 15 populations of An. darlingi from Belize, Bolivia, Brazil, French Guiana, Peru and Venezuela were used to examine the evolutionary history of this species and to test several analytical assumptions. Results demonstrated (1 parsimony analysis is equally informative compared to distance analysis using NJ; (2 clades or clusters are more strongly supported when these two regions are combined compared to either region separately; (3 evidence (in the form of remnants of older haplotype lineages for two colonization events; and (4 significant genetic divergence within the population from Peixoto de Azevedo (State of Mato Grosso, Brazil. The oldest lineage includes populations from Peixoto, Boa Vista (State of Roraima and Dourado (State of São Paulo.

  8. Islands and Stepping-Stones: Comparative Population Structure of Anopheles gambiae sensu stricto and Anopheles arabiensis in Tanzania and Implications for the Spread of Insecticide Resistance.

    OpenAIRE

    Deodatus Maliti; Hilary Ranson; Stephen Magesa; William Kisinza; Juma Mcha; Khamis Haji; Gerald Killeen; David Weetman

    2014-01-01

    Population genetic structures of the two major malaria vectors Anopheles gambiae s.s. and An. arabiensis, differ markedly across Sub-Saharan Africa, which could reflect differences in historical demographies or in contemporary gene flow. Elucidation of the degree and cause of population structure is important for predicting the spread of genetic traits such as insecticide resistance genes or artificially engineered genes. Here the population genetics of An. gambiae s.s. and An. arabiensis in ...

  9. "Comparison of Midgut Hemagglutination Activity in Three Different Geographical Populations of Anopheles stephensi"

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    HR Basseri

    2004-08-01

    Full Text Available Lectins that agglutinate red blood cells (RBCs were demonstrated in Anopheles stephensi mosquito midgut extracts using human (four groups: A, B, AB and O, RH+ rat, sheep and rabbit blood cells. Only rabbit RBCs showed agglutination reaction against the midgut extracts. Significant differences in hemagglutinin titers and carbohydrate specifity were detected between male and female mosquitoes as well as among three different geographical populations of Anopheles stephensi from south of Iran. Overall agglutinin levels were increased following a blood meal. The highest hemagglintination titers were due to Kazerun population. All hemagglutination assays were versus rabbit RBCS. A significant difference was detected among the number of egg-float ridges. Iranshahr population was different from Bandar-abbas and Kazerun population in egg-float ridges number. Bandr-abbas population was in the intermediate category. Iranshahr population fell between mysoransis and intermediate group and Kazerun population was between intermediate and type form. This study presents the first report on the occurrence of heterogeneous anti Rabbit RBC agglutinins in the midget extracts of the different geographical populations of An.stephensi with the sugar – binding specificities. The sugar- inhibition pattern was different between & within geographical population of An.stephensi.

  10. Population genetics of Plasmodium resistance genes in Anopheles gambiae: no evidence for strong selection.

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    Obbard, D J; Linton, Y-M; Jiggins, F M; Yan, G; Little, T J

    2007-08-01

    Anopheles mosquitoes are the primary vectors for malaria in Africa, transmitting the disease to more than 100 million people annually. Recent functional studies have revealed mosquito genes that are crucial for Plasmodium development, but there is presently little understanding of which genes mediate vector competence in the wild, or evolve in response to parasite-mediated selection. Here, we use population genetic approaches to study the strength and mode of natural selection on a suite of mosquito immune system genes, CTL4, CTLMA2, LRIM1, and APL2 (LRRD7), which have been shown to affect Plasmodium development in functional studies. We sampled these genes from two African populations of An. gambiae s.s., along with several closely related species, and conclude that there is no evidence for either strong directional or balancing selection on these genes. We highlight a number of challenges that need to be met in order to apply population genetic tests for selection in Anopheles mosquitoes; in particular the dearth of suitable outgroup species and the potential difficulties that arise when working within a closely-related species complex. PMID:17688548

  11. The effect of temperature on Anopheles mosquito population dynamics and the potential for malaria transmission.

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    Lindsay M Beck-Johnson

    Full Text Available The parasites that cause malaria depend on Anopheles mosquitoes for transmission; because of this, mosquito population dynamics are a key determinant of malaria risk. Development and survival rates of both the Anopheles mosquitoes and the Plasmodium parasites that cause malaria depend on temperature, making this a potential driver of mosquito population dynamics and malaria transmission. We developed a temperature-dependent, stage-structured delayed differential equation model to better understand how climate determines risk. Including the full mosquito life cycle in the model reveals that the mosquito population abundance is more sensitive to temperature than previously thought because it is strongly influenced by the dynamics of the juvenile mosquito stages whose vital rates are also temperature-dependent. Additionally, the model predicts a peak in abundance of mosquitoes old enough to vector malaria at more accurate temperatures than previous models. Our results point to the importance of incorporating detailed vector biology into models for predicting the risk for vector borne diseases.

  12. Wolbachia infections in natural Anopheles populations affect egg laying and negatively correlate with Plasmodium development

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    Shaw, W. Robert; Marcenac, Perrine; Childs, Lauren M.; Buckee, Caroline O.; Baldini, Francesco; Sawadogo, Simon P.; Dabiré, Roch K.; Diabaté, Abdoulaye; Catteruccia, Flaminia

    2016-01-01

    The maternally inherited alpha-proteobacterium Wolbachia has been proposed as a tool to block transmission of devastating mosquito-borne infectious diseases like dengue and malaria. Here we study the reproductive manipulations induced by a recently identified Wolbachia strain that stably infects natural mosquito populations of a major malaria vector, Anopheles coluzzii, in Burkina Faso. We determine that these infections significantly accelerate egg laying but do not induce cytoplasmic incompatibility or sex-ratio distortion, two parasitic reproductive phenotypes that facilitate the spread of other Wolbachia strains within insect hosts. Analysis of 221 blood-fed A. coluzzii females collected from houses shows a negative correlation between the presence of Plasmodium parasites and Wolbachia infection. A mathematical model incorporating these results predicts that infection with these endosymbionts may reduce malaria prevalence in human populations. These data suggest that Wolbachia may be an important player in malaria transmission dynamics in Sub-Saharan Africa. PMID:27243367

  13. The impact of insecticides management linked with resistance expression in Anopheles spp. populations.

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    Silva, Guilherme Liberato da; Pereira, Thiago Nunes; Ferla, Noeli Juarez; Silva, Onilda Santos da

    2016-06-01

    The resistance of some species of Anopheles to chemical insecticides is spreading quickly throughout the world and has hindered the actions of prevention and control of malaria. The main mechanism responsible for resistance in these insects appears to be the target site known as knock-down resistance (kdr), which causes mutations in the sodium channel. Even so, many countries have made significant progress in the prevention of malaria, focusing largely on vector control through long-lasting insecticide nets (LLINs), indoor residual spraying and (IRS) of insecticides. The objective of this review is to contribute with information on the more applied insecticides for the control of the main vectors of malaria, its effects, and the different mechanisms of resistance. Currently it is necessary to look for others alternatives, e.g. biological control and products derived from plants and fungi, by using other organisms as a possible regulator of the populations of malaria vectors in critical outbreaks. PMID:27383351

  14. Kdr-based insecticide resistance in Anopheles gambiae s.s populations in

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    Nwane Philippe

    2011-10-01

    Full Text Available Abstract Background The spread of insecticide resistance in the malaria mosquito, Anopheles gambiae is a serious threat for current vector control strategies which rely on the use of insecticides. Two mutations at position 1014 of the S6 transmembrane segment of domain II in the voltage gated sodium channel, known as kdr (knockdown resistance mutations leading to a change of a Leucine to a Phenylalanine (L1014F or to a Serine (L1014S confer resistance to DDT and pyrethroid insecticides in the insect. This paper presents the current distribution of the kdr alleles in wild Anopheles gambiae populations in Cameroon. Results A total of 1,405 anopheline mosquitoes were collected from 21 localities throughout Cameroon and identified as An. gambiae (N = 1,248; 88.8%, An. arabiensis (N = 120; 8.5% and An. melas (N = 37; 2.6%. Both kdr alleles 1014F and 1014S were identified in the M and S molecular forms of An. gambiae s.s. The frequency of the 1014F allele ranged from 1.7 to 18% in the M-form, and from 2 to 90% in the S-form. The 1014S allele ranged from 3-15% in the S-form and in the M-form its value was below 3%. Some specimens were found to carry both resistant kdr alleles. Conclusion This study provides an updated distribution map of the kdr alleles in wild An. gambiae populations in Cameroon. The co-occurrence of both alleles in malaria mosquito vectors in diverse ecological zones of the country may be critical for the planning and implementation of malaria vector control interventions based on IRS and ITNs, as currently ongoing in Cameroon.

  15. Molecular population genetics of the NADPH cytochrome P450 reductase (CPR) gene in Anopheles minimus.

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    Srivastava, Hemlata; Huong, Ngo Thi; Arunyawat, Uraiwan; Das, Aparup

    2014-08-01

    Development of insecticide resistance (IR) in mosquito vectors is a primary huddle to malaria control program. Since IR has genetic basis, and genes constantly evolve with response to environment for adaptation to organisms, it is important to know evolutionary pattern of genes conferring IR in malaria vectors. The mosquito Anopheles minimus is a major malaria vector of the Southeast (SE) Asia and India and is susceptible to all insecticides, and thus of interest to know if natural selection has shaped variations in the gene conferring IR. If not, the DNA fragment of such a gene could be used to infer population structure and demography of this species of malaria vector. We have therefore sequenced a ~569 bp DNA segment of the NADPH cytochrome P450 reductase (CPR) gene (widely known to confer IR) in 123 individuals of An. minimus collected in 10 different locations (eight Indian, one Thai and one Vietnamese). Two Indian population samples were completely mono-morphic in the CPR gene. In general, low genetic diversity was found with no evidence of natural selection in this gene. The data were therefore analyzed to infer population structure and demography of this species. The 10 populations could be genetically differentiated into four different groups; the samples from Thailand and Vietnam contained high nucleotide diversity. All the 10 populations conform to demographic equilibrium model with signature of past population expansion in four populations. The results in general indicate that the An. minimus mosquitoes sampled in the two SE Asian localities contain several genetic characteristics of being parts of the ancestral population.

  16. Multiple insecticide resistance mechanisms in Anopheles gambiae s.l. populations from Cameroon, Central Africa

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    Nwane Philippe

    2013-02-01

    Full Text Available Abstract Background Increasing incidence of DDT and pyrethroid resistance in Anopheles mosquitoes is seen as a limiting factor for malaria vector control. The current study aimed at an in-depth characterization of An. gambiae s.l. resistance to insecticides in Cameroon, in order to guide malaria vector control interventions. Methods Anopheles gambiae s.l. mosquitoes were collected as larvae and pupae from six localities spread throughout the four main biogeographical domains of Cameroon and reared to adults in insectaries. Standard WHO insecticide susceptibility tests were carried out with 4% DDT, 0.75% permethrin and 0.05% deltamethrin. Mortality rates and knockdown times (kdt50 and kdt95 were determined and the effect of pre-exposure to the synergists DEF, DEM and PBO was assessed. Tested mosquitoes were identified to species and molecular forms (M or S using PCR-RFLP. The hot ligation method was used to depict kdr mutations and biochemical assays were conducted to assess detoxifying enzyme activities. Results The An. arabiensis population from Pitoa was fully susceptible to DDT and permethrin (mortality rates > 98% and showed reduced susceptibility to deltamethrin. Resistance to DDT was widespread in An. gambiae s.s. populations and heterogeneous levels of susceptibility to permethrin and deltamethrin were observed. In many cases, prior exposure to synergists partially restored insecticide knockdown effect and increased mortality rates, suggesting a role of detoxifying enzymes in increasing mosquito survival upon challenge by pyrethroids and, to a lower extent DDT. The distribution of kdr alleles suggested a major role of kdr-based resistance in the S form of An. gambiae. In biochemical tests, all but one mosquito population overexpressed P450 activity, whereas baseline GST activity was low and similar in all field mosquito populations and in the control. Conclusion In Cameroon, multiple resistance mechanisms segregate in the S form of An

  17. Isoenzymatic analysis of four Anopheles (Kerteszia) bellator Dyar & Knab (Diptera: Culicidae) populations.

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    de Carvalho-Pinto, Carlos José; Lourenço-de-Oliveira, Ricardo

    2003-12-01

    Anopheles bellator is a small silvatic bromelia-breeding mosquito and is a primary human malaria vector species in Southern Brazil. The bromelia-breeding habitat of the species should accompany the Atlantic forest coastal distribution, where bromeliads are abundant. Nonetheless, records on An. bellator collections show a gap in the species geographical distribution. An. bellator has been recorded in Southern Brazil and in the Brazilian states of Bahia and Paraíba. It appears again in the island of Trinidad, in Trinidad and Tobago. The aim of this work was to measure gene flow between different populations of An. bellator collected in the northern and southern extremes of the geographic distribution of this species. Mosquitoes were captured in forest borders in Santa Catarina, São Paulo, and Bahia states in Brazil and in the island of Trinidad in Republic of Trinidad and Tobago. Genetic distances varied between 0.076 and 0.680, based on enzymatic profiles from 11 distinct isoenzymes. Results indicate the existence of low-level gene flow between Brazilian populations of An. bellator, and a gene flow was even lower between the Brazilian and the Trinidad populations. This finding lead us to hypothesize that An. bellator did not spread along the coast, but reached northeastern areas through inland routes.

  18. Isoenzymatic analysis of four Anopheles (Kerteszia bellator Dyar & Knab (Diptera: Culicidae populations

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    Carvalho-Pinto Carlos José de

    2003-01-01

    Full Text Available Anopheles bellator is a small silvatic bromelia-breeding mosquito and is a primary human malaria vector species in Southern Brazil. The bromelia-breeding habitat of the species should accompany the Atlantic forest coastal distribution, where bromeliads are abundant. Nonetheless, records on An. bellator collections show a gap in the species geographical distribution. An. bellator has been recorded in Southern Brazil and in the Brazilian states of Bahia and Paraíba. It appers again in the island of Trinidad, in Trinidad and Tobago. The aim of this work was to measure gene flow between different populations of An. bellator collected in the northern and southern extremes of the geographic distribution of this species. Mosquitoes were captured in forest borders in Santa Catarina, São Paulo, and Bahia states in Brazil and in the island of Trinidad in Republic of Trinidad and Tobago. Genetic distances varied between 0.076 and 0.680, based on enzymatic profiles from 11 distinct isoenzymes. Results indicate the existence of low-level gene flow between Brazilian populations of An. bellator, and a gene flow was even lower between the Brazilian and the Trinidad populations. This finding lead us to hypothesize that An. bellator did not spread along the coast, but reached northeastern areas through inland routes.

  19. Use of carbon-13 as a population marker for Anopheles arabiensis in a sterile insect technique (SIT) context

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    Knols Bart GJ; Mayr Leo; Hood-Nowotny Rebecca

    2006-01-01

    Abstract Background Monitoring of sterile to wild insect ratios in field populations can be useful to follow the progress in genetic control programmes such as the Sterile Insect Technique (SIT). Of the numerous methods for marking insects most are not suitable for use in mass rearing and mass release. Suitable ones include dye marking, genetic marking and chemical marking. Methods The feasibility of using the stable isotope of carbon, 13C, as a potential chemical marker for Anopheles arabien...

  20. Modelling Anopheles gambiae s.s. Population Dynamics with Temperature- and Age-Dependent Survival

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    Céline Christiansen-Jucht

    2015-05-01

    Full Text Available Climate change and global warming are emerging as important threats to human health, particularly through the potential increase in vector- and water-borne diseases. Environmental variables are known to affect substantially the population dynamics and abundance of the poikilothermic vectors of disease, but the exact extent of this sensitivity is not well established. Focusing on malaria and its main vector in Africa, Anopheles gambiae sensu stricto, we present a set of novel mathematical models of climate-driven mosquito population dynamics motivated by experimental data suggesting that in An. gambiae, mortality is temperature and age dependent. We compared the performance of these models to that of a “standard” model ignoring age dependence. We used a longitudinal dataset of vector abundance over 36 months in sub-Saharan Africa for comparison between models that incorporate age dependence and one that does not, and observe that age-dependent models consistently fitted the data better than the reference model. This highlights that including age dependence in the vector component of mosquito-borne disease models may be important to predict more reliably disease transmission dynamics. Further data and studies are needed to enable improved fitting, leading to more accurate and informative model predictions for the An. gambiae malaria vector as well as for other disease vectors.

  1. Modelling Anopheles gambiae s.s. Population Dynamics with Temperature- and Age-Dependent Survival.

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    Christiansen-Jucht, Céline; Erguler, Kamil; Shek, Chee Yan; Basáñez, María-Gloria; Parham, Paul E

    2015-06-01

    Climate change and global warming are emerging as important threats to human health, particularly through the potential increase in vector- and water-borne diseases. Environmental variables are known to affect substantially the population dynamics and abundance of the poikilothermic vectors of disease, but the exact extent of this sensitivity is not well established. Focusing on malaria and its main vector in Africa, Anopheles gambiae sensu stricto, we present a set of novel mathematical models of climate-driven mosquito population dynamics motivated by experimental data suggesting that in An. gambiae, mortality is temperature and age dependent. We compared the performance of these models to that of a "standard" model ignoring age dependence. We used a longitudinal dataset of vector abundance over 36 months in sub-Saharan Africa for comparison between models that incorporate age dependence and one that does not, and observe that age-dependent models consistently fitted the data better than the reference model. This highlights that including age dependence in the vector component of mosquito-borne disease models may be important to predict more reliably disease transmission dynamics. Further data and studies are needed to enable improved fitting, leading to more accurate and informative model predictions for the An. gambiae malaria vector as well as for other disease vectors. PMID:26030468

  2. The population genomics of trans-specific inversion polymorphisms in Anopheles gambiae.

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    White, Bradley J; Cheng, Changde; Sangaré, Djibril; Lobo, Neil F; Collins, Frank H; Besansky, Nora J

    2009-09-01

    In the malaria mosquito Anopheles gambiae polymorphic chromosomal inversions may play an important role in adaptation to environmental variation. Recently, we used microarray-based divergence mapping combined with targeted resequencing to map nucleotide differentiation between alternative arrangements of the 2La inversion. Here, we applied the same technique to four different polymorphic inversions on the 2R chromosome of An. gambiae. Surprisingly, divergence was much lower between alternative arrangements for all 2R inversions when compared to the 2La inversion. For one of the rearrangements, 2Ru, we successfully mapped a very small region (approximately 100 kb) of elevated divergence. For the other three rearrangements, we did not identify any regions of significantly high divergence, despite ample independent evidence from natural populations of geographic clines and seasonal cycling, and stable heterotic polymorphisms in laboratory populations. If these inversions are the targets of selection as hypothesized, we suggest that divergence between rearrangements may have escaped detection due to retained ancestral polymorphism in the case of the youngest 2R rearrangements and to extensive gene flux in the older 2R inversion systems that segregate in both An. gambiae and its sibling species An. arabiensis. PMID:19581444

  3. Modelling Anopheles gambiae s.s. Population Dynamics with Temperature- and Age-Dependent Survival

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    Christiansen-Jucht, Céline; Erguler, Kamil; Shek, Chee Yan; Basáñez, María-Gloria; Parham, Paul E.

    2015-01-01

    Climate change and global warming are emerging as important threats to human health, particularly through the potential increase in vector- and water-borne diseases. Environmental variables are known to affect substantially the population dynamics and abundance of the poikilothermic vectors of disease, but the exact extent of this sensitivity is not well established. Focusing on malaria and its main vector in Africa, Anopheles gambiae sensu stricto, we present a set of novel mathematical models of climate-driven mosquito population dynamics motivated by experimental data suggesting that in An. gambiae, mortality is temperature and age dependent. We compared the performance of these models to that of a “standard” model ignoring age dependence. We used a longitudinal dataset of vector abundance over 36 months in sub-Saharan Africa for comparison between models that incorporate age dependence and one that does not, and observe that age-dependent models consistently fitted the data better than the reference model. This highlights that including age dependence in the vector component of mosquito-borne disease models may be important to predict more reliably disease transmission dynamics. Further data and studies are needed to enable improved fitting, leading to more accurate and informative model predictions for the An. gambiae malaria vector as well as for other disease vectors. PMID:26030468

  4. Low linkage disequilibrium in wild Anopheles gambiae s.l. populations

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    Harris Caroline

    2010-09-01

    Full Text Available Abstract Background In the malaria vector Anopheles gambiae, understanding diversity in natural populations and genetic components of important phenotypes such as resistance to malaria infection is crucial for developing new malaria transmission blocking strategies. The design and interpretation of many studies here depends critically on Linkage disequilibrium (LD. For example in association studies, LD determines the density of Single Nucleotide Polymorphisms (SNPs to be genotyped to represent the majority of the genomic information. Here, we aim to determine LD in wild An. gambiae s.l. populations in 4 genes potentially involved in mosquito immune responses against pathogens (Gambicin, NOS, REL2 and FBN9 using previously published and newly generated sequences. Results The level of LD between SNP pairs in cloned sequences of each gene was determined for 7 species (or incipient species of the An. gambiae complex. In all tested genes and species, LD between SNPs was low: even at short distances (2 2 ranged from 0.073 to 0.766. In most genes and species LD decayed very rapidly with increasing inter-marker distance. Conclusions These results are of great interest for the development of large scale polymorphism studies, as LD generally falls below any useful limit. It indicates that very fine scale SNP detection will be required to give an overall view of genome-wide polymorphism. Perhaps a more feasible approach to genome wide association studies is to use targeted approaches using candidate gene selection to detect association to phenotypes of interest.

  5. High level of pyrethroid resistance in an Anopheles funestus population of the Chokwe District in Mozambique.

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    Nelson Cuamba

    Full Text Available BACKGROUND: Although Anopheles funestus is difficult to rear, it is crucial to analyse field populations of this malaria vector in order to successfully characterise mechanisms of insecticide resistance observed in this species in Africa. In this study we carried out a large-scale field collection and rearing of An. funestus from Mozambique in order to analyse its susceptibility status to insecticides and to broadly characterise the main resistance mechanisms involved in natural populations. METHODOLOGY/PRINCIPAL FINDINGS: 3,000 F(1 adults were obtained through larval rearing. WHO susceptibility assays indicated a very high resistance to pyrethroids with no mortality recorded after 1 h 30 min exposure and less than 50% mortality at 3 h 30 min. Resistance to the carbamate, bendiocarb was also noted, with 70% mortality after 1h exposure. In contrast, no DDT resistance was observed, indicating that no kdr-type resistance was involved. The sequencing of the acetylcholinesterase gene indicated the absence of the G119S and F455W mutations associated with carbamate and organophosphate resistance. This could explain the absence of malathion resistance in this population. Both biochemical assays and quantitative PCR implicated up-regulated P450 genes in pyrethroid resistance, with GSTs playing a secondary role. The carbamate resistance observed in this population is probably conferred by the observed altered AChE with esterases also involved. CONCLUSION/SIGNIFICANCE: The high level of pyrethroid resistance in this population despite the cessation of pyrethroid use for IRS in 1999 is a serious concern for resistance management strategies such as rotational use of insecticides. As DDT has now been re-introduced for IRS, susceptibility to DDT needs to be closely monitored to prevent the appearance and spread of resistance to this insecticide.

  6. Morphological and molecular characteristics of malaria vector anopheles superpictus populations in Iran

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    Shemshad K.

    2007-10-01

    Full Text Available Background: Anopheles superpictus is one of the main malaria vectors in Iran. The mosquitoes of this species are found throughout the Iranian plateau up to 2000 meters above sea level in the Alborz Mountains, south of the Zagros Mountains, and in the plains near the Caspian Sea and Persian Gulf. It has been reported that different geographical populations of An. superpictus play different roles in malaria transmission. Based on the presence or absence of a black spot/band on the apical segment of the female maxillary palpi, two morphological forms have been reported in this species. This work has been conducted to study other morphological features as well as the genetic structure of these two forms of An. superpictus in Iran. Methods: The different morphological characteristics of 35 different populations were observed and recorded. An 887 bp portion of the mitochondrial DNA (mtDNA cytochrome oxidase subunit I (COI was amplified and assayed by restriction fragment length polymorphism (RFLP using 18 enzymes and PCR-direct sequencing techniques.Results: Among the morphological characteristics studied, there are significant differences between the two forms with regard to the length of the palp light band (p<0.01, wing length (p<0.5, and the distance from the branching point of the II/IV veins to the tip of the wing (p<0.05. Results also revealed that these two forms are sympatric in most localities of Iran. RFLP analysis and sequences of about 710 bp of the gene showed that there was great variation between and/or within the populations, but these variations were not associated with the morphological forms.Conclusion: This is the first comprehensive study on the morphological and molecular characteristics of An. superpictus in the literature. To determine the role of these morphological forms or genetic haplotypes in malaria transmission, further molecular, cytological, morphological, and epidemiological studies are necessary.

  7. Population structure of the malaria vector Anopheles darlingi in a malaria-endemic region of Eastern Amazonian Brazil

    DEFF Research Database (Denmark)

    Conn, Jan E.; Vineis, Joseph H.; Bollback, Jonathan Paul;

    2006-01-01

    Anopheles darlingi is the primary malaria vector in Latin America, and is especially important in Amazonian is the primary malaria vector in Latin America, and is especially important in Amazonian Brazil. Historically, control efforts have been focused on indoor house spraying using a variety....... darlingi including evidence for a population bottleneck in Peixoto, we analyzed eight microsatellite loci of 256 individuals including evidence for a population bottleneck in Peixoto, we analyzed eight microsatellite loci of 256 individuals from seven locations in Brazil: three in Amapa State, three...

  8. Islands and stepping-stones: comparative population structure of Anopheles gambiae sensu stricto and Anopheles arabiensis in Tanzania and implications for the spread of insecticide resistance.

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    Deodatus Maliti

    Full Text Available Population genetic structures of the two major malaria vectors Anopheles gambiae s.s. and An. arabiensis, differ markedly across Sub-Saharan Africa, which could reflect differences in historical demographies or in contemporary gene flow. Elucidation of the degree and cause of population structure is important for predicting the spread of genetic traits such as insecticide resistance genes or artificially engineered genes. Here the population genetics of An. gambiae s.s. and An. arabiensis in the central, eastern and island regions of Tanzania were compared. Microsatellite markers were screened in 33 collections of female An. gambiae s.l., originating from 22 geographical locations, four of which were sampled in two or three years between 2008 and 2010. An. gambiae were sampled from six sites, An. arabiensis from 14 sites, and both species from two sites, with an additional colonised insectary sample of each species. Frequencies of the knock-down resistance (kdr alleles 1014S and 1014F were also determined. An. gambiae exhibited relatively high genetic differentiation (average pairwise FST = 0.131, significant even between nearby samples, but without clear geographical patterning. In contrast, An. arabiensis exhibited limited differentiation (average FST = 0.015, but strong isolation-by-distance (Mantel test r = 0.46, p = 0.0008. Most time-series samples of An. arabiensis were homogeneous, suggesting general temporal stability of the genetic structure. An. gambiae populations from Dar es Salaam and Bagamoyo were found to have high frequencies of kdr 1014S (around 70%, with almost 50% homozygote but was at much lower frequency on Unguja Island, with no. An. gambiae population genetic differentiation was consistent with an island model of genetic structuring with highly restricted gene flow, contrary to An. arabiensis which was consistent with a stepping-stone model of extensive, but geographically-restricted gene flow.

  9. Genetic population structure of the malaria vector Anopheles baimaii in north-east India using mitochondrial DNA

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    Sarma Devojit K

    2012-03-01

    Full Text Available Abstract Background Anopheles baimaii is a primary vector of human malaria in the forest settings of Southeast Asia including the north-eastern region of India. Here, the genetic population structure and the basic population genetic parameters of An. baimaii in north-east India were estimated using DNA sequences of the mitochondrial cytochrome oxidase sub unit II (COII gene. Methods Anopheles baimaii were collected from 26 geo-referenced locations across the seven north-east Indian states and the COII gene was sequenced from 176 individuals across these sites. Fifty-seven COII sequences of An. baimaii from six locations in Bangladesh, Myanmar and Thailand from a previous study were added to this dataset. Altogether, 233 sequences were grouped into eight population groups, to facilitate analyses of genetic diversity, population structure and population history. Results A star-shaped median joining haplotype network, unimodal mismatch distribution and significantly negative neutrality tests indicated population expansion in An. baimaii with the start of expansion estimated to be ~0.243 million years before present (MYBP in north-east India. The populations of An. baimaii from north-east India had the highest haplotype and nucleotide diversity with all other populations having a subset of this diversity, likely as the result of range expansion from north-east India. The north-east Indian populations were genetically distinct from those in Bangladesh, Myanmar and Thailand, indicating that mountains, such as the Arakan mountain range between north-east India and Myanmar, are a significant barrier to gene flow. Within north-east India, there was no genetic differentiation among populations with the exception of the Central 2 population in the Barail hills area that was significantly differentiated from other populations. Conclusions The high genetic distinctiveness of the Central 2 population in the Barail hills area of the north-east India should be

  10. Ecological Genomics of Anopheles gambiae Along a Latitudinal Cline: A Population-Resequencing Approach

    OpenAIRE

    Cheng, Changde; White, Bradley J.; Kamdem, Colince; Mockaitis, Keithanne; Costantini, Carlo; Matthew W Hahn; Besansky, Nora J

    2012-01-01

    The association between fitness-related phenotypic traits and an environmental gradient offers one of the best opportunities to study the interplay between natural selection and migration. In cases in which specific genetic variants also show such clinal patterns, it may be possible to uncover the mutations responsible for local adaptation. The malaria vector, Anopheles gambiae, is associated with a latitudinal cline in aridity in Cameroon; a large inversion on chromosome 2L of this mosquito ...

  11. The Population Genomics of Trans-Specific Inversion Polymorphisms in Anopheles gambiae

    OpenAIRE

    White, Bradley J.; Cheng, Changde; Sangaré, Djibril; Lobo, Neil F.; Collins, Frank H.; Besansky, Nora J

    2009-01-01

    In the malaria mosquito Anopheles gambiae polymorphic chromosomal inversions may play an important role in adaptation to environmental variation. Recently, we used microarray-based divergence mapping combined with targeted resequencing to map nucleotide differentiation between alternative arrangements of the 2La inversion. Here, we applied the same technique to four different polymorphic inversions on the 2R chromosome of An. gambiae. Surprisingly, divergence was much lower between alternativ...

  12. The impact of insecticides management linked with resistance expression in Anopheles spp. populations

    OpenAIRE

    Guilherme Liberato da Silva; Thiago Nunes Pereira; Noeli Juarez Ferla; Onilda Santos da Silva

    2016-01-01

    Abstract The resistance of some species of Anopheles to chemical insecticides is spreading quickly throughout the world and has hindered the actions of prevention and control of malaria. The main mechanism responsible for resistance in these insects appears to be the target site known as knock-down resistance (kdr), which causes mutations in the sodium channel. Even so, many countries have made significant progress in the prevention of malaria, focusing largely on vector control through long-...

  13. Microsatellite data suggest significant population structure and differentiation within the malaria vector Anopheles darlingi in Central and South America

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    Achee Nicole L

    2008-03-01

    Full Text Available Abstract Background Anopheles darlingi is the most important malaria vector in the Neotropics. An understanding of A. darlingi's population structure and contemporary gene flow patterns is necessary if vector populations are to be successfully controlled. We assessed population genetic structure and levels of differentiation based on 1,376 samples from 31 localities throughout the Peruvian and Brazilian Amazon and Central America using 5–8 microsatellite loci. Results We found high levels of polymorphism for all of the Amazonian populations (mean RS = 7.62, mean HO = 0.742, and low levels for the Belize and Guatemalan populations (mean RS = 4.3, mean HO = 0.457. The Bayesian clustering analysis revealed five population clusters: northeastern Amazonian Brazil, southeastern and central Amazonian Brazil, western and central Amazonian Brazil, Peruvian Amazon, and the Central American populations. Within Central America there was low non-significant differentiation, except for between the populations separated by the Maya Mountains. Within Amazonia there was a moderate level of significant differentiation attributed to isolation by distance. Within Peru there was no significant population structure and low differentiation, and some evidence of a population expansion. The pairwise estimates of genetic differentiation between Central America and Amazonian populations were all very high and highly significant (FST = 0.1859 – 0.3901, P DA and FST distance-based trees illustrated the main division to be between Central America and Amazonia. Conclusion We detected a large amount of population structure in Amazonia, with three population clusters within Brazil and one including the Peru populations. The considerable differences in Ne among the populations may have contributed to the observed genetic differentiation. All of the data suggest that the primary division within A. darlingi corresponds to two white gene genotypes between Amazonia (genotype 1

  14. Behavioural determinants of gene flow in malaria vector populations: Anopheles gambiae males select large females as mates

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    Yan G

    2002-08-01

    Full Text Available Abstract Background Plasmodium-refractory mosquitoes are being rapidly developed for malaria control but will only succeed if they can successfully compete for mates when released into the wild. Pre-copulatory behavioural traits maintain genetic population structure in wild mosquito populations and mating barriers have foiled previous attempts to control malaria vectors through sterile male release. Methods Varying numbers of virgin male and female Anopheles gambiae Giles, from two strains of different innate sizes, were allowed to mate under standardized conditions in laboratory cages, following which, the insemination status, oviposition success and egg batch size of each female was assessed. The influence of male and female numbers, strain combination and female size were determined using logistic regression, correlation analysis and a simple mechanistic model of male competition for females. Results Male An. gambiae select females on the basis of size because of much greater fecundity among large females. Even under conditions where large numbers of males must compete for a smaller number of females, the largest females are more likely to become inseminated, to successfully oviposit and to produce large egg batches. Conclusions Sexual selection, on the basis of size, could either promote or limit the spread of malaria-refractory genes into wild populations and needs to be considered in the continued development and eventual release of transgenic vectors. Fundamental studies of behavioural ecology in malaria vectors such as An. gambiae can have important implications for malaria control and should be prioritised for more extensive investigation in the future.

  15. Development of vegetable farming: a cause of the emergence of insecticide resistance in populations of Anopheles gambiae in urban areas of Benin

    OpenAIRE

    Braïma James; Djouaka Rousseau F; Asidi Alex; Yadouleton Anges; Agossou Christian D; Akogbeto Martin C

    2009-01-01

    Abstract Background A fast development of urban agriculture has recently taken place in many areas in the Republic of Benin. This study aims to assess the rapid expansion of urban agriculture especially, its contribution to the emergence of insecticide resistance in populations of Anopheles gambiae. Methods The protocol was based on the collection of sociological data by interviewing vegetable farmers regarding various agricultural practices and the types of pesticides used. Bioassay tests we...

  16. Malaria in Kakuma refugee camp, Turkana, Kenya: facilitation of Anopheles arabiensis vector populations by installed water distribution and catchment systems

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    Cetron Martin S

    2011-06-01

    Full Text Available Abstract Background Malaria is a major health concern for displaced persons occupying refugee camps in sub-Saharan Africa, yet there is little information on the incidence of infection and nature of transmission in these settings. Kakuma Refugee Camp, located in a dry area of north-western Kenya, has hosted ca. 60,000 to 90,000 refugees since 1992, primarily from Sudan and Somalia. The purpose of this study was to investigate malaria prevalence and attack rate and sources of Anopheles vectors in Kakuma refugee camp, in 2005-2006, after a malaria epidemic was observed by staff at camp clinics. Methods Malaria prevalence and attack rate was estimated from cases of fever presenting to camp clinics and the hospital in August 2005, using rapid diagnostic tests and microscopy of blood smears. Larval habitats of vectors were sampled and mapped. Houses were sampled for adult vectors using the pyrethrum knockdown spray method, and mapped. Vectors were identified to species level and their infection with Plasmodium falciparum determined. Results Prevalence of febrile illness with P. falciparum was highest among the 5 to 17 year olds (62.4% while malaria attack rate was highest among the two to 4 year olds (5.2/1,000/day. Infected individuals were spatially concentrated in three of the 11 residential zones of the camp. The indoor densities of Anopheles arabiensis, the sole malaria vector, were similar during the wet and dry seasons, but were distributed in an aggregated fashion and predominantly in the same zones where malaria attack rates were high. Larval habitats and larval populations were also concentrated in these zones. Larval habitats were man-made pits of water associated with tap-stands installed as the water delivery system to residents with year round availability in the camp. Three percent of A. arabiensis adult females were infected with P. falciparum sporozoites in the rainy season. Conclusions Malaria in Kakuma refugee camp was due mainly

  17. Use of carbon-13 as a population marker for Anopheles arabiensis in a sterile insect technique (SIT context

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    Knols Bart GJ

    2006-01-01

    Full Text Available Abstract Background Monitoring of sterile to wild insect ratios in field populations can be useful to follow the progress in genetic control programmes such as the Sterile Insect Technique (SIT. Of the numerous methods for marking insects most are not suitable for use in mass rearing and mass release. Suitable ones include dye marking, genetic marking and chemical marking. Methods The feasibility of using the stable isotope of carbon, 13C, as a potential chemical marker for Anopheles arabiensis was evaluated in the laboratory. Labeled-13C glucose was incorporated into the larval diet in a powder or liquid form. The contribution of adult sugar feeding to the total mosquito carbon pool and the metabolically active carbon pool was determined by tracing the decline of the enrichment of the adult male mosquito as it switched from a labeled larval diet to an unlabeled adult diet. This decline in the adult was monitored by destructive sampling of the whole mosquito and analyzed using isotope ratio mass spectrometry. Results A two-pool model was used to describe the decline of the 13C-enrichment of adult mosquitoes. The proportion of the total adult carbon pool derived from the adult sugar diet over the life span of mosquitoes was determined and the ratio of structural carbon, with a low turnover rate to metabolically active non-structural carbon was assessed. The uptake and turnover of sugar in the metabolically active fraction suggests that after 3 days >70% of the active fraction carbon is derived from sugar feeding (increasing to >90% by day 7, indicating the high resource demand of male mosquitoes. Conclusion It was possible to "fix" the isotopic label in adult An. arabiensis and to detect the label at an appropriate concentration up to 21 days post-emergence. The optimum labeling treatment would cost around 250 US$ per million mosquitoes. Stable isotope marking may thus aid research on the fate of released insects besides other population

  18. Population genetic structure of the major malaria vector Anopheles darlingi (Diptera: Culicidae from the Brazilian Amazon, using microsatellite markers

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    Vera Margarete Scarpassa

    2007-06-01

    Full Text Available The population genetic structure of Anopheles darlingi, the major human malaria vector in the Neotropics, was examined using seven microsatellite loci from nine localities in central and western Amazonian Brazil. High levels of genetic variability were detected (5-25 alleles per locus; H E = 0.519-0.949. There was deviation from Hardy-Weinberg Equilibrium for 59.79% of the tests due to heterozygote deficits, while the analysis of linkage disequilibrium was significant for only two of 189 (1.05% tests, most likely caused by null alleles. Genetic differentiation (F ST = 0.001-0.095; Nm = 4.7-363.8 indicates that gene flow is extensive among locations < 152 km apart (with two exceptions and reduced, but not absent, at a larger geographic scale. Genetic and geographic distances were significantly correlated (R² = 0.893, P < 0.0002, supporting the isolation by distance (IBD model. The overall estimate of Ne was 202.4 individuals under the linkage disequilibrium model, and 8 under the heterozygote excess model. Analysis of molecular variance showed that nearly all variation (~ 94% was within sample locations. The UPGMA phenogram clustered the samples geographically, with one branch including 5/6 of the state of Amazonas localities and the other branch the Acre, Rondônia, and remaining Amazonas localities. Taken together, these data suggest little genetic structure for An. darlingi from central and western Amazonian Brazil. These findings also imply that the IBD model explains nearly all of the differentiation detected. In practical terms, populations of An. darlingi at distances < 152 km should respond similarly to vector control measures, because of high gene flow.

  19. Evidence of carbamate resistance in urban populations of Anopheles gambiae s.s. mosquitoes resistant to DDT and deltamethrin insecticides in Lagos, South-Western Nigeria

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    Oduola Adedayo O

    2012-06-01

    Full Text Available Abstract Background Resistance monitoring is essential in ensuring the success of insecticide based vector control programmes. This study was carried out to assess the susceptibility status of urban populations of Anopheles gambiae to carbamate insecticide being considered for vector control in mosquito populations previously reported to be resistant to DDT and permethrin. Methods Two – three day old adult female Anopheles mosquitoes reared from larval collections in 11 study sites from Local Government Areas of Lagos were exposed to test papers impregnated with DDT 4%, deltamethrin 0.05% and propoxur 0.1% insecticides. Additional tests were carried out to determine the susceptibility status of the Anopheles gambiae population to bendiocarb insecticide. Members of the A. gambiae complex, the molecular forms, were identified by PCR assays. The involvement of metabolic enzymes in carbamate resistance was assessed using Piperonyl butoxide (PBO synergist assays. The presence of kdr-w/e and ace-1R point mutations responsible for DDT-pyrethroid and carbamate resistance mechanisms was also investigated by PCR. Results Propoxur resistance was found in 10 out of the 11 study sites. Resistance to three classes of insecticides was observed in five urban localities. Mortality rates in mosquitoes exposed to deltamethrin and propoxur did not show any significant difference (P > 0.05 but was significantly higher (P A. gambiae s.s (M form. The kdr -w point mutation at allelic frequencies between 45%-77% was identified as one of the resistant mechanisms responsible for DDT and pyrethroid resistance. Ace-1R point mutation was absent in the carbamate resistant population. However, the possible involvement of metabolic resistance was confirmed by synergistic assays conducted. Conclusion Evidence of carbamate resistance in A. gambiae populations already harbouring resistance to DDT and permethrin is a clear indication that calls for the implementation of

  20. Sensitivity of Anopheles gambiae population dynamics to meteo-hydrological variability: a mechanistic approach

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    Gilioli Gianni

    2011-10-01

    Full Text Available Abstract Background Mechanistic models play an important role in many biological disciplines, and they can effectively contribute to evaluate the spatial-temporal evolution of mosquito populations, in the light of the increasing knowledge of the crucial driving role on vector dynamics played by meteo-climatic features as well as other physical-biological characteristics of the landscape. Methods In malaria eco-epidemiology landscape components (atmosphere, water bodies, land use interact with the epidemiological system (interacting populations of vector, human, and parasite. In the background of the eco-epidemiological approach, a mosquito population model is here proposed to evaluate the sensitivity of An. gambiae s.s. population to some peculiar thermal-pluviometric scenarios. The scenarios are obtained perturbing meteorological time series data referred to four Kenyan sites (Nairobi, Nyabondo, Kibwesi, and Malindi representing four different eco-epidemiological settings. Results Simulations highlight a strong dependence of mosquito population abundance on temperature variation with well-defined site-specific patterns. The upper extreme of thermal perturbation interval (+ 3°C gives rise to an increase in adult population abundance at Nairobi (+111% and Nyabondo (+61%, and a decrease at Kibwezi (-2% and Malindi (-36%. At the lower extreme perturbation (-3°C is observed a reduction in both immature and adult mosquito population in three sites (Nairobi -74%, Nyabondo -66%, Kibwezi -39%, and an increase in Malindi (+11%. A coherent non-linear pattern of population variation emerges. The maximum rate of variation is +30% population abundance for +1°C of temperature change, but also almost null and negative values are obtained. Mosquitoes are less sensitive to rainfall and both adults and immature populations display a positive quasi-linear response pattern to rainfall variation. Conclusions The non-linear temperature-dependent response is in

  1. Highly efficient Cas9-mediated gene drive for population modification of the malaria vector mosquito Anopheles stephensi.

    Science.gov (United States)

    Gantz, Valentino M; Jasinskiene, Nijole; Tatarenkova, Olga; Fazekas, Aniko; Macias, Vanessa M; Bier, Ethan; James, Anthony A

    2015-12-01

    Genetic engineering technologies can be used both to create transgenic mosquitoes carrying antipathogen effector genes targeting human malaria parasites and to generate gene-drive systems capable of introgressing the genes throughout wild vector populations. We developed a highly effective autonomous Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-associated protein 9 (Cas9)-mediated gene-drive system in the Asian malaria vector Anopheles stephensi, adapted from the mutagenic chain reaction (MCR). This specific system results in progeny of males and females derived from transgenic males exhibiting a high frequency of germ-line gene conversion consistent with homology-directed repair (HDR). This system copies an ∼ 17-kb construct from its site of insertion to its homologous chromosome in a faithful, site-specific manner. Dual anti-Plasmodium falciparum effector genes, a marker gene, and the autonomous gene-drive components are introgressed into ∼ 99.5% of the progeny following outcrosses of transgenic lines to wild-type mosquitoes. The effector genes remain transcriptionally inducible upon blood feeding. In contrast to the efficient conversion in individuals expressing Cas9 only in the germ line, males and females derived from transgenic females, which are expected to have drive component molecules in the egg, produce progeny with a high frequency of mutations in the targeted genome sequence, resulting in near-Mendelian inheritance ratios of the transgene. Such mutant alleles result presumably from nonhomologous end-joining (NHEJ) events before the segregation of somatic and germ-line lineages early in development. These data support the design of this system to be active strictly within the germ line. Strains based on this technology could sustain control and elimination as part of the malaria eradication agenda. PMID:26598698

  2. Malaria in Suriname: a new era : impact of modified intervention strategies on Anopheles darlingi populations and malaria incidence

    NARCIS (Netherlands)

    Hiwat-van Laar, H.

    2011-01-01

    Malaria is an infectious disease caused by Plasmodiumblood parasites which live inside the human host and are spread by Anopheles mosquitoes.Every year an estimated 225 million new cases and near 800.000 malaria deaths are reported. Control of the disease is a formidable task involving all three liv

  3. Ammonium sulphate fertiliser increases larval populations of Anopheles arabiensis and culicine mosquitoes in rice fields

    DEFF Research Database (Denmark)

    Mutero, C M; Ng'ang'a, P N; Wekoyela, P;

    2004-01-01

    Field experiments were conducted in central Kenya, to study the effect of ammonium sulphate fertiliser ((NH(4))(2)SO(4)) on mosquito larval populations in rice fields. The experiments used a complete randomised block design having four blocks with two experimental ponds per block, and the fertili......Field experiments were conducted in central Kenya, to study the effect of ammonium sulphate fertiliser ((NH(4))(2)SO(4)) on mosquito larval populations in rice fields. The experiments used a complete randomised block design having four blocks with two experimental ponds per block......, and the fertiliser and control treatments allocated randomly among the ponds. Student's two-sample unpaired t-test was used to test for the significance of differences between the relative counts of larvae in fertiliser and control treatments. The results showed a significant overall increase in the larval...... populations of An. arabiensis (Pfertiliser. Significantly more fourth instar larvae of An. arabiensis were collected in fertiliser than control plots (Pfertiliser application had...

  4. Dynamics of knockdown pyrethroid insecticide resistance alleles in a field population of Anopheles gambiae s.s. in southwestern Nigeria

    Directory of Open Access Journals (Sweden)

    T.S. Awolola, A.O. Oduola, I.O. Oyewole, J.B. Obansa, C.N. Amajoh

    2007-09-01

    Full Text Available Background & objectives: Pyrethroid insecticide resistance in the malaria vector Anopheles gambiaeGiles is mainly associated with reduced target site sensitivity arising from a single point mutation inthe sodium channel gene, often referred to as knockdown resistance (kdr. This resistance mechanismis widespread in West Africa and was reported for the first time in Nigeria in 2002. Here we presentchanges in the susceptibility/resistance status of the molecular ‘M’ and ‘S’ forms of An. gambiae andthe frequency of the kdr alleles from 2002–05.Methods: Adult anophelines were sampled quarterly inside human dwellings from January 2002 toDecember 2005 and adults reared from wild larvae were identified using morphological keys. Samplesbelonging to the An. gambiae complex were subjected to PCR assays for species identification anddetection of molecular ‘M’ and ‘S’ forms. Insecticide susceptibility tests were carried out usingstandard WHO procedures and test kits only on 2–3 days old adult An. gambiae s.s. reared fromlarval collections. The kdr genotypes were determined in both live and dead specimens of An. gambiaes.s. using alleles-specific polymerase chain reaction diagnostic tests.Results: The overall collection showed that the molecular ‘S’ form was predominant (>60% but theproportions of both forms in the mosquito populations from 2002–05 were not statistically different.Both forms also occurred throughout the period without apparent relationship to wet or dry season.Insecticide susceptibility tests did not show any significant increase in the resistance status recordedfor either Permethrin or DDT from 2002–05, rather, an improvement in the susceptibility status ofthe mosquitoes to these insecticides was observed from 2004–05 relative to the tests performed in2002–03.Conclusion: The proportion of the molecular ‘M’ and ‘S’ form of An. gambiae and the kdr frequencieshave not increased significantly from 2002

  5. Cotton pest management practices and the selection of pyrethroid resistance in Anopheles gambiae population in Northern Benin

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    Yadouleton Anges

    2011-04-01

    Full Text Available Abstract Background Pyrethroid insecticides, carbamate and organophosphate are the classes of insecticides commonly used in agriculture for crop protection in Benin. Pyrethroids remain the only class of insecticides recommended by the WHO for impregnation of bed nets. Unfortunately, the high level of pyrethroid resistance in Anopheles gambiae s.l., threatens to undermine the success of pyrethroid treated nets. This study focuses on the investigation of agricultural practices in cotton growing areas, and their direct impact on larval populations of An. gambiae in surrounding breeding sites. Methods The protocol was based on the collection of agro-sociological data where farmers were subjected to semi-structured questionnaires based on the strategies used for crop protection. This was complemented by bioassay tests to assess the susceptibility of malaria vectors to various insecticides. Molecular analysis was performed to characterize the resistance genes and the molecular forms of An. gambiae. Insecticide residues in soil samples from breeding sites were investigated to determine major factors that can inhibit the normal growth of mosquito larvae by exposing susceptible and resistant laboratory strains. Results There is a common use by local farmers of mineral fertilizer NPK at 200 kg/ha and urea at 50 kg/hectare following insecticide treatments in both the Calendar Control Program (CCP and the Targeted Intermittent Control Program (TICP. By contrast, no chemicals are involved in Biological Program (BP where farmers use organic and natural fertilizers which include animal excreta. Susceptibility test results confirmed a high resistance to DDT. Mean mortality of An. gambiae collected from the farms practicing CCP, TICP and BP methods were 33%, 42% and 65% respectively. An. gambiae populations from areas using the CCP and TICP programs showed resistance to permethrin with mortality of 50% and 58% respectively. By contrast, bioassay test results of

  6. [Laboratory evaluation of alpha-cypermethrin insecticide efficacy on Anopheles gambiae populations of Côte d'Ivoire resistant to permethrin and deltamethrin].

    Science.gov (United States)

    Koffi, A A; Darriet, F; N'Guessan, R; Doannio, J M; Carnevale, P

    1999-02-01

    Susceptibility tests were carried out in laboratory conditions to evaluate the efficacy of alpha-cypermethrin (a synthetic pyrethroid never used in Côte d'Ivoire) for malaria vector control. Five wild populations of Anopheles gambiae originating from M'bé, Yaokoffikro, Korhogo, Kafiné and Daola and two laboratory reared strains (Kisumu susceptible and Kou permethrin resistant selected strain) were tested. The diagnostic dosage of alpha-cypermethrin for the sensitive strain Kisumu was 2.5 x 10(-3)%. A comparative study of the susceptibility of samples of wild populations of An. gambiae was carried out according to the WHO standard susceptibility test. Impregnated papers with 4% DDT, 0.25% permethrin, 0.025% deltamethrin and 0.0025% alpha-cypermethrin were used. The results showed that except for mosquitoes from M'bé, all the other populations were resistant to these insecticides. Bioassays were carried out with alpha-cypermethrin at the operational dosage of 20 mg a.i./m2 on the same population and laboratory reared strains. The results showed the efficacy of this insecticide on both the Kisumu strain and the population from M'bé, a maintained efficacy for the Daloa, Kafiné and Korhogo mosquito populations, but the wild anopheline population from Yaokoffikro clearly appeared fully resistant.

  7. Co-occurrence and distribution of East (L1014S) and West (L1014F) African knock-down resistance in Anopheles gambiae sensu lato population of Tanzania

    Science.gov (United States)

    Kabula, Bilali; Kisinza, William; Tungu, Patrick; Ndege, Chacha; Batengana, Benard; Kollo, Douglas; Malima, Robert; Kafuko, Jessica; Mohamed, Mahdi; Magesa, Stephen

    2014-01-01

    Objective Insecticide resistance molecular markers can provide sensitive indicators of resistance development in Anopheles vector populations. Assaying these makers is of paramount importance in the resistance monitoring programme. We investigated the presence and distribution of knock-down resistance (kdr) mutations in Anopheles gambiae s.l. in Tanzania. Methods Indoor-resting Anopheles mosquitoes were collected from 10 sites and tested for insecticide resistance using the standard WHO protocol. Polymerase chain reaction-based molecular diagnostics were used to genotype mosquitoes and detect kdr mutations. Results The An. gambiae tested were resistance to lambdacyhalothrin in Muheza, Arumeru and Muleba. Out of 350 An. gambiae s.l. genotyped, 35% were An. gambiae s.s. and 65% An. arabiensis. L1014S and L1014F mutations were detected in both An. gambiae s.s. and An. arabiensis. L1014S point mutation was found at the allelic frequency of 4–33%, while L1014F was at the allelic frequency 6–41%. The L1014S mutation was much associated with An. gambiae s.s. (χ2 = 23.41; P lambdacialotrina en Muheza, Arumeru y Muleba. De 350 An. gambiae s.l. genotipados, 35% eran An. gambiae s.s. y 65% eran An. arabiensis. Se detectaron mutaciones L1014S y L1014F tanto en An. gambiae s.s. como en An. arabiensis. La mutación puntual L1014S se encontró con una frecuencia alélica de 4-33%, mientras que L1014F tenía una frecuencia alélica de 6-14%. La mutación L1014S estaba ampliamente asociada a An. gambiae s.s. (Chi-Cuadrado = 23.41; P lambdacialotrina (P < 0.001). Conclusión La simultaneidad de mutaciones de L1014S y L1014F junto con informes de resistencia a los insecticidas sugiere que la resistencia a piretroides se está convirtiendo en un fenómeno común entre las poblaciones del vector de la malaria en Tanzania. La presencia de la mutación L1014F en estas poblaciones del Este de África indican la diseminación del gen a lo largo del continente africano

  8. Knockdown resistance in Anopheles vagus, An. sinensis, An. paraliae and An. peditaeniatus populations of the Mekong region

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    Keokenchanh Kalouna

    2010-07-01

    Full Text Available Abstract Background In the Mekong region (Vietnam, Cambodia and Laos, a large investigation was conducted to assess the susceptibility of Anopheles species against DDT and pyrethroids. In this study, the resistance status of the potential malaria vectors An. vagus, An. sinensis, An. paraliae and An. peditaeniatus was assessed. Methods Bioassays were performed on field collected unfed female mosquitoes using the standard WHO susceptibility tests. In addition, the DIIS6 region of the para-type sodium channel gene was amplified and sequenced and four allele-specific PCR assays were developed to assess the kdr frequencies. Results In Southern Vietnam all species were DDT and pyrethroid resistant, which might suggest the presence of a kdr resistance mechanism. Sequence-analysis of the DIIS6 region of the para-type sodium channel gene revealed the presence of a L1014S kdr mutation in An. vagus, An. sinensis and An. paraliae. In An. peditaeniatus, a low frequency L1014S kdr mutation was found in combination with a high frequency L1014F kdr mutation. For pyrethroids and DDT, no genotypic differentiation was found between survivors and non-survivors for any of these species. In the two widespread species, An. vagus and An. sinensis, kdr was found only in southern Vietnam and in Cambodia near the Vietnamese border. Conclusions Different levels of resistance were measured in Laos, Cambodia and Vietnam. The kdr mutation in different Anopheles species seems to occur in the same geographical area. These species breed in open agricultural lands where malaria endemicity is low or absent and vector control programs less intensive. It is therefore likely that the selection pressure occurred on the larval stages by insecticides used for agricultural purposes.

  9. Relationship between kdr mutation and resistance to pyrethroid and DDT insecticides in natural populations of Anopheles gambiae.

    Science.gov (United States)

    Reimer, Lisa; Fondjo, Etienne; Patchoké, Salomon; Diallo, Brehima; Lee, Yoosook; Ng, Arash; Ndjemai, Hamadou M; Atangana, Jean; Traore, Sekou F; Lanzaro, Gregory; Cornel, Anthony J

    2008-03-01

    The spread of insecticide resistance genes in Anopheles gambiae Giles sensu stricto threatens to compromise vector-based malaria control programs. Two mutations at the same locus in the voltage-gated sodium channel gene are known to confer knockdown resistance (kdr) to pyrethroids and DDT. Kdr-e involves a leucine-serine substitution, and it was until recently thought to be restricted to East Africa, whereas kdr-w, which involves a leucine-phenylalanine substitution, is associated with resistance in West Africa. In this study, we analyze the frequency and relationship between the kdr genotypes and resistance to type I and type II pyrethroids and DDT by using WHO test kits in both the Forest-M and S molecular forms of An. gambiae in Cameroon. Both kdr-w and kdr-e polymorphisms were found in sympatric An. gambiae, and in many cases in the same mosquito. Kdr-e and kdr-w were detected in both forms, but they were predominant in the S form. Both kdr-e and kdr-w were closely associated with resistance to DDT and weakly associated with resistance to type II pyrethroids. Kdr-w conferred greater resistance to permethrin than kdr-e. We also describe a modified diagnostic designed to detect both resistant alleles simultaneously.

  10. Study on Fungal Flora in the Midgut of the Larva and Adult of the Different Populations of the Malaria Vector Anopheles stephensi

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    L Tajedin

    2009-07-01

    Full Text Available Abstract Background: Many microorganisms in midgut of mosquito challenge with their host and also other pathogens pre­sent in midgut. The aim of this study was presence of non-pathogens microorganisms like fungal flora which may be cru­cial on interaction between vectors and pathogens."nMethods: Different populations of Anopheles stephensi were reared in insectary and objected to determine fungal flora in their midguts. The midgut paunch of mosquito adults and larvae as well as breading water and larval food sam­ples transferred on Subaru-dextrose agar, in order to detect the environment fungus."nResults: Although four fungi, Aspergillus, Rhizopus, Geotrichum and Sacharomyces were found in the food and wa­ter, but only Aspiragilus observed in the midgut of larvae. No fungus was found in the midgut of adults. This is the first report on fungal flora in the midgut of the adults and larvae of An. stephensi and possible stadial transmission of fungi from immature stages to adults."nConclusion: The midgut environment of adults is not compatible for survivorship of fungi but the larval midgut may con­tain few fungi as a host or even pathogen.

  11. Comparative susceptibility to permethrin of two Anopheles gambiae s.l. populations from Southern Benin, regarding mosquito sex, physiological status, and mosquito age

    Institute of Scientific and Technical Information of China (English)

    Nazaire Azoun; Rock Akpon; Roseric Azondekon; Alex Asidi; Martin Akogbto

    2014-01-01

    Objective: To investigate what kind of mosquito sample is necessary for the determination of insecticide susceptibility in malaria vectors. Methods:Larvae and pupae of Anopheles gambiae s.l. (An. gambiae) mosquitoes were collected from the breeding sites in Littoral and Oueme departments. The Centers for Disease Control and Prevention (CDC) susceptibility tests were conducted on unfed male and female mosquitoes aged 2-5 days old. CDC susceptibility tests were also conducted on unfed, blood fed and gravid female mosquitoes aged 2-5 days old. These susceptibility tests were also conducted on unfed and blood fed female mosquitoes aged 2-5 days old and 20 days old. CDC biochemical assay using synergist was also carried out to detect any increase in the activity of enzyme typically involved in insecticide metabolism. Results:Female An. gambiae Ladji and Sekandji populations were more susceptible than the males when they were unfed and aged 2-5 days old. The mortality rates of blood fed female An. gambiae Ladji and Sekandji populations aged 2-5 days old were lower than those obtained when females were unfed. In addition, the mortality rates of gravid female An. gambiae Ladji and Sekandji populations aged 2-5 days old were lower than those obtained when they were unfed. The mortality rate obtained when female An. gambiae Sekandji populations were unfed and aged 20 days old was higher than the one obtained when these populations were unfed and aged 2-5 days old. The results obtained after effects of synergist penicillin in beeswax on F1 progeny of An. gambiae Ladji populations resistant to permethrin showed that mono-oxygenases were involved in permethrin resistant F1 progeny from Ladji. Conclusions: The resistance is a hereditary and dynamic phenomenon which can be due to metabolic mechanisms like overproduction of detoxifying enzymes activity. Many factors influence vector susceptibility to insecticide. Among these factors, there are mosquito sex, mosquito age, its

  12. Distribution of ace-1R and resistance to carbamates and organophosphates in Anopheles gambiae s.s. populations from Côte d'Ivoire

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    Ahoua Alou Ludovic P

    2010-06-01

    Full Text Available Abstract Background The spread of pyrethroid resistance in Anopheles gambiae s.s. is a critical issue for malaria vector control based on the use of insecticide-treated nets. Carbamates and organophosphates insecticides are regarded as alternatives or supplements to pyrethroids used in nets treatment. It is, therefore, essential to investigate on the susceptibility of pyrethroid resistant populations of An. gambiae s.s. to these alternative products. Methods In September 2004, a cross sectional survey was conducted in six localities in Côte d'Ivoire: Toumbokro, Yamoussoukro, Toumodi in the Southern Guinea savannah, Tiassalé in semi-deciduous forest, then Nieky and Abidjan in evergreen forest area. An. gambiae populations from these localities were previously reported to be highly resistant to pyrethroids insecticides. Anopheline larvae were collected from the field and reared to adults. Resistance/susceptibility to carbamates (0.4% carbosulfan, 0.1% propoxur and organophosphates (0.4% chlorpyrifos-methyl, 1% fenitrothion was assessed using WHO bioassay test kits for adult mosquitoes. Then, PCR assays were run to determine the molecular forms (M and (S, as well as phenotypes for insensitive acetylcholinesterase (AChE1 due to G119S mutation. Results Bioassays showed carbamates (carbosulfan and propoxur resistance in all tested populations of An. gambiae s.s. In addition, two out of the six tested populations (Toumodi and Tiassalé were also resistant to organophosphates (mortality rates ranged from 29.5% to 93.3%. The M-form was predominant in tested samples (91.8%. M and S molecular forms were sympatric at two localities but no M/S hybrids were detected. The highest proportion of S-form (7.9% of An. gambiae identified was in sample from Toumbokro, in the southern Guinea savannah. The G119S mutation was found in both M and S molecular forms with frequency from 30.9 to 35.2%. Conclusion This study revealed a wide distribution of insensitive

  13. Use of carbon-13 as a population marker for Anopheles arabiensis in a sterile insect technique (SIT) context

    NARCIS (Netherlands)

    Hood-Nowotny, R.C.; Mayr, L.; Knols, B.G.J.

    2006-01-01

    Background - Monitoring of sterile to wild insect ratios in field populations can be useful to follow the progress in genetic control programmes such as the Sterile Insect Technique (SIT). Of the numerous methods for marking insects most are not suitable for use in mass rearing and mass release. Sui

  14. Collapse of Anopheles darlingi populations in Suriname after introduction of insecticide-treated nets (ITNs); malaria down to near elimination level

    NARCIS (Netherlands)

    Hiwat, H.; Mitro, S.; Samjhawan, A.; Sardjoe, P.; Soekhoe, T.; Takken, W.

    2012-01-01

    A longitudinal study of malaria vectors was carried out in three villages in Suriname between 2006 and 2010. During 13,392 man hours of collections, 3,180 mosquitoes were collected, of which 33.7% were anophelines. Of these, Anopheles darlingi accounted for 88.1%, and An. nuneztovari accounted for 1

  15. Taxonomy Icon Data: Anopheles stephensi [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Anopheles stephensi Anopheles stephensi Arthropoda Anopheles_stephensi_L.png Anopheles_stephen...si_NL.png Anopheles_stephensi_S.png Anopheles_stephensi_NS.png http://biosciencedbc.jp/taxonomy_i...con/icon.cgi?i=Anopheles+stephensi&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Anopheles+stephensi&...t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Anopheles+stephensi&t=S htt...p://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Anopheles+stephensi&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=149 ...

  16. Using remote sensing to map larval and adult populations of Anopheles hyrcanus (Diptera: Culicidae a potential malaria vector in Southern France

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    Roger François

    2008-02-01

    Full Text Available Abstract Background Although malaria disappeared from southern France more than 60 years ago, suspicions of recent autochthonous transmission in the French Mediterranean coast support the idea that the area could still be subject to malaria transmission. The main potential vector of malaria in the Camargue area, the largest river delta in southern France, is the mosquito Anopheles hyrcanus (Diptera: Culicidae. In the context of recent climatic and landscape changes, the evaluation of the risk of emergence or re-emergence of such a major disease is of great importance in Europe. When assessing the risk of emergence of vector-borne diseases, it is crucial to be able to characterize the arthropod vector's spatial distribution. Given that remote sensing techniques can describe some of the environmental parameters which drive this distribution, satellite imagery or aerial photographs could be used for vector mapping. Results In this study, we propose a method to map larval and adult populations of An. hyrcanus based on environmental indices derived from high spatial resolution imagery. The analysis of the link between entomological field data on An. hyrcanus larvae and environmental indices (biotopes, distance to the nearest main productive breeding sites of this species i.e., rice fields led to the definition of a larval index, defined as the probability of observing An. hyrcanus larvae in a given site at least once over a year. Independent accuracy assessments showed a good agreement between observed and predicted values (sensitivity and specificity of the logistic regression model being 0.76 and 0.78, respectively. An adult index was derived from the larval index by averaging the larval index within a buffer around the trap location. This index was highly correlated with observed adult abundance values (Pearson r = 0.97, p An. hyrcanus larval and adult populations from the landscape indices. Conclusion This work shows that it is possible to use

  17. Trends in DDT and pyrethroid resistance in Anopheles gambiae s.s. populations from urban and agro-industrial settings in southern Cameroon

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    Kerah-Hinzoumbé Clément

    2009-09-01

    Full Text Available Abstract Background Pyrethroid insecticides are widely used for insect pest control in Cameroon. In certain insect species, particularly the malaria vector Anopheles gambiae, resistance to this class of insecticides is a source of great concern and needs to be monitored in order to sustain the efficacy of vector control operations in the fields. This study highlights trends in DDT and pyrethroid resistance in wild An. gambiae populations from South Cameroon. Methods Mosquitoes were collected between 2001 and 2007 in four sites in South Cameroon, where insecticides are used for agricultural or personal protection purposes. Insecticide use was documented in each site by interviewing residents. Batches of 2-4 days old adult female mosquitoes reared from larval collections were tested for susceptibility to DDT, permethrin and deltamethrin using standard WHO procedures. Control, dead and survivors mosquitoes from bioassays were identified by PCR-RFLP and characterized for the kdr mutations using either the AS-PCR or the HOLA method. Results Four chemical insecticide groups were cited in the study sites: organochlorines, organophosphates, carbamates and pyrethroids. These chemicals were used for personal, crop or wood protection. In the four An. gambiae populations tested, significant variation in resistance levels, molecular forms composition and kdr frequencies were recorded in the time span of the study. Increases in DDT and pyrethroid resistance, as observed in most areas, were generally associated with an increase in the relative frequency of the S molecular form carrying the kdr mutations at higher frequencies. In Mangoum, however, where only the S form was present, a significant increase in the frequency of kdr alleles between 2003 to 2007 diverged with a decrease of the level of resistance to DDT and pyrethroids. Analyses of the kdr frequencies in dead and surviving mosquitoes showed partial correlation between the kdr genotypes and resistance

  18. Expression of the cytochrome P450s, CYP6P3 and CYP6M2 are significantly elevated in multiple pyrethroid resistant populations of Anopheles gambiae s.s. from Southern Benin and Nigeria

    Directory of Open Access Journals (Sweden)

    Ranson Hilary

    2008-11-01

    Full Text Available Abstract Background Insecticide resistance in Anopheles mosquitoes is threatening the success of malaria control programmes. This is particularly true in Benin where pyrethroid resistance has been linked to the failure of insecticide treated bed nets. The role of mutations in the insecticide target sites in conferring resistance has been clearly established. In this study, the contribution of other potential resistance mechanisms was investigated in Anopheles gambiae s.s. from a number of localities in Southern Benin and Nigeria. The mosquitoes were sampled from a variety of breeding sites in a preliminary attempt to investigate the role of contamination of mosquito breeding sites in selecting for resistance in adult mosquitoes. Results All mosquitoes sampled belonged to the M form of An. gambiae s.s. There were high levels of permethrin resistance in an agricultural area (Akron and an urban area (Gbedjromede, low levels of resistance in mosquito samples from an oil contaminated site (Ojoo and complete susceptibility in the rural Orogun location. The target site mutation kdrW was detected at high levels in two of the populations (Akron f = 0.86 and Gbedjromede f = 0.84 but was not detected in Ojoo or Orogun. Microarray analysis using the Anopheles gambiae detox chip identified two P450s, CYP6P3 and CYP6M2 up regulated in all three populations, the former was expressed at particularly high levels in the Akron (12.4-fold and Ojoo (7.4-fold populations compared to the susceptible population. Additional detoxification and redox genes were also over expressed in one or more populations including two cuticular pre-cursor genes which were elevated in two of the three resistant populations. Conclusion Multiple resistance mechanisms incurred in the different breeding sites contribute to resistance to permethrin in Benin. The cytochrome P450 genes, CYP6P3 and CYP6M2 are upregulated in all three resistant populations analysed. Several additional potential

  19. Attractive toxic sugar bait (ATSB) methods decimate populations of Anopheles malaria vectors in arid environments regardless of the local availability of favoured sugar-source blossoms

    OpenAIRE

    Beier John C; Müller Günter C; Gu Weidong; Arheart Kristopher L; Schlein Yosef

    2012-01-01

    Abstract Background Attractive toxic sugar bait (ATSB) methods are a new and promising "attract and kill" strategy for mosquito control. Sugar-feeding female and male mosquitoes attracted to ATSB solutions, either sprayed on plants or in bait stations, ingest an incorporated low-risk toxin such as boric acid and are killed. This field study in the arid malaria-free oasis environment of Israel compares how the availability of a primary natural sugar source for Anopheles sergentii mosquitoes: f...

  20. Anopheles (Anopheles) petragnani Del Vecchio 1939-a new mosquito species for Germany.

    Science.gov (United States)

    Becker, Norbert; Pfitzner, Wolf Peter; Czajka, Christina; Kaiser, Achim; Weitzel, Thomas

    2016-07-01

    The so far known species of the Anopheles Claviger Complex, Anopheles claviger s.s. and Anopheles petragnani, can only be distinguished by partial overlapping characteristics of immature stages and by nucleotide sequence variation of the genomic ribosomal DNA (rDNA) internal transcribed spacer 2 (ITS2) region. The known distribution of An. petragnani is so far restricted to the western Mediterranean region, whereas An. claviger s.s. occurs across most of Europe, up to the Middle East and North Africa. In our study, we investigated the larval mosquito fauna in rock pools of the Murg valley (Black Forest, Germany) once a month from April to December 2015.Among other species, larvae belonging to the Anopheles Claviger Complex were found. The fourth instar larvae were morphologically identified by chaetotaxy of the head and abdomen. The results were confirmed by a multiplex PCR and additional sequencing of the amplificates.Of the 1289 collected larvae from the rock pools, seven belonged to the Anopheles Claviger Complex. Five individuals were determined morphologically as An. petragnani and two as An. claviger s.s. The associated mosquito fauna comprised of Aedes japonicus japonicus (548 individuals), Culex pipiens s.l. and Culex torrentium (493 individuals) and Culex hortensis (241 individuals).This is the first record of An. petragnani north of the Alps. Further studies will reveal whether this is an isolated population of An. petragnani and if the investigated rock pool breeding sites represent typical habitats of this species in temperate regions in Central Europe.

  1. "Use of Random Amplified Polymorphic DNA Polymerase Chain Reaction (RAPD-PCR and ITS2 PCR assays for differentiation of populations and putative sibling species of Anopheles fluviatilis (Diptera: Culicidae in Iran"

    Directory of Open Access Journals (Sweden)

    SR Naddaf Dezfouli

    2002-09-01

    Full Text Available Anopheles fluviatilis complex is known to be a vector of malaria in Iran. Since mosquitoes of this species cover a wide geographical range in Iran, they might have evolved into different separated populations. Random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR assay was used to differentiate geographic populations of this species. DNA was extracted from individual mosquitoes from 8 localities in 4 south and southeast provinces and amplified in PCR reactions using 18 single primers of arbitrary nucleotide sequence. Results of RAPD-PCR showed that Kazeroun populations could simply be differentiated from other populations using a diagnostic fragment amplified with primer UBC-306. But other populations could not be differentiated either visually or by means of statistical analysis. Moreover ITS2 fragments of some selected specimens were amplified using a pair of universal primer and sequenced as a key standard for detection of putative sibling species. Sequence analysis of the ITS2 fragments revealed a very high (100% homology among the populations. These findings are crucial in epidemiological studies concerning relatedness of geographic populations and vector movement in the region. Results of RAPD-PCR and ITS2 analysis suggest that this taxon in Iran comprises of only one species with a low genetic variation among geographic populations.

  2. The Anopheles albitarsis complex with the recognition of Anopheles oryzalimnetes Wilkerson and Motoki, n. sp. and Anopheles janconnae Wilkerson and Sallum, n. sp. (Diptera: Culicidae

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    Maysa Tiemi Motoki

    2009-09-01

    Full Text Available The Anopheles (Nyssorhynchus albitarsis complex includes six species: An. albitarsis, Anopheles oryzalimnetes Wilkerson and Motoki, n. sp., Anopheles marajoara, Anopheles deaneorum, Anopheles janconnae Wilkerson and Sallum, n. sp. and An. albitarsis F. Except for An. deaneorum, species of the complex are indistinguishable when only using morphology. The problematic distinction among species of the complex has made study of malaria transmission and ecology of An. albitarsis s.l. difficult. Consequently, involvement of species of the An. albitarsis complex in human Plasmodium transmission is not clear throughout its distribution range. With the aim of clarifying the taxonomy of the above species, with the exception of An. albitarsis F, we present comparative morphological and morphometric analyses, morphological redescriptions of three species and description of two new species using individuals from populations in Brazil, Paraguay, Argentina and Venezuela. The study included characters from adult females, males, fourth-instar larvae, pupae and male genitalia of An. albitarsis, An. marajoara, An. deaneorum and An. oryzalimnetes n. sp. For An. janconnae n. sp. only characters of the female, male and male genitalia were analyzed. Fourth-instar larvae, pupae and male genitalia characteristics of all five species are illustrated. Bionomics and distribution data are given based on published literature records.

  3. Distribution and frequency of kdr mutations within Anopheles gambiae s.l. populations and first report of the ace.1 G119S mutation in Anopheles arabiensis from Burkina Faso (West Africa.

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    Roch K Dabiré

    Full Text Available An entomological survey was carried out at 15 sites dispersed throughout the three eco-climatic regions of Burkina Faso (West Africa in order to assess the current distribution and frequency of mutations that confer resistance to insecticides in An. gambiae s.l. populations in the country. Both knockdown (kdr resistance mutation variants (L1014F and L1014S, that confer resistance to pyrethroid insecticides, were identified concomitant with the ace-1 G119S mutation confirming the presence of multiple resistance mechanisms in the An. gambiae complex in Burkina Faso. Compared to the last survey, the frequency of the L1014F kdr mutation appears to have remained largely stable and relatively high in all species. In contrast, the distribution and frequency of the L1014S mutation has increased significantly in An. gambiae s.l. across much of the country. Furthermore we report, for the first time, the identification of the ace.1 G119S mutation in An. arabiensis populations collected at 8 sites [corrected]. This mutation, which confers resistance to organophosphate and carbamate insecticides, has been reported previously only in the An. gambiae S and M molecular forms. This finding is significant as organophosphates and carbamates are used in indoor residual sprays (IRS to control malaria vectors as complementary strategies to the use of pyrethroid impregnated bednets. The occurrence of the three target-site resistance mutations in both An. gambiae molecular forms and now An. arabiensis has significant implications for the control of malaria vector populations in Burkina Faso and for resistance management strategies based on the rotation of insecticides with different modes of action.

  4. Using Stable Isotopes of Carbon and Nitrogen to Mark Wild Populations of Anopheles and Aedes Mosquitoes in South-Eastern Tanzania

    Science.gov (United States)

    Opiyo, Mercy A.; Hamer, Gabriel L.; Lwetoijera, Dickson W.; Auckland, Lisa D.; Majambere, Silas; Okumu, Fredros O.

    2016-01-01

    Background Marking wild mosquitoes is important for understanding their ecology, behaviours and role in disease transmission. Traditional insect marking techniques include using fluorescent dyes, protein labels, radioactive labels and tags, but such techniques have various limitations; notably low marker retention and inability to mark wild mosquitoes at source. Stable isotopes are gaining wide spread use for non-invasive marking of arthropods, permitting greater understanding of mosquito dispersal and responses to interventions. We describe here a simple technique for marking naturally-breeding malaria and dengue vectors using stable isotopes of nitrogen (15N) and carbon (13C), and describe potential field applications. Methods We created man-made aquatic mosquito habitats and added either 15N-labelled potassium nitrate or 13C-labelled glucose, leaving non-adulterated habitats as controls. We then allowed wild mosquitoes to lay eggs in these habitats and monitored their development in situ. Pupae were collected promptly as they appeared and kept in netting cages. Emergent adults (in pools of ~4 mosquitoes/pool) and individually stored pupae were desiccated and analysed using Isotope Ratio Mass Spectrometry (IRMS). Findings Anopheles gambiae s.l and Aedes spp. from enriched 13C and enriched 15N larval habitats had significantly higher isotopic levels than controls (P = 0.005), and both isotopes produced sufficient distinction between marked and unmarked mosquitoes. Mean δ15N for enriched females and males were 275.6±65.1 and 248.0±54.6, while mean δ15N in controls were 2.1±0.1 and 3.9±1.7 respectively. Similarly, mean δ13C for enriched females and males were 36.08±5.28 and 38.5±6.86, compared to -4.3±0.2 and -7.9±3.6 in controls respectively. Mean δ15N and δ13C was significantly higher in any pool containing at least one enriched mosquito compared to pools with all unenriched mosquitoes, P<0.001. In all cases, there were variations in standardized

  5. Comparative biology and reproductive behaviour of a laboratory-adapted Redco strain of Anopheles Gambiae Giles (Diptera; culicidae and wild populations of the same species

    International Nuclear Information System (INIS)

    The sterile insect technique involves mass rearing of male insects for sterility purpose. This heavily relies on male fitness and genetic compatibility of laboratory-adapted male insects and the wild to ensure successful competition with their male counterpart in the wild. Uniform environment in the laboratory as compared to the wild conditions might lead to genetic drift which might lead to reduced sexual competitiveness, fitness, morphological changes or changes in the sexual behaviour of mosquitoes. This work investigated the sexual compatibility, morphometry and sexual behaviour of laboratory-adapted strain and wild strain of Anopheles gambiae under laboratory conditions. These measurements were done by observing swarm formation, genitalia rotation, percentage insemination, fecundity, fertility, wing length, wing width, thoracic width, body length, body size index and wing size index. Morphometric studies of laboratory-adapted and wild strain of Anopheles gambiae were carried out by observing the wing length, body length and thoracic length under Lecia 4D stereoscope in order to find out variations in the body size between the two strains. The results showed significant difference between thoracic width and wing length between the laboratory-adapted strain and wild strain. Indices such as body size index and wing length index also showed significant difference between the two strains; laboratory-adapted REDCO strain (BSI 4.45 ± 0.10, p = 0.010 ; WSI 1.92 ± 0.07, p = 0.026) and wild REDCO strain ( 4.08 ± 0.10, p = 0.010 ; WSI 1.73 ± 0.04, p = 0.026 ). Body length of laboratory-adapted male mosquitoes (4.24 ± 0.05, p = 0.462) was not significantly different from its thoracic width, wing length, and wing width. The wild strain on the other hand had significant difference between its body length (4.19 ± 0.04, p = 0.462), thoracic width (0.096 ± 0.02, p = 0.002 ) and wing length (2.99 ± 0.03, p = 0.050 ). In the mating experiment, egg production in each of

  6. Larvicidal activities of chinaberry, neem and Bacillus thuringiensis israelensis (Bti) to an insecticide resistant population of Anopheles arabiensis from Tolay, Southwest Ethiopia

    Institute of Scientific and Technical Information of China (English)

    Assalif Demissew; Meshesha Balkew; Melaku Girma

    2016-01-01

    Objective: To elucidate the larvicidal potency of neem, chinaberry and Bacillus thur-ingiensis israelensis (Bti) to larvae of Anopheles arabiensis under semi-field condition and adult susceptibility/resistance to the conventionally used insecticides in Tolay, Southwestern Ethiopia. Methods: Wild collected 3rd and 4th stage larvae were exposed to neem, and chinaberry seed powder dissolved in water and Bti in artificial containers at three treatment levels:0.2, 0.1 and 0.05 g/m2 and controls were free of treatments. Larval and pupal mortalities were monitored daily and residual activities were determined. The experiments were replicated three times. The World Health Organization tube test for all classes of in-secticides was conducted on adult Anopheles arabiensis reared from field collected larvae and pupae. Data were analyzed using STATA software version 11. Results: In the first application, neem powder caused 88.9%, 87.9%and 79.4%larval and pupal mortality at 0.2, 0.1 and 0.05 g/m2 after 4.3, 6.0 and 5.7 days, respectively. The cor-responding killing effect of chinaberry was 80.3%, 62.1%and 30.3%after 7.0, 7.7 and 8.3 days respectively. Bti at all treatments killed 100%after 24 h except 2.7 days for 0.05 g/m2. Adult mosquitoes were susceptible only for fenitrothion and pirimiphos-methyl with 100%mortality while resistant to deltamethrin, alpha-cypermethrin, etofenprox and dichloro-diphenyl-tricgloroethane with only 9.0%, 3.0%, 5.1%and 2.0%mortalities respectively. Conclusions: Neem, chinaberry and Bti showed potent larvicidal and pupicidal activ-ities. However, in the area, high level of mosquito resistance to pyrethroids and dichloro-diphenyl-tricgloroethane was seen which will pose serious challenge to vector control in the future. Therefore, using integrated approach including these botanical larvicides is warranted to manage insecticide resistance.

  7. Cannibalism and predation among larvae of the Anopheles gambiae complex

    NARCIS (Netherlands)

    Koenraadt, C.J.M.; Takken, W.

    2003-01-01

    Among the aquatic developmental stages of the Anopheles gambiae complex (Diptera: Culicidae), both inter- and intra-specific interactions influence the resulting densities of adult mosquito populations. For three members of the complex, An. arabiensis Patton, An. quadriannulatus (Theobald) and An. g

  8. Mermithid nematodes found in adult Anopheles from southeastern Senegal

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    Kobylinski Kevin C

    2012-06-01

    Full Text Available Abstract Background Over two dozen mermithid nematodes have been described parasitizing mosquitoes worldwide, however, only two species were found in Africa. Mermithid nematodes kill their mosquito host upon emergence, which suggests that they could be developed as biological control agents of mosquitoes. Both Romanomermis culicivorax and Romanomermis iyengari have been reared for mass release to control numerous Anopheles species vector populations, and in one instance this may have led to reduced malaria prevalence in a human population. Methods Anopheles mosquitoes were collected during a malaria study in southeastern Senegal. Two different adult blood fed mosquitoes had a single mermithid nematode emerge from their anus while they were being held post-capture. Primers from the 18 S rDNA were developed to sequence nematode DNA and screen mosquitoes for mermithid DNA. 18 S rDNA from the Senegalese mermithid and other mermithid entries in GenBank were used to create a Maximum Parsimony tree of the Mermithidae family. Results The mermithid was present in 1.8% (10/551 of the sampled adult Anopheles species in our study area. The mermithid was found in An. gambiae s.s., An. funestus, and An. rufipes from the villages of Ndebou, Boundoucondi, and Damboucoye. Maximum parsimony analysis confirmed that the nematode parasites found in Anopheles were indeed mermithid parasites, and of the mermithid sequences available in GenBank, they are most closely related to Strelkovimermis spiculatus. Conclusions To our knowledge, this is the first report of mermithids from adult Anopheles mosquitoes in Senegal. The mermithid appears to infect Anopheles mosquitoes that develop in diverse larval habitats. Although maximum parsimony analysis determined the mermithid was closely related to Strelkovimermis spiculatus, several characteristics of the mermithid were more similar to the Empidomermis genus. Future mermithid isolations will hopefully allow: formal

  9. Expression of the cytochrome P450s, CYP6P3 and CYP6M2 are significantly elevated in multiple pyrethroid resistant populations of Anopheles gambiae s.s. from Southern Benin and Nigeria

    OpenAIRE

    Ranson Hilary; Akogbeto Martin C; Coulibaly Ousmane N; Bakare Adekunle A; Djouaka Rousseau F; Hemingway Janet; Strode Clare

    2008-01-01

    Abstract Background Insecticide resistance in Anopheles mosquitoes is threatening the success of malaria control programmes. This is particularly true in Benin where pyrethroid resistance has been linked to the failure of insecticide treated bed nets. The role of mutations in the insecticide target sites in conferring resistance has been clearly established. In this study, the contribution of other potential resistance mechanisms was investigated in Anopheles gambiae s.s. from a number of loc...

  10. Male motion coordination in swarming Anopheles gambiae and Anopheles coluzzii

    Science.gov (United States)

    The Anopheles gambiae species complex comprises the primary vectors of malaria in much of sub-Saharan Africa; most of the mating in these species occurs in swarms composed almost entirely of males. Intermittent, parallel flight patterns in such swarms have been observed, but a detailed description o...

  11. Ecology of Anopheles spp. in Central Lombok Regency

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    Majematang Mading

    2014-06-01

    Full Text Available Malaria remains a public health problem in West Nusa Tenggara Province. Central Lombok District is one of the areas with high case of malaria. Annual Malaria Incidence (AMI was increased from 5.9 ‰ in 2006, 6.7‰ up to 8.1‰ in 2008. The objective of the study is to describe the ecological condition of Anopheles spp. through observation, measurement of environmental variables, larvae and adult collection. This research was an observational research with cross-sectional study. The population of this study is all mosquitos and breeding habitats of Anopheles spp. that exist in the research location. Ecological observations carried out on anopheles breeding habitats including acidity, salinity, shaded places and aquatic biota. Air temperature and humidity measured at the adult mosquitoes trapping sites. The result showed that pH values of water is around 9.00, salinity in the breeding habitats around 14 ppm, and water biota (i.e. moss, grass, shrimps, fishes, tadpoles and crabs surrounded by bushes with larvae density 0,1-28,8 each dipping. The air measurement at the time was between 23°-27° Celsius and 65%-84% humidity. This research concludes that ecology and environmental conditions were supporting the development of larvae and adult mosquito of Anopheles spp.

  12. ANOSPEX: a stochastic, spatially explicit model for studying Anopheles metapopulation dynamics.

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    Olugbenga O Oluwagbemi

    Full Text Available Anopheles mosquitoes transmit malaria, a major public health problem among many African countries. One of the most effective methods to control malaria is by controlling the Anopheles mosquito vectors that transmit the parasites. Mathematical models have both predictive and explorative utility to investigate the pros and cons of different malaria control strategies. We have developed a C++ based, stochastic spatially explicit model (ANOSPEX; Ano pheles Spatially-Explicit to simulate Anopheles metapopulation dynamics. The model is biologically rich, parameterized by field data, and driven by field-collected weather data from Macha, Zambia. To preliminarily validate ANOSPEX, simulation results were compared to field mosquito collection data from Macha; simulated and observed dynamics were similar. The ANOSPEX model will be useful in a predictive and exploratory manner to develop, evaluate and implement traditional and novel strategies to control malaria, and for understanding the environmental forces driving Anopheles population dynamics.

  13. Factors influencing the spatial distribution of Anopheles larvae in Coimbatore District, Tamil Nadu, India.

    Science.gov (United States)

    Arjunan, Naresh Kumar; Kadarkarai, Murugan; Kumar, Shobana; Pari, Madhiyazhagan; Thiyagarajan, Nataraj; Vincent, C Thomas; Barnard, Donald R

    2015-12-01

    Malaria causes extensive morbidity and mortality in humans and results in significant economic losses in India. The distribution of immature malaria-transmitting Anopheles mosquitoes was studied in 17 villages in Coimbatore District as a prelude to the development and implementation of vector control strategies that are intended to reduce the risk of human exposure to potentially infectious mosquitoes. Eight Anopheles species were recorded. The most numerous species were Anopheles vagus, Anopheles subpictus, and Anopheles hyrcanus. The location of mosquito development sites and the density of larvae in each village was evaluated for correlation with selected demographic, biologic, and land use parameters using remote sensing and geographic information systems (GIS) technology. We found the number of mosquito development sites in a village and the density of larvae in such sites to be positively correlated with human population density but not the surface area (km(2)) of the village. The number of mosquito development sites and the density of larvae in each site were not correlated. Data from this study are being used to construct a GIS-based mapping system that will enable the location of aquatic habitats with Anopheles larvae in the Coimbatore District, Tamil Nadu, India as target sites for the application of vector control. PMID:26364718

  14. Cladistic analysis of the subgenus Anopheles (Anopheles) Meigen (Diptera: Culicidae) based on morphological characters.

    Science.gov (United States)

    Collucci, Eliana; Sallum, Maria Anice Mureb

    2007-06-01

    In the present study, we used morphological characters to estimate phylogenetic relationships among members of the subgenus Anopheles Meigen. Phylogenetic analyses were carried out for 36 species of Anopheles (Anopheles). An. (Stethomyia) kompi Edwards, An. (Lophopodomyia) gilesi (Peryassú), Bironella hollandi Taylor, An. (Nyssorhynchus) oswaldoi (Peryassú) and An. (Cellia) maculatus Theobald were employed as outgroups. One hundred one characters of the external morphology of the adult male, adult female, fourth-instar larva, and pupa were scored and analyzed under the parsimony criterion in PAUP. Phylogenetic relationships among the series and several species informal groups of Anopheles (Anopheles) were hypothesized. The results suggest that Anopheles (Anopheles) is monophyletic. Additionally, most species groups included in the analysis were demonstrated to be monophyletic.

  15. Cladistic analysis of the subgenus Anopheles (Anopheles Meigen (Diptera: Culicidae based on morphological characters

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    Eliana Collucci

    2007-06-01

    Full Text Available In the present study, we used morphological characters to estimate phylogenetic relationships among members of the subgenus Anopheles Meigen. Phylogenetic analyses were carried out for 36 species of Anopheles (Anopheles. An. (Stethomyia kompi Edwards, An. (Lophopodomyia gilesi (Peryassú, Bironella hollandi Taylor, An. (Nyssorhynchus oswaldoi (Peryassú and An. (Cellia maculatus Theobald were employed as outgroups. One hundred one characters of the external morphology of the adult male, adult female, fourth-instar larva, and pupa were scored and analyzed under the parsimony criterion in PAUP. Phylogenetic relationships among the series and several species informal groups of Anopheles (Anopheles were hypothesized. The results suggest that Anopheles (Anopheles is monophyletic. Additionally, most species groups included in the analysis were demonstrated to be monophyletic.

  16. Variability and genetic differentiation among Anopheles (Ano. intermedius Chagas, 1908 and Anopheles (Ano. mattogrossensis Lutz & Neiva, 1911 (Diptera: Culicidae from the Brazilian Amazon

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    Joselita Maria Mendes dos Santos

    2005-10-01

    Full Text Available Anopheles (Anopheles intermedius and Anopheles (Ano. mattogrossensis are Brazilian anopheline species belonging to the scarcely studied Anopheles subgenus. Few studies have been done on the genetic differentiation of these species. Both species have been found infected by Plasmodium and are sympatric with other anopheline species from the Nyssorhynchus subgenus. Eighteen enzymatic loci were analyzed in larval specimens of An. intermedius and An. mattogrossensis aiming to estimate the variability and genetic differentiation between these species. An. mattogrossensis population showed higher genetic variability (P = 44.4 and Ho = 0.081 ± 0.031 than that of An. intermedius (P = 33.3 and Ho = 0.048 ± 0.021. Most analyzed loci showed genotypic frequencies according to Hardy-Weinberg equilibrium, except for LAP1 and LAP2 in An. intermedius, and EST1 and PGM loci in An. mattogrossensis. The genetic distance between these species (D = 0.683 was consistent with the inter-specific values reported for Anopheles subgenus. We verified that the polymorphism and heterozygosity percentile values found in both species and compared to those in the literature, showed no relation between the level of isozyme variability and geographical distribution. The low variability found in these two species is probably more related to the niche they occupy than to their geographic distribution.

  17. A simplified high-throughput method for pyrethroid knock-down resistance (kdr) detection in Anopheles gambiae

    OpenAIRE

    Walker Edward D; Black William C; Randle Nadine P; McCall P J; Ranson Hilary; Lynd Amy; Donnelly Martin J

    2005-01-01

    Abstract Background A single base pair mutation in the sodium channel confers knock-down resistance to pyrethroids in many insect species. Its occurrence in Anopheles mosquitoes may have important implications for malaria vector control especially considering the current trend for large scale pyrethroid-treated bednet programmes. Screening Anopheles gambiae populations for the kdr mutation has become one of the mainstays of programmes that monitor the development of insecticide resistance. Th...

  18. 基于mtDNA-COI基因序列分析我国中华按蚊种群的遗传结构%Analysis of population genetic structure of Anopheles sinensis based on mitochondrial DNA cytochrome oxidase subunit I gene fragment

    Institute of Scientific and Technical Information of China (English)

    常雪莲; 钟代斌; 李小聪; 黄亚铭; 朱国鼎; 魏星; 夏惠; 陈晓光; 方强

    2015-01-01

    目的:探讨我国中华按蚊种群遗传多样性、遗传分化及种群系统发育关系。方法本实验采用2010-2012年间在我国山东,安徽,江苏,贵州,广西和云南等6个不同地理环境采集的中华按蚊样品,进行线粒体COI基因扩增并测序。采用Bioedit 7.0软件对测序结果进行比对分析;运用DnaSP 5.0软件确定种群遗传结构特点;应用Arlequin 3.1软件计算种群的遗传距离及遗传分化系数;通过IBDWS在线软件来明确遗传距离与地理距离的相关性;使用PHYLIP 3.6软件构建种群系统发育进化树。结果六个中华按蚊种群共123个雌蚊个体的PCR产物成功扩增和测序。PCR扩增中华按蚊线粒体COI基因序列大小为814 bp,平均A+T含量(71.2%)>平均G+C含量(28.8%)。线粒体COI序列分析结果显示,种群具有丰富的遗传多样性;分子变异等级分析表明中华按蚊遗传分化主要来自于种群内部;种群间存在一定的地理隔离现象。中性检验,错配分析及聚类进化树结果显示:中华按蚊种群发展经历扩张状态,而云南种群相对其他种群较独立,在系统树中为孤立一支。结论线粒体COI基因可以作为研究中华按蚊种群遗传结构和系统进化的理想分子标志。云南种群遗传发育较其他地理种群具有一定特殊性。%Objective To study the population genetic variation, genetic diversity and phylogenesis of Anopheles sinensis in China. Methods Anopheles sinensis samples collected from Shandong, Anhui, Jiangsu, Guizhou, and Yunnan Provinces and Guangxi Zhuang Autonomous Region with different geographical conditions between 2010 and 2012 were analyzed by mitochondrial DNA cytochrome oxidase subunit I (mtDNA-COI) gene amplification and sequencing. Bioedit 7.0 and DnaSP 5.0 software was used to compare the gene sequences and analyze the population genetic structure, respectively. Arlequin 3.1 was used to calculate the

  19. Biologia de Anopheles (Kerteszia neivai H., D. & K., 1913 (Diptera: Culicidae en la costa Pacífica de Colombia: II. Fluctuación de la población adulta Biologia do Anopheles (Kerteszia neivai H., D. & K., 1913 (Diptera: Culicidae na costa do Pacífico Colombiano: II. Flutuação da população adulta Biology of Anopheles (Kerteszia neivai H., D. & K., 1913 (Diptera: Culicidae on the Pacific Coast of Colombia: II. Adult population fluctuation

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    Rodrigo Astaiza V.

    1988-04-01

    abundantes em árvores de manguezais. Na localidade foram estudados: a flutuação populacional, alguns aspectos ecológicos e etológicos dos adultos dessa espécie, com o objetivo de determinar seu papel na transmissão da malária. Todos os mosquitos foram coletados utilizando-se iscas humanas. O máximo de atividade ocorre nas horas crepusculares de manhã e da tarde (5:30 às 6:30 e 18:00 às 19:00 h. No período noturno, a atividade intradomiciliar é muito baixa, sendo ausente no peridomicílio durante o dia. O estado de desenvolvimento ovariano de fêmeas, coletadas nas horas de atividade máxima, mostrou a existência de duas populações de mosquitos: uma, na sua maioria constituída de indivíduos jovens, que procuram seu alimento nas horas da tarde; e uma outra, composta por indivíduos mais velhos, que procuram seu alimento nas horas da manhã. O estudo da variação sazonal mostrou que as populações são menores nos meses de pouca precipitação; na medida em que vai aumentando o índice pluviométrico cresce o número de mosquitos. Discutiu-se a relação existente entre a presença das populações de mosquitos com a prevalência de maláia no homem, sugerindo-se que A. neivai seja a responsável pela transmissão da malária na zona estudada.At Charambirá, a village in Istmina county, Department of Chocó, on the Pacific Coast of Colombia, malaria is endemic and is associated with large populations of Anopheles (Kerteszia neivai, which breed, in water which collects in epiphytic plants of the Bromeliaceae family, very abundant on mangrove trees. Population fluctuation, behavioral and ecological features of adult A. neivai were studied at this locality in an attempt to clarify its role in malaria transmission. Human bait was used in all captures of mosquitoes. Peaks of activity occurred at dawn and at sunset (5:30 to 6:30 and 18:00 to 19:00 hours. Very low biting activity was noted indoors at night and none at all outdoors during the day. The stage of

  20. Molecular Marker Confirmation for Member of Anopheles barbirostris Van Der Wulp 1884 in Different Localities

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    Tri Baskoro Tunggul Satoto

    2015-11-01

    Full Text Available Vector and non-vector forms of Anopheles barbirostris have been recognized in Indonesia. However, because of their similarity in morphology, they were considered to be a single species. This information has led to the hypothesis that Anopheles barbirostris is a complex of species, which are morphologically indistinguishable from each other by ordinary methods. Objectives of the research was to identify the member of Anopheles barbirostris by PCR Assay. Samples were taken from two localities in Java, two in Sulawesi, two in Flores Indonesia, one from Thailand, one from China. The study was to develop a PCR-based technique of rDNA ITS2 region. Results showed that there are at least four species within the Anopheles barbirostris population studied, namely Anopheles barbirostris species DW, DX, DY and DZ. The length of the sequence amplified for species W, species X, species Y, and species Z were 339bps, 247bps, 165bps. and 157bps, respectively. Verification of the method was carried out with 270 mosquitoes from eight different field-collection sites using various sampling methods. Samples collected from Singaraja-Flores were identified as species W and X. All specimens collected from human bite outdoors were identified as species X; this species showed to be predominant among indoor light trap, indoor human bite and indoor resting collections Samples from Reo-Flores were identified as species W and X. All specimens from Manado and Palopo in Sulawesiwere identified as species Z. Similarly only species Y was found in samples from Thailand, while specimens from Salaman and Jambu in Java were identified as species W or species X. These species-specific molecular markers for the Anopheles barbirostris, complex appear to be reliable over a wide geographical area. However, larger number of samples is still needed from throughout the range of this species.Key words: Anopheles barbirostris, ITS2, PCR, Specific primer diagnostic

  1. Locomotor behavioral responses of Anopheles minimus and Anopheles harrisoni to alpha-cypermethrin in Thailand.

    Science.gov (United States)

    Malaithong, Naritsara; Tisgratog, Rungarun; Tainchum, Krajana; Prabaripai, Atchariya; Juntarajumnong, Waraporn; Bangs, Michael J; Chareonviriyaphap, Theeraphap

    2011-09-01

    Excito-repellency responses of 3 test populations, representing 2 sibling species within the Minimus Complex, Anopheles minimus and An. harrisoni, were characterized for contact irritant and noncontact repellent actions of chemicals during and after exposure to alpha-cypermethrin at half the recommended field (0.010 g/m2), the recommended field (0.020 g/m2), and double the recommended field concentration (0.040 g/m2), using an excito-repellency escape chamber system. Two field populations of An. minimus and An. harrisoni collected from the malaria-endemic areas in Tak and Kanchanuburi provinces in western Thailand, respectively, were tested along with a laboratory population of An. minimus maintained since 1993. Females of all 3 test populations rapidly escaped after direct contact with treated surfaces for each concentration. In general, increased escape responses in the An. minimus test populations were proportionate to increased insecticide dosages. The greatest escape response for An. harrisoni was observed at the operational field concentration of alpha-cypermethrin. The noncontact repellency response to alpha-cypermethrin was comparatively weak for all 3 test populations, but significantly different from each paired contact test and respective noncontact controls. We conclude that strong contact irritancy is a major action of alpha-cypermethrin, whereas noncontact repellency plays no role in the escape responses of 2 species in the Minimus Complex in Thailand.

  2. Determinants of Anopheles seasonal distribution patterns across a forest to periurban gradient near Iquitos, Peru.

    Science.gov (United States)

    Reinbold-Wasson, Drew D; Sardelis, Michael R; Jones, James W; Watts, Douglas M; Fernandez, Roberto; Carbajal, Faustino; Pecor, James E; Calampa, Carlos; Klein, Terry A; Turell, Michael J

    2012-03-01

    As part of a field ecology study of arbovirus and malaria activity in the Amazon Basin, Loreto Department, Peru, we collected mosquitoes landing on humans at a forest site and inside and outside of residences and military barracks at periurban, rural, and village sites. We collected 11 Anopheles spp. from these four sites. An. darlingi, the principal malaria vector in the region, accounted for 98.7% of all Anopheles spp. collected at Puerto Almendra. Peaks in landing activity occurred during the December and April collection periods. However, the percent of sporozoite-positive Anopheles spp. was highest 1-2 months later, when landing activity decreased to approximately 10% of the peak activity periods. At all sites, peak landing activity occurred about 2 hours after sunset. These data provide a better understanding of the taxonomy, population density, and seasonal and habitat distribution of potential malaria vectors within the Amazon Basin region.

  3. Control of pyrethroid-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes with chlorfenapyr in Benin

    NARCIS (Netherlands)

    N'Guessan, R.; Boko, P.; Odjo, A.; Knols, B.G.J.; Akogbeto, M.; Rowland, M.

    2009-01-01

    Objective To compare the efficacy of chlorfenapyr applied on mosquito nets and as an indoor residual spray against populations of Anopheles gambiae and Culex quinquefasciatus in an area of Benin that shows problematic levels of pyrethroid resistance. Method Eight-week trial conducted in experimental

  4. Effect of larval crowding on mating competitiveness of Anopheles gambiae mosquitoes

    NARCIS (Netherlands)

    Ng'habi, K.R.; John, B.; Nkwengulila, G.; Knols, B.G.J.; Killeen, G.F.; Ferguson, H.M.

    2005-01-01

    Background: The success of sterile or transgenic Anopheles for malaria control depends on their mating competitiveness within wild populations. Current evidence suggests that transgenic mosquitoes have reduced fitness. One means of compensating for this fitness deficit would be to identify environme

  5. Biologia de Anopheles (Kerteszia neivai H., D. & K., 1913 (Diptera: Culicidae en la costa Pacífica de Colombia: I. Fluctuación de la población larval y características de sus criaderos Biologia de Anopheles (Kerteszia neivai H., D. & K,, 1913 (Diptera: Culicidae na costa do Pacífico Colombiano: I. Flutuação da população larval e características dos seus berçários (criadouros Biology of Anopheles (Kerteszia neivai H., D. & K., 1913 (Diptera: Culicidae on the Pacific coast of Colombia: I. Fluctuation of larval population and characteristics of the breeding places

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    César Murillo B.

    1988-04-01

    encontram coleções de água que funcionam como criadouros dessa espécie de anofelino. Tomaram-se dados de temperatura, pH e volume da água contida em cada bromélia. O maior número de larvas foi detectado no estrato 1 (manguezal em uma altitude inferior a 4 m, porém não se teve evidência significativa de estratificação vertical da população larval de A. neivai até os 8 m de altitude. Evidenciou-se uma correlação linear positiva do número de larvas com o volume de água contida em cada uma das bromélias; por outro lado, observou-se também uma correlação direta de precipitação mensal acumulada com a flutuação populacional dessa espécie. Os índices larvais mais altos foram observados nos meses de março a abril e de julho a agosto. A mortalidade larval foi alta no primeiro estádio (43,5%, sendo que 23,7% sobreviveram até o quarto estádio.The fluctuation of the larval population and characteristics of the breeding places of Anopheles (Kerteszia neivai were studied in the village of Charambirá, Istmina county, Department of Chocó. This mosquito species is considered to be the malaria vector in this region of the Pacific coast of Colombia. The vegetation in the vicinity of the town was classified in three strata according to foliage coverage, and 100 m² quadrants were set up for sampling epiphytic plants of the Bromeliaceae family, which serve as breeding sites for this anopheline. Data corresponding to height, temperature, pH and water volume were taken for each bromeliad plant studied. The largest number of larvae were found in the mangrove forest (stratum 1 below a height of 4 m, although no significant evidence was found for vertical stratification of larvae below a height of 8 m. A positive linear correlation was found between the water volume and the number of larvae of A. neivai observed in each bromeliad. In addition a direct relation was found between cumulative monthly rainfall and the fluctuation of the larval population. The greatest

  6. Limited usefulness of microsatellite markers from the malaria vector Anopheles gambiae when applied to the closely related species Anopheles melas.

    Science.gov (United States)

    Deitz, Kevin C; Reddy, Vamsi P; Reddy, Michael R; Satyanarayanah, Neha; Lindsey, Michael W; Overgaard, Hans J; Jawara, Musa; Caccone, Adalgisa; Slotman, Michel A

    2012-07-01

    Anopheles melas is a brackish water mosquito found in coastal West Africa where it is a dominant malaria vector locally. In order to facilitate genetic studies of this species, 45 microsatellite loci originally developed for Anopheles gambiae were sequenced in An. melas. Those that were suitable based on repeat number and flanking regions were examined in 2 natural populations from Equatorial Guinea. Only 15 loci were eventually deemed suitable as polymorphic markers in An. melas populations. These loci were screened in 4 populations from a wider geographic range. Heterozygosity estimates ranged from 0.18 to 0.79, and 2.5-15 average alleles were observed per locus, yielding 13 highly polymorphic markers and 2 loci with lower variability. To examine the usefulness of microsatellite markers when applied in a sibling species, the original An. gambiae specific markers were used to amplify 5 loci in An. melas. Null alleles were found for 1 An. gambiae marker. We discuss the pitfalls of using microsatellite loci across closely related species and conclude that in addition to the problem of null alleles associated with this practice, many loci may prove to be of very limited use as polymorphic markers even when used in a sibling species. PMID:22593601

  7. Adaptation through chromosomal inversions in Anopheles

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    Diego eAyala

    2014-05-01

    Full Text Available Chromosomal inversions have been repeatedly involved in local adaptation in a large number of animals and plants. The ecological and behavioral plasticity of Anopheles species - human malaria vectors - is mirrored by high amounts of polymorphic inversions. The adaptive significance of chromosomal inversions has been consistently attested by strong and significant correlations between their frequencies and a number of phenotypic traits. Here, we provide an extensive literature review of the different adaptive traits associated with chromosomal inversions in the genus Anopheles. Traits having important consequences for the success of present and future vector control measures, such as insecticide resistance and behavioral changes, are discussed.

  8. Factors affecting fungus-induced larval mortality in Anopheles gambiae and Anopheles stephensi

    NARCIS (Netherlands)

    Bukhari, S.T.; Middelman, A.; Koenraadt, C.J.M.; Takken, W.; Knols, B.G.J.

    2010-01-01

    Background Entomopathogenic fungi have shown great potential for the control of adult malaria vectors. However, their ability to control aquatic stages of anopheline vectors remains largely unexplored. Therefore, how larval characteristics (Anopheles species, age and larval density), fungus (species

  9. Using a near-infrared spectrometer to estimate the age of anopheles mosquitoes exposed to pyrethroids.

    Directory of Open Access Journals (Sweden)

    Maggy T Sikulu

    Full Text Available We report on the accuracy of using near-infrared spectroscopy (NIRS to predict the age of Anopheles mosquitoes reared from wild larvae and a mixed age-wild adult population collected from pit traps after exposure to pyrethroids. The mosquitoes reared from wild larvae were estimated as <7 or ≥7 d old with an overall accuracy of 79%. The age categories of Anopheles mosquitoes that were not exposed to the insecticide papers were predicted with 78% accuracy whereas the age categories of resistant, susceptible and mosquitoes exposed to control papers were predicted with 82%, 78% and 79% accuracy, respectively. The ages of 85% of the wild-collected mixed-age Anopheles were predicted by NIRS as ≤8 d for both susceptible and resistant groups. The age structure of wild-collected mosquitoes was not significantly different for the pyrethroid-susceptible and pyrethroid-resistant mosquitoes (P = 0.210. Based on these findings, NIRS chronological age estimation technique for Anopheles mosquitoes may be independent of insecticide exposure and the environmental conditions to which the mosquitoes are exposed.

  10. Isoenzymatic variability among five Anopheles species belonging to the Nyssorhynchus and Anopheles subgenera of the Amazon region, Brazil

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    Joselita Maria Mendes dos Santos

    2003-03-01

    Full Text Available An isoenzymatic comparative analysis of the variability and genetics differentiation among Anopheles species was done in populations of An. (Nys. intermedius and An. (Ano. mattogrossensis of the Anopheles subgenus, and of An. darlingi, An. albitarsis and An. triannulatus of the Nyssorhynchus subgenus, with the aim of detecting differences between both subgenera and of estimating the degree of genetic intere specific divergence. Samples from Macapá, State of Amapá and Janauari Lake, near Manaus, State of Amazonas, were analyzed for eight isoenzymatic loci. Analysis revealed differences in the average number of alleles per locus (1.6-2.3 and heterozygosity (0.060-0.284. However, the proportion of polymorphic loci was the same for An. (Nys. darlingi, An. (Nys. triannulatus and An. (Ano. mattogrossensis (50%, but differed for An. (Nys. albitarsis (62.5% and An. (Ano. intermedius (25%. Only the IDH1 (P > 0.5 locus in all species studied was in Hardy-Weinberg equilibrium. The fixation index demonstrated elevated genetic structuring among species, based on values of Fst = 0.644 and genetic distance (0.344-0.989. Genetic difference was higher between An. (Nys. triannulatus and An. (Ano. intermedius (0.989 and smaller between An. (Nys. albitarsis sensu lato and An. (Nys. darlingi (0.344. The data show interspecific genetic divergence which differs from the phylogenetic hypothesis based on morphological characters.

  11. Genomic Dark Matter Illuminated: Anopheles Y Chromosomes.

    Science.gov (United States)

    Redmond, Seth N; Neafsey, Daniel E

    2016-08-01

    Hall et al. have strategically used long-read sequencing technology to characterize the structure and highly repetitive content of the Y chromosome in Anopheles malaria mosquitoes. Their work confirms that this important but elusive heterochromatic sex chromosome is evolving extremely rapidly and harbors a remarkably small number of genes.

  12. Genomic Dark Matter Illuminated: Anopheles Y Chromosomes.

    Science.gov (United States)

    Redmond, Seth N; Neafsey, Daniel E

    2016-08-01

    Hall et al. have strategically used long-read sequencing technology to characterize the structure and highly repetitive content of the Y chromosome in Anopheles malaria mosquitoes. Their work confirms that this important but elusive heterochromatic sex chromosome is evolving extremely rapidly and harbors a remarkably small number of genes. PMID:27263828

  13. Insecticide resistance status in Anopheles gambiae in southern Benin

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    Corbel Vincent

    2010-03-01

    Full Text Available Abstract Background The emergence of pyrethroid resistance in Anopheles gambiae has become a serious concern to the future success of malaria control. In Benin, the National Malaria Control Programme has recently planned to scaling up long-lasting insecticidal nets (LLINs and indoor residual spraying (IRS for malaria prevention. It is, therefore, crucial to monitor the level and type of insecticide resistance in An. gambiae, particularly in southern Benin where reduced efficacy of insecticide-treated nets (ITNs and IRS has previously been reported. Methods The protocol was based on mosquito collection during both dry and rainy seasons across forty districts selected in southern Benin. Bioassay were performed on adults collected from the field to assess the susceptibility of malaria vectors to insecticide-impregnated papers (permethrin 0.75%, delthamethrin 0.05%, DDT 4%, and bendiocarb 0.1% following WHOPES guidelines. The species within An. gambiae complex, molecular form and presence of kdr and ace-1 mutations were determined by PCR. Results Strong resistance to permethrin and DDT was found in An. gambiae populations from southern Benin, except in Aglangandan where mosquitoes were fully susceptible (mortality 100% to all insecticides tested. PCR showed the presence of two sub-species of An. gambiae, namely An. gambiae s.s, and Anopheles melas, with a predominance for An. gambiae s.s (98%. The molecular M form of An. gambiae was predominant in southern Benin (97%. The kdr mutation was detected in all districts at various frequency (1% to 95% whereas the Ace-1 mutation was found at a very low frequency (≤ 5%. Conclusion This study showed a widespread resistance to permethrin in An. gambiae populations from southern Benin, with a significant increase of kdr frequency compared to what was observed previously in Benin. The low frequency of Ace-1 recorded in all populations is encouraging for the use of bendiocarb as an alternative insecticide to

  14. Paridade de Anopheles cruzii em Floresta Ombrófila Densa no Sul do Brasil Anopheles cruzii parity in dense rain forest in Southern Brazil

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    Ana Caroline Dalla Bona

    2006-12-01

    first oviposition. It was observed that Anopheles cruzii populations comprised young mosquitoes, probably due to high mortality among parous females. CONCLUSIONS: The likely gonotrophic discordance is epidemiologically relevant because female mosquitoes can search for more than one host to complete the maturation of their eggs.

  15. Man-biting activity of Anopheles (Nyssorhynchus albimanus and An. (Kerteszia neivai (Diptera: Culicidae in the Pacific Lowlands of Colombia

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    Yezid Solarte

    1996-04-01

    Full Text Available The daily man-biting activity of Anopheles (Nyssorhynchus albimanus and An. (Kerteszia neivai was determined in four ecologically distinct settlements of the Naya River, Department of Valle, Colombia. Differences were found among the settlements with respect to the mosquito species present, intradomiciliary and extradomiciliary biting activity and population densities.

  16. Participation of irradiated Anopheles arabiensis males in swarms following field release in Sudan

    OpenAIRE

    Ageep, Tellal B; Damiens, David; Alsharif, Bashir; Ahmed, Ayman; Salih, Elwaleed HO; Ahmed, Fayez TA; Diabaté, Abdoulaye; Lees, Rosemary S.; Gilles, Jeremie RL; El Sayed, Badria B

    2014-01-01

    Background The success of the sterile insect technique (SIT) depends the release of large numbers of sterile males, which are able to compete for mates with the wild male population within the target area. Unfortunately, the processes of colonisation, mass production and irradiation may reduce the competitiveness of sterile males through genetic selection, loss of natural traits and somatic damage. In this context, the capacity of released sterile Anopheles arabiensis males to survive, disper...

  17. Insecticide susceptibility status of Aedes aegypti and Anopheles stephensi larvae against temephos in Delhi, India

    OpenAIRE

    Singh, R. K.; P.K.Mittal; Gaurav Kumar; Dhiman, R.C.

    2014-01-01

    Temephos is used as a larvicide in urban areas in India to control the population of mosquito vectors viz. Anopheles stephensi and Aedes aegypti. The susceptibility status of Ae. aegypti and An. stephensi to temophos in various zones of Municipal Corporation of Delhi was evaluated using the WHO method for determining larval susceptibility test kit. Results revealed that the larval mortality of Ae. aegypti collected from different localities ranged between 64.88% to 98.22%. The highest mortali...

  18. Anopheles darlingi and Anopheles marajoara (Diptera: Culicidae susceptibility to pyrethroids in an endemic area of the Brazilian Amazon

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    Allan Kardec Ribeiro Galardo

    2015-12-01

    Full Text Available Abstract: INTRODUCTION: This study aimed to evaluate the susceptibility of Anopheles darlingi Root (1926 and Anopheles marajoara Galvão & Damasceno (1942 to pyrethroids used by the National Malaria Control Program in Brazil. METHODS: Mosquitoes from Amapá, Brazilian Amazon, were assessed for resistance to cypermethrin, deltamethrin, and alpha-cypermethrin. Insecticide-impregnated bottles were used as suggested by the CDC/Atlanta. RESULTS: Diagnostic dose for Anopheles darlingi was 12.5µg/bottle during 30 min of exposure. Concentrations for Anopheles marajoara were 20µg/bottle of cypermethrin and deltamethrin and 12.5µg/bottle of alpha-cypermethrin. CONCLUSIONS : No resistance was recorded for Anopheles darlingi , but Anopheles marajoara requires attention.

  19. Genomic islands of speciation in Anopheles gambiae.

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    2005-09-01

    Full Text Available The African malaria mosquito, Anopheles gambiae sensu stricto (A. gambiae, provides a unique opportunity to study the evolution of reproductive isolation because it is divided into two sympatric, partially isolated subtaxa known as M form and S form. With the annotated genome of this species now available, high-throughput techniques can be applied to locate and characterize the genomic regions contributing to reproductive isolation. In order to quantify patterns of differentiation within A. gambiae, we hybridized population samples of genomic DNA from each form to Affymetrix GeneChip microarrays. We found that three regions, together encompassing less than 2.8 Mb, are the only locations where the M and S forms are significantly differentiated. Two of these regions are adjacent to centromeres, on Chromosomes 2L and X, and contain 50 and 12 predicted genes, respectively. Sequenced loci in these regions contain fixed differences between forms and no shared polymorphisms, while no fixed differences were found at nearby control loci. The third region, on Chromosome 2R, contains only five predicted genes; fixed differences in this region were also verified by direct sequencing. These "speciation islands" remain differentiated despite considerable gene flow, and are therefore expected to contain the genes responsible for reproductive isolation. Much effort has recently been applied to locating the genes and genetic changes responsible for reproductive isolation between species. Though much can be inferred about speciation by studying taxa that have diverged for millions of years, studying differentiation between taxa that are in the early stages of isolation will lead to a clearer view of the number and size of regions involved in the genetics of speciation. Despite appreciable levels of gene flow between the M and S forms of A. gambiae, we were able to isolate three small regions of differentiation where genes responsible for ecological and behavioral

  20. The complete mitochondrial genome of Anopheles minimus (Diptera: Culicidae) and the phylogenetics of known Anopheles mitogenomes.

    Science.gov (United States)

    Hua, Ya-Qiong; Ding, Yi-Ran; Yan, Zhen-Tian; Si, Feng-Ling; Luo, Qian-Chun; Chen, Bin

    2016-06-01

    Anopheles minimus is an important vector of human malaria in southern China and Southeast Asia. The phylogenetics of mosquitoes has not been well resolved, and the mitochondrial genome (mtgenome) has proven to be an important marker in the study of evolutionary biology. In this study, the complete mtgenome of An. minimus was sequenced for the first time. It is 15 395 bp long and encodes 37 genes, including 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs) and a non-coding region. The gene organization is consistent with those of known Anopheles mtgenomes. The mtgenome performs a clear bias in nucleotide composition with a positive AT-skew and a negative GC-skew. All 13 PCGs prefer to use the codon UUA (Leu), ATN as initiation codon but cytochrome-oxidase subunit 1 (COI) and ND5, with TCG and GTG, and TAA as termination codon, but COI, COII, COIII and ND4, all with the incomplete T. tRNAs have the typical clover-leaf structure, but tRNA(Ser(AGN)) is consistent with known Anopheles mtgenomes. The control region includes a conserved T-stretch and a (TA)n stretch, and has the highest A+T content at 93.1%. The phylogenetics of An. minimus with 18 other Anopheles species was constructed by maximum likelihood and Bayesian inference, based on concatenated PCG sequences. The subgenera, Cellia and Anopheles, and Nyssorhynchus and Kerteszia have mutually close relationships, respectively. The Punctulatus group and Leucosphyrus group of Neomyzomyia Series, and the Albitarsis group of Albitarsis Series were suggested to be monophyletic. The monophyletic status of the subgenera, Cellia, Anopheles, Nyssorhynchus and Kerteszia need to be further elucidated. PMID:26852698

  1. Laboratory studies on the olfactory behaviour of Anopheles quadriannulatus

    NARCIS (Netherlands)

    Pates, H.V.; Takken, W.; Curtis, C.F.

    2005-01-01

    The host preference of Anopheles quadriannulatus Theobald (Diptera: Culicidae), the zoophilic member of the malaria mosquito complex Anopheles gambiae Giles, was investigated in a dual-choice olfactometer. Naïve female mosquitoes were exposed to CO2, acetone, 1-octen-3-ol, and skin emanations from c

  2. Absence of knockdown resistance suggests metabolic resistance in the main malaria vectors of the Mekong region

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    Sochantha Tho

    2009-04-01

    Full Text Available Abstract Background As insecticide resistance may jeopardize the successful malaria control programmes in the Mekong region, a large investigation was previously conducted in the Mekong countries to assess the susceptibility of the main malaria vectors against DDT and pyrethroid insecticides. It showed that the main vector, Anopheles epiroticus, was highly pyrethroid-resistant in the Mekong delta, whereas Anopheles minimus sensu lato was pyrethroid-resistant in northern Vietnam. Anopheles dirus sensu stricto showed possible resistance to type II pyrethroids in central Vietnam. Anopheles subpictus was DDT- and pyrethroid-resistant in the Mekong Delta. The present study intends to explore the resistance mechanisms involved. Methods By use of molecular assays and biochemical assays the presence of the two major insecticide resistance mechanisms, knockdown and metabolic resistance, were assessed in the main malaria vectors of the Mekong region. Results Two FRET/MCA assays and one PCR-RFLP were developed to screen a large number of Anopheles populations from the Mekong region for the presence of knockdown resistance (kdr, but no kdr mutation was observed in any of the study species. Biochemical assays suggest an esterase mediated pyrethroid detoxification in An. epiroticus and An. subpictus of the Mekong delta. The DDT resistance in An. subpictus might be conferred to a high GST activity. The pyrethroid resistance in An. minimus s.l. is possibly associated with increased detoxification by esterases and P450 monooxygenases. Conclusion As different metabolic enzyme systems might be responsible for the pyrethroid and DDT resistance in the main vectors, each species may have a different response to alternative insecticides, which might complicate the malaria vector control in the Mekong region.

  3. Evaluating the potential of the sterile insect technique for malaria control: relative fitness and mating compatibility between laboratory colonized and a wild population of Anopheles arabiensis from the Kruger National Park, South Africa

    OpenAIRE

    Hunt Richard H; Chirwa Tobias F; Brooke Basil D; Munhenga Givemore; Coetzee Maureen; Govender Danny; Koekemoer Lizette L

    2011-01-01

    Abstract Background The successful suppression of a target insect population using the sterile insect technique (SIT) partly depends on the premise that the laboratory insects used for mass rearing are genetically compatible with the target population, that the mating competitiveness of laboratory reared males is at least comparable to that of their wild counterparts, and that mass rearing and sterilization processes do not in themselves compromise male fitness to a degree that precludes them...

  4. Thermal limits of wild and laboratory strains of two African malaria vector species, Anopheles arabiensis and Anopheles funestus

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    Lyons Candice L

    2012-07-01

    Full Text Available Abstract Background Malaria affects large parts of the developing world and is responsible for almost 800,000 deaths annually. As climates change, concerns have arisen as to how this vector-borne disease will be impacted by changing rainfall patterns and warming temperatures. Despite the importance and controversy surrounding the impact of climate change on the potential spread of this disease, little information exists on the tolerances of several of the vector species themselves. Methods Using a ramping protocol (to assess critical thermal limits - CT and plunge protocol (to assess lethal temperature limits - LT information on the thermal tolerance of two of Africa’s important malaria vectors, Anopheles arabiensis and Anopheles funestus was collected. The effects of age, thermal acclimation treatment, sex and strain (laboratory versus wild adults were investigated for CT determinations for each species. The effects of age and sex for adults and life stage (larvae, pupae, adults were investigated for LT determinations. Results In both species, females are more tolerant to low and high temperatures than males; larvae and pupae have higher upper lethal limits than do adults. Thermal acclimation of adults has large effects in some instances but small effects in others. Younger adults tend to be more tolerant of low or high temperatures than older age groups. Long-standing laboratory colonies are sufficiently similar in thermal tolerance to field-collected animals to provide reasonable surrogates when making inferences about wild population responses. Differences between these two vectors in their thermal tolerances, especially in larvae and pupae, are plausibly a consequence of different habitat utilization. Conclusions Limited plasticity is characteristic of the adults of these vector species relative to others examined to date, suggesting limited scope for within-generation change in thermal tolerance. These findings and the greater tolerance

  5. Food of larval Anopheles culicifacies and Anopheles varuna in a stream habitat in Sri Lanka

    DEFF Research Database (Denmark)

    Piyaratne, M K; Amerasinghe, P H; Amerasinghe, F P;

    2005-01-01

    No previous studies have been conducted on the natural food of larval Anopheles culicifacies s.l. (the major malaria vector) and An. varuna (a secondary vector) in Sri Lanka. The present study analyzed the contents of guts dissected from larvae collected from pools in a natural stream-cum-irrigat...

  6. Biting behavior of Anopheles mosquitoes in Costa Marques, Rondonia, Brazil

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    Terry A. Klein

    1991-03-01

    Full Text Available Mosquito collections were made in and near Costa Marques, Rondonia, Brazil, to determine anopheline anthropophilic/zoophilic behavior. Collections from a non-illuminated, bovine-baited trap and indoor and outdoor human-bait collections were compared. Anopheles darlingi and Anopheles deaneorum were more anthropophilic than the other anophelines collected. The remainder of the Anopheles species were collected much morefrequently in bovine-baited traps than in human-bait collections. Anopheles darlingi and An. deaneorum were more frequently collected inside houses than the other anopheline species. But, when collections were made in a house with numerous openings in the walls, there were few differences in the percentages of each species biting man indoors versus outdoors. Anopheles darlingi was the predominant mosquito collected, both inside and outside houses, and had the strongest anthropophilic feeding behavior of the anophelines present.Para determinar o comportamento antropofilico e zoofilico dos anofelinos, foram capturados mosquitos na periferia e na zona urbana de Costa Marques, Rondônia, Brasil. Foram comparadas as capturas feitas à noite, com iscas bovinas e humanas, dentro efora de casa. O Anopheles darlingi e o Anopheles deaneorumforam mais antropojilicos do que os outros anofelinos capturados. O restante das espécies anofelinas foi capturado mais freqüentemente nas iscas bovinas do que nas humanas. Anopheles darlingi e Anopheles deaneorumforam capturados dentro de casa com mais freqüência do que as outras espécies anofelinas. Porém, quando a captura foi feita em casas com muitas aberturas nas paredes houve pouca diferença nas porcentagens de cada espécie sugadora de humanos dentro efora de casa. Anopheles darlingi foi o mosquito capturado com mais freqüência, dentro e fora de casa, e apresentava maior antropofilia em relação aos outros anofelinos presentes.

  7. Evaluating the potential of the sterile insect technique for malaria control: relative fitness and mating compatibility between laboratory colonized and a wild population of Anopheles arabiensis from the Kruger National Park, South Africa

    Directory of Open Access Journals (Sweden)

    Hunt Richard H

    2011-10-01

    Full Text Available Abstract Background The successful suppression of a target insect population using the sterile insect technique (SIT partly depends on the premise that the laboratory insects used for mass rearing are genetically compatible with the target population, that the mating competitiveness of laboratory reared males is at least comparable to that of their wild counterparts, and that mass rearing and sterilization processes do not in themselves compromise male fitness to a degree that precludes them from successfully competing for mates in the wild. This study investigated the fitness and sexual cross-compatibility between samples of field collected and laboratory reared An. arabiensis under laboratory conditions. Results The physiological and reproductive fitness of the MALPAN laboratory strain is not substantially modified with respect to the field population at Malahlapanga. Further, a high degree of mating compatibility between MALPAN and the Malahlapanga population was established based on cross-mating experiments. Lastly, the morphological characteristics of hybrid ovarian polytene chromosomes further support the contention that the MALPAN laboratory colony and the An. arabiensis population at Malahlapanga are genetically homogenous and therefore compatible. Conclusions It is concluded that the presence of a perennial and isolated population of An. arabiensis at Malahlapanga presents a unique opportunity for assessing the feasibility of SIT as a malaria vector control option. The MALPAN laboratory colony has retained sufficient enough measures of reproductive and physiological fitness to present as a suitable candidate for male sterilization, mass rearing and subsequent mass release of sterile males at Malahlapanga in order to further assess the feasibility of SIT in a field setting.

  8. Random amplified polymorphic DNA analysis of Anopheles nuneztovari (Diptera: Culicidae from Western and Northeastern Colombia

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    Carmen Elisa Posso

    2003-06-01

    Full Text Available Random amplified polymorphic DNA (RAPD markers were used to analyze 119 DNA samples of three Colombian Anopheles nuneztovari populations to study genetic variation and structure. Genetic diversity, estimated from heterozygosity, averaged 0.34. Genetic flow was greater between the two populations located in Western Colombia (F ST: 0.035; Nm: 6.8 but lower between these two and the northeastern population (F ST: 0.08; Nm: 2.8. According to molecular variance analysis, the genetic distance between populations was significant (phiST 0.1131, P < 0.001. The variation among individuals within populations (phiST 0.8869, P < 0.001was also significant, suggesting a greater degree of population subdivision, not considered in this study. Both the parameters evaluated and the genetic flow suggest that Colombian An. nuneztovari populations are co-specific.

  9. Robust and regulatory expression of defensin A gene driven by vitellogenin promoter in transgenic Anopheles stephensi

    Institute of Scientific and Technical Information of China (English)

    CHEN XiaoGuang; ZHANG YaJing; ZHENG XueLi; WANG ChunMei

    2007-01-01

    The use of genetically modified mosquitoes to reduce or replace field populations is a new strategy to control mosquito-borne diseases. The precondition of the implementation of this strategy is the ability to manipulate the genome of mosquitoes and to induce specific expression of the effector molecules driven by a suitable promoter. The objective of this study is to evaluate the expression of defensin A gene of Anopheles sinensis under the control of a vitellogenin promoter in transgenic Anopheles stephensi. The regulatory region of Anopheles gambiae vitellogenin was cloned and subcloned into transfer vector pSLFa consisting of an expression cassette with defensin A coding sequence. Then, the expression cassette was transferred into transformation vector pBac[3xP3-DsRedafm] using Asc I digestion. The recombinant plasmid DNA of pBac[3xP3DsRed-AgVgT2-DefA] and helper plasmid DNA of phsp-pBac were micro-injected into embryos of An. stephensi. The positive transgenic mosquitoes were screened by observing specific red fluorescence in the eyes of G1 larvae. Southern blot analysis showed that a single-copy transgene integrated into the genome of An. stephensi. RT-PCR analysis showed that the defensin A gene expressed specifically in fat bodies of female mosquitoes after a blood meal. Interestingly, the mRNA of defensin A is more stable compared with that of the endogenous vitellogenin gene. After multiple blood meals, the expression of defensin A appeared as a reducible and non-cycling type, a crucial feature for its anti-pathogen effect. From data above, we concluded that the regulatory function of the Vg promoter and the expression of defensin A gene were relatively conserved in different species of anopheles mosquitoes. These molecules could be used as candidates in the development of genetically modified mosquitoes.

  10. Neuropeptides and Peptide Hormones in Anopheles gambiae

    Science.gov (United States)

    Riehle, Michael A.; Garczynski, Stephen F.; Crim, Joe W.; Hill, Catherine A.; Brown, Mark R.

    2002-10-01

    The African malaria mosquito, Anopheles gambiae, is specialized for rapid completion of development and reproduction. A vertebrate blood meal is required for egg production, and multiple feedings subsequently allow transmission of malaria parasites, Plasmodium spp. Regulatory peptides from 35 genes annotated from the A. gambiae genome likely coordinate these and other physiological processes. Plasmodium parasites may affect actions of newly identified insulin-like peptides, which coordinate growth and reproduction of its vector, A. gambiae, as in Drosophila melanogaster, Caenorhabditis elegans, and mammals. This genomic information provides a basis to expand understanding of hematophagy and pathogen transmission in this mosquito.

  11. Additional selection for insecticide resistance in urban malaria vectors: DDT resistance in Anopheles arabiensis from Bobo-Dioulasso, Burkina Faso.

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    Christopher M Jones

    Full Text Available In the city of Bobo-Dioulasso in Burkina Faso, Anopheles arabiensis has superseded Anopheles gambiae s.s. as the major malaria vector and the larvae are found in highly polluted habitats normally considered unsuitable for Anopheles mosquitoes. Here we show that An. gambiae s.l. adults emerging from a highly polluted site in the city centre (Dioulassoba have a high prevalence of DDT resistance (percentage mortality after exposure to diagnostic dose=65.8% in the dry season and 70.4% in the rainy season, respectively. An investigation into the mechanisms responsible found an unexpectedly high frequency of the 1014S kdr mutation (allele frequency=0.4, which is found at very low frequencies in An. arabiensis in the surrounding rural areas, and an increase in transcript levels of several detoxification genes, notably from the glutathione transferase and cytochrome P450 gene families. A number of ABC transporter genes were also expressed at elevated levels in the DDT resistant An. arabiensis. Unplanned urbanisation provides numerous breeding grounds for mosquitoes. The finding that Anopheles mosquitoes adapted to these urban breeding sites have a high prevalence of insecticide resistance has important implications for our understanding of the selective forces responsible for the rapid spread of insecticide resistant populations of malaria vectors in Africa.

  12. Genetic and phenotypic variation of the malaria vector Anopheles atroparvus in southern Europe

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    Romi Roberto

    2011-01-01

    Full Text Available Abstract Background There is a growing concern that global climate change will affect the potential for pathogen transmission by insect species that are vectors of human diseases. One of these species is the former European malaria vector, Anopheles atroparvus. Levels of population differentiation of An. atroparvus from southern Europe were characterized as a first attempt to elucidate patterns of population structure of this former malaria vector. Results are discussed in light of a hypothetical situation of re-establishment of malaria transmission. Methods Genetic and phenotypic variation was analysed in nine mosquito samples collected from five European countries, using eight microsatellite loci and geometric morphometrics on 21 wing landmarks. Results Levels of genetic diversity were comparable to those reported for tropical malaria vectors. Low levels of genetic (0.004 FST An. atroparvus populations spanning over 3,000 km distance. Genetic differentiation (0.202 FST An. atroparvus and Anopheles maculipennis s.s. Differentiation between sibling species was not so evident at the phenotype level. Conclusions Levels of population differentiation within An. atroparvus were low and not correlated with geographic distance or with putative physical barriers to gene flow (Alps and Pyrenées. While these results may suggest considerable levels of gene flow, other explanations such as the effect of historical population perturbations can also be hypothesized.

  13. Factors affecting fungus-induced larval mortality in Anopheles gambiae and Anopheles stephensi

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    Takken Willem

    2010-01-01

    Full Text Available Abstract Background Entomopathogenic fungi have shown great potential for the control of adult malaria vectors. However, their ability to control aquatic stages of anopheline vectors remains largely unexplored. Therefore, how larval characteristics (Anopheles species, age and larval density, fungus (species and concentration and environmental effects (exposure duration and food availability influence larval mortality caused by fungus, was studied. Methods Laboratory bioassays were performed on the larval stages of Anopheles gambiae and Anopheles stephensi with spores of two fungus species, Metarhizium anisopliae and Beauveria bassiana. For various larval and fungal characteristics and environmental effects the time to death was determined and survival curves established. These curves were compared by Kaplan Meier and Cox regression analyses. Results Beauveria bassiana and Metarhizium anisopliae caused high mortality of An. gambiae and An. stephensi larvae. However, Beauveria bassiana was less effective (Hazard ratio (HR Metarhizium anisopliae. Anopheles stephensi and An. gambiae were equally susceptible to each fungus. Older larvae were less likely to die than young larvae (HR Conclusions This study shows that both fungus species have potential to kill mosquitoes in the larval stage, and that mortality rate depends on fungus species itself, larval stage targeted, larval density and amount of nutrients available to the larvae. Increasing the concentration of fungal spores or reducing the exposure time to spores did not show a proportional increase and decrease in mortality rate, respectively, because the spores clumped together. As a result spores did not provide uniform coverage over space and time. It is, therefore, necessary to develop a formulation that allows the spores to spread over the water surface. Apart from formulation appropriate delivery methods are also necessary to avoid exposing non-target organisms to fungus.

  14. A major genetic locus controlling natural Plasmodium falciparum infection is shared by East and West African Anopheles gambiae

    OpenAIRE

    Koella Jacob C; Sharakhov Igor; Xia Ai; Lambrechts Louis; Markianos Kyriacos; Riehle Michelle M; Vernick Kenneth D

    2007-01-01

    Abstract Background Genetic linkage mapping identified a region of chromosome 2L in the Anopheles gambiae genome that exerts major control over natural infection by Plasmodium falciparum. This 2L Plasmodium-resistance interval was mapped in mosquitoes from a natural population in Mali, West Africa, and controls the numbers of P. falciparum oocysts that develop on the vector midgut. An important question is whether genetic variation with respect to Plasmodium-resistance exists across Africa, a...

  15. Physiology and development of the M and S molecular forms of Anopheles gambiae in Burkina Faso (West Africa)

    OpenAIRE

    Mouline, Karine; Mamai, W.; Agnew, P.; Tchonfienet, M.; Brengues, Cécile; Dabiré, R.; Robert, Vincent; Simard, Frédéric

    2012-01-01

    In West Africa, M and S molecular forms of Anopheles gambiae sensu stricto (Diptera: Culicidae) Giles, frequently occur together, although with different population bionomics. The S form typically breeds in rain-dependant water collections and is present during the rainy season only whereas the M form can thrive all year long in areas with permanent breeding opportunities. In the present study, we explored physiological and developmental trade-offs at play in laboratory colonies and field pop...

  16. Living at the edge: biogeographic patterns of habitat segregation conform to speciation by niche expansion in Anopheles gambiae

    OpenAIRE

    Costantini Carlo; Ayala Diego; Guelbeogo Wamdaogo M; Pombi Marco; Some Corentin Y; Bassole Imael HN; Ose Kenji; Fotsing Jean-Marie; Sagnon N'Falé; Fontenille Didier; Besansky Nora J; Simard Frédéric

    2009-01-01

    Abstract Background Ongoing lineage splitting within the African malaria mosquito Anopheles gambiae is compatible with ecological speciation, the evolution of reproductive isolation by divergent natural selection acting on two populations exploiting alternative resources. Divergence between two molecular forms (M and S) identified by fixed differences in rDNA, and characterized by marked, although incomplete, reproductive isolation is occurring in West and Central Africa. To elucidate the rol...

  17. A Physical Map for an Asian Malaria Mosquito, Anopheles stephensi

    OpenAIRE

    Maria V Sharakhova; Xia, Ai; Tu, Zhijian; Shouche, Yogesh S.; Unger, Maria F; Sharakhov, Igor V

    2010-01-01

    Physical mapping is a useful approach for studying genome organization and evolution as well as for genome sequence assembly. The availability of polytene chromosomes in malaria mosquitoes provides a unique opportunity to develop high-resolution physical maps. We report a 0.6-Mb-resolution physical map consisting of 422 DNA markers hybridized to 379 chromosomal sites of the Anopheles stephensi polytene chromosomes. This makes An. stephensi second only to Anopheles gambiae in density of a phys...

  18. Anopheles salivary gland proteomes from major malaria vectors

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    Fontaine Albin

    2012-11-01

    Full Text Available Abstract Background Antibody responses against Anopheles salivary proteins can indicate individual exposure to bites of malaria vectors. The extent to which these salivary proteins are species-specific is not entirely resolved. Thus, a better knowledge of the diversity among salivary protein repertoires from various malaria vector species is necessary to select relevant genus-, subgenus- and/or species-specific salivary antigens. Such antigens could be used for quantitative (mosquito density and qualitative (mosquito species immunological evaluation of malaria vectors/host contact. In this study, salivary gland protein repertoires (sialomes from several Anopheles species were compared using in silico analysis and proteomics. The antigenic diversity of salivary gland proteins among different Anopheles species was also examined. Results In silico analysis of secreted salivary gland protein sequences retrieved from an NCBInr database of six Anopheles species belonging to the Cellia subgenus (An. gambiae, An. arabiensis, An. stephensi and An. funestus and Nyssorhynchus subgenus (An. albimanus and An. darlingi displayed a higher degree of similarity compared to salivary proteins from closely related Anopheles species. Additionally, computational hierarchical clustering allowed identification of genus-, subgenus- and species-specific salivary proteins. Proteomic and immunoblot analyses performed on salivary gland extracts from four Anopheles species (An. gambiae, An. arabiensis, An. stephensi and An. albimanus indicated that heterogeneity of the salivary proteome and antigenic proteins was lower among closely related anopheline species and increased with phylogenetic distance. Conclusion This is the first report on the diversity of the salivary protein repertoire among species from the Anopheles genus at the protein level. This work demonstrates that a molecular diversity is exhibited among salivary proteins from closely related species despite their

  19. DDT-resistance in Anopheles stephensi.

    Science.gov (United States)

    DAVIDSON, G; JACKSON, C E

    1961-01-01

    In view of the increasing number of reports from different parts of the world indicating resistance to DDT in both adults and larvae of Anopheles stephensi, an important malaria vector, a series of laboratory studies has been carried out on the degree, the pattern and the mode of inheritance of resistance in this species. A DDT-resistant strain from Iraq and a susceptible strain from India were used.In four sets of observations made in the course of tests on both adults and larvae a monofactorial type of inheritance was indicated, and the factor involved was shown to be dependent for its expression on the genetic background.DDT-resistance in A. stephensi appears to be similar in most respects to that in A. sundaicus. PMID:13883789

  20. The role of hemocytes in Anopheles gambiae antiplasmodial immunity.

    Science.gov (United States)

    Ramirez, Jose Luis; Garver, Lindsey S; Brayner, Fábio André; Alves, Luiz Carlos; Rodrigues, Janneth; Molina-Cruz, Alvaro; Barillas-Mury, Carolina

    2014-01-01

    Hemocytes synthesize key components of the mosquito complement-like system, but their role in the activation of antiplasmodial responses has not been established. The effect of activating Toll signaling in hemocytes on Plasmodium survival was investigated by transferring hemocytes or cell-free hemolymph from donor mosquitoes in which the suppressor cactus was silenced. These transfers greatly enhanced antiplasmodial immunity, indicating that hemocytes are active players in the activation of the complement-like system, through an effector/effectors regulated by the Toll pathway. A comparative analysis of hemocyte populations between susceptible G3 and the refractory L3-5 Anopheles gambiae mosquito strains did not reveal significant differences under basal conditions or in response to Plasmodium berghei infection. The response of susceptible mosquitoes to different Plasmodium species revealed similar kinetics following infection with P. berghei,P. yoelii or P. falciparum, but the strength of the priming response was stronger in less compatible mosquito-parasite pairs. The Toll, Imd,STAT or JNK signaling cascades were not essential for the production of the hemocyte differentiation factor (HDF) in response to P. berghei infection, but disruption of Toll, STAT or JNK abolished hemocyte differentiation in response to HDF. We conclude that hemocytes are key mediators of A. gambiae antiplasmodial responses. PMID:23886925

  1. Comparative susceptibility to Plasmodium falciparum of the molecular forms M and S of Anopheles gambiae and Anopheles arabiensis

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    Boudin Christian

    2011-09-01

    Full Text Available Abstract Background The different taxa belonging to Anopheles gambiae complex display phenotypic differences that may impact their contribution to malaria transmission. More specifically, their susceptibility to infection, resulting from a co-evolution between parasite and vector, might be different. The aim of this study was to compare the susceptibility of M and S molecular forms of Anopheles gambiae and Anopheles arabiensis to infection by Plasmodium falciparum. Methods F3 progenies of Anopheles gambiae s.l. collected in Senegal were infected, using direct membrane feeding, with P. falciparum gametocyte-containing blood sampled on volunteer patients. The presence of oocysts was determined by light microscopy after 7 days, and the presence of sporozoite by ELISA after 14 days. Mosquito species and molecular forms were identified by PCR. Results The oocyst rate was significantly higher in the molecular S form (79.07% than in the M form (57.81%, Fisher's exact test p Anopheles arabiensis (55.38%, Fisher's exact test vs. S group p An. gambiae S form (1.72 ± 0.26 than in the An. gambiae M form (0.64 ± 0.04, p An. arabiensis group (0.58 ± 0.04, vs. S group, p Anopheles arabiensis 50.85%, Fisher's exact test vs. S group p Conclusion Infected in the same experimental conditions, the molecular form S of An. gambiae is more susceptible to infection by P. falciparum than the molecular form M of An. gambiae and An. arabiensis.

  2. Spermless males elicit large-scale female responses to mating in the malaria mosquito Anopheles gambiae

    Science.gov (United States)

    Thailayil, Janis; Magnusson, Kalle; Godfray, H. Charles J.; Crisanti, Andrea; Catteruccia, Flaminia

    2011-01-01

    Anopheles gambiae sensu stricto is the major vector of malaria, a disease with devastating consequences for human health. Given the constant spread of the disease, alternative approaches to the use of insecticides are urgently needed to control vector populations. Females of this species undergo large behavioral changes after mating, which include a life-long refractoriness to further insemination and the induction of egg laying in blood-fed individuals. Genetic control strategies aimed at impacting Anopheles fertility through the release of sterile males are being advocated to reduce the size of mosquito field populations. Such strategies depend on the ability of the released sterile males to mate successfully with wild females and to switch off the female receptivity to further copulation. Here we evaluate the role of sperm in regulating female behavioral responses after mating in An. gambiae. We developed spermless males by RNAi silencing of a germ cell differentiation gene. These males mated successfully and preserved standard accessory gland functions. Females mated to spermless males exhibited normal postcopulatory responses, which included laying large numbers of eggs upon blood feeding and becoming refractory to subsequent insemination. Moreover, spermless males induced transcriptional changes in female reproductive genes comparable to those elicited by fertile males. Our data demonstrate that, in contrast to Drosophila, targeting sperm in An. gambiae preserves normal male and female reproductive behavior for the traits and time frame analyzed and validate the use of approaches based on incapacitation or elimination of sperm for genetic control of vector populations to block malaria transmission. PMID:21825136

  3. Quantification of the efficiency of treatment of Anopheles gambiae breeding sites with petroleum products by local communities in areas of insecticide resistance in the Republic of Benin

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    Doannio Julien MC MC

    2007-05-01

    Full Text Available Abstract Background The emergence of Anopheles populations capable of withstanding lethal doses of insecticides has weakened the efficacy of most insecticide based strategies of vector control and, has highlighted the need for developing new insecticidal molecules or, improving the efficacy of existing insecticides or abandoning those to which resistance has emerged. The use of petroleum products (PP against mosquito larvae had an immense success during early programmes of malaria control, but these compounds were abandoned and replaced in the 1950s by synthetic insecticides probably because of the high performances given by these new products. In the current context of vector resistance, it is important to elucidate the empirical use of PP by quantifying their efficiencies on resistant strains of Anopheles. Methods Larvae of Anopheles Ladji a local resistant strain were exposed to increasing concentrations of various PP (kerosene, petrol and engine oils for 24 hours and the lethal activities recorded. The highest concentration (HiC having no lethal activity (also referred as the NOEL or no effect level and the lowest concentration (LoC100 yielding 100% mortality were rated for each PP on the Ladji strain. Prior to laboratory analysis, KAP studies were conducted in three traditional communities were insecticide resistance is clearly established to confirm the use of PP against mosquitoes. Results Laboratory analysis of petrol, kerosene and engine oils, clearly established their lethal activities on resistant strains of Anopheles larvae. Contrary to existing references, this research revealed that exposed larvae of Anopheles were mostly killed by direct contact toxicity and not by suffocation as indicated in some earlier reports. Conclusion This research could serve as scientific basis to backup the empirical utilisation of PP on mosquito larvae and to envisage possibilities of using PP in some traditional settings where Anopheles have developed

  4. Effects of Anti-Mosquito Salivary Glands and Deglycosylated Midgut Antibodies of Anopheles stephensi on Fecundity and Longevity

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    H Mohammadzadeh Hajipirloo

    2005-09-01

    Full Text Available With the aim of controlling malaria by reducing vector population, the effects of antibodies produced against salivary glands and deglycosylated midgut antigens of Anopheles stephensi mosquitoes on fecundity and longevity of the same species were tested. Three deglycosylated preparations of midgut and two preparations of salivary glands were produced, conjugated with aluminum hydroxide gel, and subcutaneously injected to shoulders of TO (Turner Out-bred mice. After 4 immunizations and assurance of enough antibody production against utilized antigenic suspensions, effects of blood feeding on immunized and control mice were assayed. Insoluble preparation of midgut showed the strongest effect with 23.5% reduction in egg laying, and increasing death rate of vectors in third day after feeding. No significant reduction in fecundity or survivorship was seen with other preparations. Anopheles midgut insoluble antigens are potential candidates for designing vaccines against malaria vectors and further investigations need to be done to find effective antigens and the best way of their use.

  5. Unexpected high losses of Anopheles gambiae larvae due to rainfall.

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    Krijn P Paaijmans

    Full Text Available BACKGROUND: Immature stages of the malaria mosquito Anopheles gambiae experience high mortality, but its cause is poorly understood. Here we study the impact of rainfall, one of the abiotic factors to which the immatures are frequently exposed, on their mortality. METHODOLOGY/PRINCIPAL FINDINGS: We show that rainfall significantly affected larval mosquitoes by flushing them out of their aquatic habitat and killing them. Outdoor experiments under natural conditions in Kenya revealed that the additional nightly loss of larvae caused by rainfall was on average 17.5% for the youngest (L1 larvae and 4.8% for the oldest (L4 larvae; an additional 10.5% (increase from 0.9 to 11.4% of the L1 larvae and 3.3% (from 0.1 to 3.4% of the L4 larvae were flushed away and larval mortality increased by 6.9% (from 4.6 to 11.5% and 1.5% (from 4.1 to 5.6% for L1 and L4 larvae, respectively, compared to nights without rain. On rainy nights, 1.3% and 0.7% of L1 and L4 larvae, respectively, were lost due to ejection from the breeding site. CONCLUSIONS/SIGNIFICANCE: This study demonstrates that immature populations of malaria mosquitoes suffer high losses during rainfall events. As these populations are likely to experience several rain showers during their lifespan, rainfall will have a profound effect on the productivity of mosquito breeding sites and, as a result, on the transmission of malaria. These findings are discussed in the light of malaria risk and changing rainfall patterns in response to climate change.

  6. Pyrethroid resistance in southern African Anopheles funestus extends to Likoma Island in Lake Malawi

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    Edwardes M

    2010-12-01

    Full Text Available Abstract Background A mosquito survey was carried out on the island of Likoma in Lake Malawi with a view to collecting baseline data to determine the feasibility of implementing an integrated malaria vector control programme. No vector control interventions are currently being applied on the island apart from the sporadic use of treated and untreated bed nets. Results Large numbers of Anopheles funestus were found resting inside houses. WHO susceptibility tests were carried out on wild caught females and 1-5 day old F-1 female progeny. Wild caught females were tested on deltamethrin (77.8% mortality and bendiocarb (56.4% mortality. Female progeny were tested on deltamethrin (41.4% mortality, permethrin (40.4%, bendiocarb (52.5%, propoxur (7.4%, malathion, fenitrothion, DDT, dieldrin (all 100% and pirimiphos-methyl (98.9%. The malaria parasite rate was 4.9%. A small number of Anopheles arabiensis were also collected. Conclusion This locality is 1,500 km north of the currently known distribution of pyrethroid resistant An. funestus in southern Africa. The susceptibility results mirror those found in southern Mozambique and South African populations, but are markedly different to An. funestus populations in Uganda, indicating that the Malawi resistance has spread from the south.

  7. Cytogenetic evidence for a species complex within Anopheles pseudopunctipennis theobald (Diptera: Culicidae).

    Science.gov (United States)

    Coetzee, M; Estrada-Franco, J G; Wunderlich, C A; Hunt, R H

    1999-04-01

    Anopheles pseudopunctipennis was collected from Acapulco, Mexico and Sallee River, Grenada, West Indies and used in cross-mating experiments. Larvae from the cross, Mexico female X Grenada male, died in the third instar. However, adult progeny were obtained from the reciprocal cross Grenada female x Mexico male. These hybrid males had testes with apparently normal appearance but some without viable sperm. Polytene chromosomes obtained from hybrid females exhibited extensive asynapsis of the X chromosomes. Previously undescribed fixed inversion differences between the two populations were noted on the X chromosome. It is concluded that the two populations belong to different species. The Grenada population is designated An. pseudopunctipennis species C, since it is the third taxon recognized in this species complex.

  8. Ecotope-Based Entomological Surveillance and Molecular Xenomonitoring of Multidrug Resistant Malaria Parasites in Anopheles Vectors

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    Prapa Sorosjinda-Nunthawarasilp

    2014-01-01

    Full Text Available The emergence and spread of multidrug resistant (MDR malaria caused by Plasmodium falciparum or Plasmodium vivax have become increasingly important in the Greater Mekong Subregion (GMS. MDR malaria is the heritable and hypermutable property of human malarial parasite populations that can decrease in vitro and in vivo susceptibility to proven antimalarial drugs as they exhibit dose-dependent drug resistance and delayed parasite clearance time in treated patients. MDR malaria risk situations reflect consequences of the national policy and strategy as this influences the ongoing national-level or subnational-level implementation of malaria control strategies in endemic GMS countries. Based on our experience along with current literature review, the design of ecotope-based entomological surveillance (EES and molecular xenomonitoring of MDR falciparum and vivax malaria parasites in Anopheles vectors is proposed to monitor infection pockets in transmission control areas of forest and forest fringe-related malaria, so as to bridge malaria landscape ecology (ecotope and ecotone and epidemiology. Malaria ecotope and ecotone are confined to a malaria transmission area geographically associated with the infestation of Anopheles vectors and particular environments to which human activities are related. This enables the EES to encompass mosquito collection and identification, salivary gland DNA extraction, Plasmodium- and species-specific identification, molecular marker-based PCR detection methods for putative drug resistance genes, and data management. The EES establishes strong evidence of Anopheles vectors carrying MDR P. vivax in infection pockets epidemiologically linked with other data obtained during which a course of follow-up treatment of the notified P. vivax patients receiving the first-line treatment was conducted. For regional and global perspectives, the EES would augment the epidemiological surveillance and monitoring of MDR falciparum and

  9. Populism

    OpenAIRE

    Abts, Koenraad; van Kessel, Stijn

    2015-01-01

    Populism is a concept applied to a wide range of political movements and actors across the globe. There is, at the same time, considerable confusion about the attributes and manifestation of populism, as well as its impact on democracy. This contribution identifies the defining elements of the populist ideology and discusses the varieties in which populism manifests itself, for instance as a component of certain party families. We finally discuss various normative interpretations of populism,...

  10. Metabolic pathways in Anopheles stephensi mitochondria.

    Science.gov (United States)

    Giulivi, Cecilia; Ross-Inta, Catherine; Horton, Ashley A; Luckhart, Shirley

    2008-10-15

    No studies have been performed on the mitochondria of malaria vector mosquitoes. This information would be valuable in understanding mosquito aging and detoxification of insecticides, two parameters that have a significant impact on malaria parasite transmission in endemic regions. In the present study, we report the analyses of respiration and oxidative phosphorylation in mitochondria of cultured cells [ASE (Anopheles stephensi Mos. 43) cell line] from A. stephensi, a major vector of malaria in India, South-East Asia and parts of the Middle East. ASE cell mitochondria share many features in common with mammalian muscle mitochondria, despite the fact that these cells are of larval origin. However, two major differences with mammalian mitochondria were apparent. One, the glycerol-phosphate shuttle plays as major a role in NADH oxidation in ASE cell mitochondria as it does in insect muscle mitochondria. In contrast, mammalian white muscle mitochondria depend primarily on lactate dehydrogenase, whereas red muscle mitochondria depend on the malate-oxaloacetate shuttle. Two, ASE mitochondria were able to oxidize proline at a rate comparable with that of alpha-glycerophosphate. However, the proline pathway appeared to differ from the currently accepted pathway, in that oxoglutarate could be catabolized completely by the tricarboxylic acid cycle or via transamination, depending on the ATP need.

  11. Bionomics of Anopheles spp. (Diptera: Culicidae) in a malaria endemic region of Sukabumi, West Java, Indonesia.

    Science.gov (United States)

    Stoops, Craig A; Rusmiarto, Saptoro; Susapto, Dwiko; Munif, Amurl; Andris, Heri; Barbara, Kathryn A; Sukowati, Supratman

    2009-12-01

    A 15-month bionomic study of Anopheles species was conducted in two ecologically distinct villages (coastal and upland) of Sukabumi District, West Java, Indonesia from June 2006 to September 2007. Mosquitoes were captured using human-landing collections at both sites. During the study, a total of 17,100 Anopheles mosquitoes comprising 13 Anopheles species were caught: 9,151 at the coastal site and 7,949 at the upland site. Anopheles barbirostris, Anopheles maculatus, and Anopheles vagus were the predominant species caught at the coastal site, and Anopheles aconitus, Anopheles barbirostris, and An. maculatus predominated in the upland site. Overall, species were exophagic at both sites, but there was variation between species. Anopheles aconitus was endophagic at the coastal site, exophagic at the upland site, collected most often in April 2007 and had a peak landing time between 22:00 and 23:00. Anopheles sundaicus was only collected at the coastal site, exophagic, collected most often in October 2006, and had a peak landing time between 19:00 and 20:00. Potential malaria vector species such An. aconitus, An. maculatus, and An. sundaicus were present throughout the year. None of the 7,770 Anopheles tested using CSP-ELISA were positive for malaria, although the risk for malaria outbreaks in Sukabumi district remains high.

  12. Bionomics of the malaria vector Anopheles farauti in Temotu Province, Solomon Islands: issues for malaria elimination

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    Mackenzie Donna O

    2011-05-01

    Full Text Available Abstract Background In the Solomon Islands, the Malaria Eradication Programmes of the 1970s virtually eliminated the malaria vectors: Anopheles punctulatus and Anopheles koliensis, both late night biting, endophagic species. However, the vector, Anopheles farauti, changed its behaviour to bite early in the evening outdoors. Thus, An. farauti mosquitoes were able to avoid insecticide exposure and still maintain transmission. Thirty years on and the Solomon Islands are planning for intensified malaria control and localized elimination; but little is currently known about the behaviour of the vectors and how they will respond to intensified control. Methods In the elimination area, Temotu Province, standard entomological collection methods were conducted in typical coastal villages to determine the vector, its ecology, biting density, behaviour, longevity, and vector efficacy. These vector surveys were conducted pre-intervention and post-intervention following indoor residual spraying and distribution of long-lasting insecticidal nets. Results Anopheles farauti was the only anopheline in Temotu Province. In 2008 (pre-intervention, this species occurred in moderate to high densities (19.5-78.5 bites/person/night and expressed a tendency to bite outdoors, early in the night (peak biting time 6-8 pm. Surveys post intervention showed that there was little, if any, reduction in biting densities and no reduction in the longevity of the vector population. After adjusting for human behaviour, indoor biting was reduced from 57% pre-intervention to 40% post-intervention. Conclusion In an effort to learn from historical mistakes and develop successful elimination programmes, there is a need for implementing complimentary vector control tools that can target exophagic and early biting vectors. Intensified indoor residual spraying and long-lasting insecticide net use has further promoted the early, outdoor feeding behaviour of An. farauti in the Solomon Islands

  13. Pteridine fluorescence for age determination of Anopheles mosquitoes.

    Science.gov (United States)

    Wu, D; Lehane, M J

    1999-02-01

    The age structure of mosquito populations is of great relevance to understanding the dynamics of disease transmission and in monitoring the success of control operations. Unfortunately, the ovarian dissection methods currently available for determining the age of adult mosquitoes are technically difficult, slow and may be of limited value, because the proportion of diagnostic ovarioles in the ovary declines with age. By means of reversed-phase HPLC this study investigated the malaria vectors Anopheles gambiae and An. stephensi to see if changes in fluorescent pteridine pigments, which have been used in other insects to determine the age of field-caught individuals, may be useful for age determination in mosquitoes. Whole body fluorescence was inversely proportional to age (P 91%) up to 30 days postemergence, with the regression values: y = 40580-706x for An. gambiae, and y = 52896-681x for An. stephensi. In both species the main pteridines were 6-biopterin, pterin-6-carboxylic acid and an unidentified fluorescent compound. An. gambiae had only 50-70% as much fluorescence as An. stephensi, and fluorescent compounds were relatively more concentrated in the head than in the thorax (ratios 1:0.8 An. gambiae; 1:0.5 An. stephensi). The results of this laboratory study are encouraging. It seems feasible that this simpler and faster technique of fluorescence quantification could yield results of equivalent accuracy to the interpretation of ovarian dissection. A double-blind field trial comparing the accuracy of this technique to marked, released and recaptured mosquitoes is required to test the usefulness of the pteridine method in the field. PMID:10194749

  14. The Anopheles dirus complex: spatial distribution and environmental drivers

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    Defourny Pierre

    2007-03-01

    Full Text Available Abstract Background The Anopheles dirus complex includes efficient malaria vectors of the Asian forested zone. Studies suggest ecological and biological differences between the species of the complex but variations within species suggest possible environmental influences. Behavioural variation might determine vector capacity and adaptation to changing environment. It is thus necessary to clarify the species distributions and the influences of environment on behavioural heterogeneity. Methods A literature review highlights variation between species, influences of environmental drivers, and consequences on vector status and control. The localisation of collection sites from the literature and from a recent project (MALVECASIA produces detailed species distributions maps. These facilitate species identification and analysis of environmental influences. Results The maps give a good overview of species distributions. If species status partly explains behavioural heterogeneity, occurrence and vectorial status, some environmental drivers have at least the same importance. Those include rainfall, temperature, humidity, shade, soil type, water chemistry and moon phase. Most factors are probably constantly favourable in forest. Biological specificities, behaviour and high human-vector contact in the forest can explain the association of this complex with high malaria prevalence, multi-drug resistant Plasmodium falciparum and partial control failure of forest malaria in Southeast Asia. Conclusion Environmental and human factors seem better than species specificities at explaining behavioural heterogeneity. Although forest seems essential for mosquito survival, adaptations to orchards and wells have been recorded. Understanding the relationship between landscape components and mosquito population is a priority in foreseeing the influence of land-cover changes on malaria occurrence and in shaping control strategies for the future.

  15. INSECTICIDAL ACTIVITIES OF ESSENTIAL OILS EXTRACTED FROM THREE SPECIES OF POACEAE ON ANOPHELES GAMBIAE SPP, MAJOR VECTOR OF MALARIA

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    Dominique C. K. Sohounhloué

    2010-12-01

    Full Text Available In this paper, the insecticidal activities on Anopheles gambiae spp of the essential oils (EO extracted from the dry leaves of some species collected in Benin were studied. The essential oil yields are 2.8, 1.7 and 1.4�0respectively for Cymbopogon schoanenthus (L. Spreng (CS, Cymbopogon citratus Stapf. (CC and Cymbopogon giganteus (Hochst. Chiov (CG. The GC/MS analysis showed that the EO of CS had a larger proportion in oxygenated monoterpenes (86.3�20whereas those of the sheets of CC and CG are relatively close proportions (85.5�0and 82.7�0respectively with. The piperitone (68.5�  2-carene (11.5� and -eudesmol (4.6�20are the major components of the EO of CS while trans para-mentha-1(7,8-dien-2-ol (31.9� trans para-mentha-2,8-dien-1-ol (19.6� cis para-mentha-2,8-dien-1-ol (7.2� trans piperitol (6.3�20and limonene (6.3�20prevailed in the EO of CG. The EO of CC revealed a rich composition in geranial (41.3� neral (33� myrcene (10.4� and geraniol (6.6� The biological tests have shown that these three EO induced 100�0mortality of Anopheles gambiae to 1.1, 586.58 and 1549 µg•cm-2 respectively for CC, CS and CG. These effects are also illustrated by weak lethal concentration for 50�0anopheles population (CC: 0.306; CS: 152.453 and CG: 568.327 µg•cm-2 in the same order of reactivity. The EO of CC appeared most active on two stocks (sensitive and resistant of Anopheles gambiae.

  16. Analysis on the monitoring results of Anopheles in Donggang city in 2011%2011年东港市按蚊监测结果分析

    Institute of Scientific and Technical Information of China (English)

    张平; 陈哲

    2013-01-01

    目的 准确掌握东港市媒介按蚊种群构成、分布和种群密度及季节消长,为科学实施《中国消除疟疾行动计划(2010-2020年)》项目提供全面准确的基础数据.方法 诱蚊灯法、栖息蚊虫捕捉法、人诱帐法.结果 诱蚊灯法捕获的按蚊占捕蚊总数的19.83%,按蚊活动时间为6月上旬-10月下旬,高峰季节为7-9月,夜间20:00-24:00时及清晨4:00-5:00时是按蚊吸血活动高峰.结论 东港地区按蚊密度较高是蚊种构成比的第3位,是该地区蚊虫防治工作的重点.%Objective To grasp accurately the population composition, distribution, population density and seasonal fluctuation of Anopheles in Donggang city, and provide basic data comprehensively and accurately for the implementation of "eliminate malaria action plan (2010 -2020) in China" project. Methods Using mosquito lamp method, inhabiting mosquito catching method and net luring method. Results A mosquito trapping lamp method to capture Anopheles accounted for 19. 83% ,Anopheles activity time from early June to October, the peak was from July to November,Anopheles vampire peak activity was in 20:00 24:00 and 4:00 5:00. Conclusion Density of A-nopheles is high in Donggang city,and is the third of the mosquito composition. It is the control focus in Donggang city.

  17. Phytochemistry and larvicidal activity of Eucalyptus camaldulensisagainst malaria vector,Anopheles stephensi

    Institute of Scientific and Technical Information of China (English)

    Sedaghat Mohamad Medhi; SaneiAli Reza; Khnavi Mahnaz; Abai Mohammad Reza; Hadjiakhoondi Abbas; MohtaramiFatemeh; VatandoostHassan

    2010-01-01

    Objective:To determine phytochemistry and larvicidal activity ofEucalyptus camaldulensis againstAnopheles stephensi.Methods:The chemical compositions of the leaf essential oils were analyzed using gas chromatography/mass spectrometry (GC/MS). The larvicidal activity of essential oils and extract of leaf were tested against 4th instar larvae of laboratory-rearedAnopheles stephensi.Results:GC/MS analyses identified the presence of28 compounds corresponding to 99.60%of the total oil. The main constituents in the leaf essential oil were1,8-cineole(69.46%), γ-Terpinene(15.10%), α-Pinene(5.47%)and Globulol(2%). The leaf extract and volatile oil exerted significant larvicidal activity withLC50 values of89.85 and397.75ppm, respectively. Clear dose-response relationships were established with the highest dose of320 ppm essential oil extract resulted almost100% mortality in the population.Conclusions:The larvicidal properties suggest that the essential oil of plant is a potential source of valuable larvicidal compounds against malaria vector and can be used as an alternative to synthetic insecticides.

  18. Recent reduction in the water level of Lake Victoria has created more habitats for Anopheles funestus

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    Futami Kyoko

    2008-07-01

    Full Text Available Abstract Background The water level of Lake Victoria has fallen more than 1.5 m since 1998, revealing a narrow strip of land along the shore. This study determined whether the recent drop in the water level has created additional breeding grounds for malaria vectors. Methods The recent and past shorelines were estimated using landmarks and a satellite image. The locations of breeding habitats were recorded using a GPS unit during the high and low lake water periods. GIS was used to determine whether the breeding habitats were located on newly emerged land between the new and old shorelines. Results Over half of the breeding habitats existed on newly emerged land. Fewer habitats for the Anopheles gambiae complex were found during the low water level period compared to the high water period. However, more habitats for Anopheles funestus were found during the high water level period, and they were all located on the newly emerged land. Conclusion The recent reduction in water level of Lake Victoria has increased the amount of available habitat for A. funestus. The results suggest that the water drop has substantially affected the population of this malaria vector in the Lake Victoria basin, particularly because the lake has a long shoreline that may harbour many new breeding habitats.

  19. Microsporidium Infecting Anopheles supepictus (Diptera: Culicidae Larvae

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    Seyed-Mohammad Omrani

    2016-01-01

    Full Text Available Background: Microsporidia are known to infect a wide variety of animals including mosquitoes (Diptera: Cu­licidae. In a recent study on the mosquito fauna of Chahar Mahal and Bakhtiari Province, at the central western part of Iran, a few larvae of Anopheles superpictus were infected with a microsporidium-resembled microorganism. Cur­rent investigation deals with the identification of the responsible microorganism at the genus level.Methods: Fresh infected larvae were collected from the field. After determining the species identity they were dis­sected to extract their infective contents. Wet preparations were checked for general appearance and the size of the pathogenic microorganism. Fixed preparations were stained with Geimsa and Ryan-Blue modified Trichrome tech­niques to visualize further morphological characters. The obtained light microscopy data were used in the identifica­tion process.Results: The infected larvae were bulged by a whitish material filling the involved segments corresponding to a microsporidium infection. Bottle-shaped semioval spores ranged 4.33±0.19×2.67±0.12 and 4.18±0.43×2.45±0.33 micron in wet and fixed preparations, respectively. They were mostly arranged in globular structures comprised of 8 spores. These data was in favor of a species from the genus Parathelohania in the family Ambliosporidae.Conclusion: This is the first report of a microsporidium infection in An. superpictus. The causative agent is diag­nosed as a member of the genus Parathelohania. Further identification down to the species level needs to determine its ultrastructural characteristics and the comparative analysis of ss rRNA sequence data. It is also necessary to un­derstand the detail of the components of the transmission cycle.

  20. Biology & control of Anopheles culicifacies Giles 1901.

    Science.gov (United States)

    Sharma, V P; Dev, V

    2015-05-01

    Malaria epidemiology is complex due to multiplicity of disease vectors, sibling species complex and variations in bionomical characteristics, vast varied terrain, various ecological determinants. There are six major mosquito vector taxa in India, viz. Anopheles culicifacies, An. fluviatilis, An. stephensi, An. minimus, An. dirus and An. sundaicus. Among these, An. culicifacies is widely distributed and considered the most important vector throughout the plains and forests of India for generating bulk of malaria cases (>60% annually). Major malaria epidemics are caused by An. culicifaices. It is also the vector of tribal malaria except parts of Odisha and Northeastern States of India. An. culicifacies has been the cause of perennial malaria transmission in forests, and over the years penetrated the deforested areas of Northeast. An. culicifacies participates in malaria transmission either alone or along with An. stephensi or An. fluviatilis. The National Vector Borne Disease Control Programme (NVBDCP) spends about 80 per cent malaria control budget annually in the control of An. culicifacies, yet it remains one of the most formidable challenges in India. With recent advances in molecular biology there has been a significant added knowledge in understanding the biology, ecology, genetics and response to interventions, requiring stratification for cost-effective and sustainable malaria control. Research leading to newer interventions that are evidence-based, community oriented and sustainable would be useful in tackling the emerging challenges in malaria control. Current priority areas of research should include in-depth vector biology and control in problem pockets, preparation of malaria-risk maps for focused and selective interventions, monitoring insecticide resistance, cross-border initiative and data sharing, and coordinated control efforts for achieving transmission reduction, and control of drug-resistant malaria. The present review on An. culicifacies

  1. Temperature influence on embryonic development of Anopheles albitarsis and Anopheles aquasalis

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    Sabrina Cardozo Gonçalvez de Carvalho

    2002-12-01

    Full Text Available Temperature influence on the embryonic development of Anopheles aquasalis and An. albitarsis was investigated. At 26ºC, 75% and 60% of respectively An. aquasalis and An. albitarsis eggs hatched, with one peak of eclosion, between the 2nd and 3rd day after oviposition. At 20 ± 2ºC, around 66-70% of An. aquasalis eggs hatched, with one eclosion peak, on the 5th day. On the other hand, An. albitarsis eclosion at 21 ± 2ºC decreased to 10-22%, with two eclosion peaks, on the 4th-5th day and on the 9th-12th day. These data indicate a stronger temperature influence over An.albitarsis than over An. aquasalis embryos.

  2. Description of the egg of Anopheles (Anopheles intermedius (Peryassu, 1908 (Diptera: Culicidae by scanning electron microscopy

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    Oswaldo Paulo Forattini

    1997-01-01

    Full Text Available The egg of Anopheles (Anopheles intermedius (Peryassu, 1908 is described and illustrated with scanning electron micrographs. Literature data on An. (Ano. maculipes (Theobald, 1903 is providedOs ovos de An. intermedius foram descritos e ilustrados por Costa Lima (1929. Este autor, baseando-se nos desenhos de Peryassu (1908 para An. maculipes, chamou atenção para o fato do ovo desta espécie ser semelhante ao de An. maculipes. Posteriormente, Causey e col. (1944, estudando os ovos de An. intermedius e An. maculipes ao estereomicroscópio, diferenciou-os por caracteres da franja. Em An. intermedius a franja é oblíqua ao eixo longitudinal do ovo, mas perpendicular em An. maculipes. Causey e col. (1944 ilustraram as variações morfológicas que encontraram na franja do ovo de An. intermedius. Os autores observaram que a franja apresentava-se descotínua em alguns espécimens de An. intermedius, tornando-se em pequenos círculos nessa região. Embora semelhante ao de An. maculipes, os ovos de An. intermedius podem ser facilmente reconhecidos por características da franja, flutuadores e tubérculos lobados, como pode ser observado na descrição. Contudo, será necessário estudar a morfologia dos ovos de outras espécies do subgênero para que se possa estabelecer as diferenças e fazer comparações precisas entre as espécies

  3. The evolution of the Anopheles 16 genomes project

    NARCIS (Netherlands)

    Neafsey, Daniel E.; Christophides, George K.; Collins, Frank H.; Emrich, Scott J.; Fontaine, Michael C.; Gelbart, William; Hahn, Matthew W.; Howell, Paul I.; Kafatos, Fotis C.; Lawson, Daniel; Muskavitch, Marc A. T.; Waterhouse, Robert M.; Williams, Louise J.; Besansky, Nora J.

    2013-01-01

    We report the imminent completion of a set of reference genome assemblies for 16 species of Anopheles mosquitoes. In addition to providing a generally useful resource for comparative genomic analyses, these genome sequences will greatly facilitate exploration of the capacity exhibited by some Anophe

  4. Nigeria Anopheles vector database: an overview of 100 years' research.

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    Patricia Nkem Okorie

    Full Text Available Anopheles mosquitoes are important vectors of malaria and lymphatic filariasis (LF, which are major public health diseases in Nigeria. Malaria is caused by infection with a protozoan parasite of the genus Plasmodium and LF by the parasitic worm Wuchereria bancrofti. Updating our knowledge of the Anopheles species is vital in planning and implementing evidence based vector control programs. To present a comprehensive report on the spatial distribution and composition of these vectors, all published data available were collated into a database. Details recorded for each source were the locality, latitude/longitude, time/period of study, species, abundance, sampling/collection methods, morphological and molecular species identification methods, insecticide resistance status, including evidence of the kdr allele, and P. falciparum sporozoite rate and W. bancrofti microfilaria prevalence. This collation resulted in a total of 110 publications, encompassing 484,747 Anopheles mosquitoes in 632 spatially unique descriptions at 142 georeferenced locations being identified across Nigeria from 1900 to 2010. Overall, the highest number of vector species reported included An. gambiae complex (65.2%, An. funestus complex (17.3%, An. gambiae s.s. (6.5%. An. arabiensis (5.0% and An. funestus s.s. (2.5%, with the molecular forms An. gambiae M and S identified at 120 locations. A variety of sampling/collection and species identification methods were used with an increase in molecular techniques in recent decades. Insecticide resistance to pyrethroids and organochlorines was found in the main Anopheles species across 45 locations. Presence of P. falciparum and W. bancrofti varied between species with the highest sporozoite rates found in An. gambiae s.s, An. funestus s.s. and An. moucheti, and the highest microfilaria prevalence in An. gambiae s.l., An. arabiensis, and An. gambiae s.s. This comprehensive geo-referenced database provides an essential baseline on

  5. Urban agriculture and Anopheles habitats in Dar es Salaam, Tanzania.

    Science.gov (United States)

    Dongus, Stefan; Nyika, Dickson; Kannady, Khadija; Mtasiwa, Deo; Mshinda, Hassan; Gosoniu, Laura; Drescher, Axel W; Fillinger, Ulrike; Tanner, Marcel; Killeen, Gerry F; Castro, Marcia C

    2009-05-01

    A cross-sectional survey of agricultural areas, combined with routinely monitored mosquito larval information, was conducted in urban Dar es Salaam, Tanzania, to investigate how agricultural and geographical features may influence the presence of Anopheles larvae. Data were integrated into a geographical information systems framework, and predictors of the presence of Anopheles larvae in farming areas were assessed using multivariate logistic regression with independent random effects. It was found that more than 5% of the study area (total size 16.8 km2) was used for farming in backyard gardens and larger open spaces. The proportion of habitats containing Anopheles larvae was 1.7 times higher in agricultural areas compared to other areas (95% confidence interval = 1.56-1.92). Significant geographic predictors of the presence of Anopheles larvae in gardens included location in lowland areas, proximity to river, and relatively impermeable soils. Agriculture-related predictors comprised specific seedbed types, mid-sized gardens, irrigation by wells, as well as cultivation of sugar cane or leafy vegetables. Negative predictors included small garden size, irrigation by tap water, rainfed production and cultivation of leguminous crops or fruit trees. Although there was an increased chance of finding Anopheles larvae in agricultural sites, it was found that breeding sites originated by urban agriculture account for less than a fifth of all breeding sites of malaria vectors in Dar es Salaam. It is suggested that strategies comprising an integrated malaria control effort in malaria-endemic African cities include participatory involvement of farmers by planting shade trees near larval habitats.

  6. Urban agriculture and Anopheles habitats in Dar es Salaam, Tanzania

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    Stefan Dongus

    2009-05-01

    Full Text Available A cross-sectional survey of agricultural areas, combined with routinely monitored mosquito larval information, was conducted in urban Dar es Salaam, Tanzania, to investigate how agricultural and geographical features may influence the presence of Anopheles larvae. Data were integrated into a geographical information systems framework, and predictors of the presence of Anopheles larvae in farming areas were assessed using multivariate logistic regression with independent random effects. It was found that more than 5% of the study area (total size 16.8 km2 was used for farming in backyard gardens and larger open spaces. The proportion of habitats containing Anopheles larvae was 1.7 times higher in agricultural areas compared to other areas (95% confidence interval = 1.56-1.92. Significant geographic predictors of the presence of Anopheles larvae in gardens included location in lowland areas, proximity to river, and relatively impermeable soils. Agriculture-related predictors comprised specific seedbed types, mid-sized gardens, irrigation by wells, as well as cultivation of sugar cane or leafy vegetables. Negative predictors included small garden size, irrigation by tap water, rainfed production and cultivation of leguminous crops or fruit trees. Although there was an increased chance of finding Anopheles larvae in agricultural sites, it was found that breeding sites originated by urban agriculture account for less than a fifth of all breeding sites of malaria vectors in Dar es Salaam. It is suggested that strategies comprising an integrated malaria control effort in malaria-endemic African cities include participatory involvement of farmers by planting shade trees near larval habitats.

  7. Morphological Analysis of Anopheles vagus Donitz, 1902 (Diptera : Culicidae in fresh water and brackish water habitats = Variasi Morfologi Anopheles vagus Donitz, 1902 (Diptera : Culicidae dari Habitat Air Tawar dan Air Payau

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    Siti Alfiah

    2014-10-01

    Full Text Available ENGLISHAbstractAnopheles subpictus had habitat variation and showed genetic difference. So, the variation of habitat of An. vagus may support the hypothesa that An. vagus had genetic and morphology variation, same as An. subpictus.The aimed of this research was analyze morphology and chaetotaxy difference between An. vagus in fresh water and brackish water. The subject of the study was An. vagus collected from Kesongo Village, Tuntang Subdistrict, Semarang (fresh water and Jatimalang Village, Purwodadi Subdistrict, Purworejo (brackish water. Anopheles vagus were collected and individually reared. One sample in every batch was used to make larvae skin, pupae skin and adult specimen of An. vagus. The result showed that there were intra and inter population variation between An. vagus in fresh water and brackish water. The variations were on the size and number of hair branches and filaments. The conclution of this research were the morphology and chaetotaxy of female An. vagus in fresh water and brackish water showed no different. Intra and interpopulation An. vagus in fresh water and brackish water were caused by the difference of geography location (allopatric speciation.INDONESIANVariasi habitat terjadi pada An. subpictus, variasi habitat yang berbeda menunjukkan variasi genetik yang berbeda. Oleh karena itu variasi habitat An. vagus diduga akan bepengaruh terhadap variasi genetik dan morfologi. Tujuan penelitian adalah menganalisis perbedaan morfologi dan kaetotaksi Anopheles vagus habitat air tawar dan air payau. Subyek penelitian adalah An. vagus habitat air tawar di Desa Kesongo, Kecamatan Tuntang, Kabupaten Semarang dan An. vagus habitat air payau di Desa Jatimalang, Kecamatan Purwodadi, Kabupaten Purworejo. Anopheles vagus yang diperoleh, di rearing secara individual. Tiap indukan diambil satu sampel keturunannya dan dibuat preparat skin larva, skin pupa dan nyamuk dewasa betina. Hasil menunjukkan bahwa Anopheles vagus betina habitat air

  8. Status of insecticide susceptibility in Anopheles arabiensis from Mwea rice irrigation scheme, Central Kenya

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    Vulule John M

    2006-06-01

    Full Text Available Abstract Background Control of the Anopheline mosquito vectors of malaria by use of insecticides has been shown to impact on both morbidity and mortality due to this disease. Evidence of insecticide resistance in different settings necessitates surveillance studies to allow prompt detection of resistance should it arise and thus enable its management. Possible resistance by Anopheles arabiensis mosquitoes from Mwea rice irrigation scheme in Central Kenya to insecticides in the four classes of insecticides approved by WHO for indoor residual spraying was investigated. Methods Susceptibility to DDT (an organochlorine, fenitrothion (an organophosphate, bendiocarb (a carbamate, lambdacyhalothrin and permethrin (both pyrethroids was tested using standard WHO diagnostic bioassay kits. Bioassays were performed on non-blood fed mosquitoes one- to three-day old. Knockdown was recorded every 10 min and mortality 24 h post-exposure was noted. Results Mortality 24 h post-exposure was 100% for all insecticides except for lambdacyhalothrin, which averaged 99.46%. Knockdown rates at 10 min intervals were not significantly different between the Mwea population and the susceptible KISUMU strain of Anopheles gambiae sensu stricto control. The KDT50 and KDT95 values for the Mwea population were either lower than those for the control or higher by factors of no more than 2 for most comparisons and compared well with those of An. gambiae sensu lato categorized as susceptible in other studies. Conclusion These results suggest that the Mwea population of An. arabiensis is susceptible to all the insecticides tested. This implies that vector control measures employing any of these insecticides would not be hampered by resistance.

  9. Geometric morphometric analysis of Colombian Anopheles albimanus (Diptera: Culicidae) reveals significant effect of environmental factors on wing traits and presence of a metapopulation

    OpenAIRE

    Giovan F Gómez; Márquez, Edna J.; Gutiérrez, Lina A.; Conn, Jan E.; Correa, Margarita M.

    2014-01-01

    Anopheles albimanus is a major malaria mosquito vector in Colombia. In the present study, wing variability (size and shape) in An. albimanus populations from Colombian Maracaibo and Chocó bio-geographical eco-regions and the relationship of these phenotypic traits with environmental factors were evaluated. Microsatellite and morphometric data facilitated a comparison of the genetic and phenetic structure of this species. Wing size was influenced by elevation and relative humidity, whereas win...

  10. Towards a sterile insect technique field release of Anopheles arabiensis mosquitoes in Sudan: Irradiation, transportation, and field cage experimentation

    OpenAIRE

    Malcolm Colin A; El-Motasim Waleed M; Hassan Mo'awia M; Helinski Michelle EH; Knols Bart GJ; El-Sayed Badria

    2008-01-01

    Abstract Background The work described in this article forms part of a study to suppress a population of the malaria vector Anopheles arabiensis in Northern State, Sudan, with the Sterile Insect Technique. No data have previously been collected on the irradiation and transportation of anopheline mosquitoes in Africa, and the first series of attempts to do this in Sudan are reported here. In addition, experiments in a large field cage under near-natural conditions are described. Methods Mosqui...

  11. Toxicity of essential oil from Indian borage on the larvae of the African malaria vector mosquito, Anopheles gambiae

    OpenAIRE

    Kweka Eliningaya J; Senthilkumar Annadurai; Venkatesalu Venugopalan

    2012-01-01

    Abstract Background Essential oils are currently studied for the control of different disease vectors, because of their efficacy on targeted organisms. In the present investigation, the larvicidal potential of essential oil extracted from Indian borage (Plectranthus amboinicus) was studied against the African anthropophagic malaria vector mosquito, Anopheles gambiae. The larvae of An. gambiae s.s laboratory colony and An. gambiae s.l of wild populations were assayed and the larval mortality w...

  12. A CRISPR-Cas9 Gene Drive System Targeting Female Reproduction in the Malaria Mosquito vector Anopheles gambiae

    OpenAIRE

    Hammond, Andrew; Galizi, Roberto; Kyrou, Kyros; Simoni, Alekos; Siniscalchi, Carla; Katsanos, Dimitris; Gribble, Matthew; Baker, Dean; Marois, Eric; Russell, Steven; Burt, Austin; Windbichler, Nikolai; Crisanti, Andrea; Nolan, Tony

    2015-01-01

    Gene-drive systems that enable super-Mendelian inheritance of a transgene have the potential to modify insect populations over a timeframe of a few years [AU please provide a real estimate, this seems vague]. We describe CRISPR-Cas9 endonuclease constructs that function as gene-drive systems in Anopheles gambiae, the main vector for malaria [AU:OK?]. We identified three genes (AGAP005958, AGAP011377 and AGAP007280) that confer a recessive female sterility phenotype upon disruption, and insert...

  13. PRELIMINARY NOTES ON THE DEVELOPMENT OF DDT RESISTANCE IN ANOPHELES CULICIFACIES

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    A.Zaini

    1973-09-01

    Full Text Available Anopheles culicifacies is the vector of malaria in southeastern part of Iran, India, West Pakistan and Ceylon. In 1959 the LC50 % DDT in the Panchmahal district of Gujarat state (India had increased. DDT resistant population of A. culicifacies has been reported from West Pakistan, Burma and Iran. After application of DDT in 1959, the density of A. culicifacies decreased sharply. The susceptibility test carried out in 1963 showed that the LC50 was 0.5%.After DDT spraying, followed by Dieldrin, for about 10 years the density of A. culicifacies was so negligible that it was not possible to perform susceptibility tests. By April and May of 1973 the density of A.culicifacies in Saidabad, Khairabad and Hit in Baluchesten province, Southeast of Iran, increased to about 500 per shelter. The susceptibility tests carried out showed that A. culicfacies is resistant to DDT and susceptible to Dieldrin and Malathion.

  14. COMPARATIVE TOXICITIES OF FOUR WHO-RECOMMENDED LARVICIDES AGAINST LAB STRAIN OF ANOPHELES STEPHENSI IN IRAN

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    H. Vatandoost

    1999-08-01

    Full Text Available Investigation on the current response of An.stephensi larvae to four WHO recommended larvicides, i.e. Malathion, temephos, chlorpyrifos and fenitrothion, were carried out in the laboratory in 1999. Diagnostic concentrations of pesticides only yielded 100% mortality with malathion. In contrast, levels of susceptibility to temphos, chlorpyrifos (0.025 mg/l and temephos (0.625 mg/l killed 72%, 90% and 87% of the population of An. Stephensi, respectively. At the LC50 level the efficacies of chlorpyrifos and fenitrothion was higher than malathion and temephos. Relative toxicity of chlorpyrifos and fenitrothion was 6 and 24 times more than temephos and Malathion. The findings of this study suggest that the diagnostic dose of organophosphate larvicides depends on time, location, strain and genetically background of resistance to insecticides; hence they can be attributed to all species of anopheles.

  15. Random amplified polymorphic DNA (RAPD) markers readily distinguish cryptic mosquito species (Diptera: Culicidae: Anopheles).

    Science.gov (United States)

    Wilkerson, R C; Parsons, T J; Albright, D G; Klein, T A; Braun, M J

    1993-01-01

    The usefulness of random amplified polymorphic DNA (RAPD) was examined as a potential tool to differentiate cryptic mosquito species. It proved to be a quick, effective means of finding genetic markers to separate two laboratory populations of morphologically indistinguishable African malaria vectors, Anopheles gambiae and An. arabiensis. In an initial screening of fifty-seven RAPD primers, 377 bands were produced, 295 of which differed between the two species. Based on criteria of interpretability, simplicity and reproducibility, thirteen primers were chosen for further screening using DNA from thirty individuals of each species. Seven primers produced diagnostic bands, five of which are described here. Some problematic characteristics of RAPD banding patterns are discussed and approaches to overcome these are suggested. PMID:8269099

  16. Relationship of Remote Sensing Normalized Differential Vegetation Index to Anopheles Density and Malaria Incidence Rate

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To study the relationship of remote sensing normalized differential vegetation index (NDVI) to Anopheles density and malaria incidence rate. Methods Data of monthly average climate, environment, Anopheles density and malaria incidence rate, and remote sensing NDVI were collected from 27 townships of 10 counties in southeastern Yunnan Province from 1984 to 1993. The relationship of remote sensing ecological proxy index, NDVI, to Anopheles density and malaria incidence rate was studied by principal component analysis, factor analysis and grey correlation analysis. Results The correlation matrix showed that NDVI highly correlated with Anopheles density in 4 townships of Mengla, Jinghong, and Yuanjiang counties, but in other 23 townships the relationship was not clear. Principal component and factor analyses showed that remote sensing NDVI was the representative index of the first principal component and the first common factor of Anopheles density evaluation. Grey correlation analysis showed that in rainy season NDVI had a high grey correlation with Anopheles density and malaria incidence rate. The grey correlation analysis showed that in rainy season the grey degree of NDVI correlated with Anopheles. Minimus density was 0.730, and 0.713 with Anopheles sinensis density, and 0.800 with malarial incidence rate. Conclusion Remote sensing NDVI can serve as a sensitive evaluation index of Anopheles density and malaria incidence rate.

  17. Biochemical basis of permethrin resistance in Anopheles arabiensis from Lower Moshi, north-eastern Tanzania

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    Oxborough Richard M

    2010-07-01

    Full Text Available Abstract Background Development of resistance to different classes of insecticides is a potential threat to malaria control. With the increasing coverage of long-lasting insecticide-treated nets in Tanzania, the continued monitoring of resistance in vector populations is crucial. It may facilitate the development of novel strategies to prevent or minimize the spread of resistance. In this study, metabolic-based mechanisms conferring permethrin (pyrethroid resistance were investigated in Anopheles arabiensis of Lower Moshi, Kilimanjaro region of north-eastern Tanzania. Methods WHO susceptibility test kits were used to detect resistance to permethrin in An. arabiensis. The levels and mechanisms of permethrin resistance were determined using CDC bottle bioassays and microplate (biochemical assays. In bottle bioassays, piperonyl butoxide (PBO and s,s,s-tributyl phosphorotrithioate (DEF were used as synergists to inhibit mixed function oxidases and non-specific esterases respectively. Biochemical assays were carried out in individual mosquitoes to detect any increase in the activity of enzymes typically involved in insecticide metabolism (mixed function oxidases, α- and β-esterases. Results Anopheles arabiensis from the study area was found to be partially resistant to permethrin, giving only 87% mortality in WHO test kits. Resistance ratios at KT50 and KT95 were 4.0 and 4.3 respectively. The permethrin resistance was partially synergized by DEF and by PBO when these were mixed with permethrin in bottle bioassays and was fully synergized when DEF and PBO were used together. The levels of oxidase and β-esterase activity were significantly higher in An. arabiensis from Lower Moshi than in the laboratory susceptible strain. There was no difference in α-esterase activity between the two strains. Conclusion Elevated levels of mixed function oxidases and β-esterases play a role in detoxification of permethrin in the resistant An. arabiensis population

  18. Genome-Wide Divergence in the West-African Malaria Vector Anopheles melas

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    Kevin C. Deitz

    2016-09-01

    Full Text Available Anopheles melas is a member of the recently diverged An. gambiae species complex, a model for speciation studies, and is a locally important malaria vector along the West-African coast where it breeds in brackish water. A recent population genetic study of An. melas revealed species-level genetic differentiation between three population clusters. An. melas West extends from The Gambia to the village of Tiko, Cameroon. The other mainland cluster, An. melas South, extends from the southern Cameroonian village of Ipono to Angola. Bioko Island, Equatorial Guinea An. melas populations are genetically isolated from mainland populations. To examine how genetic differentiation between these An. melas forms is distributed across their genomes, we conducted a genome-wide analysis of genetic differentiation and selection using whole genome sequencing data of pooled individuals (Pool-seq from a representative population of each cluster. The An. melas forms exhibit high levels of genetic differentiation throughout their genomes, including the presence of numerous fixed differences between clusters. Although the level of divergence between the clusters is on a par with that of other species within the An. gambiae complex, patterns of genome-wide divergence and diversity do not provide evidence for the presence of pre- and/or postmating isolating mechanisms in the form of speciation islands. These results are consistent with an allopatric divergence process with little or no introgression.

  19. Seasonality and Locality Affect the Diversity of Anopheles gambiae and Anopheles coluzzii Midgut Microbiota from Ghana.

    Science.gov (United States)

    Akorli, Jewelna; Gendrin, Mathilde; Pels, Nana Adjoa P; Yeboah-Manu, Dorothy; Christophides, George K; Wilson, Michael D

    2016-01-01

    Symbiotic bacteria can have important implications in the development and competence of disease vectors. In Anopheles mosquitoes, the composition of the midgut microbiota is largely influenced by the larval breeding site, but the exact factors shaping this composition are currently unknown. Here, we examined whether the proximity to urban areas and seasons have an impact on the midgut microbial community of the two major malaria vectors in Africa, An. coluzzii and An. gambiae. Larvae and pupae were collected from selected habitats in two districts of Ghana during the dry and rainy season periods. The midgut microbiota of adults that emerged from these collections was determined by 454-pyrosequencing of the 16S ribosomal DNA. We show that in both mosquito species, Shewanellaceae constituted on average of 54% and 73% of the midgut microbiota from each site in the dry and rainy season, respectively. Enterobacteriaceae was found in comparatively low abundance below 1% in 22/30 samples in the dry season, and in 25/38 samples in the rainy season. Our data indicate that seasonality and locality significantly affect both the diversity of microbiota and the relative abundance of bacterial families with a positive impact of dry season and peri-urban settings.

  20. Seasonality and Locality Affect the Diversity of Anopheles gambiae and Anopheles coluzzii Midgut Microbiota from Ghana

    Science.gov (United States)

    Gendrin, Mathilde; Pels, Nana Adjoa P.; Yeboah-Manu, Dorothy; Christophides, George K.; Wilson, Michael D.

    2016-01-01

    Symbiotic bacteria can have important implications in the development and competence of disease vectors. In Anopheles mosquitoes, the composition of the midgut microbiota is largely influenced by the larval breeding site, but the exact factors shaping this composition are currently unknown. Here, we examined whether the proximity to urban areas and seasons have an impact on the midgut microbial community of the two major malaria vectors in Africa, An. coluzzii and An. gambiae. Larvae and pupae were collected from selected habitats in two districts of Ghana during the dry and rainy season periods. The midgut microbiota of adults that emerged from these collections was determined by 454-pyrosequencing of the 16S ribosomal DNA. We show that in both mosquito species, Shewanellaceae constituted on average of 54% and 73% of the midgut microbiota from each site in the dry and rainy season, respectively. Enterobacteriaceae was found in comparatively low abundance below 1% in 22/30 samples in the dry season, and in 25/38 samples in the rainy season. Our data indicate that seasonality and locality significantly affect both the diversity of microbiota and the relative abundance of bacterial families with a positive impact of dry season and peri-urban settings. PMID:27322614

  1. On the conspecificity of Anopheles fluviatilis species S with Anopheles minimus species C

    Indian Academy of Sciences (India)

    O P Singh; D Chandra; N Nanda; S K Sharma; Pe Than Htun; T Adak; S K Subbarao; A P Dash

    2006-12-01

    Anopheles fluviatilis and An. minimus complexes, each comprising of at least three sibling species, are closely related and important malaria vectors in Oriental Region. Recently An. fluviatilis species S, which is a highly efficient malaria vector in India, has been made conspecific with An. minimus species C (senior synonym) on the basis of homology in 335 base pair nucleotide sequence of D3 domain of 28S ribosomal DNA (rDNA). We examined the conspecificity of these two nominal species by obtaining and analysing the DNA sequences of nuclear ribosomal loci internal transcribed spacer 2 (ITS2) and D2-D3 domain of 28S rDNA (28S-D2/D3) from those of An. fluviatilis S and An. minimus C. We found that the sequences of An. fluviatilis S are appreciably different from those of An. minimus C with pair-wise distance (Kimura-2-parametre model) of 3.6 and 0.7% for loci ITS2 and 28S-D2/D3, respectively. Pair-wise distance and phylogenetic analyses using ITS2 sequences of members of Minimus and Fluviatilis Complexes revealed that An. fluviatilis S is distantly related to An. minimus C as compared to any other members of the Fluviatilis Complex. These findings suggest that the two nominal species, An. fluviatilis S and An. minimus C, do not merit synonymy. The study also confirms that the reported species An. fluviatilis X is synonym with species S.

  2. Mating competitiveness of sterile male Anopheles coluzzii in large cages

    OpenAIRE

    Maïga, H.; Damiens, D.; Niang, A.; Sawadogo, SP; Fatherhaman, O.; Lees, RS; Roux, O.; Dabiré, RK; Ouédraogo, GA; Tripet, F; Diabaté, A.; Gilles, JR

    2014-01-01

    Background: Understanding the factors that account for male mating competitiveness is critical to the development of the sterile insect technique (SIT). Here, the effects of partial sterilization with 90 Gy of radiation on sexual competitiveness of Anopheles coluzzii allowed to mate in different ratios of sterile to untreated males have been assessed. Moreover, competitiveness was compared between males allowed one versus two days of contact with females. Methods: Sterile and untreated males ...

  3. Resistance Mechanisms of Anopheles stephensi (Diptera: Culicidae) to Temephos

    OpenAIRE

    Aboozar Soltani; Hassan Vatandoost; MohammadAli Oshaghi; Naseh Maleki-Ravasan; AhmadAli Enayati; Fatemeh Asgarian

    2014-01-01

    Background: Anopheles stephensi is a sub-tropical species and has been considered as one of the most important vector of human malaria throughout the Middle East and South Asian region including the malarious areas of southern Iran. Current reports confirmed An. stephensi resistance to temephos in Oman and India. However, there is no comprehensive research on mechanisms of temephos resistance in An. stephensi in the literature. This study was designed in order to clarify the enzymatic and mol...

  4. In depth annotation of the Anopheles gambiae mosquito midgut transcriptome

    OpenAIRE

    Padrón, Alejandro; Molina-Cruz, Alvaro; Quinones, Mariam; Ribeiro, José MC; Ramphul, Urvashi; Rodrigues, Janneth; Shen, Kui; Haile, Ashley; Ramirez, José Luis; Barillas-Mury, Carolina

    2014-01-01

    Background Genome sequencing of Anopheles gambiae was completed more than ten years ago and has accelerated research on malaria transmission. However, annotation needs to be refined and verified experimentally, as most predicted transcripts have been identified by comparative analysis with genomes from other species. The mosquito midgut—the first organ to interact with Plasmodium parasites—mounts effective antiplasmodial responses that limit parasite survival and disease transmission. High-th...

  5. Highly evolvable malaria vectors : the genomes of 16 Anopheles mosquitoes

    OpenAIRE

    Neafsey, Daniel E; Waterhouse, Robert M.; Abai, Mohammad R.; Aganezov, Sergey S.; Alekseyev, Max A.; Allen, James E.; Amon, James; Arcà, Bruno; Arensburger, Peter; Artemov, Gleb; Assour, Lauren A.; Basseri, Hamidreza; Berlin, Aaron; Birren, Bruce W.; Blandin, Stephanie A.

    2015-01-01

    Variation in vectorial capacity for human malaria among Anopheles mosquito species is determined by many factors, including behavior, immunity, and life history. To investigate the genomic basis of vectorial capacity and explore new avenues for vector control, we sequenced the genomes of 16 anopheline mosquito species from diverse locations spanning similar to 100 million years of evolution. Comparative analyses show faster rates of gene gain and loss, elevated gene shuffling on the X chromos...

  6. Quantitative research of reproduction and survival of Anopheles sinensis indifferent areas%不同地理株中华按蚊生殖、存活定量研究

    Institute of Scientific and Technical Information of China (English)

    曲传智; 苏寿汦; 杨柳萍; 杨瑞琴; 王仲文; 王梅英; 苏天运

    2000-01-01

    Aim: To probe whether the biological characteristics of reproduction and survival of Anopheles sinensis in differentgeographical strains were same. Methods: The same method of quantitative research on Anopheles sinensis in different geographicalstrains at the same conditions was simultaneously carried out. Results: The characteristic values of reproduction and survival ofAnopheles sinensis in Zhengzhou, Shanghai and Fujian were figured out,and the survival and reproductive curves of Anopheles sinen-sis were drown up. Significance of each corresponding values was tested. The characteristics of reproduction and survival of Anophe-les sinensis in the three areas are very closed,having no significant differences (P > 0.05). C onnclusion: It can be explained thatthe changes of population number of Anopheles sinensis in different areas are identical at the same conditions.%目的:探讨不同地理株(株)的中华按蚊生殖、存活等生物学特性是否相同。方法:采用定量研究的方法,同时同条件下对不同株的中华按蚊进行相同的定量研究。结果:求出郑州、上海、福建株中华按蚊存活和生殖特性值,对其各对应值进行了显著性检验。3株中华按蚊生殖、存活特性非常接近,相互之间差异无显著性(P>O.05)。结论:提示在条件相同情况下,不同株中华按蚊的种群数量变动一致。

  7. The Anopheles community and the role of Anopheles minimus on malaria transmission on the China-Myanmar border

    OpenAIRE

    Yu, Guo; Yan, Guiyun; Zhang, Naixin; Zhong, Daibin; Wang, Ying(School of Physics, Shandong University, Jinan, 250100, PR China); He, Zhengbo; Yan, Zhentian; Fu, Wenbo; Yang, Feilong; Chen, Bin

    2013-01-01

    Abstract Background Malaria around the China-Myanmar border is a serious health problem in the countries of South-East Asia. An. minimus is a principle malaria vector with a wide geographic distribution in this area. Malaria is endemic along the boundary between Yunnan province in China and the Kachin State of Myanmar where the local Anopheles community (species composition) and the malaria transmission vectors have never been clarified. ...

  8. Evolutionary dynamics of the Ty3/gypsy LTR retrotransposons in the genome of Anopheles gambiae.

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    Jose Manuel C Tubio

    Full Text Available Ty3/gypsy elements represent one of the most abundant and diverse LTR-retrotransposon (LTRr groups in the Anopheles gambiae genome, but their evolutionary dynamics have not been explored in detail. Here, we conduct an in silico analysis of the distribution and abundance of the full complement of 1045 copies in the updated AgamP3 assembly. Chromosomal distribution of Ty3/gypsy elements is inversely related to arm length, with densities being greatest on the X, and greater on the short versus long arms of both autosomes. Taking into account the different heterochromatic and euchromatic compartments of the genome, our data suggest that the relative abundance of Ty3/gypsy LTRrs along each chromosome arm is determined mainly by the different proportions of heterochromatin, particularly pericentric heterochromatin, relative to total arm length. Additionally, the breakpoint regions of chromosomal inversion 2La appears to be a haven for LTRrs. These elements are underrepresented more than 7-fold in euchromatin, where 33% of the Ty3/gypsy copies are associated with genes. The euchromatin on chromosome 3R shows a faster turnover rate of Ty3/gypsy elements, characterized by a deficit of proviral sequences and the lowest average sequence divergence of any autosomal region analyzed in this study. This probably reflects a principal role of purifying selection against insertion for the preservation of longer conserved syntenyc blocks with adaptive importance located in 3R. Although some Ty3/gypsy LTRrs show evidence of recent activity, an important fraction are inactive remnants of relatively ancient insertions apparently subject to genetic drift. Consistent with these computational predictions, an analysis of the occupancy rate of putatively older insertions in natural populations suggested that the degenerate copies have been fixed across the species range in this mosquito, and also are shared with the sibling species Anopheles arabiensis.

  9. Bendiocarb, a potential alternative against pyrethroid resistant Anopheles gambiae in Benin, West Africa

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    Irish Seth

    2010-07-01

    Full Text Available Abstract Background Anopheles gambiae, the main malaria vector in Benin has developed high level of resistance to pyrethroid insecticides, which is a serious concern to the future use of long-lasting insecticidal nets (LLIN and indoor residual spraying (IRS. In this context, one of the pathways available for malaria vector control would be to investigate alternative classes of insecticides with different mode of action than that of pyrethroids. The goal of this study was to evaluate under field conditions the efficacy of a carbamate (bendiocarb and an organophosphate (fenitrothion against pyrethroid-resistant An. gambiae s.s. Methods Wild populations and females from laboratory colonies of five days old An. gambiae were bio-assayed during this study. Two pyrethroids (deltamethrin and alphacypermethrin, an organophosphate (fenitrothion, a carbamate (bendiocarb and a mixture of an organophosphate (chlorpyriphos + a pyrethroid deltamethrin were compared in experimental huts as IRS treatments. Insecticides were applied in the huts using a hand-operated compression sprayer. The deterrency, exophily, blood feeding rate and mortality induced by these insecticides against An. gambiae were compared to the untreated control huts. Results Deltamethrin, alphacypermethrin and bendiocarb treatment significantly reduced mosquito entry into the huts (p An. gambiae (in the first month and 77.8% (in the fourth month. Bendiocarb and the mixture chlorpyriphos/deltamethrin mortality rates ranged from 97.9 to 100% the first month and 77.7-88% the third month respectively. Conclusion After four months, fenitrothion, bendiocarb and the mixture chlorpyriphos/deltamethrin performed effectively against pyrethroid-resistant Anopheles. These results showed that bendiocarb could be recommended as an effective insecticide for use in IRS operations in Benin, particularly as the mixture chlorpyriphos/deltamethrin does not have WHOPES authorization and complaints were mentioned

  10. Genome-wide transcriptional analysis of genes associated with acute desiccation stress in Anopheles gambiae.

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    Mei-Hui Wang

    Full Text Available Malaria transmission in sub-Saharan Africa varies seasonally in intensity. Outbreaks of malaria occur after the beginning of the rainy season, whereas, during the dry season, reports of the disease are less frequent. Anopheles gambiae mosquitoes, the main malaria vector, are observed all year long but their densities are low during the dry season that generally lasts several months. Aestivation, seasonal migration, and local adaptation have been suggested as mechanisms that enable mosquito populations to persist through the dry season. Studies of chromosomal inversions have shown that inversions 2La, 2Rb, 2Rc, 2Rd, and 2Ru are associated with various physiological changes that confer aridity resistance. However, little is known about how phenotypic plasticity responds to seasonally dry conditions. This study examined the effects of desiccation stress on transcriptional regulation in An. gambiae. We exposed female An. gambiae G3 mosquitoes to acute desiccation and conducted a genome-wide analysis of their transcriptomes using the Affymetrix Plasmodium/Anopheles Genome Array. The transcription of 248 genes (1.7% of all transcripts was significantly affected in all experimental conditions, including 96 with increased expression and 152 with decreased expression. In general, the data indicate a reduction in the metabolic rate of mosquitoes exposed to desiccation. Transcripts accumulated at higher levels during desiccation are associated with oxygen radical detoxification, DNA repair and stress responses. The proportion of transcripts within 2La and 2Rs (2Rb, 2Rc, 2Rd, and 2Ru (67/248, or 27% is similar to the percentage of transcripts located within these inversions (31%. These data may be useful in efforts to elucidate the role of chromosomal inversions in aridity tolerance. The scope of application of the anopheline genome demonstrates that examining transcriptional activity in relation to genotypic adaptations greatly expands the number of

  11. Review of Temephos Discriminating Concentration for Monitoring the Susceptibility of Anopheles labranchiae (Falleroni, 1926, Malaria Vector in Morocco

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    C. Faraj

    2010-01-01

    Full Text Available In Morocco, the resistance monitoring of Anopheles labranchiae larvae to temephos is done using discriminating concentration of 0.125 mg, which is half of the WHO recommended dose for Anopheles. However, this dosage seemed to be too high to allow an early detection of the resistance and its revision was found necessary. The present study was carried out during May-June 2008 and 2009 in nine provinces from the north-west of the country. The aim was to determine the lethal concentrations LC100 of temephos for the most susceptible populations and to define the discriminating dosage as the double of this value. The bioassays were conducted according to WHO standard operating protocol to establish the dose-mortality relationship and deduct the LC50 and LC95. The results of this study indicated that the LC100 obtained on the most susceptible populations was close to 0.05 mg/l. Therefore, the temephos discriminating dosage for susceptibility monitoring of An. labranchiae larvae in Morocco was set to be 0.1 mg/l.

  12. The role of reactive oxygen species on Plasmodium melanotic encapsulation in Anopheles gambiae

    OpenAIRE

    Kumar, Sanjeev; Christophides, George K.; Cantera, Rafael; Charles, Bradley; Han, Yeon Soo; Meister, Stephan; Dimopoulos, George; Kafatos, Fotis C.; Barillas-Mury, Carolina

    2003-01-01

    Malaria transmission depends on the competence of some Anopheles mosquitoes to sustain Plasmodium development (susceptibility). A genetically selected refractory strain of Anopheles gambiae blocks Plasmodium development, melanizing, and encapsulating the parasite in a reaction that begins with tyrosine oxidation, and involves three quantitative trait loci. Morphological and microarray mRNA expression analysis suggest that the refractory and susceptible strains have broad physiological differe...

  13. Effect of Novaluron (Rimon 10 EC) on the mosquitoes Anopheles albimanus, Anopheles pseudopunctipennis, Aedes aegypti, Aedes albopictus and Culex quinquefasciatus from Chiapas, Mexico.

    Science.gov (United States)

    Arredondo-Jiménez, J I; Valdez-Delgado, K M

    2006-12-01

    Dengue fever is a serious problem in Mexico and vector control has not been effective enough at preventing outbreaks. Malaria is largely under control, but it is important that new control measures continue to be developed. Novaluron, a novel host-specific insect growth regulator and chitin synthesis inhibitor, has proved to be effective against agricultural pests, but its efficacy against larval mosquito vectors under field conditions remains unknown. In accordance with the World Health Organization Pesticide Evaluation Scheme, phase I, II and III studies were conducted to evaluate the efficacy and residual effect of Novaluron (Rimon 10 EC, Makhteshim, Beer-Sheva, Israel) on the malaria vectors Anopheles albimanus Wiedemann (Diptera: Culicidae) and Anopheles pseudopunctipennis Theobald, the dengue vectors Aedes aegypti (L) and Aedes albopictus Skuse and the nuisance mosquito Culex quinquefasciatus Say. Laboratory susceptibility tests yielded diagnostic concentrations for all five target species. Field trials to identify the optimum field dosage of Novaluron against Anopheles mosquitoes were carried out under semi-natural conditions in artificial plots and in vessels with wild mosquitoes. Efficacy was measured by monitoring mortality of larvae and pupae and the percentage of inhibition of emergence from floating cages. Dosages of Novaluron for field tests were based on pupal LC(99) (lethal concentration 99%) of An. pseudopunctipennis (0.166 mg/L) in plots and average pupal LC(99) of Ae. aegypti and Ae. albopictus (0.55 mg/L). At all dosages tested, Novaluron significantly reduced larval populations of An. albimanus, Culex coronator Dyar & Knab, Ae. albopictus and Cx. quinquefasciatus by approximately 90%, inhibited adult emergence of An. albimanus and An. pseudopunctipennis by approximately 97% for almost 4 months in experimental plots, and inhibited adult emergence of Ae. aegypti and Ae. albopictus by approximately 97% for up to 14 weeks. Recommended dosages of

  14. The polymorphism and the geographical distribution of the knockdown resistance (kdr of Anopheles sinensis in the Republic of Korea

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    Kang Seunghyun

    2012-05-01

    Full Text Available Abstract Background In the Republic of Korea (ROK, six sibling species of the Anopheles sinensis complex are considered the vector species of malaria, but data on their susceptibilities to malaria and vector capacities have been controversial. The intensive use of insecticides has contributed to the rapid development and spread of insecticide resistance in the An. sinensis complex. Knockdown resistance (kdr to pyrethroids and DDT in the An. sinensis complex is associated with a mutation in codon 1014 of the voltage-gated sodium channel (VGSC gene. Because the degree of insecticide resistance varies among mosquito species and populations, the detection of kdr mutations among the six sibling species of the An. sinensis complex is a prerequisite for establishing effective long-term vector control strategies in the ROK Methods In order to investigate species-specific kdr mutations, An. sinensis complex specimens have been collected from 22 sites in the ROK. Because of the difficulties with species identifications that are based only on morphological characteristics, molecular identification methods have been conducted on every specimen. Part of the IIS6 domain of the VGSC was polymerase chain reaction-amplified and directly sequenced. Results The molecular analyses revealed that mutations existed at codon 1014 only in An. sinensis sensu stricto and no mutations were found in the other five Anopheles species. In An. sinensis s.s., one wild type (TTG L1014 and three mutant types (TTT L1014F, TTC L1014F, and TGT L1014C of kdr alleles were detected. The TTC L1014F mutation was observed for the first time in this species. Conclusions The fact that the highly polymorphic kdr gene is only observed in An. sinensis s.s., out of the six Anopheles species and their geographical distribution suggest the need for future studies of insecticide resistance monitoring and investigations of species-specific resistance mechanisms in order to build successful malaria

  15. Malaria vectors in the Brazilian Amazon: Anopheles of the subgenus Nyssorhynchus Anopheles do subgênero Nyssorhynchus, vetores da malária na Amazônia brasileira

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    Wanderli Pedro TADEI

    2000-04-01

    Full Text Available Various species of Anopheles (Nyssorhynchus were studied in the Amazon with the objective of determining their importance as malaria vectors. Of the 33 known Anopheles species occurring in the Amazon, only 9 were found to be infected with Plasmodium. The different species of this subgenus varied both in diversity and density in the collection areas. The populations showed a tendency towards lower density and diversity in virgin forest than in areas modified by human intervention. The principal vector, An. darlingi, is anthropophilic with a continuous activity cycle lasting the entire night but peaking at sunset and sunrise. These species (Nyssorhynchus are peridomiciliary, entering houses to feed on blood and immediately leaving to settle on nearby vegetation. Anopheles nuneztovari proved to be zoophilic, crepuscular and peridomiciliary. These habits may change depending on a series of external factors, especially those related to human activity. There is a possibility that sibling species exist in the study area and they are being studied with reference to An. darlingi, An. albitarsis and An. nuneztovari. The present results do not suggest the existence of subpopulations of An. darlingi in the Brazilian Amazon.Várias espécies de Anopheles (Nyssorhynchus foram estudadas na Amazônia a fim de se determinar sua importância na transmissão da malária. Das 33 espécies de Anopheles de ocorrência conhecida na Amazônia, apenas 8 foram encontradas infectadas por Plasmodium. O principal vetor, An. darlingi, é antropofílico com um ciclo contínuo de atividade que dura a noite inteira mas que tem picos ao anoitecer e ao amanhecer. As diferentes espécies desse subgênero variaram tanto em diversidade como em densidade nas áreas de coleta. A população de anofelinos apresentou tendências de menor densidade e diversidade em florestas virgens do que em áreas que sofreram intervenção humana. Essas espécies (Nyssorhynchus são peridomiciliares

  16. Wide cross-reactivity between Anopheles gambiae and Anopheles funestus SG6 salivary proteins supports exploitation of gSG6 as a marker of human exposure to major malaria vectors in tropical Africa

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    Petrarca Vincenzo

    2011-07-01

    Full Text Available Abstract Background The Anopheles gambiae gSG6 is an anopheline-specific salivary protein which helps female mosquitoes to efficiently feed on blood. Besides its role in haematophagy, gSG6 is immunogenic and elicits in exposed individuals an IgG response, which may be used as indicator of exposure to the main African malaria vector A. gambiae. However, malaria transmission in tropical Africa is sustained by three main vectors (A. gambiae, Anopheles arabiensis and Anopheles funestus and a general marker, reflecting exposure to at least these three species, would be especially valuable. The SG6 protein is highly conserved within the A. gambiae species complex whereas the A. funestus homologue, fSG6, is more divergent (80% identity with gSG6. The aim of this study was to evaluate cross-reactivity of human sera to gSG6 and fSG6. Methods The A. funestus SG6 protein was expressed/purified and the humoral response to gSG6, fSG6 and a combination of the two antigens was compared in a population from a malaria hyperendemic area of Burkina Faso where both vectors were present, although with a large A. gambiae prevalence (>75%. Sera collected at the beginning and at the end of the high transmission/rainy season, as well as during the following low transmission/dry season, were analysed. Results According to previous observations, both anti-SG6 IgG level and prevalence decreased during the low transmission/dry season and showed a typical age-dependent pattern. No significant difference in the response to the two antigens was found, although their combined use yielded in most cases higher IgG level. Conclusions Comparative analysis of gSG6 and fSG6 immunogenicity to humans suggests the occurrence of a wide cross-reactivity, even though the two proteins carry species-specific epitopes. This study supports the use of gSG6 as reliable indicator of exposure to the three main African malaria vectors, a marker which may be useful to monitor malaria transmission

  17. [Malaria, anopheles, the anti-malaria campaign in French Guyana: between dogmatism and judgment].

    Science.gov (United States)

    Raccurt, C P

    1997-01-01

    The recrudescence of malaria in French Guiana involves both border regions. One notes the predominance of Plasmodium falciparum along the Maroni River on the Surinam frontier and the transmission of both Plasmodium falciparum and Plasmodium vivax in amerindian settlements along the Oyapock River on the Brazilian frontier. The main mosquito vector is the endoexophile species, Anopheles darlingi. The role of man-biting forest anophelines in malaria transmission is still unclear. At the present time, malaria control is based on curative treatment of the confirmed cases (approximately 4,000 cases a year by active and passive screening). Vector control is supported by annual houses insecticides spraying and, to a lesser degree, use of insecticide-impregnated bednets. The main limiting factors for successful control have been difficulty in implementing a strategy adapted to the cultures of the amerindian and bushnegro populations living on either side of the river-frontiers and in organizing effective cross-border cooperation. The alleged role of immigration in transmission dynamics has been more speculative than real. However the growth of the population and the increase of human activities inside rain forest areas have favorized Anopheles darlingi breeding by uncontrolled deforestation. This situation need to be monitored closely. Information campaigns to improve public awareness could be useful. Following measures could improve control in sparsely populated, remote areas: to promote an integrated preventive program for a real community-wide distribution of primary health care; to discontinue insecticides spraying in houses which is poorly accepted by the bushnegro population and unsuitable to the amerindian dwellings; to support the use of personal protection; to initiate an effective anopheline larvae control; to determine the impact of the transmission during day-time activities especially among very small settlements far from the main villages where members of the

  18. Anopheles larval abundance and diversity in three rice agro-village complexes Mwea irrigation scheme, central Kenya

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    Mwangangi Joseph M

    2010-08-01

    Full Text Available Abstract Background The diversity and abundance of Anopheles larvae has significant influence on the resulting adult mosquito population and hence the dynamics of malaria transmission. Studies were conducted to examine larval habitat dynamics and ecological factors affecting survivorship of aquatic stages of malaria vectors in three agro-ecological settings in Mwea, Kenya. Methods Three villages were selected based on rice husbandry and water management practices. Aquatic habitats in the 3 villages representing planned rice cultivation (Mbui Njeru, unplanned rice cultivation (Kiamachiri and non-irrigated (Murinduko agro-ecosystems were sampled every 2 weeks to generate stage-specific estimates of mosquito larval densities, relative abundance and diversity. Records of distance to the nearest homestead, vegetation coverage, surface debris, turbidity, habitat stability, habitat type, rice growth stage, number of rice tillers and percent Azolla cover were taken for each habitat. Results Captures of early, late instars and pupae accounted for 78.2%, 10.9% and 10.8% of the total Anopheles immatures sampled (n = 29,252, respectively. There were significant differences in larval abundance between 3 agro-ecosystems. The village with 'planned' rice cultivation had relatively lower Anopheles larval densities compared to the villages where 'unplanned' or non-irrigated. Similarly, species composition and richness was higher in the two villages with either 'unplanned' or limited rice cultivation, an indication of the importance of land use patterns on diversity of larval habitat types. Rice fields and associated canals were the most productive habitat types while water pools and puddles were important for short periods during the rainy season. Multiple logistic regression analysis showed that presence of other invertebrates, percentage Azolla cover, distance to nearest homestead, depth and water turbidity were the best predictors for Anopheles mosquito larval

  19. BIONOMICS AND ECOLOGY OF ANOPHELES LITORALIS ON BONGAO ISLAND, TAWI-TAWI PROVINCE, PHILIPPINES: IMPLICATIONS FOR VECTOR CONTROL.

    Science.gov (United States)

    Salazar, Ferdinand V; Torno, Majhalia M; Galang, Cristina; Baquilod, Mario; Bangs, Michael J

    2015-05-01

    Entomological surveys were conducted to identify Anopheles malaria vector species, their feeding and resting behaviors, and characterization of larval habitats on Bongao Island, Tawi-tawi Province, in July and November, 2007. Survey parameters included all-evening human-landing collections (HLC), evening buffalo-baited trap (BBT) collections, daytime indoor and outdoor adult resting collections, adult female age-grading, identification of natural Plasmodium infections in mosquitoes, larval habitat identification and physical/biological characterization, and adult insecticide susceptibility assays. Both surveys revealed the predominant and putative malaria vector species on Bongao Island is Anopheles litoralis. Anophelesflavirostris was collected on only one occasion. The HLC during the July survey produced approximately 4 mosquitoes/human/night (mhn). The November survey yielded 1.27 mhn due, in part, to inclement weather conditions during time of sampling. Anopheles litoralis host seeking behavior occurred throughout the evening (06:00 PM - 06:00 AM) with peak biting between 10:00 PM and 04:00 AM. This species exhibited stronger zoophilic behavior based on comparison of HLC and BBT data. HLC showed a slightly greater exophagic (outdoor) behavior (1.4:1 ratio). During the July collection, an older adult population was present (75% parous) compared to the lower numbers of An. litoralis dissected in November (25% parous). Albeit a small sample size (n=19), 10.5% of An. litoralis dissected contained midgut oocysts of Plasmodium. Daytime adult resting harborages included biotic and abiotic sites in and around partially shaded, brackish water habitats where immature stages were common. Anopheles litoralis was found susceptible to pirimiphos-methyl and four different synthetic pyrethroids. This survey provides further epidemiological evidence of the importance of An. litoralis in malaria transmission on Bongao Island, and presumably throughout much of the Sulu

  20. Immunity-related genes and gene families in Anopheles gambiae.

    Science.gov (United States)

    Christophides, George K; Zdobnov, Evgeny; Barillas-Mury, Carolina; Birney, Ewan; Blandin, Stephanie; Blass, Claudia; Brey, Paul T; Collins, Frank H; Danielli, Alberto; Dimopoulos, George; Hetru, Charles; Hoa, Ngo T; Hoffmann, Jules A; Kanzok, Stefan M; Letunic, Ivica; Levashina, Elena A; Loukeris, Thanasis G; Lycett, Gareth; Meister, Stephan; Michel, Kristin; Moita, Luis F; Müller, Hans-Michael; Osta, Mike A; Paskewitz, Susan M; Reichhart, Jean-Marc; Rzhetsky, Andrey; Troxler, Laurent; Vernick, Kenneth D; Vlachou, Dina; Volz, Jennifer; von Mering, Christian; Xu, Jiannong; Zheng, Liangbiao; Bork, Peer; Kafatos, Fotis C

    2002-10-01

    We have identified 242 Anopheles gambiae genes from 18 gene families implicated in innate immunity and have detected marked diversification relative to Drosophila melanogaster. Immune-related gene families involved in recognition, signal modulation, and effector systems show a marked deficit of orthologs and excessive gene expansions, possibly reflecting selection pressures from different pathogens encountered in these insects' very different life-styles. In contrast, the multifunctional Toll signal transduction pathway is substantially conserved, presumably because of counterselection for developmental stability. Representative expression profiles confirm that sequence diversification is accompanied by specific responses to different immune challenges. Alternative RNA splicing may also contribute to expansion of the immune repertoire. PMID:12364793

  1. CLIP proteases and Plasmodium melanization in Anopheles gambiae.

    Science.gov (United States)

    Barillas-Mury, Carolina

    2007-07-01

    Melanization is a potent immune response mediated by phenoloxidase (PO). Multiple Clip-domain serine proteases (CLIP) regulate PO activation as part of a complex cascade of proteases that are cleaved sequentially. The role of several CLIP as key activators or suppressors of the melanization responses of Anopheles gambiae to Plasmodium berghei (murine malaria) has been established recently using a genome-wide reverse genetics approach. Important differences in regulation of PO activation between An. gambiae strains were also identified. This review summarizes these findings and discusses our current understanding of the An. gambiae melanization responses to Plasmodium. PMID:17512801

  2. Function and composition of male accessory gland secretions in Anopheles gambiae: a comparison with other insect vectors of infectious diseases

    Science.gov (United States)

    Baldini, Francesco; Gabrieli, Paolo; Rogers, David W.; Catteruccia, Flaminia

    2012-01-01

    Human malaria, a major public health burden in tropical and subtropical countries, is transmitted exclusively by the bite of a female Anopheles mosquito. Malaria control strategies aimed at inducing sexual sterility in natural vector populations are an attractive alternative to the use of insecticides. However, despite their importance as disease vectors, limited information is available on the molecular mechanisms regulating fertility in Anopheles mosquitoes. In the major malaria vector, An. gambiae, the full complement of sperm and seminal fluid required for a female’s lifelong egg production is obtained from a single mating event. This single mating has important consequences for the physiology and behavior of An. gambiae females: in particular, they become refractory to further insemination, and they start laying eggs. In other insects including Drosophila, similar post-copulatory changes are induced by seminal proteins secreted by the male accessory glands and transferred to the female during mating. In this review, we analyze the current state of knowledge on the function and characterization of male seminal proteins in An. gambiae, and provide a comparative assessment of the role of these male reproductive factors in other mosquito vectors of human disease in which female post-copulatory behavior has been studied. Knowledge of the factors and mechanisms regulating fertility in An. gambiae and other vectors can help the design of novel control strategies to fight the spread of disease. PMID:22943543

  3. Mating activates the heme peroxidase HPX15 in the sperm storage organ to ensure fertility in Anopheles gambiae

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    Shaw, W. Robert; Teodori, Eleonora; Mitchell, Sara N.; Baldini, Francesco; Gabrieli, Paolo; Rogers, David W.; Catteruccia, Flaminia

    2014-01-01

    Anopheles gambiae mosquitoes are major African vectors of malaria, a disease that kills more than 600,000 people every year. Given the spread of insecticide resistance in natural mosquito populations, alternative vector control strategies aimed at reducing the reproductive success of mosquitoes are being promoted. Unlike many other insects, An. gambiae females mate a single time in their lives and must use sperm stored in the sperm storage organ, the spermatheca, to fertilize a lifetime's supply of eggs. Maintenance of sperm viability during storage is therefore crucial to the reproductive capacity of these mosquitoes. However, to date, no information is available on the factors and mechanisms ensuring sperm functionality in the spermatheca. Here we identify cellular components and molecular mechanisms used by An. gambiae females to maximize their fertility. Pathways of energy metabolism, cellular transport, and oxidative stress are strongly regulated by mating in the spermatheca. We identify the mating-induced heme peroxidase (HPX) 15 as an important factor in long-term fertility, and demonstrate that its function is required during multiple gonotrophic cycles. We find that HPX15 induction is regulated by sexually transferred 20-hydroxy-ecdysone (20E), a steroid hormone that is produced by the male accessory glands and transferred during copulation, and that expression of this peroxidase is mediated via the 20E nuclear receptor. To our knowledge, our findings provide the first evidence of the mechanisms regulating fertility in Anopheles, and identify HPX15 as a target for vector control. PMID:24711401

  4. Molecular evidence for a single taxon, Anopheles nuneztovari s.l., from two endemic malaria regions in Colombia

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    Luz Marina Jaramillo

    2011-12-01

    Full Text Available To elucidate the Anopheles nuneztovari s.l. taxonomic status at a microgeographic level in four malaria endemic localities from Antioquia and Córdoba, Colombia, fragments of the cytochrome oxidase subunit I (COI and the white gene were used. The COI analysis showed low genetic differentiation with fixation index (F ST levels between -0.02-0.137 and Nm values between 3-∞, indicating the presence of high gene flow among An. nuneztovari s.l. populations from the four localities. The COI network showed a single most common haplotype, type 1 (n = 55, present in all localities, as the likely ancestral haplotype. Analysis of the white gene showed that An. nuneztovari s.l. populations from both departments grouped with haplotypes 19 and 20, which are part of lineage 3 reported previously. The results of the present study suggest that An. nuneztovari s.l. is a single taxon in the area of the present study.

  5. Identification of field caught Anopheles gambiae s.s. and Anopheles arabiensis by TaqMan single nucleotide polymorphism genotyping

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    Bayoh Nabie M

    2007-02-01

    Full Text Available Abstract Background Identification of Anopheles gambiae s.s. and Anopheles arabiensis from field-collected Anopheles gambiae s.l. is often necessary in basic and applied research, and in operational control programmes. The currently accepted method involves use of standard polymerase chain reaction amplification of ribosomal DNA (rDNA from the 3' 28S to 5' intergenic spacer region of the genome, and visual confirmation of amplicons of predicted size on agarose gels, after electrophoresis. This report describes development and evaluation of an automated, quantitative PCR method based upon TaqMan™ single nucleotide polymorphism (SNP genotyping. Methods Standard PCR, and TaqMan SNP genotyping with newly designed primers and fluorophore-labeled probes hybridizing to sequences of complementary rDNA specific for either An. gambiae s.s. or An. arabiensis, were conducted in three experiments involving field-collected An. gambiae s.l. from western Kenya, and defined laboratory strains. DNA extraction was from a single leg, sonicated for five minutes in buffer in wells of 96-well PCR plates. Results TaqMan SNP genotyping showed a reaction success rate, sensitivity, and species specificity comparable to that of standard PCR. In an extensive field study, only 29 of 3,041 (0.95% were determined to be hybrids by TaqMan (i.e., having rDNA sequences from both species, however, all but one were An. arabiensis by standard PCR, suggesting an acceptably low (ca. 1% error rate for TaqMan genotyping in mistakenly identifying species hybrids. Conclusion TaqMan SNP genotyping proved to be a sensitive and rapid method for identification of An. gambiae s.l. and An. arabiensis, with a high success rate, specific results, and congruence with the standard PCR method.

  6. Evaluation of Insecticides Susceptibility and Malaria Vector Potential of Anopheles annularis s.l. and Anopheles vagus in Assam, India

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    Dhiman, Sunil; Yadav, Kavita; Rabha, Bipul; Goswami, Diganta; Hazarika, S.; Tyagi, Varun

    2016-01-01

    During the recent past, development of DDT resistance and reduction to pyrethroid susceptibility among the malaria vectors has posed a serious challenge in many Southeast Asian countries including India. Current study presents the insecticide susceptibility and knock-down data of field collected Anopheles annularis sensu lato and An. vagus mosquito species from endemic areas of Assam in northeast India. Anopheles annularis s.l. and An. vagus adult females were collected from four randomly selected sentinel sites in Orang primary health centre (OPHC) and Balipara primary health centre (BPHC) areas, and used for testing susceptibility to DDT, malathion, deltamethrin and lambda-cyhalothrin. After insecticide susceptibility tests, mosquitoes were subjected to VectorTest™ assay kits to detect the presence of malaria sporozoite in the mosquitoes. An. annularis s.l. was completely susceptible to deltamethrin, lambda-cyhalothrin and malathion in both the study areas. An. vagus was highly susceptible to deltamethrin in both the areas, but exhibited reduced susceptibility to lambda-cyhalothrin in BPHC. Both the species were resistant to DDT and showed very high KDT50 and KDT99 values for DDT. Probit model used to calculate the KDT50 and KDT99 values did not display normal distribution of percent knock-down with time for malathion in both the mosquito species in OPHC (pp = 0.0), and also for deltamethrin to An. vagus in BPHC area (χ2 = 15.4; p = 0.004). Minimum infection rate (MIR) of Plasmodium sporozoite for An. vagus was 0.56 in OPHC and 0.13 in BPHC, while for An. annularis MIR was found to be 0.22 in OPHC. Resistance management strategies should be identified to delay the expansion of resistance. Testing of field caught Anopheles vectors from different endemic areas for the presence of malaria sporozoite may be useful to ensure their role in malaria transmission. PMID:27010649

  7. Evaluation of Insecticides Susceptibility and Malaria Vector Potential of Anopheles annularis s.l. and Anopheles vagus in Assam, India.

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    Sunil Dhiman

    Full Text Available During the recent past, development of DDT resistance and reduction to pyrethroid susceptibility among the malaria vectors has posed a serious challenge in many Southeast Asian countries including India. Current study presents the insecticide susceptibility and knock-down data of field collected Anopheles annularis sensu lato and An. vagus mosquito species from endemic areas of Assam in northeast India. Anopheles annularis s.l. and An. vagus adult females were collected from four randomly selected sentinel sites in Orang primary health centre (OPHC and Balipara primary health centre (BPHC areas, and used for testing susceptibility to DDT, malathion, deltamethrin and lambda-cyhalothrin. After insecticide susceptibility tests, mosquitoes were subjected to VectorTest™ assay kits to detect the presence of malaria sporozoite in the mosquitoes. An. annularis s.l. was completely susceptible to deltamethrin, lambda-cyhalothrin and malathion in both the study areas. An. vagus was highly susceptible to deltamethrin in both the areas, but exhibited reduced susceptibility to lambda-cyhalothrin in BPHC. Both the species were resistant to DDT and showed very high KDT50 and KDT99 values for DDT. Probit model used to calculate the KDT50 and KDT99 values did not display normal distribution of percent knock-down with time for malathion in both the mosquito species in OPHC (p<0.05 and An. vagus in BPHC (χ2 = 25.3; p = 0.0, and also for deltamethrin to An. vagus in BPHC area (χ2 = 15.4; p = 0.004. Minimum infection rate (MIR of Plasmodium sporozoite for An. vagus was 0.56 in OPHC and 0.13 in BPHC, while for An. annularis MIR was found to be 0.22 in OPHC. Resistance management strategies should be identified to delay the expansion of resistance. Testing of field caught Anopheles vectors from different endemic areas for the presence of malaria sporozoite may be useful to ensure their role in malaria transmission.

  8. Bioinformatics-Based Identification of Chemosensory Proteins in African Malaria Mosquito, Anopheles gambiae

    Institute of Scientific and Technical Information of China (English)

    Zhengxi Li; Zuorui Shen; Jingjiang Zhou; Lin Field

    2003-01-01

    Chemosensory proteins (CSPs) are identifiable by four spatially conserved Cysteine residues in their primary structure or by two disulfide bridges in their tertiary structure according to the previously identified olfactory specific-D related proteins. A genomics- and bioinformatics-based approach is taken in the present study to identify the putative CSPs in the malaria-carrying mosquito, Anopheles gambiae. The results show that five out of the nine annotated candidates are the most possible Anopheles CSPs of A. gambiae. This study lays the foundation for further functional identification of Anopheles CSPs, though all of these candidates need additional experimental verification.

  9. Insecticide susceptibility status of Aedes aegypti and Anopheles stephensi larvae against temephos in Delhi, India

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    R.K. Singh

    2014-09-01

    Full Text Available Temephos is used as a larvicide in urban areas in India to control the population of mosquito vectors viz. Anopheles stephensi and Aedes aegypti. The susceptibility status of Ae. aegypti and An. stephensi to temophos in various zones of Municipal Corporation of Delhi was evaluated using the WHO method for determining larval susceptibility test kit. Results revealed that the larval mortality of Ae. aegypti collected from different localities ranged between 64.88% to 98.22%. The highest mortality was recorded from Sangam Vihar (98.22% and lowest was recorded from Majnu ka tila (64.88%. Ae. aegypti larvae collected from Sangam Vihar locality was found fully susceptible to temephos, from two localities viz. Uttam Nagar and Pitampura of study area were tolerant to temephos, and from five localities viz. Majnu ka tila, Shastri Park, Mayur Vihar II, Tilak Bridge and Nagal Dewat showed development of resistance against temephos at diagnostic concentrations. However, larval populations of An. stephensi were fully susceptible to temephos in all the localities. The present study indicates the possible development of resistance against temephos in the larvae of Ae. aegypti in some areas in Delhi.

  10. Anophelism in a former malaria area of northeastern Spain.

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    Rubén Bueno-Marí

    2013-12-01

    Full Text Available A field study on diversity and distribution of anophelines currently present in a past endemic malaria area of Spain was carried out in order to identify possible risk areas of local disease transmission.Multiple larval sites were sampled from June to October of 2011 in the Region of Somontano de Barbastro (Northeastern Spain. The sampling effort was fixed at 10 minutes which included the active search for larvae in each biotope visited.A total of 237 larval specimens belonging to four Anopheles species (Anopheles atroparvus, An. claviger, An. maculipennis and An. petragnani were collected and identified.Malaria receptivity in the study area is high, especially in the area of Cinca river valley, due to the abundance of breeding sites of An. atroparvus very close to human settlements. Although current socio-economic conditions in Spain reduce possibilities of re-emergence of malaria transmission, it is evident that certain entomological and epidemiological vigilance must be maintained and even increased in the context of current processes of climate change and globalization.

  11. A proteomic investigation of soluble olfactory proteins in Anopheles gambiae.

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    Guido Mastrobuoni

    Full Text Available Odorant-binding proteins (OBPs and chemosensory proteins (CSPs are small soluble polypeptides that bind semiochemicals in the lymph of insect chemosensilla. In the genome of Anopheles gambiae, 66 genes encode OBPs and 8 encode CSPs. Here we monitored their expression through classical proteomics (2D gel-MS analysis and a shotgun approach. The latter method proved much more sensitive and therefore more suitable for tiny biological samples as mosquitoes antennae and eggs. Females express a larger number and higher quantities of OBPs in their antennae than males (24 vs 19. OBP9 is the most abundant in the antennae of both sexes, as well as in larvae, pupae and eggs. Of the 8 CSPs, 4 were detected in antennae, while SAP3 was the only one expressed in larvae. Our proteomic results are in fairly good agreement with data of RNA expression reported in the literature, except for OBP4 and OBP5, that we could not identify in our analysis, nor could we detect in Western Blot experiments. The relatively limited number of soluble olfactory proteins expressed at relatively high levels in mosquitoes makes further studies on the coding of chemical messages at the OBP level more accessible, providing for few specific targets. Identification of such proteins in Anopheles gambiae might facilitate future studies on host finding behavior in this important disease vector.

  12. Molecular evolution of immune genes in the malaria mosquito Anopheles gambiae.

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    Tovi Lehmann

    Full Text Available BACKGROUND: As pathogens that circumvent the host immune response are favoured by selection, so are host alleles that reduce parasite load. Such evolutionary processes leave their signature on the genes involved. Deciphering modes of selection operating on immune genes might reveal the nature of host-pathogen interactions and factors that govern susceptibility in host populations. Such understanding would have important public health implications. METHODOLOGY/FINDINGS: We analyzed polymorphisms in four mosquito immune genes (SP14D1, GNBP, defensin, and gambicin to decipher selection effects, presumably mediated by pathogens. Using samples of Anopheles arabiensis, An. quadriannulatus and four An. gambiae populations, as well as published sequences from other Culicidae, we contrasted patterns of polymorphisms between different functional units of the same gene within and between populations. Our results revealed selection signatures operating on different time scales. At the most recent time scale, within-population diversity revealed purifying selection. Between populations and between species variation revealed reduced differentiation (GNBP and gambicin at coding vs. noncoding- regions, consistent with balancing selection. McDonald-Kreitman tests between An. quadriannulatus and both sibling species revealed higher fixation rate of synonymous than nonsynonymous substitutions (GNBP in accordance with frequency dependent balancing selection. At the longest time scale (>100 my, PAML analysis using distant Culicid taxa revealed positive selection at one codon in gambicin. Patterns of genetic variation were independent of exposure to human pathogens. SIGNIFICANCE AND CONCLUSIONS: Purifying selection is the most common form of selection operating on immune genes as it was detected on a contemporary time scale on all genes. Selection for "hypervariability" was not detected, but negative balancing selection, detected at a recent evolutionary time scale

  13. The Genetic Basis of Host Preference and Resting Behavior in the Major African Malaria Vector, Anopheles arabiensis

    Science.gov (United States)

    Main, Bradley J; Lee, Yoosook; Ferguson, Heather M.; Kreppel, Katharina S.; Kihonda, Anicet; Govella, Nicodem J.; Collier, Travis C.; Cornel, Anthony J.; Eskin, Eleazar; Kang, Eun Yong; Nieman, Catelyn C.; Weakley, Allison M.; Lanzaro, Gregory C.

    2016-01-01

    Malaria transmission is dependent on the propensity of Anopheles mosquitoes to bite humans (anthropophily) instead of other dead end hosts. Recent increases in the usage of Long Lasting Insecticide Treated Nets (LLINs) in Africa have been associated with reductions in highly anthropophilic and endophilic vectors such as Anopheles gambiae s.s., leaving species with a broader host range, such as Anopheles arabiensis, as the most prominent remaining source of transmission in many settings. An. arabiensis appears to be more of a generalist in terms of its host choice and resting behavior, which may be due to phenotypic plasticity and/or segregating allelic variation. To investigate the genetic basis of host choice and resting behavior in An. arabiensis we sequenced the genomes of 23 human-fed and 25 cattle-fed mosquitoes collected both in-doors and out-doors in the Kilombero Valley, Tanzania. We identified a total of 4,820,851 SNPs, which were used to conduct the first genome-wide estimates of “SNP heritability” for host choice and resting behavior in this species. A genetic component was detected for host choice (human vs cow fed; permuted P = 0.002), but there was no evidence of a genetic component for resting behavior (indoors versus outside; permuted P = 0.465). A principal component analysis (PCA) segregated individuals based on genomic variation into three groups which were characterized by differences at the 2Rb and/or 3Ra paracentromeric chromosome inversions. There was a non-random distribution of cattle-fed mosquitoes between the PCA clusters, suggesting that alleles linked to the 2Rb and/or 3Ra inversions may influence host choice. Using a novel inversion genotyping assay, we detected a significant enrichment of the standard arrangement (non-inverted) of 3Ra among cattle-fed mosquitoes (N = 129) versus all non-cattle-fed individuals (N = 234; χ2, p = 0.007). Thus, tracking the frequency of the 3Ra in An. arabiensis populations may be of use to infer

  14. Genetic diversity in two sibling species of the Anopheles punctulatus group of mosquitoes on Guadalcanal in the Solomon Islands

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    Harada Masakazu

    2008-11-01

    Full Text Available Abstract Background The mosquito Anopheles irenicus, a member of the Anopheles punctulatus group, is geographically restricted to Guadalcanal in the Solomon Islands. It shows remarkable morphological similarities to one of its sibling species, An. farauti sensu stricto (An. farauti s.s., but is dissimilar in host and habitat preferences. To infer the genetic variations between these two species, we have analyzed mitochondrial cytochrome oxidase subunit II (COII and nuclear ribosomal internal transcribed spacer 2 (ITS2 sequences from Guadalcanal and from one of its nearest neighbours, Malaita, in the Solomon Islands. Results An. farauti s.s. was collected mostly from brackish water and by the human bait method on both islands, whereas An. irenicus was only collected from fresh water bodies on Guadalcanal Island. An. irenicus is distributed evenly with An. farauti s.s. (ΦSC = 0.033, 0.38% and its range overlaps in three of the seven sampling sites. However, there is a significant population genetic structure between the species (ΦCT = 0.863, P ST = 0.865, P FST = 0.878, P An. irenicus is a monophyletic species, not a hybrid, and is closely related to the An. farauti s.s. on Guadalcanal. The time estimator suggests that An. irenicus diverged from the ancestral An. farauti s.s. on Guadalcanal within 29,000 years before present (BP. An. farauti s.s. expanded much earlier on Malaita (texp = 24,600 BP than the populations on Guadalcanal (texp = 16,800 BP for An. farauti s.s. and 14,000 BP for An. irenicus. Conclusion These findings suggest that An. irenicus and An. farauti s.s. are monophyletic sister species living in sympatry, and their populations on Guadalcanal have recently expanded. Consequently, the findings further suggest that An. irenicus diverged from the ancestral An. farauti s.s. on Guadalcanal.

  15. Evaluation of Insecticides Susceptibility and Malaria Vector Potential of Anopheles annularis s.l. and Anopheles vagus in Assam, India.

    Science.gov (United States)

    Dhiman, Sunil; Yadav, Kavita; Rabha, Bipul; Goswami, Diganta; Hazarika, S; Tyagi, Varun

    2016-01-01

    During the recent past, development of DDT resistance and reduction to pyrethroid susceptibility among the malaria vectors has posed a serious challenge in many Southeast Asian countries including India. Current study presents the insecticide susceptibility and knock-down data of field collected Anopheles annularis sensu lato and An. vagus mosquito species from endemic areas of Assam in northeast India. Anopheles annularis s.l. and An. vagus adult females were collected from four randomly selected sentinel sites in Orang primary health centre (OPHC) and Balipara primary health centre (BPHC) areas, and used for testing susceptibility to DDT, malathion, deltamethrin and lambda-cyhalothrin. After insecticide susceptibility tests, mosquitoes were subjected to VectorTest™ assay kits to detect the presence of malaria sporozoite in the mosquitoes. An. annularis s.l. was completely susceptible to deltamethrin, lambda-cyhalothrin and malathion in both the study areas. An. vagus was highly susceptible to deltamethrin in both the areas, but exhibited reduced susceptibility to lambda-cyhalothrin in BPHC. Both the species were resistant to DDT and showed very high KDT50 and KDT99 values for DDT. Probit model used to calculate the KDT50 and KDT99 values did not display normal distribution of percent knock-down with time for malathion in both the mosquito species in OPHC (puseful to ensure their role in malaria transmission. PMID:27010649

  16. Mosquitoes of Anopheles hyrcanus (Diptera, Culicidae) Group: Species Diagnostic and Phylogenetic Relationships.

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    Khrabrova, Natalia V; Andreeva, Yulia V; Sibataev, Anuarbek K; Alekseeva, Svetlana S; Esenbekova, Perizat A

    2015-09-01

    Herein, we report the results of study of Anopheles species in Primorsk and Khabarovsk regions of Russia. Three species of the Anopheles hyrcanus group: An. kleini, An. pullus, and An. lesteri were identified by molecular taxonomic diagnostics for the first time in Russia. Surprisingly, An. sinensis, which earlier was considered the only species of Anopheles in Russian Far East, was not observed. We analyzed nucleotide variation in the 610-bp fragment of the 5' end of the cytochrome c oxidase subunit I (COI) region. All species possessed a distinctive set of COI sequences. A maximum likelihood phylogenetic tree was constructed for members of the hyrcanus group. The examined Anopheles hyrcanus group members could be divided into two major subgroups: subgroup 1 (An. hyrcanus and An. pullus) and subgroup 2 (An. sinensis, An. kleini, and An. lesteri), which were found to be monophyletic.

  17. Molecular comparison of topotypic specimens confirms Anopheles (Nyssorhynchus dunhami Causey (Diptera: Culicidae in the Colombian Amazon

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    Freddy Ruiz

    2010-11-01

    Full Text Available The presence of Anopheles (Nyssorhynchus dunhami Causey in Colombia (Department of Amazonas is confirmed for the first time through direct comparison of mtDNA cytochrome c oxidase I (COI barcodes and nuclear rDNA second internal transcribed spacer (ITS2 sequences with topotypic specimens of An. dunhami from Tefé, Brazil. An. dunhami was identified through retrospective correlation of DNA sequences following misidentification as Anopheles nuneztovari s.l. using available morphological keys for Colombian mosquitoes. That An. dunhami occurs in Colombia and also possibly throughout the Amazon Basin, is of importance to vector control programs, as this non-vector species is morphologically similar to known malaria vectors including An. nuneztovari, Anopheles oswaldoi and Anopheles trinkae. Species identification of An. dunhami and differentiation from these closely related species are highly robust using either DNA ITS2 sequences or COI DNA barcode. DNA methods are advocated for future differentiation of these often sympatric taxa in South America.

  18. Chemical Composition and Repellent Activity of Achillea vermiculata and Satureja hortensis against Anopheles stephensi

    OpenAIRE

    Masoumeh Pirmohammadi; Mansoureh Shayeghi; Hassan Vatandoost; Mohammad Reza Abaei; Ali Mohammadi; Akbar Bagheri; Mehdi Khoobdel; Hasan Bakhshi; Maryam Pirmohammadi; Maryam Tavassoli

    2016-01-01

    Background: One of the best ways to control the malaria disease and to be protected human against Anopheles mos­quito biting is the use of repellents. Throughout repellents, herbal ones may be an appropriate and safe source for protection.Methods: Chemical constituents of Achillea vermiculata and Satoreja hortensis were determined by using gas chromatography-mass spectrometry. Efficacy and the protection time of these plants were assessed on Anopheles stephensi under the laboratory condition....

  19. Assessment of Anopheles salivary antigens as individual exposure biomarkers to species-specific malaria vector bites

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    Ali Zakia M I

    2012-12-01

    Full Text Available Abstract Background Malaria transmission occurs during the blood feeding of infected anopheline mosquitoes concomitant with a saliva injection into the vertebrate host. In sub-Saharan Africa, most malaria transmission is due to Anopheles funestus s.s and to Anopheles gambiae s.l. (mainly Anopheles gambiae s.s. and Anopheles arabiensis. Several studies have demonstrated that the immune response against salivary antigens could be used to evaluate individual exposure to mosquito bites. The aim of this study was to assess the use of secreted salivary proteins as specific biomarkers of exposure to An. gambiae and/or An. funestus bites. Methods For this purpose, salivary gland proteins 6 (SG6 and 5′nucleotidases (5′nuc from An. gambiae (gSG6 and g-5′nuc and An. funestus (fSG6 and f-5′nuc were selected and produced in recombinant form. The specificity of the IgG response against these salivary proteins was tested using an ELISA with sera from individuals living in three Senegalese villages (NDiop, n = 50; Dielmo, n = 38; and Diama, n = 46 that had been exposed to distinct densities and proportions of the Anopheles species. Individuals who had not been exposed to these tropical mosquitoes were used as controls (Marseille, n = 45. Results The IgG responses against SG6 recombinant proteins from these two Anopheles species and against g-5′nucleotidase from An. gambiae, were significantly higher in Senegalese individuals compared with controls who were not exposed to specific Anopheles species. Conversely, an association was observed between the level of An. funestus exposure and the serological immune response levels against the f-5′nucleotidase protein. Conclusion This study revealed an Anopheles salivary antigenic protein that could be considered to be a promising antigenic marker to distinguish malaria vector exposure at the species level. The epidemiological interest of such species-specific antigenic markers is discussed.

  20. Comparative evaluation of systemic drugs for their effects against Anopheles gambiae

    OpenAIRE

    Butters, Matthew P.; Kobylinski, Kevin C.; Deus, Kelsey M.; da Silva, Ines Marques; GRAY, MEG; sylla, massamba; Foy, Brian D.

    2011-01-01

    Laboratory and field studies have shown that ivermectin, a drug that targets invertebrate ligand-gated ion channels (LGICs), is potently active against Anopheles spp. mosquitoes at concentrations present in human blood after standard drug administrations; thus ivermectin holds promise as a mass human-administered endectocide that could help suppress malaria parasite transmission. We evaluated other systemic LGIC-targeting drugs for their activities against the African malaria vector Anopheles...

  1. Entomological indices of Anopheles gambiae sensu lato at a rural community in south-west Nigeria

    OpenAIRE

    M.A.E. Noutcha; C.I. Anumdu

    2009-01-01

    Background & objectives: Investigations were conducted to obtain key entomological indices of Anopheles gambiae s.l. at Igbo-Ora, a rural community in south-west Nigeria. Methods: Mosquitoes were caught daily for a week from rooms where tenants had slept the previous night in each of the four months June, July (2001), and August, September (2002). Anopheles gambiae s.l. sibling species were PCR-identified, the blood meal origin was determined by direct ELISA, and the circumsporozoite antigen ...

  2. EFEKTIVITAS INSEKTISIDA ORGANOCHLORIN OMS-1558 DALAM PENGENDALIAN VEKTOR MALARIA ANOPHELES ACONITUS DONITZ YANG SUDAH KEBAL TERHADAP DDT

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    Barodji Barodji

    2012-09-01

    Full Text Available A village-scale trial of organochlorin compound OMS-1558 as an 70% water-dispersible powder (wdp and applied as an indoor residual spray at 2 gr/m2, was carried out against the DDT—resistant malaria vector Anopheles aconitus near Semarang, Central Java. Result of this trial, as evaluated by human-vector contact rates, resting densities and parous rate showed effectiveness against the vector populations for only about one week or less. In contact bioassay tests mortalities of 50% or greater for one week, while mortalities from air-borne bioassay tests were negligible. It was concluded that DDT—resistant malaria vector can not be controlled by this insecticide. The result of susceptibility tests showed there is cross resistance between DDT and new organochlorin OMS-1558.

  3. Insecticide resistance in Anopheles gambiae from south-western Chad, Central Africa

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    Etang Josiane

    2008-09-01

    Full Text Available Abstract Background Indoor residual spraying and insecticide-treated nets (ITN are essential components of malaria vector control in Africa. Pyrethroids are the only recommended compounds for nets treatment because they are fast-acting insecticides with low mammalian toxicity. However, there is growing concern that pyrethroid resistance may threaten the sustainability of ITN scaling-up programmes. Here, insecticide susceptibility was investigated in Anopheles gambiae sensu lato from an area of large scale ITN distribution programme in south-western Chad. Methods Susceptibility to 4% DDT, 0.05% deltamethrin, 0.75% permethrin, 0.1% bendiocarb and 5% malathion was assessed using the WHO standard procedures for adult mosquitoes. Tests were carried out with two to four days-old, non-engorged female mosquitoes. The An. gambiae Kisumu strain was used as a reference. Knockdown effect was recorded every 5 min and mortality scored 24 h after exposure. Mosquitoes were identified to species and molecular form by PCR-RFLP and genotypes at the kdr locus were determined in surviving specimens by Hot Oligonucleotide Ligation Assay (HOLA. Results During this survey, full susceptibility to malathion was recorded in all samples. Reduced susceptibility to bendiocarb (mortality rate of 96.1% was found in one sample out of nine assayed. Increased tolerance to pyrethroids was detected in most samples (8/9 with mortality rates ranging from 70.2 to 96.6% for deltamethrin and from 26.7 to 96.3% for permethrin. Pyrethroid tolerance was not associated with a significant increase of knock-down times. Anopheles arabiensis was the predominant species of the An. gambiae complex in the study area, representing 75 to 100% of the samples. Screening for kdr mutations detected the L1014F mutation in 88.6% (N = 35 of surviving An. gambiae sensu stricto S form mosquitoes. All surviving An. arabiensis (N = 49 and M form An. gambiae s.s. (N = 1 carried the susceptible allele

  4. Inhibition of Anopheles gambiae odorant receptor function by mosquito repellents.

    Science.gov (United States)

    Tsitoura, Panagiota; Koussis, Konstantinos; Iatrou, Kostas

    2015-03-20

    The identification of molecular targets of insect repellents has been a challenging task, with their effects on odorant receptors (ORs) remaining a debatable issue. Here, we describe a study on the effects of selected mosquito repellents, including the widely used repellent N,N-diethyl-meta-toluamide (DEET), on the function of specific ORs of the African malaria vector Anopheles gambiae. This study, which has been based on quantitative measurements of a Ca(2+)-activated photoprotein biosensor of recombinant OR function in an insect cell-based expression platform and a sequential compound addition protocol, revealed that heteromeric OR (ORx/Orco) function was susceptible to strong inhibition by all tested mosquito repellents except DEET. Moreover, our results demonstrated that the observed inhibition was due to efficient blocking of Orco (olfactory receptor coreceptor) function. This mechanism of repellent action, which is reported for the first time, is distinct from the mode of action of other characterized insect repellents including DEET. PMID:25657000

  5. Organization of olfactory centres in the malaria mosquito Anopheles gambiae

    Science.gov (United States)

    Riabinina, Olena; Task, Darya; Marr, Elizabeth; Lin, Chun-Chieh; Alford, Robert; O'Brochta, David A.; Potter, Christopher J.

    2016-01-01

    Mosquitoes are vectors for multiple infectious human diseases and use a variety of sensory cues (olfactory, temperature, humidity and visual) to locate a human host. A comprehensive understanding of the circuitry underlying sensory signalling in the mosquito brain is lacking. Here we used the Q-system of binary gene expression to develop transgenic lines of Anopheles gambiae in which olfactory receptor neurons expressing the odorant receptor co-receptor (Orco) gene are labelled with GFP. These neurons project from the antennae and maxillary palps to the antennal lobe (AL) and from the labella on the proboscis to the suboesophageal zone (SEZ), suggesting integration of olfactory and gustatory signals occurs in this brain region. We present detailed anatomical maps of olfactory innervations in the AL and the SEZ, identifying glomeruli that may respond to human body odours or carbon dioxide. Our results pave the way for anatomical and functional neurogenetic studies of sensory processing in mosquitoes. PMID:27694947

  6. Maternal environment shapes the life history and susceptibility to malaria of Anopheles gambiae mosquitoes

    Directory of Open Access Journals (Sweden)

    Lorenz Lena M

    2011-12-01

    Full Text Available Abstract Background It is becoming generally recognized that an individual's phenotype can be shaped not only by its own genotype and environmental experience, but also by its mother's environment and condition. Maternal environmental factors can influence mosquitoes' population dynamics and susceptibility to malaria, and therefore directly and indirectly the epidemiology of malaria. Methods In a full factorial experiment, the effects of two environmental stressors - food availability and infection with the microsporidian parasite Vavraia culicis - of female mosquitoes (Anopheles gambiae sensu stricto on their offspring's development, survival and susceptibility to malaria were studied. Results The offspring of A. gambiae s.s. mothers infected with V. culicis developed into adults more slowly than those of uninfected mothers. This effect was exacerbated when mothers were reared on low food. Maternal food availability had no effect on the survival of their offspring up to emergence, and microsporidian infection decreased survival only slightly. Low food availability for mothers increased and V. culicis-infection of mothers decreased the likelihood that the offspring fed on malaria-infected blood harboured malaria parasites (but neither maternal treatment influenced their survival up to dissection. Conclusions Resource availability and infection with V. culicis of A. gambiae s.s. mosquitoes not only acted as direct environmental stimuli for changes in the success of one generation, but could also lead to maternal effects. Maternal V. culicis infection could make offspring more resistant and less likely to transmit malaria, thus enhancing the efficacy of the microsporidian for the biological control of malaria.

  7. Authentication scheme for routine verification of genetically similar laboratory colonies: a trial with Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    Sutcliffe Alice C

    2009-10-01

    Full Text Available Abstract Background When rearing morphologically indistinguishable laboratory strains concurrently, the threat of unintentional genetic contamination is constant. Avoidance of accidental mixing of strains is difficult due to the use of common equipment, technician error, or the possibility of self relocation by adult mosquitoes ("free fliers". In many cases, laboratory strains are difficult to distinguish because of morphological and genetic similarity, especially when laboratory colonies are isolates of certain traits from the same parental strain, such as eye color mutants, individuals with certain chromosomal arrangements or high levels of insecticide resistance. Thus, proving genetic integrity could seem incredibly time-consuming or impossible. On the other hand, lacking proof of genetically isolated laboratory strains could question the validity of research results. Results We present a method for establishing authentication matrices to routinely distinguish and confirm that laboratory strains have not become physically or genetically mixed through contamination events in the laboratory. We show a specific example with application to Anopheles gambiae sensu stricto strains at the Malaria Research and Reference Reagent Resource Center. This authentication matrix is essentially a series of tests yielding a strain-specific combination of results. Conclusion These matrix-based methodologies are useful for several mosquito and insect populations but must be specifically tailored and altered for each laboratory based on the potential contaminants available at any given time. The desired resulting authentication plan would utilize the least amount of routine effort possible while ensuring the integrity of the strains.

  8. The evolution of TEP1, an exceptionally polymorphic immunity gene in Anopheles gambiae

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    Yan Guiyun

    2008-10-01

    Full Text Available Abstract Background Host-parasite coevolution can result in balancing selection, which maintains genetic variation in the susceptibility of hosts to parasites. It has been suggested that variation in a thioester-containing protein called TEP1 (AGAP010815 may alter the ability of Anopheles mosquitoes to transmit Plasmodium parasites, and high divergence between alleles of this gene suggests the possible action of long-term balancing selection. We studied whether TEP1 is a case of an ancient balanced polymorphism in an animal immune system. Results We found evidence that the high divergence between TEP1 alleles is the product of genetic exchange between TEP1 and other TEP loci, i.e. gene conversion. Additionally, some TEP1 alleles showed unexpectedly low variability. Conclusion The TEP1 gene appears to be a chimera produced from at least two other TEP loci, and the divergence between TEP1 alleles is probably not caused by long-term balancing selection, but is instead due to two independent gene conversion events from one of these other genes. Nevertheless, TEP1 still shows evidence of natural selection, in particular there appears to have been recent changes in the frequency of alleles that has diminished polymorphism within each allelic class. Although the selective force driving this dynamic was not identified, given that susceptibility to Plasmodium parasites is known to be associated with allelic variation in TEP1, these changes in allele frequencies could alter the vectoring capacity of populations.

  9. Sexual transfer of the steroid hormone 20E induces the postmating switch in Anopheles gambiae

    Science.gov (United States)

    Gabrieli, Paolo; Kakani, Evdoxia G.; Mitchell, Sara N.; Mameli, Enzo; Want, Elizabeth J.; Mariezcurrena Anton, Ainhoa; Serrao, Aurelio; Baldini, Francesco; Catteruccia, Flaminia

    2014-01-01

    Female insects generally mate multiple times during their lives. A notable exception is the female malaria mosquito Anopheles gambiae, which after sex loses her susceptibility to further copulation. Sex in this species also renders females competent to lay eggs developed after blood feeding. Despite intense research efforts, the identity of the molecular triggers that cause the postmating switch in females, inducing a permanent refractoriness to further mating and triggering egg-laying, remains elusive. Here we show that the male-transferred steroid hormone 20-hydroxyecdysone (20E) is a key regulator of monandry and oviposition in An. gambiae. When sexual transfer of 20E is impaired by partial inactivation of the hormone and inhibition of its biosynthesis in males, oviposition and refractoriness to further mating in the female are strongly reduced. Conversely, mimicking sexual delivery by injecting 20E into virgin females switches them to an artificial mated status, triggering egg-laying and reducing susceptibility to copulation. Sexual transfer of 20E appears to incapacitate females physically from receiving seminal fluids by a second male. Comparative analysis of microarray data from females after mating and after 20E treatment indicates that 20E-regulated molecular pathways likely are implicated in the postmating switch, including cytoskeleton and musculature-associated genes that may render the atrium impenetrable to additional mates. By revealing signals and pathways shaping key processes in the An. gambiae reproductive biology, our data offer new opportunities for the control of natural populations of malaria vectors. PMID:25368171

  10. Molecular characterization, biological forms and sporozoite rate of Anopheles stephensi in southern Iran

    Institute of Scientific and Technical Information of China (English)

    Ali Reza Chavshin; Mohammad Ali Oshaghi; Hasan Vatandoost; Ahmad Ali Hanafi-Bojd; Ahmad Raeisi; Fatemeh Nikpoor

    2014-01-01

    Objective: To identify the biological forms, sporozoite rate and molecular characterization of the Anopheles stephensi (An. stephensi) in Hormozgan and Sistan-Baluchistan provinces, the most important malarious areas in Iran. Methods: Wild live An. stephensi samples were collected from different malarious areas in southern Iran. The biological forms were identified based on number of egg-ridges. Molecular characterization of biological forms was verified by analysis of the mitochondrial cytochrome oxidase subunit I and II (mtDNA-COI/COII). The Plasmodium infection was examined in the wild female specimens by species-specific nested–PCR method. Results: Results showed that all three biological forms including mysorensis, intermediate and type are present in the study areas. Molecular investigations revealed no genetic variation between mtDNA COI/COII sequences of the biological forms and no Plasmodium parasites was detected in the collected mosquito samples. Conclusions:Presence of three biological forms with identical sequences showed that the known biological forms belong to a single taxon and the various vectorial capacities reported for these forms are more likely corresponded to other epidemiological factors than to the morphotype of the populations. Lack of malaria parasite infection in An. stephensi, the most important vector of malaria, may be partly due to the success and achievement of ongoing active malaria control program in the region.

  11. Cuticular hydrocarbon discrimination/variation among strains of the mosquito, Anopheles (Cellia) stephensi Liston.

    Science.gov (United States)

    Anyanwu, G I; Davies, D H; Molyneux, D H; Phillips, A; Milligan, P J

    1993-06-01

    Cuticular lipids were removed from adult female Anopheles stephensi Liston and the hydrocarbons present were separated and quantified by gas chromatography. Comparison was made between the hydrocarbons of four An. stephensi strains: Russ, sensitive to DDT and malathion and originally isolated in the former U.S.S.R.; Beech, a DDT-resistant Indian strain with high sensitivity to Plasmodium species; St Mal, a strain from Pakistan shown to be resistant to malathion; and Iraq, a DDT-susceptible strain from Iraq. Discriminant analysis indicated that the four groups were distinct and that, on average, 78% of the population could be separated on the basis of the quantities of some of the cuticular hydrocarbons. The profiles of Beech and Russ or Russ and St Mal could be separated in 98% of the cases. There was reduced segregation between the profiles of St. Mal and Iraq, suggesting greater similarity in the hydrocarbons of these two strains. The usefulness of cuticular hydrocarbon in determining species relationships is discussed. PMID:8257238

  12. Datura metel-synthesized silver nanoparticles magnify predation of dragonfly nymphs against the malaria vector Anopheles stephensi.

    Science.gov (United States)

    Murugan, Kadarkarai; Dinesh, Devakumar; Kumar, Prabhu Jenil; Panneerselvam, Chellasamy; Subramaniam, Jayapal; Madhiyazhagan, Pari; Suresh, Udaiyan; Nicoletti, Marcello; Alarfaj, Abdullah A; Munusamy, Murugan A; Higuchi, Akon; Mehlhorn, Heinz; Benelli, Giovanni

    2015-12-01

    Malaria is a life-threatening disease caused by parasites transmitted to people and animals through the bites of infected mosquitoes. The employ of synthetic insecticides to control Anopheles populations leads to high operational costs, non-target effects, and induced resistance. Recently, plant-borne compounds have been proposed for efficient and rapid extracellular synthesis of mosquitocidal nanoparticles. However, their impact against predators of mosquito larvae has been poorly studied. In this study, we synthesized silver nanoparticles (AgNPs) using the Datura metel leaf extract as reducing and stabilizing agent. The biosynthesis of AgNPs was confirmed analyzing the excitation of surface plasmon resonance using ultraviolet-visible (UV-vis) spectroscopy. Scanning electron microscopy (SEM) showed the clustered and irregular shapes of AgNPs, with a mean size of 40-60 nm. The presence of silver was determined by energy-dispersive X-ray (EDX) spectroscopy. Fourier transform infrared (FTIR) spectroscopy analysis investigated the identity of secondary metabolites, which may be acting as AgNP capping agents. In laboratory, LC50 of D. metel extract against Anopheles stephensi ranged from 34.693 ppm (I instar larvae) to 81.500 ppm (pupae). LC50 of AgNP ranged from 2.969 ppm (I instar larvae) to 6.755 ppm (pupae). Under standard laboratory conditions, the predation efficiency of Anax immaculifrons nymphs after 24 h was 75.5 % (II instar larvae) and 53.5 % (III instar larvae). In AgNP-contaminated environment, predation rates were boosted to 95.5 and 78 %, respectively. Our results documented that D. metel-synthesized AgNP might be employed at rather low doses to reduce larval populations of malaria vectors, without detrimental effects on behavioral traits of young instars of the dragonfly Anax immaculifrons.

  13. Participation of irradiated Anopheles arabiensis males in swarms following field release in Sudan

    International Nuclear Information System (INIS)

    BACKGROUND: The success of the SIT depends on the; release of large numbers of sterile males, which are able to; compete for mates with the wild male population within the; target area. The processes of colonisation, mass production; and irradiation may reduce the competitiveness of sterile; males through genetic selection, loss of natural traits and; somatic damage. In this context, the capacity of released; sterile Anopheles arabiensis males to survive, disperse and; participate in swarms occurring at varying distances from; the release site was studied using mark-release-recapture; techniques.; METHODS: In order to assess their participation in; swarms, irradiated and marked laboratory-reared male; mosquitoes were released 50, 100 or 200 m from the; known site of a large swarm on three consecutive nights.; Males were collected from this large swarm on subsequent; nights. Over the three days a total of 8,100 males were released.; Mean distance travelled (MDT), daily probability of; survival and estimated population size were calculated; from the recapture data. An effect of male age at the time; of release on these parameters was observed.; RESULTS: Five per cent of the males released over three; days were recaptured. In two-, three- and four-day-old; males, MDT was 118, 178 and 170 m, and the daily survival; probability 0.95, 0.90 and 0.75, respectively. From the; recapture data on the first day following each release, the; Lincoln index gives an estimation of 32,546 males in the; natural population.; DISCUSSION: Sterile An. arabiensis males released into; the field were able to find and participate in existing; swarms, and possibly even initiate swarms. The survival; probability decreased with the age of male on release but; the swarm participation and the distance travelled by older; males seemed higher than for younger males. The inclusion; of a pre-release period may thus be beneficial to male competitiveness; and increase the attractiveness of adult sexing

  14. Dynamics of insecticide resistance in malaria vectors in Benin: first evidence of the presence of L1014S kdr mutation in Anopheles gambiae from West Africa

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    Ranson Hilary

    2011-09-01

    Full Text Available Abstract Background Insecticide resistance monitoring is essential to help national programmers to implement more effective and sustainable malaria control strategies in endemic countries. This study reported the spatial and seasonal variations of insecticide resistance in malaria vectors in Benin, West Africa. Methods Anopheles gambiae s.l populations were collected from October 2008 to June 2010 in four sites selected on the basis of different use of insecticides and environment. WHO susceptibility tests were carried out to detect resistance to DDT, fenitrothion, bendiocarb, permethrin and deltamethrin. The synergist piperonyl butoxide was used to assess the role of non-target site mechanisms in pyrethroid resistance. Anopheles gambiae mosquitoes were identified to species and to molecular M and S forms using PCR techniques. Molecular and biochemical assays were carried out to determine kdr and Ace.1R allelic frequencies and activity of the detoxification enzymes. Results Throughout the surveys very high levels of mortality to bendiocarb and fenitrothion were observed in An. gambiae s.l. populations. However, high frequencies of resistance to DDT and pyrethroids were seen in both M and S form of An. gambiae s.s. and Anopheles arabiensis. PBO increased the toxicity of permethrin and restored almost full susceptibility to deltamethrin. Anopheles gambiae s.l. mosquitoes from Cotonou and Malanville showed higher oxidase activity compared to the Kisumu susceptible strain in 2009, whereas the esterase activity was higher in the mosquitoes from Bohicon in both 2008 and 2009. A high frequency of 1014F kdr allele was initially showed in An. gambiae from Cotonou and Tori-Bossito whereas it increased in mosquitoes from Bohicon and Malanville during the second year. For the first time the L1014S kdr mutation was found in An. arabiensis in Benin. The ace.1R mutation was almost absent in An. gambiae s.l. Conclusion Pyrethroid and DDT resistance is

  15. The neotype of anopheles albitarsis (Diptera: culicidae O neótipo de Anopheles albitarsis (Diptera: Culicidae

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    Maria Goreti Rosa-Freitas

    1989-09-01

    Full Text Available Anopheles albitarsis neotype is described from specimens collected in Baradero, Argentina, in Shannon's trap, in horse and pig stables and on the progeny of engorded females. The description includes illustrations of adult female, male and female genitalias, scanning electron miscroscopy of the eggs and complete chaetotaxy of pupa and larva. The importance for electing a neotype is based on the realization that An. albitarsis is a complex of cryptic species. It is an attempt to provide typt-locality specimens with which other memebers of the group can be compared.O neótipo de Anopheles albitarsis é descrito a partir de espécimens coletados em armadilha tipo Shannon, em estábulos de cavalos e porcos e progênies de fêmeas ingurgitadas em Baradero, Argentina, localidade-tipo da espécie. A descrição inclui ilustrações da fêmea adulda, genitálias masculina e feminina, ovos em microscopia eletrônica de varredura e da quetotaxia completa das larvas de 4º estádio e pupas. A eleição de um neótipo para albitarsis baseia-se em dados recentes que apontam a espécie como um complexo de espécies crípticas, o que evidencia a importância de uma descrição detalhada de espécimens da localidade-tipo com o qual outros membros do grupo possam ser comparados.

  16. Comportamento exófilo de Anopheles darlingi Root, em região meridional do Brasil Exophilic behavior of Anopheles darlingi Root in a Southern Region of Brazil

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    Oswaldo Paulo Forattini

    1987-08-01

    Full Text Available Observou-se o comportamento da população "Araraquara" de Anopheles darlingi, em seu ambiente original e em relação à sua atividade exófila com isca humana. As coletas foram realizadas às margens do rio Jacaré-Pepira, no Município de Dourado, Estado de São Paulo, Brasil. O ciclo nictemeral caracteriza-se pelo aspecto bimodal, com os dois picos correspondentes a cada crepúsculo, ou seja, vespertino e matutino. O seu detalhamento permitiu detectar bimodalidade secundária, subdividindo cada pico em um eocrepuscular precedendo ao intracrepuscular propriamente dito. A variação sazonal revelou aumento do número de mosquitos na estação chuvosa e quente e nítido declínio na seca e fria. Embora com dados insuficientes, houve indícios de que o An. albitarsis local, apresente também ritmo bimodal em seu ciclo diário de atividade.Fortnightly 25-hour catches, with human bait, were carried out in a modified environment of the "Jacaré-Pepira" River, Dourado County, S. Paulo, Brazil which is the original region of the "Araraquara" strain of Anopheles darlingi. The exophylic biting activity was mostly nocturnal with bimodal rhythm, showing two clear peaks corresponding, respectively, to dusk and dawn. Going into crepuscular details two secondary peaks were observed, an eocrepuscular preceding the intracrepuscular one As, by means of chromosome arrangement studies, this population was found to have low polymorphism, it is supposed that those rhythms are, in a good measure, of endogenous command. The number of mosquitoes biting increased during the hot, wet season and decreased remarkably during the dry, cold one. There was some evidence that An albitarsis may also show a bimodality in its nocturnal biting activity rhythm.

  17. African water storage pots for the delivery of the Entomopathogenic fungus Metarhizium anisopliae to the Malaria vectors Anopheles gambiae s.s. and Anopheles funestus

    NARCIS (Netherlands)

    Farenhorst, M.; Farina, D.; Scholte, E.J.; Takken, W.; Hunt, R.H.; Coetzee, M.; Knols, B.G.J.

    2008-01-01

    We studied the use of African water storage pots for point source application of Metarhizium anisopliae against the malaria vectors Anopheles gambiae s.s. and An. funestus. Clay pots were shown to be attractive resting sites for male and female An. gambiae s.s. and were not repellent after impregnat

  18. Confirmation of Anopheles (Anopheles calderoni Wilkerson, 1991 (Diptera: Culicidae in Colombia and Ecuador through molecular and morphological correlation with topotypic material

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    Ranulfo González

    2010-12-01

    Full Text Available The morphologically similar taxa Anopheles calderoni, Anopheles punctimacula, Anopheles malefactor and Anopheles guarao are commonly misidentified. Isofamilies collected in Valle de Cauca, Colombia, showed morphological characters most similar to An. calderoni, a species which has never previously been reported in Colombia. Although discontinuity of the postsubcostal pale spots on the costa (C and first radial (R1 wing veins is purportedly diagnostic for An. calderoni, the degree of overlap of the distal postsubcostal spot on C and R1 were variable in Colombian specimens (0.003-0.024. In addition, in 98.2% of larvae, seta 1-X was located off the saddle and seta 3-C had 4-7 branches in 86.7% of specimens examined. Correlation of DNA sequences of the second internal transcribed spacer and mtDNA cytochrome c oxidase subunit I gene (COI barcodes (658 bp of the COI gene generated from Colombian progeny material and wild-caught mosquitoes from Ecuador with those from the Peruvian type series of An. calderoni confirmed new country records. DNA barcodes generated for the closely related taxa, An. malefactor and An. punctimacula are also presented for the first time. Examination of museum specimens at the University of the Valle, Colombia, revealed the presence of An. calderoni in inland localities across Colombia and at elevations up to 1113 m.

  19. Salivary gland proteome analysis reveals modulation of anopheline unique proteins in insensitive acetylcholinesterase resistant Anopheles gambiae mosquitoes.

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    Sylvie Cornelie

    Full Text Available Insensitive acetylcholinesterase resistance due to a mutation in the acetylcholinesterase (ace encoding ace-1 gene confers cross-resistance to organophosphate and carbamate insecticides in Anopheles gambiae populations from Central and West Africa. This mutation is associated with a strong genetic cost revealed through alterations of some life history traits but little is known about the physiological and behavioural changes in insects bearing the ace-1(R allele. Comparative analysis of the salivary gland contents between An. gambiae susceptible and ace-1(R resistant strains was carried out to charaterize factors that could be involved in modifications of blood meal process, trophic behaviour or pathogen interaction in the insecticide-resistant mosquitoes. Differential analysis of the salivary gland protein profiles revealed differences in abundance for several proteins, two of them showing major differences between the two strains. These two proteins identified as saglin and TRIO are salivary gland-1 related proteins, a family unique to anopheline mosquitoes, one of them playing a crucial role in salivary gland invasion by Plasmodium falciparum sporozoites. Differential expression of two other proteins previously identified in the Anopheles sialome was also observed. The differentially regulated proteins are involved in pathogen invasion, blood feeding process, and protection against oxidation, relevant steps in the outcome of malaria infection. Further functional studies and insect behaviour experiments would confirm the impact of the modification of the sialome composition on blood feeding and pathogen transmission abilities of the resistant mosquitoes. The data supports the hypothesis of alterations linked to insecticide resistance in the biology of the primary vector of human malaria in Africa.

  20. An Evolution-Based Screen for Genetic Differentiation between Anopheles Sister Taxa Enriches for Detection of Functional Immune Factors.

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    Christian Mitri

    2015-12-01

    Full Text Available Nucleotide variation patterns across species are shaped by the processes of natural selection, including exposure to environmental pathogens. We examined patterns of genetic variation in two sister species, Anopheles gambiae and Anopheles coluzzii, both efficient natural vectors of human malaria in West Africa. We used the differentiation signature displayed by a known coordinate selective sweep of immune genes APL1 and TEP1 in A. coluzzii to design a population genetic screen trained on the sweep, classified a panel of 26 potential immune genes for concordance with the signature, and functionally tested their immune phenotypes. The screen results were strongly predictive for genes with protective immune phenotypes: genes meeting the screen criteria were significantly more likely to display a functional phenotype against malaria infection than genes not meeting the criteria (p = 0.0005. Thus, an evolution-based screen can efficiently prioritize candidate genes for labor-intensive downstream functional testing, and safely allow the elimination of genes not meeting the screen criteria. The suite of immune genes with characteristics similar to the APL1-TEP1 selective sweep appears to be more widespread in the A. coluzzii genome than previously recognized. The immune gene differentiation may be a consequence of adaptation of A. coluzzii to new pathogens encountered in its niche expansion during the separation from A. gambiae, although the role, if any of natural selection by Plasmodium is unknown. Application of the screen allowed identification of new functional immune factors, and assignment of new functions to known factors. We describe biochemical binding interactions between immune proteins that underlie functional activity for malaria infection, which highlights the interplay between pathogen specificity and the structure of immune complexes. We also find that most malaria-protective immune factors display phenotypes for either human or rodent

  1. An Evolution-Based Screen for Genetic Differentiation between Anopheles Sister Taxa Enriches for Detection of Functional Immune Factors.

    Science.gov (United States)

    Mitri, Christian; Bischoff, Emmanuel; Takashima, Eizo; Williams, Marni; Eiglmeier, Karin; Pain, Adrien; Guelbeogo, Wamdaogo M; Gneme, Awa; Brito-Fravallo, Emma; Holm, Inge; Lavazec, Catherine; Sagnon, N'Fale; Baxter, Richard H; Riehle, Michelle M; Vernick, Kenneth D

    2015-12-01

    Nucleotide variation patterns across species are shaped by the processes of natural selection, including exposure to environmental pathogens. We examined patterns of genetic variation in two sister species, Anopheles gambiae and Anopheles coluzzii, both efficient natural vectors of human malaria in West Africa. We used the differentiation signature displayed by a known coordinate selective sweep of immune genes APL1 and TEP1 in A. coluzzii to design a population genetic screen trained on the sweep, classified a panel of 26 potential immune genes for concordance with the signature, and functionally tested their immune phenotypes. The screen results were strongly predictive for genes with protective immune phenotypes: genes meeting the screen criteria were significantly more likely to display a functional phenotype against malaria infection than genes not meeting the criteria (p = 0.0005). Thus, an evolution-based screen can efficiently prioritize candidate genes for labor-intensive downstream functional testing, and safely allow the elimination of genes not meeting the screen criteria. The suite of immune genes with characteristics similar to the APL1-TEP1 selective sweep appears to be more widespread in the A. coluzzii genome than previously recognized. The immune gene differentiation may be a consequence of adaptation of A. coluzzii to new pathogens encountered in its niche expansion during the separation from A. gambiae, although the role, if any of natural selection by Plasmodium is unknown. Application of the screen allowed identification of new functional immune factors, and assignment of new functions to known factors. We describe biochemical binding interactions between immune proteins that underlie functional activity for malaria infection, which highlights the interplay between pathogen specificity and the structure of immune complexes. We also find that most malaria-protective immune factors display phenotypes for either human or rodent malaria, with

  2. Parasite killing in malaria non-vector mosquito Anopheles culicifacies species B: implication of nitric oxide synthase upregulation.

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    Sonam Vijay

    Full Text Available BACKGROUND: Anopheles culicifacies, the main vector of human malaria in rural India, is a complex of five sibling species. Despite being phylogenetically related, a naturally selected subgroup species B of this sibling species complex is found to be a poor vector of malaria. We have attempted to understand the differences between vector and non-vector Anopheles culicifacies mosquitoes in terms of transcriptionally activated nitric oxide synthase (AcNOS physiologies to elucidate the mechanism of refractoriness. Identification of the differences between genes and gene products that may impart refractory phenotype can facilitate development of novel malaria transmission blocking strategies. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a study on phylogenetically related susceptible (species A and refractory (species B sibling species of An. culicifacies mosquitoes to characterize biochemical and molecular differences in AcNOS gene and gene elements and their ability to inhibit oocyst growth. We demonstrate that in species B, AcNOS specific activity and nitrite/nitrates in mid-guts and haemolymph were higher as compared to species A after invasion of the mid-gut by P. vivax at the beginning and during the course of blood feeding. Semiquantitative RT-PCR and real time PCR data of AcNOS concluded that this gene is more abundantly expressed in midgut of species B than in species A and is transcriptionally upregulated post blood meals. Dietary feeding of L-NAME along with blood meals significantly inhibited midgut AcNOS activity leading to an increase in oocyst production in An. culicifacies species B. CONCLUSIONS/SIGNIFICANCE: We hypothesize that upregulation of mosquito innate cytotoxicity due to NOS in refractory strain to Plasmodium vivax infection may contribute to natural refractoriness in An. culicifacies mosquito population. This innate capacity of refractory mosquitoes could represent the ancestral function of the mosquito immune system against

  3. DETECTION OF PUTATIVE ANTIMALARIAL-RESISTANT PLASMODIUM VIVAX IN ANOPHELES VECTORS AT THAILAND-CAMBODIA AND THAILAND-MYANMAR BORDERS.

    Science.gov (United States)

    Rattaprasert, Pongruj; Chaksangchaichot, Panee; Wihokhoen, Benchawan; Suparach, Nutjaree; Sorosjinda-Nunthawarasilp, Prapa

    2016-03-01

    Monitoring of multidrug-resistant (MDR)falciparum and vivax malaria has recently been included in the Global Plan for Artemisinin Resistance Containment (GPARC) of the Greater Mekong Sub-region, particularly at the Thailand-Cambodia and Thailand-Myanmar borders. In parallel to GPARC, monitoring MDR malaria parasites in anopheline vectors is an ideal augment to entomological surveillance. Employing Plasmodium- and species-specific nested PCR techniques, only P. vivax was detected in 3/109 salivary gland DNA extracts of anopheline vectors collected during a rainy season between 24-26 August 2009 and 22-24 September 2009 and a dry season between 29-31 December 2009 and 16-18 January 2010. Indoor and out- door resting mosquitoes were collected in Thong Pha Phum District, Kanchanaburi Province (border of Thailand-Myanmar) and Bo Rai District, Trat Province (border of Thailand-Cambodia): one sample from Anopheles dirus at the Thailand-Cambodia border and two samples from An. aconitus from Thailand-Myanmar border isolate. Nucleotide sequencing of dihydrofolate reductase gene revealed the presence in all three samples of four mutations known to cause high resistance to antifolate pyrimethamine, but no mutations were found in multidrug resistance transporter 1 gene that are associated with (falciparum) resistance to quinoline antimalarials. Such findings indicate the potential usefulness of this approach in monitoring the prevalence of drug-resistant malaria parasites in geographically regions prone to the development of drug resistance and where screening of human population at risk poses logistical and ethical problems. Keywords: Anopheles spp, Plasmodium vivax, antimalarial resistance, Greater Mekong Sub-region, nested PCR, vector surveillance PMID:27244954

  4. Comparison of experimental hut entrance and exit behavior between Anopheles darlingi from the Cayo District, Belize, and Zungarococha, Peru.

    Science.gov (United States)

    Sachs, Paige; Diaz Rodriguez, Gloria Alicia; Briceno, Ireneo; King, Russell; Achee, Nicole L; Grieco, John P

    2013-12-01

    Anopheles darlingi is a major vector for malaria in Central and South America. Behavioral, ecological, genetic, and morphologic variability has been observed across its wide distribution. Recent studies have documented that 2 distinct genotypes exist for An. darlingi: a northern lineage (Belize, Guatemala, Colombia, Venezuela, and Panama) and a southern lineage (Amazonia and southern Brazil). In order to determine if these genotypes exhibited different behavioral traits, entrance and exit movement patterns between 2 field populations of An. darlingi that represented each genotype were evaluated using experimental huts. The Belize population exhibited bimodal entrance, with peak entry occurring between 7:00-8:00 p.m. and 5:00-6:00 a.m. and peak exiting occurring between 7:00-8:00 p.m. The Peru population exhibited unimodal entrance, with peak entry occurring between 10:00-11:00 p.m. and peak exiting occurring between 11:00-12:00 a.m. with a secondary smaller peak at 2:30 a.m. Entrance and exit behavioral patterns were significantly different between the Belize and Peru populations of An. darlingi (log-rank [Mantel-Cox] P < 0.001). Information from the present study will be used in the future to determine if there is a correlation between genotype and host-seeking behavior and can be used in the present for regional vector risk assessment.

  5. A CRISPR-Cas9 gene drive system targeting female reproduction in the malaria mosquito vector Anopheles gambiae.

    Science.gov (United States)

    Hammond, Andrew; Galizi, Roberto; Kyrou, Kyros; Simoni, Alekos; Siniscalchi, Carla; Katsanos, Dimitris; Gribble, Matthew; Baker, Dean; Marois, Eric; Russell, Steven; Burt, Austin; Windbichler, Nikolai; Crisanti, Andrea; Nolan, Tony

    2016-01-01

    Gene drive systems that enable super-Mendelian inheritance of a transgene have the potential to modify insect populations over a timeframe of a few years. We describe CRISPR-Cas9 endonuclease constructs that function as gene drive systems in Anopheles gambiae, the main vector for malaria. We identified three genes (AGAP005958, AGAP011377 and AGAP007280) that confer a recessive female-sterility phenotype upon disruption, and inserted into each locus CRISPR-Cas9 gene drive constructs designed to target and edit each gene. For each targeted locus we observed a strong gene drive at the molecular level, with transmission rates to progeny of 91.4 to 99.6%. Population modeling and cage experiments indicate that a CRISPR-Cas9 construct targeting one of these loci, AGAP007280, meets the minimum requirement for a gene drive targeting female reproduction in an insect population. These findings could expedite the development of gene drives to suppress mosquito populations to levels that do not support malaria transmission. PMID:26641531

  6. A CRISPR-Cas9 gene drive system targeting female reproduction in the malaria mosquito vector Anopheles gambiae.

    Science.gov (United States)

    Hammond, Andrew; Galizi, Roberto; Kyrou, Kyros; Simoni, Alekos; Siniscalchi, Carla; Katsanos, Dimitris; Gribble, Matthew; Baker, Dean; Marois, Eric; Russell, Steven; Burt, Austin; Windbichler, Nikolai; Crisanti, Andrea; Nolan, Tony

    2016-01-01

    Gene drive systems that enable super-Mendelian inheritance of a transgene have the potential to modify insect populations over a timeframe of a few years. We describe CRISPR-Cas9 endonuclease constructs that function as gene drive systems in Anopheles gambiae, the main vector for malaria. We identified three genes (AGAP005958, AGAP011377 and AGAP007280) that confer a recessive female-sterility phenotype upon disruption, and inserted into each locus CRISPR-Cas9 gene drive constructs designed to target and edit each gene. For each targeted locus we observed a strong gene drive at the molecular level, with transmission rates to progeny of 91.4 to 99.6%. Population modeling and cage experiments indicate that a CRISPR-Cas9 construct targeting one of these loci, AGAP007280, meets the minimum requirement for a gene drive targeting female reproduction in an insect population. These findings could expedite the development of gene drives to suppress mosquito populations to levels that do not support malaria transmission.

  7. The resting sites and blood-meal sources of Anopheles minimus in Taiwan

    Directory of Open Access Journals (Sweden)

    Chen Yung-Chen

    2008-06-01

    Full Text Available Abstract Background The WHO declared Taiwan free from malaria in 1965, but in 2003 the reporting of two introduced cases in a rural area suggested a possible local transmission of this disease. Therefore, understanding the resting sites and the blood sources of Anopheles minimus is crucial in order to provide information for implementing vector control strategies. Methods During a two-year survey, mosquitoes were collected in houses and their surrounding areas and at the bank of larval habitats by backpack aspirators in 17 villages in rural areas of southern and eastern Taiwan for 1 hr. On the same day, blacklight traps were hung downward overnight. Blood-fed mosquito samples were analysed by PCR. Results Of the 195 total households surveyed by backpack aspirators, no Anopheles adults were collected inside the houses, while a single Anopheles minimus and a single Anopheles maculatus were collected outside of the houses. On the same day, 23 An. minimus, two An. maculatus, two Anopheles ludlowae, two Anopheles sinensis, and one Anopheles tessellatus were collected along the bank of larval habitats. In blacklight traps hung outside of the houses in the villages, 69 An. minimus, 62 An. ludlowae, 31 An. sinensis, and 19 An. maculatus were collected. In larval habitats, 98 An. ludlowae, 64 An. minimus, 49 An. sinensis, and 14 An. maculatus were collected. Of a total of 10 blood-fed samples, An. minimus fed on four animals including bovine (60%, dogs (20%, pig (10%, and non-chicken avian (10%. Conclusion Anopheles minimus, an opportunist feeder in Taiwan, was not collected inside the houses, but was found outside of the houses in villages and surrounding larval habitats. Therefore, an outdoor transmission of malaria is likely to occur and, thus, the bed nets, which are favoured for controlling the late biting of An. minimus, should be a very efficient and effective method for those local residents who sleep outdoors. Additionally, space spray of

  8. The nicotinic acetylcholine receptor gene family of the malaria mosquito, Anopheles gambiae.

    Science.gov (United States)

    Jones, Andrew K; Grauso, Marta; Sattelle, David B

    2005-02-01

    Nicotinic acetylcholine receptors (nAChRs) mediate fast cholinergic synaptic transmission in the insect nervous system and are targets of widely selling insecticides. We have identified the nAChR gene family from the genome of the malaria mosquito vector, Anopheles gambiae, to be the second complete insect nAChR gene family described following that of Drosophila melanogaster. Like Drosophila, Anopheles possesses 10 nAChR subunits with orthologous relationships evident between the two insects. Interestingly, the Anopheles orthologues of Dbeta2 and Dbeta3 possess the vicinal cysteines that define alpha subunits. As with Dalpha4 and Dalpha6, the Anopheles orthologues are alternatively spliced at equivalent exons. Reverse transcription-polymerase chain reaction analysis shows that RNA A-to-I editing sites conserved between Dalpha6 of Drosophila and alpha7-2 of the tobacco budworm, Heliothis virescens, are not shared with the equivalent nAChR subunit of Anopheles. Indeed, RNA-editing sites identified in functionally significant regions of Dbeta1, Dalpha5, and Dalpha6 are not conserved in the mosquito orthologues, indicating considerable divergence of RNA molecules targeted for editing within the insect order Diptera. These findings shed further light on the diversity of nAChR subunits and may present a useful basis for the development of improved malaria control agents by enhancing our understanding of a validated mosquito insecticide target.

  9. Identification of one capa and two pyrokinin receptors from the malaria mosquito Anopheles gambiae

    DEFF Research Database (Denmark)

    Olsen, Stine S; Cazzamali, Giuseppe; Williamson, Michael;

    2007-01-01

    We cloned the cDNA of three evolutionarily related G protein-coupled receptors from the malaria mosquito Anopheles gambiae and functionally expressed them in Chinese hamster ovary cells. One receptor, Ang-Capa-R, was only activated by the two Anopheles capa neuropeptides Ang-capa-1 (GPTVGLFAFPRVa......We cloned the cDNA of three evolutionarily related G protein-coupled receptors from the malaria mosquito Anopheles gambiae and functionally expressed them in Chinese hamster ovary cells. One receptor, Ang-Capa-R, was only activated by the two Anopheles capa neuropeptides Ang-capa-1...... (GPTVGLFAFPRVamide) and Ang-capa-2 (pQGLVPFPRVamide) with EC(50) values of 8.6x10(-9)M and 3.3x10(-9)M, respectively, but not by any other known mosquito neuropeptide. The second receptor, Ang-PK-1-R, was selectively activated by the Anopheles pyrokinin-1 peptides Ang-PK-1-1 (AGGTGANSAMWFGPRLamide) and Ang-PK-1......-2 (AAAMWFGPRLamide) with EC(50) values of 3.3x10(-8)M and 2.5x10(-8)M, respectively, but not by mosquito capa or pyrokinin-2 peptides. For the third receptor, Ang-PK-2-R, the most potent ligands were the pyrokinin-2 peptides Ang-PK-2-1 (DSVGENHQRPPFAPRLamide) and Ang-PK-2-2 (NLPFSPRLamide) with EC(50) values of 5.2x...

  10. Anopheles gambiae Purine Nucleoside Phosphorylase: Catalysis, Structure, and Inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Taylor,E.; Rinaldo-Matthis, A.; Li, L.; Ghanem, M.; Hazleton, K.; Cassera, M.; Almo, S.; Schramm, V.

    2007-01-01

    The purine salvage pathway of Anopheles gambiae, a mosquito that transmits malaria, has been identified in genome searches on the basis of sequence homology with characterized enzymes. Purine nucleoside phosphorylase (PNP) is a target for the development of therapeutic agents in humans and purine auxotrophs, including malarial parasites. The PNP from Anopheles gambiae (AgPNP) was expressed in Escherichia coli and compared to the PNPs from Homo sapiens (HsPNP) and Plasmodium falciparum (PfPNP). AgPNP has kcat values of 54 and 41 s-1 for 2'-deoxyinosine and inosine, its preferred substrates, and 1.0 s-1 for guanosine. However, the chemical step is fast for AgPNP at 226 s-1 for guanosine in pre-steady-state studies. 5'-Deaza-1'-aza-2'-deoxy-1'-(9-methylene)-Immucillin-H (DADMe-ImmH) is a transition-state mimic for a 2'-deoxyinosine ribocation with a fully dissociated N-ribosidic bond and is a slow-onset, tight-binding inhibitor with a dissociation constant of 3.5 pM. This is the tightest-binding inhibitor known for any PNP, with a remarkable Km/Ki* of 5.4 x 107, and is consistent with enzymatic transition state predictions of enhanced transition-state analogue binding in enzymes with enhanced catalytic efficiency. Deoxyguanosine is a weaker substrate than deoxyinosine, and DADMe-Immucillin-G is less tightly bound than DADMe-ImmH, with a dissociation constant of 23 pM for AgPNP as compared to 7 pM for HsPNP. The crystal structure of AgPNP was determined in complex with DADMe-ImmH and phosphate to a resolution of 2.2 Angstroms to reveal the differences in substrate and inhibitor specificity. The distance from the N1' cation to the phosphate O4 anion is shorter in the AgPNP{center_dot}DADMe-ImmH{center_dot}PO4 complex than in HsPNP{center_dot}DADMe-ImmH{center_dot}SO4, offering one explanation for the stronger inhibitory effect of DADMe-ImmH for AgPNP.

  11. Larval control of Anopheles (Nyssorhinchus darlingi using granular formulation of Bacillus sphaericus in abandoned gold-miners excavation pools in the Brazilian Amazon Rainforest

    Directory of Open Access Journals (Sweden)

    Allan Kardec Ribeiro Galardo

    2013-09-01

    Full Text Available INTRODUCTION: Use of a Bacillus sphaericus based mosquito larvicide was evaluated as an intervention for malaria vector control at a mining site in Amapá, Brazil. Impacts on larval and adult densities of the primary vector Anopheles darlingi were measured over the course of a 52 week study period. METHODS: In Calçoene, State of Amapá, gold mining activity occurs in 19 mining sites in gold-miners of Lourenço. Large pools are formed in mining sites and naturally colonized by Anopheles darlingi. During one year, the impact of applications of VectoLex(r CG to these larval sources was evaluated. Applications of 20kg/ha were made as needed, based on 10 immature (3rd, 4th instars and pupae surveillance of health and established thresholds. RESULTS: One hundred percent initial control was observed 48h after each treatment. The pools received from 2-10 (5.3±1.6 treatments during the year. The average re-treatment interval in productive pools was 9.4±4.3 weeks. During weeks 3-52 of the study, mean density of late stage larvae was 78% and pupae were 93% lower in the treated pools than in untreated pools (p< 0.0001, n=51 while reduction of adult mosquitoes was 53% in comparison to the untreated area during the last five months of the study, which were the rainy season (p<0.001. CONCLUSIONS: VectoLex(r CG reduced immature Anopheles darlingi infestation levels during the entire study period, and reduced adult mosquito populations during the rainy season.

  12. Larval control of Anopheles (Nyssorhinchus darlingi using granular formulation of Bacillus sphaericus in abandoned gold-miners excavation pools in the Brazilian Amazon Rainforest

    Directory of Open Access Journals (Sweden)

    Allan Kardec Ribeiro Galardo

    2013-04-01

    Full Text Available INTRODUCTION: Use of a Bacillus sphaericus based mosquito larvicide was evaluated as an intervention for malaria vector control at a mining site in Amapá, Brazil. Impacts on larval and adult densities of the primary vector Anopheles darlingi were measured over the course of a 52 week study period. METHODS: In Calçoene, State of Amapá, gold mining activity occurs in 19 mining sites in gold-miners of Lourenço. Large pools are formed in mining sites and naturally colonized by Anopheles darlingi. During one year, the impact of applications of VectoLex(r CG to these larval sources was evaluated. Applications of 20kg/ha were made as needed, based on 10 immature (3rd, 4th instars and pupae surveillance of health and established thresholds. RESULTS: One hundred percent initial control was observed 48h after each treatment. The pools received from 2-10 (5.3±1.6 treatments during the year. The average re-treatment interval in productive pools was 9.4±4.3 weeks. During weeks 3-52 of the study, mean density of late stage larvae was 78% and pupae were 93% lower in the treated pools than in untreated pools (p< 0.0001, n=51 while reduction of adult mosquitoes was 53% in comparison to the untreated area during the last five months of the study, which were the rainy season (p<0.001. CONCLUSIONS: VectoLex(r CG reduced immature Anopheles darlingi infestation levels during the entire study period, and reduced adult mosquito populations during the rainy season.

  13. Bacterial diversity associated with wild caught Anopheles mosquitoes from Dak Nong Province, Vietnam using culture and DNA fingerprint.

    Directory of Open Access Journals (Sweden)

    Chung Thuy Ngo

    Full Text Available Microbiota of Anopheles midgut can modulate vector immunity and block Plasmodium development. Investigation on the bacterial biodiversity in Anopheles, and specifically on the identification of bacteria that might be used in malaria transmission blocking approaches, has been mainly conducted on malaria vectors of Africa. Vietnam is an endemic country for both malaria and Bancroftian filariasis whose parasitic agents can be transmitted by the same Anopheles species. No information on the microbiota of Anopheles mosquitoes in Vietnam was available previous to this study.The culture dependent approach, using different mediums, and culture independent (16S rRNA PCR - TTGE method were used to investigate the bacterial biodiversity in the abdomen of 5 Anopheles species collected from Dak Nong Province, central-south Vietnam. Molecular methods, sequencing and phylogenetic analysis were used to characterize the microbiota.The microbiota in wild-caught Anopheles was diverse with the presence of 47 bacterial OTUs belonging to 30 genera, including bacterial genera impacting Plasmodium development. The bacteria were affiliated with 4 phyla, Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria, the latter being the dominant phylum. Four bacterial genera are newly described in Anopheles mosquitoes including Coxiella, Yersinia, Xanthomonas, and Knoellia. The bacterial diversity per specimen was low ranging from 1 to 4. The results show the importance of pairing culture and fingerprint methods to better screen the bacterial community in Anopheles mosquitoes.Sampled Anopheles species from central-south Vietnam contained a diverse bacterial microbiota that needs to be investigated further in order to develop new malaria control approaches. The combination of both culture and DNA fingerprint methods allowed a thorough and complementary screening of the bacterial community in Anopheles mosquitoes.

  14. Bacterial Diversity Associated with Wild Caught Anopheles Mosquitoes from Dak Nong Province, Vietnam Using Culture and DNA Fingerprint

    Science.gov (United States)

    Ngo, Chung Thuy; Aujoulat, Fabien; Veas, Francisco; Jumas-Bilak, Estelle; Manguin, Sylvie

    2015-01-01

    Background Microbiota of Anopheles midgut can modulate vector immunity and block Plasmodium development. Investigation on the bacterial biodiversity in Anopheles, and specifically on the identification of bacteria that might be used in malaria transmission blocking approaches, has been mainly conducted on malaria vectors of Africa. Vietnam is an endemic country for both malaria and Bancroftian filariasis whose parasitic agents can be transmitted by the same Anopheles species. No information on the microbiota of Anopheles mosquitoes in Vietnam was available previous to this study. Method The culture dependent approach, using different mediums, and culture independent (16S rRNA PCR – TTGE) method were used to investigate the bacterial biodiversity in the abdomen of 5 Anopheles species collected from Dak Nong Province, central-south Vietnam. Molecular methods, sequencing and phylogenetic analysis were used to characterize the microbiota. Results and Discussion The microbiota in wild-caught Anopheles was diverse with the presence of 47 bacterial OTUs belonging to 30 genera, including bacterial genera impacting Plasmodium development. The bacteria were affiliated with 4 phyla, Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria, the latter being the dominant phylum. Four bacterial genera are newly described in Anopheles mosquitoes including Coxiella, Yersinia, Xanthomonas, and Knoellia. The bacterial diversity per specimen was low ranging from 1 to 4. The results show the importance of pairing culture and fingerprint methods to better screen the bacterial community in Anopheles mosquitoes. Conclusion Sampled Anopheles species from central-south Vietnam contained a diverse bacterial microbiota that needs to be investigated further in order to develop new malaria control approaches. The combination of both culture and DNA fingerprint methods allowed a thorough and complementary screening of the bacterial community in Anopheles mosquitoes. PMID:25747513

  15. Inactivation of Anopheles gambiae Glutathione Transferase ε2 by Epiphyllocoumarin

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    Patience Marimo

    2016-01-01

    Full Text Available Glutathione transferases (GSTs are part of a major family of detoxifying enzymes that can catalyze the reductive dehydrochlorination of dichlorodiphenyltrichloroethane (DDT. The delta and epsilon classes of insect GSTs have been implicated in conferring resistance to this insecticide. In this study, the inactivation of Anopheles gambiae GSTε2 by epiphyllocoumarin (Tral 1 was investigated. Recombinant AgGSTε2 was expressed in Escherichia coli cells containing a pET3a-AGSTε2 plasmid and purified by affinity chromatography. Tral 1 was shown to inactivate GSTε2 both in a time-dependent manner and in a concentration-dependent manner. The half-life of GSTε2 in the presence of 25 μM ethacrynic acid (ETA was 22 minutes and with Tral 1 was 30 minutes, indicating that Tral 1 was not as efficient as ETA as an inactivator. The inactivation parameters kinact and KI were found to be 0.020 ± 0.001 min−1 and 7.5 ± 2.1 μM, respectively, after 90 minutes of incubation. Inactivation of GSTε2 by Tral 1 implies that Tral 1 covalently binds to this enzyme in vitro and would be expected to exhibit time-dependent effects on the enzyme in vivo. Tral 1, therefore, would produce irreversible effects when used together with dichlorodiphenyltrichloroethane (DDT in malaria control programmes where resistance is mediated by GSTs.

  16. TEMPAT PERKEMBANGBIAKAN ANOPHELES ACONITUS DI KABUPATEN JEPARA, JAWA TENGAH

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    Mardiana Mardiana

    2012-10-01

    Full Text Available Kabupaten Jepara adalah salah satu kabupaten endemis malaria di Jawa Tengah. Kasus malaria di Kabupaten Jepara terjadi akibat interaksi antara nyamuk/vektor, parasit, lingkungan dan manusia yang mengalami perubahan dari waktu ke waktu. Penelitian tempat perkembangbiakan vektor malaria Anopheles aconitus dilakukan di Desa Buaran, Kecamatan Mayong, Kabupaten Jepara, Jawa Tengah pada tahun 2000. Tujuan penelitian mengetahui pengaruh perubahan lingkungan alami dan perubahan buatan oleh manusia terhadap tempat perkembangbiakan An. aconitus. Metode penelitian dengan cara pengumpulan larva dan pupa yang dilakukan pada pagi hari dengan menggunakan cidukan di tempat-tempat genangan air yang diduga sebagai tempat perkembangbiakan An. aconitus Dari hasil pengambilan jentik di sawah, saluran irigasi, sungai dan lubang/kobakan bekas  galian pasir yang digenangi air, ternyata yang banyak ditemukan adalah jentik An. aconitus dari 6 spesies jentik nyamuk yang teridentifikasi. Habitat utama An. aconitus di Kabupaten Jepara adalah persawahan. Perubahan habitat terjadi dengan adanya perubahan lingkungan dan musim, dimana pada musim kemarau sebagian sawah menjadi kering, sehingga mempengaruhi peril'aku nyamuk  untuk mencari habitat yang baru seperti  sungai  dan  saluran irigasi. Selain perubahan musim juga adanya lubang/kobakan yang digenangan air bekas galian pasir di sepanjang tepi sungai, sebagai akibat perbuatan dari penduduk setempat, sehingga menjadi habitat baru dari nyamuk terutama An.aconitus. Kata Kunci : Tempat Perkembangbiakan, An. aconitus, Malaria,

  17. Resistance Mechanisms of Anopheles stephensi (Diptera: Culicidae to Temephos

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    Aboozar Soltani

    2015-10-01

    Full Text Available Background: Anopheles stephensi is a sub-tropical species and has been considered as one of the most important vector of human malaria throughout the Middle East and South Asian region including the malarious areas of southern Iran. Current reports confirmed An. stephensi resistance to temephos in Oman and India. However, there is no comprehensive research on mechanisms of temephos resistance in An. stephensi in the literature. This study was designed in order to clarify the enzymatic and molecular mechanisms of temephos resistance in this species.Methods: Profile activities of α- and ß-esterases, mixed function oxidase (MFO, glutathione-S-transferase (GST, insensitive acetylcholinesterase, and para-nitrophenyl acetate (PNPA-esterase enzymes were tested for An. stephensi strain with resistance ratio of 15.82 to temephos in comparison with susceptible strain.Results: Results showed that the mean activity of α-EST, GST and AChE enzymes were classified as altered indicating metabolic mechanisms have considerable role in resistance of An. stephensi to temephos. Molecular study using PCR-RFLP method to trace the G119S mutation in ACE-1 gene showed lack of the mutation responsible for organophosphate insecticide resistance in the temephos-selected strain of An. stephensi.Conclusion: This study showed that the altered enzymes but not targets site insensitivity of ACE-1 are responsible for temephos resistance in An. stephensi in south of Iran.

  18. Observaciones sobre Phlebotomus y Anopheles en el Callejon de Huaylas

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    Arístides Herrer

    1943-03-01

    Full Text Available Se han llevado a cabo observaciones entomológicas en relación con la verruga y el paludismo en la zona del Callejón de Huaylas comprendida desde la ciudad de Yuramarca a la de Huarás, prestando especial atención a la región del Cañón del Pato. Se indica, como resultados de tales observaciones, la presencia de las titiras: Phlebotomus verrucarum, P. peruensis, P. noguchii y una especia nueva, señalando detenidamente las localidades donde se las han encontrado. El P. verrucarum, principal trasmisor de la verruga, se halla a lo largo de toda la zona estudiada, siendo su número bastante reducido en la ciudad de Huarás. Desde Yuramarca hasta cerca de la ciudad de Carás se ha encontrado únicamente el Anopheles pseudopunctipennis, tanto larvas como adultos. Sus criaderos se encuentran principalmente en las márgenes del río Santa, en las de algunos afluentes de éste y en numerosos, manantiales.

  19. Innate immunity against malaria parasites in Anopheles gambiae

    Institute of Scientific and Technical Information of China (English)

    Yang Chenand; Zhi-Hui Weng; Liangbiao Zheng

    2008-01-01

    Malaria continues to exert a huge toll in the world today, causing approximately 400 million cases and killing between 1-2 million people annually. Most of the malaria burden is borne by countries in Africa. For this reason, the major vector for malaria in this continent, Anopheles gambiae, is under intense study. With the completion of the draft sequence of this important vector, efforts are underway to develop novel control strategies.One promising area is to harness the power of the innate immunity of this mosquito species to block the transmission of the malaria parasites. Recent studies have demonstrated that Toll and Imd signaling pathways and other immunity-related genes (encoding proteins possibly function in recognition or as effector molecules) play significant roles in two different arms of innate immunity: level of infection intensity and melanization of Plasmodium oocysts.The challenges in the future are to understand how the functions of these different genes are coordinated in defense against malaria parasites, and if different arms of innate immunity are cross-regulated or coordinated.

  20. Transcriptome analysis of Anopheles stephensi embryo using expressed sequence tags

    Indian Academy of Sciences (India)

    Kaustubh Gokhale; Deepak P Patil; Dhiraj P Dhotre; Rajnikant Dixit; Murlidhar J Mendki; Milind S Patole; Yogesh S Shouche

    2013-06-01

    Germ band retraction (GBR) stage is one of the important stages during insect development. It is associated with an extensive epithelial morphogenesis and may also be pivotal in generation of morphological diversity in insects. Despite its importance, only a handful of studies report the transcriptome repertoire of this stage in insects. Here, we report generation, annotation and analysis of ESTs from the embryonic stage (16–22 h post fertilization) of laboratory-reared Anopheles stephensi mosquitoes. A total of 1002 contigs were obtained upon clustering of 1140 high-quality ESTs, which demonstrates an astonishingly low transcript redundancy (12.1%). Putative functions were assigned only to 213 contigs (21%), comprising mainly of transcripts encoding protein synthesis machinery. Approximately 78% of the transcripts remain uncharacterized, illustrating a lack of sequence information about the genes expressed in the embryonic stages of mosquitoes. This study highlights several novel transcripts, which apart from insect development, may significantly contribute to the essential biological complexity underlying insect viability in adverse environments. Nonetheless, the generated sequence information from this work provides a comprehensive resource for genome annotation, microarray development, phylogenetic analysis and other molecular biology applications in entomology.

  1. FAUNA DAN TEMPAT PERKEMBANGBIAKAN POTENSIAL NYAMUK Anopheles spp DI KECAMATAN MAYONG, KABUPATEN JEPARA, JAWA TENGAH

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    Mardiana Mardiana

    2012-10-01

    Full Text Available Malaria masih merupakan masalah kesehatan masyarakat di beberapa daerah pedesaan di Jawa Tengah. Usaha pemberantasan malaria telah dilakukan oleh program baik secara kimiawi maupun hayati, guna memutuskan rantai penularan. Penelitian fauna dan tempat perindukan potensial nyamuk Anopheles telah dilakukan di Desa Buaran, Kecamatan Mayong I, Kabupaten Jepara, Jawa Tengah. Penangkapan nyamuk dengan umpan orang dilakukan di dalam dan di luar rumah pada malam hari dari pukul 18.00-24.00 yang masing-masing dilakukan oleh dua orang kolektor. Penangkapan nyamuk yang istirahat di dalam dan luar rumah (vegetasi pada pagi hari dilakukan pukul 06.00-08.00, yang dilakukan satu bulan 4 kali penangkapan selama 6 bulan. Pengambilan larva dan pupa dilakukan dari pukul 06.00-08.00 pagi di tempat genangan air dan sawah serta tempat yang potensial diduga sebagai perindukan Anopheles. Hasil penangkapan selama 6 bulan, diperoleh 1248 ekor nyamuk Anopheles yang terdiri dari 6 spesies yaitu: An. aconitus 442 ekor (35,42%, An. annularis 69 ekor (5,53% , An. barbirostris 30 ekor (2,4%, An. maculatus 2 ekor (0,16%, An. tesselatus 5 ekor (0,40% dan An. vagus 700 ekor (56,09%. Populasi aconitus ditemukan dari penangkapan di luar rumah, pada bulan Juli (56,40%, Agustus (42,80% dan Oktober (39,50% sedangkan pada bulan Mei (52,9%, Juni (44% dan September (50,40% dari penangkapan di kandang sapi. Pengambilan larva dan pupa Anopheles dilakukan di tempat habitat seperti sawah yang pada bulan Aguslus terbanyak ditemukan sebesar 85 (1.70, di sungai ditemukan hanya 4 (0.08 serta di genangan air bekas telapak kaki/kobokan ditemukan sebesar 6 (0.12. Ternyata tempat perindukan yang potensial larva Anopheles pada musim kemarau, ditemukan pada sungai yang ditanami kangkung oleh masyarakat selempat. Kata kunci: Fauna, tempat perindukan, Anopheles, vector

  2. Field evaluation of deet against Anopheles farauti at Ndendo (Santa Cruz) Island, Solomon Islands.

    Science.gov (United States)

    Frances, S P; Bugoro, H; Butafa, C; Cooper, R D

    2010-09-01

    Field efficacy studies comparing two formulations of deet (N,N-diethyl-3-methylbenzamide) against mosquitoes were conducted on Ndendo Island, Solomon Islands. The repellent study was conducted at Pala village in November 2008, and the only mosquito species collected was Anopheles farauti Laveran. A formulation containing 35% deet in a gel provided >95% protection for 2 h, whereas a formulation containing 40% deet in ethanol in a spray applicator provided >95% for only 1 h. This field study demonstrated again that repellents containing deet provide a relatively short period of complete protection against Anopheles spp. PMID:20939380

  3. Molecular identification of a myosuppressin receptor from the malaria mosquito Anopheles gambiae

    DEFF Research Database (Denmark)

    Schöller, Susanne; Belmont, Martin; Cazzamali, Giuseppe;

    2005-01-01

    The insect myosuppressins (X1DVX2HX3FLRFamide) are neuropeptides that generally block insect muscle activities. We have used the genomic sequence information from the malaria mosquito Anopheles gambiae Genome Project to clone a G protein-coupled receptor that was closely related to the two...... previously cloned and characterized myosuppressin receptors from Drosophila [Proc. Natl. Acad. Sci. USA 100 (2003) 9808]. The mosquito receptor cDNA was expressed in Chinese hamster ovary cells and was found to be activated by low concentrations of Anopheles myosuppressin (TDVDHVFLRFamide; EC50, 1.6 x 10...... identification of a mosquito neuropeptide receptor....

  4. Identification of the Temperature Induced Larvicidal Efficacy of Agave angustifolia against Aedes, Culex, and Anopheles Larvae.

    Science.gov (United States)

    Kajla, Mithilesh; Bhattacharya, Kurchi; Gupta, Kuldeep; Banerjee, Ujjwal; Kakani, Parik; Gupta, Lalita; Kumar, Sanjeev

    2015-01-01

    Synthetic insecticides are generally employed to control the mosquito population. However, their injudicious over usage and non-biodegradability are associated with many adverse effects on the environment and mosquitoes. The application of environment-friendly mosquitocidals might be an alternate to overcome these issues. In this study, we found that organic or aqueous extracts of Agave angustifolia leaves exhibited a strong larvicidal activity (LD50 28.27 μg/ml) against Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi larvae within a short exposure of 12 h. The larvicidal activity of A. angustifolia is inherited and independent of the plants vegetative growth. Interestingly, the plant larvicidal activity was observed exclusively during the summer season (April-August, when outside temperature is between 30 and 50°C) and it was significantly reduced during winter season (December-February, when the outside temperature falls to ~4°C or lower). Thus, we hypothesized that the larvicidal components of A. angustifolia might be induced by the manipulation of environmental temperature and should be resistant to the hot conditions. We found that the larvicidal activity of A. angustifolia was induced when plants were maintained at 37°C in a semi-natural environment against the controls that were growing outside in cold weather. Pre-incubation of A. angustifolia extract at 100°C for 1 h killed 60% larvae in 12 h, which gradually increased to 100% mortality after 24 h. In addition, the dry powder formulation of A. angustifolia, also displayed a strong larvicidal activity after a long shelf life. Together, these findings revealed that A. angustifolia is an excellent source of temperature induced bioactive metabolites that may assist the preparedness for vector control programs competently. PMID:26793700

  5. Remote sensing and environment in the study of the malaria vector Anopheles gambiae in Mali

    Science.gov (United States)

    Rian, Sigrid Katrine Eivindsdatter

    The malaria mosquito Anopheles gambiae is the most important vector for the most devastating form of human malaria, the parasite Plasmodium falciparum. In-depth knowledge of the vector's history and environmental preferences is essential in the pursuit of new malaria mitigation strategies. Research was conducted in Mali across a range of habitats occupied by the vector, focusing on three identified chromosomal forms in the mosquito complex. The development of a 500-m landcover classification map was carried out using MODIS satellite imagery and extensive ground survey. The resulting product has the highest resolution and is the most up-to-date and most extensively ground-surveyed among land-cover maps for the study region. The new landcover classification product is a useful tool in the mapping of the varying ecological preferences of the different An. gambiae chromosomal forms. Climate and vegetation characteristics and their relationship to chromosomal forms were investigated further along a Southwest-Northeast moisture gradient in Mali. This research demonstrates particular ecological preferences of each chromosomal form, and gives a detailed examination of particular vegetation structural and climatological patterns across the study region. A key issue in current research into the population structure of An. gambiae is speciation and evolution in the complex, as an understanding of the mechanisms of change can help in the development of new mitigation strategies. A historical review of the paleoecology, archaeology, and other historical sources intended to shed light on the evolutionary history of the vector is presented. The generally held assumption that the current breed of An. gambiae emerged in the rainforest is called into question and discussed within the framework of paleoenvironment and human expansions in sub-Saharan West Africa.

  6. Cuticle thickening associated with pyrethroid resistance in the major malaria vector Anopheles funestus

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    Coetzee M

    2010-08-01

    Full Text Available Abstract Background Malaria in South Africa is primarily transmitted by Anopheles funestus Giles. Resistance to pyrethroid insecticides in An. funestus in northern Kwazulu/Natal, South Africa, and in neighbouring areas of southern Mozambique enabled populations of this species to increase their ranges into areas where pyrethroids were being exclusively used for malaria control. Pyrethroid resistance in southern African An. funestus is primarily conferred by monooxygenase enzyme metabolism. However, selection for this resistance mechanism is likely to have occurred in conjunction with other factors that improve production of the resistance phenotype. A strong candidate is cuticle thickening. This is because thicker cuticles lead to slower rates of insecticide absorption, which is likely to increase the efficiency of metabolic detoxification. Results Measures of mean cuticle thickness in laboratory samples of female An. funestus were obtained using scanning electron microscopy (SEM. These females were drawn from a laboratory colony carrying the pyrethroid resistance phenotype at a stable rate, but not fixed. Prior to cuticle thickness measurements, these samples were characterised as either more or less tolerant to permethrin exposure in one experiment, and either permethrin resistant or susceptible in another experiment. There was a significant and positive correlation between mean cuticle thickness and time to knock down during exposure to permethrin. Mean cuticle thickness was significantly greater in those samples characterised either as more tolerant or resistant to permethrin exposure compared to those characterised as either less tolerant or permethrin susceptible. Further, insecticide susceptible female An. funestus have thicker cuticles than their male counterparts. Conclusion Pyrethroid tolerant or resistant An. funestus females are likely to have thicker cuticles than less tolerant or susceptible females, and females generally have

  7. Transcription regulation of sex-biased genes during ontogeny in the malaria vector Anopheles gambiae.

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    Kalle Magnusson

    Full Text Available In Anopheles gambiae, sex-regulated genes are responsible for controlling gender dimorphism and are therefore crucial in determining the ability of female mosquitoes to transmit human malaria. The identification and functional characterization of these genes will shed light on the sexual development and maturation of mosquitoes and provide useful targets for genetic control measures aimed at reducing mosquito fertility and/or distorting the sex ratio.We conducted a genome wide transcriptional analysis of sex-regulated genes from early developmental stages through adulthood combined with functional screening of novel gonadal genes. Our results demonstrate that the male-biased genes undergo a major transcription turnover starting from larval stages to adulthood. The male biased genes at the adult stage include a significant high number of unique sequences compared to the rest of the genome. This is in contrast to female-biased genes that are much more conserved and are mainly activated during late developmental stages.The high frequency of unique sequences would indicate that male-biased genes evolve more rapidly than the rest of the genome. This finding is particularly intriguing because A. gambiae is a strictly female monogamous species suggesting that driving forces in addition to sperm competition must account for the rapid evolution of male-biased genes. We have also identified and functionally characterized a number of previously unknown A. gambiae testis- and ovary-specific genes. Two of these genes, zero population growth and a suppressor of defective silencing 3 domain of the histone deacetylase co-repressor complex, were shown to play a key role in gonad development.

  8. Genetic dissection of Anopheles gambiae gut epithelial responses to Serratia marcescens.

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    Stavros Stathopoulos

    2014-03-01

    Full Text Available Genetic variation in the mosquito Anopheles gambiae profoundly influences its ability to transmit malaria. Mosquito gut bacteria are shown to influence the outcome of infections with Plasmodium parasites and are also thought to exert a strong drive on genetic variation through natural selection; however, a link between antibacterial effects and genetic variation is yet to emerge. Here, we combined SNP genotyping and expression profiling with phenotypic analyses of candidate genes by RNAi-mediated silencing and 454 pyrosequencing to investigate this intricate biological system. We identified 138 An. gambiae genes to be genetically associated with the outcome of Serratia marcescens infection, including the peptidoglycan recognition receptor PGRPLC that triggers activation of the antibacterial IMD/REL2 pathway and the epidermal growth factor receptor EGFR. Silencing of three genes encoding type III fibronectin domain proteins (FN3Ds increased the Serratia load and altered the gut microbiota composition in favor of Enterobacteriaceae. These data suggest that natural genetic variation in immune-related genes can shape the bacterial population structure of the mosquito gut with high specificity. Importantly, FN3D2 encodes a homolog of the hypervariable pattern recognition receptor Dscam, suggesting that pathogen-specific recognition may involve a broader family of immune factors. Additionally, we showed that silencing the gene encoding the gustatory receptor Gr9 that is also associated with the Serratia infection phenotype drastically increased Serratia levels. The Gr9 antibacterial activity appears to be related to mosquito feeding behavior and to mostly rely on changes of neuropeptide F expression, together suggesting a behavioral immune response following Serratia infection. Our findings reveal that the mosquito response to oral Serratia infection comprises both an epithelial and a behavioral immune component.

  9. Identification of the temperature- induced larvicidal efficacy of Agave angustifolia against Aedes, Culex and Anopheles larvae

    Directory of Open Access Journals (Sweden)

    Mithilesh eKajla

    2016-01-01

    Full Text Available Synthetic insecticides are generally employed to control the mosquito population. However, their injudicious over usage and non-biodegradability are associated with many adverse effects on the environment and mosquitoes. The application of environment-friendly mosquitocidals might be an alternate to overcome these issues. In this study, we found that organic or aqueous extracts of Agave angustifolia leaves exhibited a strong larvicidal activity (LD50 28.27 µg/ml against Aedes aegypti, Culex quinquefasciatus and Anopheles stephensi larvae within a short exposure of 12h. The larvicidal activity of Agave angustifolia is inherited and independent of the plants vegetative growth. Interestingly, the plant larvicidal activity was observed exclusively during the summer season (April-August, when outside temperature is between 30oC to 50oC and it was significantly reduced during winter season (December-February, when the outside temperature falls to ~4oC or lower. Thus, we hypothesized that the larvicidal components of Agave angustifolia might be induced by the manipulation of environmental temperature and should be resistant to the hot conditions. We found that the larvicidal activity of Agave angustifolia was induced when plants were maintained at 37oC in a semi-natural environment against the controls that were growing outside in cold weather. Pre-incubation of Agave angustifolia extract at 100oC for 1h killed 60% larvae in 12h, which gradually increased to 100% mortality after 24h. In addition, the dry powder formulation of Agave angustifolia, also displayed a strong larvicidal activity after a long shelf life. Together, these findings revealed that Agave angustifolia is an excellent source of temperature induced bioactive metabolites that may assist the preparedness for vector control programs competently.

  10. Genetic diversity in two sibling species of the Anopheles punctulatus group of mosquitoes on Guadalcanal in the Solomon Islands

    Science.gov (United States)

    2008-01-01

    Background The mosquito Anopheles irenicus, a member of the Anopheles punctulatus group, is geographically restricted to Guadalcanal in the Solomon Islands. It shows remarkable morphological similarities to one of its sibling species, An. farauti sensu stricto (An. farauti s.s.), but is dissimilar in host and habitat preferences. To infer the genetic variations between these two species, we have analyzed mitochondrial cytochrome oxidase subunit II (COII) and nuclear ribosomal internal transcribed spacer 2 (ITS2) sequences from Guadalcanal and from one of its nearest neighbours, Malaita, in the Solomon Islands. Results An. farauti s.s. was collected mostly from brackish water and by the human bait method on both islands, whereas An. irenicus was only collected from fresh water bodies on Guadalcanal Island. An. irenicus is distributed evenly with An. farauti s.s. (ΦSC = 0.033, 0.38%) and its range overlaps in three of the seven sampling sites. However, there is a significant population genetic structure between the species (ΦCT = 0.863, P < 0.01; ΦST = 0.865, P < 0.01 and FST = 0.878, P < 0.01). Phylogenetic analyses suggest that An. irenicus is a monophyletic species, not a hybrid, and is closely related to the An. farauti s.s. on Guadalcanal. The time estimator suggests that An. irenicus diverged from the ancestral An. farauti s.s. on Guadalcanal within 29,000 years before present (BP). An. farauti s.s. expanded much earlier on Malaita (texp = 24,600 BP) than the populations on Guadalcanal (texp = 16,800 BP for An. farauti s.s. and 14,000 BP for An. irenicus). Conclusion These findings suggest that An. irenicus and An. farauti s.s. are monophyletic sister species living in sympatry, and their populations on Guadalcanal have recently expanded. Consequently, the findings further suggest that An. irenicus diverged from the ancestral An. farauti s.s. on Guadalcanal. PMID:19025663

  11. Distribution of knock-down resistance mutations in Anopheles gambiae molecular forms in west and west-central Africa

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    Caccone Adalgisa

    2008-04-01

    Full Text Available Abstract Background Knock-down resistance (kdr to DDT and pyrethroids in the major Afrotropical vector species, Anopheles gambiae sensu stricto, is associated with two alternative point mutations at amino acid position 1014 of the voltage-gated sodium channel gene, resulting in either a leucine-phenylalanine (L1014F, or a leucine-serine (L1014S substitution. In An. gambiae S-form populations, the former mutation appears to be widespread in west Africa and has been recently reported from Uganda, while the latter, originally recorded in Kenya, has been recently found in Gabon, Cameroon and Equatorial Guinea. In M-form populations surveyed to date, only the L1014F mutation has been found, although less widespread and at lower frequencies than in sympatric S-form populations. Methods Anopheles gambiae M- and S-form specimens from 19 sites from 11 west and west-central African countries were identified to molecular form and genotyped at the kdr locus either by Hot Oligonucleotide Ligation Assay (HOLA or allele-specific PCR (AS-PCR. Results The kdr genotype was determined for about 1,000 An. gambiae specimens. The L1014F allele was found at frequencies ranging from 6% to 100% in all S-form samples (N = 628, with the exception of two samples from Angola, where it was absent, and coexisted with the L1014S allele in samples from Cameroon, Gabon and north-western Angola. The L1014F allele was present in M-form samples (N = 354 from Benin, Nigeria, and Cameroon, where both M- and S-forms were sympatric. Conclusion The results represent the most comprehensive effort to analyse the overall distribution of the L1014F and L1014S mutations in An. gambiae molecular forms, and will serve as baseline data for resistance monitoring. The overall picture shows that the emergence and spread of kdr alleles in An. gambiae is a dynamic process and that there is marked intra- and inter-form heterogeneity in resistance allele frequencies. Further studies are needed to

  12. Staggered larval time-to-hatch and insecticide resistance in the major malaria vector Anopheles gambiae S form

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    Coetzee Maureen

    2010-12-01

    Full Text Available Abstract Background Anopheles gambiae is a major vector of malaria in the West African region. Resistance to multiple insecticides has been recorded in An. gambiae S form in the Ahafo region of Ghana. A laboratory population (GAH established using wild material from this locality has enabled a mechanistic characterization of each resistance phenotype as well as an analysis of another adaptive characteristic - staggered larval time-to-hatch. Methods Individual egg batches obtained from wild caught females collected from Ghana and the Republic of the Congo were monitored for staggered larval time-to-hatch. In addition, early and late larval time-to-hatch sub-colonies were selected from GAH. These selected sub-colonies were cross-mated and their hybrid progeny were subsequently intercrossed and back-crossed to the parental strains. The insecticide susceptibilities of the GAH base colony and the time-to-hatch selected sub-colonies were quantified for four insecticide classes using insecticide bioassays. Resistance phenotypes were mechanistically characterized using insecticide-synergist bioassays and diagnostic molecular assays for known reduced target-site sensitivity mutations. Results Anopheles gambiae GAH showed varying levels of resistance to all insecticide classes. Metabolic detoxification and reduced target-site sensitivity mechanisms were implicated. Most wild-caught families showed staggered larval time-to-hatch. However, some families were either exclusively early hatching or late hatching. Most GAH larvae hatched early but many egg batches contained a proportion of late hatching larvae. Crosses between the time-to-hatch selected sub-colonies yielded ambiguous results that did not fit any hypothetical models based on single-locus Mendelian inheritance. There was significant variation in the expression of insecticide resistance between the time-to-hatch phenotypes. Conclusions An adaptive response to the presence of multiple insecticide

  13. Hydric stress-dependent effects of Plasmodium falciparum infection on the survival of wild-caught Anopheles gambiae female mosquitoes

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    Aboagye-Antwi Fred

    2010-08-01

    Full Text Available Abstract Background Whether Plasmodium falciparum, the agent of human malaria responsible for over a million deaths per year, causes fitness costs in its mosquito vectors is a burning question that has not yet been adequately resolved. Understanding the evolutionary forces responsible for the maintenance of susceptibility and refractory alleles in natural mosquito populations is critical for understanding malaria transmission dynamics. Methods In natural mosquito populations, Plasmodium fitness costs may only be expressed in combination with other environmental stress factors hence this hypothesis was tested experimentally. Wild-caught blood-fed Anopheles gambiae s.s. females of the M and S molecular form from an area endemic for malaria in Mali, West Africa, were brought to the laboratory and submitted to a 7-day period of mild hydric stress or kept with water ad-libitum. At the end of this experiment all females were submitted to intense desiccation until death. The survival of all females throughout both stress episodes, as well as their body size and infection status was recorded. The importance of stress, body size and molecular form on infection prevalence and female survival was investigated using Logistic Regression and Proportional-Hazard analysis. Results Females subjected to mild stress exhibited patterns of survival and prevalence of infection compatible with increased parasite-induced mortality compared to non-stressed females. Fitness costs seemed to be linked to ookinetes and early oocyst development but not the presence of sporozoites. In addition, when females were subjected to intense desiccation stress, those carrying oocysts exhibited drastically reduced survival but those carrying sporozoites were unaffected. No significant differences in prevalence of infection and infection-induced mortality were found between the M and S molecular forms of Anopheles gambiae. Conclusions Because these results suggest that infected

  14. Fauna and some biological characteristics of Anopheles mosquitoes (Diptera:Culicidae) in Kalaleh County, Golestan Province, northeast of lran

    Institute of Scientific and Technical Information of China (English)

    Aioub Sofizadeh; Hamideh Edalat; Mohammad Reza Abai; Ahmad Ali Hanafi-Bojd

    2016-01-01

    Objective: To determine fauna and some ecological aspects of Anopheles mosquitoes in northeast of Iran. Methods: In this descriptive study, 3 villages in Kalaleh County were selected in different geographical zones. Anopheles mosquitoes were collected biweekly from May to October using standard dipping method for larvae, and hand catch, total catch, artificial pit shelter as well as night-biting collections on human and animal baits for adults. Results: Totally 399 larvae and 2 602 adults of Anopheles mosquitoes were collected and identified as 2 species: Anopheles superpictus s.l. (An. superpictus s.l.) and Anopheles maculipennis s.l. The dominant species was An. superpictus s.l. (92.1%). Activity of these mosquitoes found to be started from middle of May and extended till September with two peaks of activity in July and August. Conclusions: An. superpictus s.l. as one of the main malaria vectors in Iran as well as some other parts of the world is the dominant species in the study area. This species has high potential for transmission and possibility of establishing a transmission cycle with low abundance. Other species, Anopheles maculipennis s.l. also has introduced as a malaria vector in northern parts of Iran. As this Anopheles is a complex species, genetic studies are recommended to determine the members of this complex in the study area.

  15. A High-Affinity Adenosine Kinase from Anopheles Gambiae

    Energy Technology Data Exchange (ETDEWEB)

    M Cassera; M Ho; E Merino; E Burgos; A Rinaldo-Matthis; S Almo; V Schramm

    2011-12-31

    Genome analysis revealed a mosquito orthologue of adenosine kinase in Anopheles gambiae (AgAK; the most important vector for the transmission of Plasmodium falciparum in Africa). P. falciparum are purine auxotrophs and do not express an adenosine kinase but rely on their hosts for purines. AgAK was kinetically characterized and found to have the highest affinity for adenosine (K{sub m} = 8.1 nM) of any known adenosine kinase. AgAK is specific for adenosine at the nucleoside site, but several nucleotide triphosphate phosphoryl donors are tolerated. The AgAK crystal structure with a bound bisubstrate analogue Ap{sub 4}A (2.0 {angstrom} resolution) reveals interactions for adenosine and ATP and the geometry for phosphoryl transfer. The polyphosphate charge is partly neutralized by a bound Mg{sup 2+} ion and an ion pair to a catalytic site Arg. The AgAK structure consists of a large catalytic core in a three-layer {alpha}/{beta}/{alpha} sandwich, and a small cap domain in contact with adenosine. The specificity and tight binding for adenosine arise from hydrogen bond interactions of Asn14, Leu16, Leu40, Leu133, Leu168, Phe168, and Thr171 and the backbone of Ile39 and Phe168 with the adenine ring as well as through hydrogen bond interactions between Asp18, Gly64, and Asn68 and the ribosyl 2'- and 3'-hydroxyl groups. The structure is more similar to that of human adenosine kinase (48% identical) than to that of AK from Toxoplasma gondii (31% identical). With this extraordinary affinity for AgAK, adenosine is efficiently captured and converted to AMP at near the diffusion limit, suggesting an important role for this enzyme in the maintenance of the adenine nucleotide pool. mRNA analysis verifies that AgAK transcripts are produced in the adult insects.

  16. Mosaic genome architecture of the Anopheles gambiae species complex.

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    Rui Wang-Sattler

    Full Text Available BACKGROUND: Attempts over the last three decades to reconstruct the phylogenetic history of the Anopheles gambiae species complex have been important for developing better strategies to control malaria transmission. METHODOLOGY: We used fingerprint genotyping data from 414 field-collected female mosquitoes at 42 microsatellite loci to infer the evolutionary relationships of four species in the A. gambiae complex, the two major malaria vectors A. gambiae sensu stricto (A. gambiae s.s. and A. arabiensis, as well as two minor vectors, A. merus and A. melas. PRINCIPAL FINDINGS: We identify six taxonomic units, including a clear separation of West and East Africa A. gambiae s.s. S molecular forms. We show that the phylogenetic relationships vary widely between different genomic regions, thus demonstrating the mosaic nature of the genome of these species. The two major malaria vectors are closely related and closer to A. merus than to A. melas at the genome-wide level, which is also true if only autosomes are considered. However, within the Xag inversion region of the X chromosome, the M and two S molecular forms are most similar to A. merus. Near the X centromere, outside the Xag region, the two S forms are highly dissimilar to the other taxa. Furthermore, our data suggest that the centromeric region of chromosome 3 is a strong discriminator between the major and minor malaria vectors. CONCLUSIONS: Although further studies are needed to elucidate the basis of the phylogenetic variation among the different regions of the genome, the preponderance of sympatric admixtures among taxa strongly favor introgression of different genomic regions between species, rather than lineage sorting of ancestral polymorphism, as a possible mechanism.

  17. Chloroquine mediated modulation of Anopheles gambiae gene expression.

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    Patrícia Abrantes

    Full Text Available BACKGROUND: Plasmodium development in the mosquito is crucial for malaria transmission and depends on the parasite's interaction with a variety of cell types and specific mosquito factors that have both positive and negative effects on infection. Whereas the defensive response of the mosquito contributes to a decrease in parasite numbers during these stages, some components of the blood meal are known to favor infection, potentiating the risk of increased transmission. The presence of the antimalarial drug chloroquine in the mosquito's blood meal has been associated with an increase in Plasmodium infectivity for the mosquito, which is possibly caused by chloroquine interfering with the capacity of the mosquito to defend against the infection. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we report a detailed survey of the Anopheles gambiae genes that are differentially regulated by the presence of chloroquine in the blood meal, using an A. gambiae cDNA microarray. The effect of chloroquine on transcript abundance was evaluated separately for non-infected and Plasmodium berghei-infected mosquitoes. Chloroquine was found to affect the abundance of transcripts that encode proteins involved in a variety of processes, including immunity, apoptosis, cytoskeleton and the response to oxidative stress. This pattern of differential gene expression may explain the weakened mosquito defense response which accounts for the increased infectivity observed in chloroquine-treated mosquitoes. CONCLUSIONS/SIGNIFICANCE: The results of the present study suggest that chloroquine can interfere with several putative mosquito mechanisms of defense against Plasmodium at the level of gene expression and highlight the need for a better understanding of the impacts of antimalarial agents on parasite transmission.

  18. Seasonal changes of microfilarial infection and infectivity rates in mosquito populations within Makurdi, Benue State, Nigeria

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    Manyi, M. M

    2014-12-01

    Full Text Available Studies on the infection and infectivity rates of Wuchereria bancrofti in mosquito populations in Makurdi, Nigeria were carried out over a 12 month period in four localities. Adult female mosquitoes (4,320 were morphologically identified and dissected following standard keys and procedures. 1,040 (24.1% were Anopheles gambiae s.l.; 641 (14.8% were Anopheles funestus Giles and 2,418 (56.0% were Culex quinquefasciatus Say while 221 (5.1% were tagged ‘unidentified’ Anopheles species. The overall microfilarial infection and infectivity rates were 10.1% and 4.8% respectively. The microfilarial infection and infectivity rates differed significantly (ANOVA; χ2 test p<0.05across vector species, study months and the localities surveyed. The findings indicate that Makurdi is endemic for lymphatic filariasis, and that Anopheles gambiae s.l. and Anopheles funestus were potential vectors of lymphatic filariasis in Makurdi while Culex quinquefasciatus was the major vector. This work may provide an entomological baseline data required for evaluation and implementation of vector control interventions in the study area.

  19. Resistance Status of the Malaria Vector Mosquitoes, Anopheles stephensi and Anopheles subpictus Towards Adulticides and Larvicides in Arid and Semi-Arid Areas of India

    OpenAIRE

    Tikar, S. N.; M J Mendki; Sharma, A K; D. Sukumaran; Veer, Vijay; Prakash, Shri; Parashar, B. D.

    2011-01-01

    Susceptibility studies of malaria vectors Anopheles stephensi Liston (Diptera: Culicidae) and An. subpictus Grassi collected during 2004–2007 from various locations of Arid and Semi-Arid Zone of India were conducted by adulticide bioassay of DDT, malathion, deltamethrin and larvicide bioassay of fenthion, temephos, chlorpyriphos and malathion using diagnostic doses. Both species from all locations exhibited variable resistance to DDT and malathion from majority of location. Adults of both the...

  20. Diversitas Genetik Anopheles balabacensis, Baisas di Berbagai Daerah Indonesia Berdasarkan Sekuen Gen ITS 2 DNA Ribosom

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    Widiarti Widiarti

    2016-05-01

    Full Text Available AbstractMalaria control is remain a challenge although various attempts have been conducted. One of the issues in controlling the vectors is the presence of species complex. The species complex is an example of genetic diversity. Anopheles balabacensis, Baisas reported as complex species in various countries, but has not been widely reported in Indonesia. In order to enhance malaria control, it is important to understand the vectors and its bioecology. The aim of the study were a. to identify An. balabacensis, Baisas suspected as species complex based on ribosomal DNA the second internal transcribed spacer (ITS2 gene sequences, b. to understand the genetic diversity of An. balabacensis, Baisas collected from endemic and non endemic regions distincted by geographical distance, c. to understand the genetic relationships (taxonomi distance among An. balabacensis, Baisas from difference regions in Indonesia through reconstructing the phylogenetic trees. The results showed that An. balabacensis, Baisas in Indonesia is identified as sympatric and allopatrik complex species. There were differences which was far enough in the genetic relationships among An. balabacensis populations collected from Pusuk Lestari in the area of Meninting Health Center, West Lombok, NTB. This differences were identified as sympatric complex. In addition, base on the relationship among An. leucosphyrus group, An balabacensis, Baisas collected from Berjoko Nunukan Regency showed that the species quite far compare to An. balabacensis, Baisas originally from Central Java and Lombok NTB.Keywords : An. balabacensis, genetic variation, the second Internal Transcribed Spacer (ITS2.AbstrakPenanggulangan malaria masih banyak menemui kendala walaupun berbagai upaya telah dilakukan. Salah satu kendala yang menyulitkan dalam pengendalian vektor adalah adanya spesies kompleks pada populasi nyamuk vektor. Spesies kompleks merupakan contoh diversitas genetik. Anopheles balabacensis

  1. The effects of plant essential oils on escape response and mortality rate of Aedes aegypti and Anopheles minimus.

    Science.gov (United States)

    Sathantriphop, Sunaiyana; Achee, Nicole L; Sanguanpong, Unchalee; Chareonviriyaphap, Theeraphap

    2015-12-01

    The High Throughput Screening System (HITSS) has been applied in insecticide behavioral response studies with various mosquito species. In general, chemical or natural compounds can produce a range of insect responses: contact irritancy, spatial repellency, knock-down, and toxicity. This study characterized these actions in essential oils derived from citronella, hairy basil, catnip, and vetiver in comparison to DEET and picaridin against Aedes aegypti and Anopheles minimus mosquito populations. Results indicated the two mosquito species exhibited significantly different (P0.05) against Ae. aegypti. Spatial repellency responses were elicited in both mosquito species when exposed to all compounds, but the strength of the repellent response was dependent on compound and concentration. Data show that higher test concentrations had greatest toxic effects on both mosquito populations, but vetiver had no toxic effect on Ae. aegypti and picaridin did not elicit toxicity in either Ae. aegypti or An. minimus at any test concentration. Ultimately, this study demonstrates the ability of the HITSS assay to guide selection of effective plant essential oils for repelling, irritating, and killing mosquitoes. PMID:26611967

  2. Physiology and development of the M and S molecular forms of Anopheles gambiae in Burkina Faso (West Africa).

    Science.gov (United States)

    Mouline, K; Mamai, W; Agnew, P; Tchonfienet, M; Brengues, C; Dabire, R; Robert, V; Simard, F

    2012-12-01

    In West Africa, M and S molecular forms of Anopheles gambiae sensu stricto (Diptera: Culicidae) Giles, frequently occur together, although with different population bionomics. The S form typically breeds in rain-dependant water collections and is present during the rainy season only whereas the M form can thrive all year long in areas with permanent breeding opportunities. In the present study, we explored physiological and developmental trade-offs at play in laboratory colonies and field populations of the M and S forms that originated from an area of sympatry in Burkina Faso, where M and S larvae exhibit such habitat segregation. In the laboratory, larvae of the M form developed slower than the S form (mean values 9.51 and 8.85 days, respectively, Wilcoxon's test, P < 0.001). Although wing length and dry weight at emergence showed large variations, M females were on average 8% heavier than S females of similar wing length. Higher nutritional reserves (proteins and lipids) in teneral adults explained part of this weight difference, reflecting a better ability of the M form to garner resources at the larval stage. Furthermore, a higher rate of ovarian maturation was observed in the M form after a single bloodmeal. The relevance of these findings for parasite transmission is discussed. PMID:22681446

  3. The interaction between a sexually transferred steroid hormone and a female protein regulates oogenesis in the malaria mosquito Anopheles gambiae.

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    Francesco Baldini

    2013-10-01

    Full Text Available Molecular interactions between male and female factors during mating profoundly affect the reproductive behavior and physiology of female insects. In natural populations of the malaria mosquito Anopheles gambiae, blood-fed females direct nutritional resources towards oogenesis only when inseminated. Here we show that the mating-dependent pathway of egg development in these mosquitoes is regulated by the interaction between the steroid hormone 20-hydroxy-ecdysone (20E transferred by males during copulation and a female Mating-Induced Stimulator of Oogenesis (MISO protein. RNAi silencing of MISO abolishes the increase in oogenesis caused by mating in blood-fed females, causes a delay in oocyte development, and impairs the function of male-transferred 20E. Co-immunoprecipitation experiments show that MISO and 20E interact in the female reproductive tract. Moreover MISO expression after mating is induced by 20E via the Ecdysone Receptor, demonstrating a close cooperation between the two factors. Male-transferred 20E therefore acts as a mating signal that females translate into an increased investment in egg development via a MISO-dependent pathway. The identification of this male-female reproductive interaction offers novel opportunities for the control of mosquito populations that transmit malaria.

  4. The Interaction between a Sexually Transferred Steroid Hormone and a Female Protein Regulates Oogenesis in the Malaria Mosquito Anopheles gambiae

    Science.gov (United States)

    Baldini, Francesco; Gabrieli, Paolo; South, Adam; Valim, Clarissa; Mancini, Francesca; Catteruccia, Flaminia

    2013-01-01

    Molecular interactions between male and female factors during mating profoundly affect the reproductive behavior and physiology of female insects. In natural populations of the malaria mosquito Anopheles gambiae, blood-fed females direct nutritional resources towards oogenesis only when inseminated. Here we show that the mating-dependent pathway of egg development in these mosquitoes is regulated by the interaction between the steroid hormone 20-hydroxy-ecdysone (20E) transferred by males during copulation and a female Mating-Induced Stimulator of Oogenesis (MISO) protein. RNAi silencing of MISO abolishes the increase in oogenesis caused by mating in blood-fed females, causes a delay in oocyte development, and impairs the function of male-transferred 20E. Co-immunoprecipitation experiments show that MISO and 20E interact in the female reproductive tract. Moreover MISO expression after mating is induced by 20E via the Ecdysone Receptor, demonstrating a close cooperation between the two factors. Male-transferred 20E therefore acts as a mating signal that females translate into an increased investment in egg development via a MISO-dependent pathway. The identification of this male–female reproductive interaction offers novel opportunities for the control of mosquito populations that transmit malaria. PMID:24204210

  5. The effects of plant essential oils on escape response and mortality rate of Aedes aegypti and Anopheles minimus.

    Science.gov (United States)

    Sathantriphop, Sunaiyana; Achee, Nicole L; Sanguanpong, Unchalee; Chareonviriyaphap, Theeraphap

    2015-12-01

    The High Throughput Screening System (HITSS) has been applied in insecticide behavioral response studies with various mosquito species. In general, chemical or natural compounds can produce a range of insect responses: contact irritancy, spatial repellency, knock-down, and toxicity. This study characterized these actions in essential oils derived from citronella, hairy basil, catnip, and vetiver in comparison to DEET and picaridin against Aedes aegypti and Anopheles minimus mosquito populations. Results indicated the two mosquito species exhibited significantly different (P0.05) against Ae. aegypti. Spatial repellency responses were elicited in both mosquito species when exposed to all compounds, but the strength of the repellent response was dependent on compound and concentration. Data show that higher test concentrations had greatest toxic effects on both mosquito populations, but vetiver had no toxic effect on Ae. aegypti and picaridin did not elicit toxicity in either Ae. aegypti or An. minimus at any test concentration. Ultimately, this study demonstrates the ability of the HITSS assay to guide selection of effective plant essential oils for repelling, irritating, and killing mosquitoes.

  6. Comparison of the Insecticidal Characteristics of Commercially Available Plant Essential Oils Against Aedes aegypti and Anopheles gambiae (Diptera: Culicidae).

    Science.gov (United States)

    Norris, Edmund J; Gross, Aaron D; Dunphy, Brendan M; Bessette, Steven; Bartholomay, Lyric; Coats, Joel R

    2015-09-01

    Aedes aegypti and Anopheles gambiae are two mosquito species that represent significant threats to global public health as vectors of Dengue virus and malaria parasites, respectively. Although mosquito populations have been effectively controlled through the use of synthetic insecticides, the emergence of widespread insecticide-resistance in wild mosquito populations is a strong motivation to explore new insecticidal chemistries. For these studies, Ae. aegypti and An. gambiae were treated with commercially available plant essential oils via topical application. The relative toxicity of each essential oil was determined, as measured by the 24-h LD(50) and percentage knockdown at 1 h, as compared with a variety of synthetic pyrethroids. For Ae. aegypti, the most toxic essential oil (patchouli oil) was ∼1,700-times less toxic than the least toxic synthetic pyrethroid, bifenthrin. For An. gambiae, the most toxic essential oil (patchouli oil) was ∼685-times less toxic than the least toxic synthetic pyrethroid. A wide variety of toxicities were observed among the essential oils screened. Also, plant essential oils were analyzed via gas chromatography/mass spectrometry (GC/MS) to identify the major components in each of the samples screened in this study. While the toxicities of these plant essential oils were demonstrated to be lower than those of the synthetic pyrethroids tested, the large amount of GC/MS data and bioactivity data for each essential oil presented in this study will serve as a valuable resource for future studies exploring the insecticidal quality of plant essential oils.

  7. Radiation-induced sterility for pupal and adult stages of the malaria moquito Anopheles arabiensis

    OpenAIRE

    Helinski, M.E.H.; Parker, A.G.; Knols, B.G.J.

    2006-01-01

    Background - In the context of the Sterile Insect Technique (SIT), radiation-induced sterility in the malaria mosquito Anopheles arabiensis Patton (Diptera: Culicidae) was studied. Male mosquitoes were exposed to gamma rays in the pupal or adult stage and dose-sterility curves were determined. Methods - Pupae were irradiated shortly before emergence (at 22-26 hrs of age), and adults

  8. Larvicidal effects of a neem (Azadirachta indica) oil formulation on the malaria vector Anopheles gambiae

    NARCIS (Netherlands)

    Okumu, F.O.; Knols, B.G.J.; Fillinger, U.

    2007-01-01

    Background - Larviciding is a key strategy used in many vector control programmes around the world. Costs could be reduced if larvicides could be manufactured locally. The potential of natural products as larvicides against the main African malaria vector, Anopheles gambiae s.s was evaluated. Method

  9. Improvement of a synthetic lure for Anopheles gambiae using compounds produced by human skin microbiota

    NARCIS (Netherlands)

    Verhulst, N.O.; Mbadi, P.A.; Bukovinszkine-Kiss, G.; Mukabana, W.R.; Loon, van J.J.A.; Takken, W.; Smallegange, R.C.

    2011-01-01

    Background - Anopheles gambiae sensu stricto is considered to be highly anthropophilic and volatiles of human origin provide essential cues during its host-seeking behaviour. A synthetic blend of three human-derived volatiles, ammonia, lactic acid and tetradecanoic acid, attracts A. gambiae. In addi

  10. Olfaction in the malaria mosquito Anopheles gambiae : Electrophysiology and identification of kairomones

    NARCIS (Netherlands)

    Meijerink, J.

    1999-01-01

    Female mosquitoes of the species Anopheles gambiae Giles sensu stricto are important vectors of human malaria in Africa. It is generally assumed that they locate their human host by odours. These odours are detected by olfactory receptor neurons situated within cuticular extensions on the antenna. T

  11. Inhibition of host-seeking response and olfactory responsiveness in Anopheles gambiae following blood feeding

    NARCIS (Netherlands)

    Takken, W.; Loon, van J.J.A.; Adam, W.

    2001-01-01

    The effect of a single blood meal on the host-seeking response of Anopheles gambiae was investigated in the laboratory using a behavioural bioassay, whereas possible changes at the chemosensory level were monitored using electroantennogram recording (EAG). To avoid the possible confounding effect of

  12. Ecology of Anopheles stephensi in a malarious area, southeast of Iran.

    Science.gov (United States)

    Mehravaran, Ahmad; Vatandoost, Hassan; Oshaghi, Mohammad Ali; Abai, Mohammad Reza; Edalat, Hamideh; Javadian, Ezatoddin; Mashayekhi, Minoo; Piazak, Norair; Hanafi-Bojd, Ahmad Ali

    2012-01-01

    District of Jiroft is situated in south-east of Iran which is one of the malarious regions. Anopheles stephensi is considered as one of the main malaria vector in this region. Ecology of this species was studied in the area to understand its vector behavior for implementation of effective vector control measures. Different methods like total catch, pit shelter, night bite collection on human and animal, larval dipping methods were used for species identification, seasonal activity, anthropophilic index and egg morphological characteristics. Anthropophilicity index was assessed by ELISA test. Activity of Anopheles species started at the beginning of April, and its peak occurs in late spring. The larvae were found in the river bed with pools, stagnant streams, slow foothill streams, temporary pools, and slowly moving water with and without vegetation, drainage containers of air conditioner and palm irrigation canals. From different methods of adult collection, it was found that spray sheet collection is the appropriate method. ELISA testing of 144 blood meals of females revealed the anthropophilicity of 11.8% indicating host preference on animal, mainly cow. Ridge length and their number on the egg floats confirmed Anopheles stephensi mysorensis form. This study showed that Anopheles stephensi is the main vector of malaria in the region, although some other species may play a role. Our findings could provide a valuable clue for epidemiology and control of malaria in the southeast of Iran. PMID:22267381

  13. Tyrosine Hydroxylase is crucial for maintaining pupal tanning and immunity in Anopheles sinensis.

    Science.gov (United States)

    Qiao, Liang; Du, Minghui; Liang, Xin; Hao, Youjin; He, Xiu; Si, Fengling; Mei, Ting; Chen, Bin

    2016-01-01

    Tyrosine hydroxylase (TH), the initial enzyme in the melanin pathway, catalyzes tyrosine conversion into Dopa. Although expression and regulation of TH have been shown to affect cuticle pigmentation in insects, no direct functional studies to date have focused on the specific physiological processes involving the enzyme during mosquito development. In the current study, silencing of AsTH during the time period of continuous high expression in Anopheles sinensis pupae led to significant impairment of cuticle tanning and thickness, imposing a severe obstacle to eclosion in adults. Meanwhile, deficiency of melanin in interference individuals led to suppression of melanization, compared to control individuals. Consequently, the ability to defend exogenous microorganisms declined sharply. Accompanying down-regulation of the basal expression of five antimicrobial peptide genes resulted in further significant weakening of immunity. TH homologs as well as the composition of upstream transcription factor binding sites at the pupal stage are highly conserved in the Anopheles genus, implying that the TH-mediated functions are crucial in Anopheles. The collective evidence strongly suggests that TH is essential for Anopheles pupae tanning and immunity and provides a reference for further studies to validate the utility of the key genes involved in the melanization pathway in controlling mosquito development. PMID:27416870

  14. Role of Anopheles (Kerteszia bellator as malaria vector in Southeastern Brazil (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Oswaldo Paulo Forattini

    1999-11-01

    Full Text Available New research concerning Anopheles bellator in the southeast of the State of São Paulo, Brazil, are reported. Adult females of this mosquito showed remarkable endophily and endophagy which was even greater than An. cruzii. The epidemiological role of this anopheline as a malaria vector is discussed.

  15. Behavioural response of the malaria vector Anopheles gambiae to host plant volatiles and synthetic blends

    Science.gov (United States)

    Sugar feeding is critical for survival of malaria vectors and, although discriminative plant feeding previously has been shown to occur in Anopheles gambiae s.s., little is known about the cues mediating attraction to these plants. In this study, we investigated the role of olfaction in An. gambiae ...

  16. New selenoproteins identified in silico from the genome of Anopheles gambiae

    Institute of Scientific and Technical Information of China (English)

    JIANG Liang; LIU Qiong; CHEN Ping; GAO ZhongHong; XU HuiBi

    2007-01-01

    Selenoprotein is biosynthesized by the incorporation of selenocysteine into proteins, where the TGA codon in the open reading frame does not act as a stop signal but is translated into selenocysteine. The dual functions of TGA result in mis-annotation or lack of selenoproteins in the sequenced genomes of many species. Available computational tools fail to correctly predict selenoproteins. Thus, we developed a new method to identify selenoproteins from the genome of Anopheles gambiae computationally.Based on released genomic information, several programs were edited with PERL language to identify selenocysteine insertion sequence (SECIS) element, the coding potential of TGA codons, and cysteine-containing homologs of selenoprotein genes. Our results showed that 11365 genes were terminated with TGA codons, 918 of which contained SECIS elements. Similarity search revealed that 58genes contained Sec/Cys pairs and similar flanking regions around in-frame TGA codons. Finally, 7genes were found to fully meet requirements for selenoproteins, although they have not been annotated as selenoproteins in NCBI databases. Deduced from their basic properties, the newly found selenoproteins in the genome of Anopheles gambiae are possibly related to in vivo oxidation tolerance and protein regulation in order to interfere with anopheles' vectorial capacity of Plasmodium. This study may also provide theoretical bases for the prevention of malaria from anopheles transmission.

  17. Ecology of Anopheles Stephensi in a Malarious Area, Southeast of Iran

    Directory of Open Access Journals (Sweden)

    Norair Piazak

    2012-01-01

    Full Text Available District of Jiroft is situated in south-east of Iran which is one of the malarious regions. Anopheles stephensi is considered as one of the main malaria vector in this region. Ecology of this species was studied in the area to understand its vector behavior for implementation of effective vector control measures. Different methods like total catch, pit shelter, night bite collection on human and animal, larval dipping methods were used for species identification, seasonal activity, anthropophilic index and egg morphological characteristics. Anthropophilicity index was assessed by ELISA test. Activity of Anopheles species started at the beginning of April, and its peak occurs in late spring. The larvae were found in the river bed with pools, stagnant streams, slow foothill streams, temporary pools, and slowly moving water with and without vegetation, drainage containers of air conditioner and palm irrigation canals. From different methods of adult collection, it was found that spray sheet collection is the appropriate method. ELISA testing of 144 blood meals of females revealed the anthropophilicity of 11.8% indicating host preference on animal, mainly cow. Ridge length and their number on the egg floats confirmed Anopheles stephensi mysorensis form. This study showed that Anopheles stephensi is the main vector of malaria in the region, although some other species may play a role. Our findings could provide a valuable clue for epidemiology and control of malaria in the southeast of Iran.

  18. Species-specific chemosensory gene expression in the olfactory organs of the malaria vector Anopheles gambiae

    NARCIS (Netherlands)

    Hodges, Theresa K.; Cosme, Luciano V.; Athrey, Giridhar; Pathikonda, Sharmila; Takken, Willem; Slotman, Michel A.

    2014-01-01

    Background: The malaria mosquito Anopheles gambiae has a high preference for human hosts, a characteristic that contributes greatly to its capacity for transmitting human malaria. A sibling species, An. quadriannulatus, has a quite different host preference and feeds mostly on bovids. For this re

  19. Was Anopheles donaldi a vector of malaria in Kuala Lumpur, Malaysia, in the past?

    Science.gov (United States)

    Reid, J A

    1980-01-01

    Anopheles donaldi Reid, a member of the A. barbirostris species group, is a vector of human filariasis and probably malaria. The discovery of some old specimens of this species, collected in Kuala Lumpur town where it no longer occurs, together with evidence from the literature about past malaria in the town, suggest that donaldi may have played a part in transmitting that malaria.

  20. Sharing of antigens between Plasmodium falciparum and Anopheles albimanus Antígenos compartidos entre Plasmodium falciparum y Anopheles albimanus

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    Albina Wide

    2006-12-01

    Full Text Available The presence of common antigens between Plasmodium falciparum and Anopheles albimanus was demonstrated. Different groups of rabbits were immunized with: crude extract from female An. albimanus (EAaF, red blood cells infected with Plasmodium falciparum (EPfs, and the SPf66 synthetic malaria vaccine. The rabbit's polyclonal antibodies were evaluated by ELISA, Multiple Antigen Blot Assay (MABA, and immunoblotting. All extracts were immunogenic in rabbits according to these three techniques, when they were evaluated against the homologous antigens. Ten molecules were identified in female mosquitoes and also in P. falciparum antigens by the autologous sera. The electrophoretic pattern by SDS-PAGE was different for the three antigens evaluated. Cross-reactions between An. albimanus and P. falciparum were found by ELISA, MABA, and immunoblotting. Anti-P. falciparum and anti-SPf66 antibodies recognized ten and five components in the EAaF crude extract, respectively. Likewise, immune sera against female An. albimanus identified four molecules in the P. falciparum extract antigen. As far as we know, this is the first work that demonstrates shared antigens between anophelines and malaria parasites. This finding could be useful for diagnosis, vaccines, and the study of physiology of the immune response to malaria.Epítopes de antígenos compartidos entre Plasmodium falciparum y Anopheles albimanus fueron identificados. Diferentes grupos de conejos fueron inmunizados con: extracto crudo de mosquito hembra de An. albimanus (EAaH, glóbulos rojos infectados con P. falciparum (EPfs y la vacuna antimalárica sintética SPf66. Los anticuerpos policlonales producidos en conejos fueron evaluados por ELISA, inmunoensayo simultáneo de múltiples antígenos (MABA e Immunoblotting. Todos los extractos resultaron inmunogénicos cuando se evaluaron por ELISA, MABA e Immunoblotting. Diez moléculas fueron identificadas en los mosquitos hembras y diez en los antígenos de

  1. Insecticide resistance in Anopheles gambiae: data from the first year of a multi-country study highlight the extent of the problem

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    Sagnon N'Falé

    2009-12-01

    Full Text Available Abstract Background Insecticide resistance in malaria vectors is a growing concern in many countries which requires immediate attention because of the limited chemical arsenal available for vector control. The current extent and distribution of this resistance in many parts of the continent is unknown and yet such information is essential for the planning of effective malaria control interventions. Methods In 2008, a network was established, with financial support from WHO/TDR, to investigate the extent of insecticide resistance in malaria vectors in five African countries. Here, the results of bioassays on Anopheles gambiae sensu lato from two rounds of monitoring from 12 sentinel sites in three of the partner countries are reported. Results Resistance is very heterogeneous even over relatively small distances. Furthermore, in some sites, large differences in mortality rates were observed during the course of the malaria transmission season. Using WHO diagnostic doses, all populations from Burkina Faso and Chad and two of the four populations from Sudan were classified as resistant to permethrin and/or deltamethrin. Very high frequencies of DDT resistance were found in urban areas in Burkina Faso and Sudan and in a cotton-growing district in Chad. In areas where both An. gambiae s.s. and Anopheles arabiensis were present, resistance was found in both species, although generally at a higher frequency in An gambiae s.s. Anopheles gambiae s.l. remains largely susceptible to the organophosphate fenitrothion and the carbamate bendiocarb in the majority of the sentinel sites with the exception of two sites in Burkina Faso. In the cotton-growing region of Soumousso in Burkina Faso, the vector population is resistant to all four classes of insecticide available for malaria control. Conclusions Possible factors influencing the frequency of resistant individuals observed in the sentinel sites are discussed. The results of this study highlight the

  2. Lineage divergence detected in the malaria vector Anopheles marajoara (Diptera: Culicidae in Amazonian Brazil

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    Povoa Marinete M

    2010-10-01

    Full Text Available Abstract Background Cryptic species complexes are common among anophelines. Previous phylogenetic analysis based on the complete mtDNA COI gene sequences detected paraphyly in the Neotropical malaria vector Anopheles marajoara. The "Folmer region" detects a single taxon using a 3% divergence threshold. Methods To test the paraphyletic hypothesis and examine the utility of the Folmer region, genealogical trees based on a concatenated (white + 3' COI sequences dataset and pairwise differentiation of COI fragments were examined. The population structure and demographic history were based on partial COI sequences for 294 individuals from 14 localities in Amazonian Brazil. 109 individuals from 12 localities were sequenced for the nDNA white gene, and 57 individuals from 11 localities were sequenced for the ribosomal DNA (rDNA internal transcribed spacer 2 (ITS2. Results Distinct A. marajoara lineages were detected by combined genealogical analysis and were also supported among COI haplotypes using a median joining network and AMOVA, with time since divergence during the Pleistocene (COI sequences at the 3' end were more variable, demonstrating significant pairwise differentiation (3.82% compared to the more moderate 2.92% detected by the Folmer region. Lineage 1 was present in all localities, whereas lineage 2 was restricted mainly to the west. Mismatch distributions for both lineages were bimodal, likely due to multiple colonization events and spatial expansion (~798 - 81,045 ya. There appears to be gene flow within, not between lineages, and a partial barrier was detected near Rio Jari in Amapá state, separating western and eastern populations. In contrast, both nDNA data sets (white gene sequences with or without the retention of the 4th intron, and ITS2 sequences and length detected a single A. marajoara lineage. Conclusions Strong support for combined data with significant differentiation detected in the COI and absent in the nDNA suggest that

  3. Interplay of population genetics and dynamics in the genetic control of mosquitoes

    OpenAIRE

    Alphey, Nina; Bonsall, Michael B.

    2014-01-01

    Some proposed genetics-based vector control methods aim to suppress or eliminate a mosquito population in a similar manner to the sterile insect technique. One approach under development in Anopheles mosquitoes uses homing endonuclease genes (HEGs)—selfish genetic elements (inherited at greater than Mendelian rate) that can spread rapidly through a population even if they reduce fitness. HEGs have potential to drive introduced traits through a population without large-scale sustained releases...

  4. West African Anopheles gambiae mosquitoes harbor a taxonomically diverse virome including new insect-specific flaviviruses, mononegaviruses, and totiviruses.

    Science.gov (United States)

    Fauver, Joseph R; Grubaugh, Nathan D; Krajacich, Benjamin J; Weger-Lucarelli, James; Lakin, Steven M; Fakoli, Lawrence S; Bolay, Fatorma K; Diclaro, Joseph W; Dabiré, Kounbobr Roch; Foy, Brian D; Brackney, Doug E; Ebel, Gregory D; Stenglein, Mark D

    2016-11-01

    Anopheles gambiae are a major vector of malaria in sub-Saharan Africa. Viruses that naturally infect these mosquitoes may impact their physiology and ability to transmit pathogens. We therefore used metagenomics sequencing to search for viruses in adult Anopheles mosquitoes collected from Liberia, Senegal, and Burkina Faso. We identified a number of virus and virus-like sequences from mosquito midgut contents, including 14 coding-complete genome segments and 26 partial sequences. The coding-complete sequences define new viruses in the order Mononegavirales, and the families Flaviviridae, and Totiviridae. The identification of a flavivirus infecting Anopheles mosquitoes broadens our understanding of the evolution and host range of this virus family. This study increases our understanding of virus diversity in general, begins to define the virome of a medically important vector in its natural setting, and lays groundwork for future studies examining the potential impact of these viruses on anopheles biology and disease transmission. PMID:27639161

  5. DINAMIKA POPULASI Anopheles Aconitus KAITANYA DENGAN PREVALENSI MALARIA DI KECAMATAN CINEAM, TASIKMALAYA

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    Amrul Munif

    2012-10-01

    Full Text Available A study on the correlation of population dynamik An. aconitus with malaria prevalence was conducted in Cineam sub-district, Tasikmalaya district, West Java from August 1998 to March 2000. In 1996, outbreaks of malaria did not only occur in the coastal areas but was also spread throughout the more remote areas. Malaria transmission can be detected by the presence of infectious gametocyte dan non-immune individuals, as well as by looking at environmental factors (rainfall and also the density of vector population. The intensity of malaria transmission and the degree of malaria prevalence are affected greatly by the last factor.   The intensity is also determined by the degree of contact between the person and the vector. An. aconitus have been suspected as malaria vector in Cineam sub-district, Tasikmalaya district. The observation of the bionomics wich one component of mosquitoes and its relationship with malaria prevalence as well as the determination of Anopheles spp. as malaria vectors in endemic areas should be given attention as an effort in preventing malaria outbreaks. The high density of vector mosquitoes is partly caused by their high diversity. Determination of the prevalence value is based on the Slide positifrate (SPR that was obtained from analyzing blood samples of the  population. There was an examination on passive case detection (PCD, active case detection  (ACD, and mass blood survey (MBS of the population beforehand. Methods used in surveying dan catching the vector mosquitoes include using humans as bait both inside and outside the house, using light trap, by resting, and also spraying. The longitudinal survey methods were used. Each catched mosquito was identified by looking at its morphological features.The transmission of malaria was found to occur all year round with the highest peak found in August 1998 (SPR= 4.9%, but then declined drastically in May (SPR=2.46% and July 1999 (SPR= 2.4% The occurrence of human biting

  6. KOMPETENSI VEKTORIAL Anopheles maculatus, Theobald di KECAMATAN KOKAP, KABUPATEN KULONPROGO

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    Umi Widyastuti

    2013-07-01

    Full Text Available Abstrak Malaria masih merupakan masalah kesehatan di Kabupaten Kulonprogo, khususnya di Kecamatan Kokap. Dalam dua tahun terakhir menunjukkan bahwa pada tahun 2009, 1 dari 5 desa di Kecamatan Kokap sebagai daerah malaria dengan statifikasi Insidensi Kasus Rendah (Low Case Incidence/LCI. Pada tahun 2010 meningkat menjadi 3 desa, peningkatan kasus malaria di Kecamatan Kokap berkaitan dengan keberadaan nyamuk Anopheles yang berpotensi sebagai vektor. Beberapa spesies seperti An. maculatus, An. aconitus, dan An. balabacensis diduga sebagai vektor malaria potensial di daerah ini. Penelitian ini bertujuan untuk mengetahui kompetensi vektorial An. maculatus yang terdiri dari: kerentanan nyamuk An. maculatus terhadap Plasmodium, sifat antropofilik, angka paritas, dan kepadatan nyamuk. Kerentanan nyamuk terhadap Plasmodium diukur dengan deteksi antigen protein sporozoit (Circum Sporozoite Protein/CSP dari P. falciparum atau P. vivax pada dada-kepala dari semua nyamuk parous. Karakteristik antropofilik diukur dengan mendeteksi darah manusia pada perut nyamuk dengan kondisi penuh darah dan setengah gravid. Kedua deteksi tersebut dilakukan dengan teknik ELISA. Penelitian dilakukan pada bulan Mei sampai Oktober 2011 di dua desa yaitu: Tegiri dan Gunungrego, Kecamatan Kokap. Nyamuk ditangkap dengan menggunakan metode sesuai dengan pedoman WHO. Penangkapan dilakukan pada malam hari (18.00-06.00 terhadap nyamuk yang hinggap pada manusia di dalam rumah, di luar rumah, nyamuk yang istirahat baik di dalam rumah (dinding maupun luar rumah (sekitar kandang ternak dan penangkapan pada pagi hari (06.00-08.00. Kepadatan An. maculatus dihitung dan paritas nyamuk ditentukan dengan pembedahan ovarium secara mikroskopis. Hasil penelitian menunjukkan bahwa An. maculatus di Gunungrego rentan terhadap P. vivax dengan angka sporozoit 3,57%. Namun, CSP antigen P. vivax tidak terdeteksi pada dada-kepala nyamuk An. maculatus dari Tegiri. Antigen CSP P. falciparum negatif pada

  7. Potential Test of Papaya Leaf and Seed Extract (Carica Papaya) as Larvicides against Anopheles Mosquito Larvae Mortality. SP IN Jayapura, Papua Indonesia

    OpenAIRE

    Arsunan

    2015-01-01

    Anopheles mosquitoes, sp is the main vector of malaria disease that is widespread in many parts of the world including in Papua Province. There are four speciesof Anopheles mosquitoes, sp, in Papua namely: An.farauti, An.koliensis, An. subpictus, and An.punctulatus. Larviciding synthetic cause resistance. This study aims to analyze the potential of papaya leaf and seeds extracts (Carica papaya) as larvicides against the mosquitoes Anopheles sp. The experiment was conducted at the Laboratory o...

  8. A simplified high-throughput method for pyrethroid knock-down resistance (kdr detection in Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    Walker Edward D

    2005-03-01

    Full Text Available Abstract Background A single base pair mutation in the sodium channel confers knock-down resistance to pyrethroids in many insect species. Its occurrence in Anopheles mosquitoes may have important implications for malaria vector control especially considering the current trend for large scale pyrethroid-treated bednet programmes. Screening Anopheles gambiae populations for the kdr mutation has become one of the mainstays of programmes that monitor the development of insecticide resistance. The screening is commonly performed using a multiplex Polymerase Chain Reaction (PCR which, since it is reliant on a single nucleotide polymorphism, can be unreliable. Here we present a reliable and potentially high throughput method for screening An. gambiae for the kdr mutation. Methods A Hot Ligation Oligonucleotide Assay (HOLA was developed to detect both the East and West African kdr alleles in the homozygous and heterozygous states, and was optimized for use in low-tech developing world laboratories. Results from the HOLA were compared to results from the multiplex PCR for field and laboratory mosquito specimens to provide verification of the robustness and sensitivity of the technique. Results and Discussion The HOLA assay, developed for detection of the kdr mutation, gives a bright blue colouration for a positive result whilst negative reactions remain colourless. The results are apparent within a few minutes of adding the final substrate and can be scored by eye. Heterozygotes are scored when a sample gives a positive reaction to the susceptible probe and the kdr probe. The technique uses only basic laboratory equipment and skills and can be carried out by anyone familiar with the Enzyme-linked immunosorbent assay (ELISA technique. A comparison to the multiplex PCR method showed that the HOLA assay was more reliable, and scoring of the plates was less ambiguous. Conclusion The method is capable of detecting both the East and West African kdr alleles

  9. Acetylcholinesterases from the Disease Vectors Aedes aegypti and Anopheles gambiae: Functional Characterization and Comparisons with Vertebrate Orthologues.

    Directory of Open Access Journals (Sweden)

    Cecilia Engdahl

    Full Text Available Mosquitoes of the Anopheles (An. and Aedes (Ae. genus are principal vectors of human diseases including malaria, dengue and yellow fever. Insecticide-based vector control is an established and important way of preventing transmission of such infections. Currently used insecticides can efficiently control mosquito populations, but there are growing concerns about emerging resistance, off-target toxicity and their ability to alter ecosystems. A potential target for the development of insecticides with reduced off-target toxicity is the cholinergic enzyme acetylcholinesterase (AChE. Herein, we report cloning, baculoviral expression and functional characterization of the wild-type AChE genes (ace-1 from An. gambiae and Ae. aegypti, including a naturally occurring insecticide-resistant (G119S mutant of An. gambiae. Using enzymatic digestion and liquid chromatography-tandem mass spectrometry we found that the secreted proteins were post-translationally modified. The Michaelis-Menten constants and turnover numbers of the mosquito enzymes were lower than those of the orthologous AChEs from Mus musculus and Homo sapiens. We also found that the G119S substitution reduced the turnover rate of substrates and the potency of selected covalent inhibitors. Furthermore, non-covalent inhibitors were less sensitive to the G119S substitution and differentiate the mosquito enzymes from corresponding vertebrate enzymes. Our findings indicate that it may be possible to develop selective non-covalent inhibitors that effectively target both the wild-type and insecticide resistant mutants of mosquito AChE.

  10. Effects of adult body size on fecundity and the pre-gravid rate of Anopheles gambiae females in Tanzania.

    Science.gov (United States)

    Lyimo, E O; Takken, W

    1993-10-01

    The influence of adult body size on the pre-gravid state and fecundity was studied in Anopheles gambiae Giles females hand-caught inside houses and virgin females collected as pupae in Tanzania. Blood-fed mosquitoes were kept for 2-3 days before dissection and examination for insemination and ovarian condition. Those females which did not develop eggs were classified as pre-gravid. The number of mature eggs in those mosquitoes which became gravid was counted. Virgin females were fed and kept for egg maturation in the laboratory. Wing-length of females was measured as an index of mosquito size. The overall pre-gravid rate in the resting An.gambiae population was found to be 21% and, of these, 66% had been inseminated. In the virgin females the pre-gravid rate was 92.6%. The mean wing-length of wild females which became gravid was significantly larger than those which remained pre-gravid. There was a positive correlation between fecundity and wing-length. Smaller females tended to require two or three bloodmeals to facilitate completion of the first gonotrophic cycle. The critical size permitting oviposition from the first blood-meal was a wing-length of 3 mm. PMID:8268486

  11. Modelling sterile insect technique to control the population of Anopheles gambiae

    OpenAIRE

    James E. Gentile; Rund, Samuel SC; Gregory R. Madey

    2015-01-01

    Background There is a renewed effort to develop novel malaria control strategies as even well-implemented existing malaria control tools may fail to block transmission in some regions. Currently, transgenic implementations of the sterile insect technique (SIT) such as the release of insects with a dominant lethal, homing endonuclease genes, or flightless mosquitoes are in development. These implementations involve the release of transgenic male mosquitoes whose matings with wild females produ...

  12. The cytochrome P450 CYP6P4 is responsible for the high pyrethroid resistance in knockdown resistance-free Anopheles arabiensis.

    Science.gov (United States)

    Ibrahim, Sulaiman S; Riveron, Jacob M; Stott, Robert; Irving, Helen; Wondji, Charles S

    2016-01-01

    Pyrethroid insecticides are the front line vector control tools used in bed nets to reduce malaria transmission and its burden. However, resistance in major vectors such as Anopheles arabiensis is posing a serious challenge to the success of malaria control. Herein, we elucidated the molecular and biochemical basis of pyrethroid resistance in a knockdown resistance-free Anopheles arabiensis population from Chad, Central Africa. Using heterologous expression of P450s in Escherichia coli coupled with metabolism assays we established that the over-expressed P450 CYP6P4, located in the major pyrethroid resistance (rp1) quantitative trait locus (QTL), is responsible for resistance to Type I and Type II pyrethroid insecticides, with the exception of deltamethrin, in correlation with field resistance profile. However, CYP6P4 exhibited no metabolic activity towards non-pyrethroid insecticides, including DDT, bendiocarb, propoxur and malathion. Combining fluorescent probes inhibition assays with molecular docking simulation, we established that CYP6P4 can bind deltamethrin but cannot metabolise it. This is possibly due to steric hindrance because of the large vdW radius of bromine atoms of the dihalovinyl group of deltamethrin which docks into the heme catalytic centre. The establishment of CYP6P4 as a partial pyrethroid resistance gene explained the observed field resistance to permethrin, and its inability to metabolise deltamethrin probably explained the high mortality from deltamethrin exposure in the field populations of this Sudano-Sahelian An. arabiensis. These findings describe the heterogeneity in resistance towards insecticides, even from the same class, highlighting the need to thoroughly understand the molecular basis of resistance before implementing resistance management/control tools.

  13. The cytochrome P450 CYP6P4 is responsible for the high pyrethroid resistance in knockdown resistance-free Anopheles arabiensis

    Science.gov (United States)

    Ibrahim, Sulaiman S.; Riveron, Jacob M.; Stott, Robert; Irving, Helen; Wondji, Charles S.

    2016-01-01

    Pyrethroid insecticides are the front line vector control tools used in bed nets to reduce malaria transmission and its burden. However, resistance in major vectors such as Anopheles arabiensis is posing a serious challenge to the success of malaria control. Herein, we elucidated the molecular and biochemical basis of pyrethroid resistance in a knockdown resistance-free Anopheles arabiensis population from Chad, Central Africa. Using heterologous expression of P450s in Escherichia coli coupled with metabolism assays we established that the over-expressed P450 CYP6P4, located in the major pyrethroid resistance (rp1) quantitative trait locus (QTL), is responsible for resistance to Type I and Type II pyrethroid insecticides, with the exception of deltamethrin, in correlation with field resistance profile. However, CYP6P4 exhibited no metabolic activity towards non-pyrethroid insecticides, including DDT, bendiocarb, propoxur and malathion. Combining fluorescent probes inhibition assays with molecular docking simulation, we established that CYP6P4 can bind deltamethrin but cannot metabolise it. This is possibly due to steric hindrance because of the large vdW radius of bromine atoms of the dihalovinyl group of deltamethrin which docks into the heme catalytic centre. The establishment of CYP6P4 as a partial pyrethroid resistance gene explained the observed field resistance to permethrin, and its inability to metabolise deltamethrin probably explained the high mortality from deltamethrin exposure in the field populations of this Sudano-Sahelian An. arabiensis. These findings describe the heterogeneity in resistance towards insecticides, even from the same class, highlighting the need to thoroughly understand the molecular basis of resistance before implementing resistance management/control tools. PMID:26548743

  14. Ecological niche partitioning between Anopheles gambiae molecular forms in Cameroon: the ecological side of speciation

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    Fotsing Jean-Marie

    2009-05-01

    Full Text Available Abstract Background Speciation among members of the Anopheles gambiae complex is thought to be promoted by disruptive selection and ecological divergence acting on sets of adaptation genes protected from recombination by polymorphic paracentric chromosomal inversions. However, shared chromosomal polymorphisms between the M and S molecular forms of An. gambiae and insufficient information about their relationship with ecological divergence challenge this view. We used Geographic Information Systems, Ecological Niche Factor Analysis, and Bayesian multilocus genetic clustering to explore the nature and extent of ecological and chromosomal differentiation of M and S across all the biogeographic domains of Cameroon in Central Africa, in order to understand the role of chromosomal arrangements in ecological specialisation within and among molecular forms. Results Species distribution modelling with presence-only data revealed differences in the ecological niche of both molecular forms and the sibling species, An. arabiensis. The fundamental environmental envelope of the two molecular forms, however, overlapped to a large extent in the rainforest, where they occurred in sympatry. The S form had the greatest niche breadth of all three taxa, whereas An. arabiensis and the M form had the smallest niche overlap. Correspondence analysis of M and S karyotypes confirmed that molecular forms shared similar combinations of chromosomal inversion arrangements in response to the eco-climatic gradient defining the main biogeographic domains occurring across Cameroon. Savanna karyotypes of M and S, however, segregated along the smaller-scale environmental gradient defined by the second ordination axis. Population structure analysis identified three chromosomal clusters, each containing a mixture of M and S specimens. In both M and S, alternative karyotypes were segregating in contrasted environments, in agreement with a strong ecological adaptive value of

  15. Baseline Susceptibility of Different Geographical Strains of Anopheles stephensi (Diptera: Culicidae to Temephos in Malarious Areas of Irana.

    Directory of Open Access Journals (Sweden)

    Aboozar Soltani

    2013-06-01

    Full Text Available Malaria still remains a public health problem in Iran. There are different vector control interventions such as insecticide spraying. The present study was carried out to determine the susceptibility status of Anopheles stephensi larvae to temephos as a national plan for monitoring and mapping of insecticide resistance.Eight different localities in two main malarious provinces were determined as field collecting sites. Mosquitoes were collected from the field and reared in an insectray. Susceptibility assays were carried out according to the WHO method. The laboratory reared susceptible Beech-Lab strain was used for comparison. Data were analyzed using Probit analysis to determine LC50 and LC90 values.Susceptibility of An. stephensi to temephos indicated that the LC50 ranged from 0.0022 mg/l to 0.0141 mg/l. Although all field strains were susceptible to temephos, considerable variations in temephos resistance ratios of field strains were noticed from all the localities studied in comparison with the susceptible strain. A low level of resistance ratio was noticed in An. stephensi populations except for the Chabahar strain (RR= 4.27 fold. All field-collected An. stephensi populations exhibited homogeneity to the larvicide except for Bandar Abbas and Hormoodar village strains (P> 0.05%.Due to intensive use of temephos in the neighboring countries and occurrence of resistant to this insecticide in the main malaria vector in the region, insecticide resistance gene may evolve in the populations of An. stephensi. If temephos be applied as a larvicide it should be used judiciously for resistance management, as rotation strategy.

  16. Baseline Susceptibility of Different Geographical Strains of Anopheles stephensi (Diptera: Culicidae to Temephos in Malarious Areas of Iran

    Directory of Open Access Journals (Sweden)

    Aboozar Soltani

    2013-03-01

    Full Text Available Background: Malaria still remains a public health problem in Iran. There are different vector control interventions such as insecticide spraying. The present study was carried out to determine the susceptibility status of Anopheles stephensi larvae to temephos as a national plan for monitoring and mapping of insecticide resistanceMethods: Eight different localities in two main malarious provinces were determined as field collecting sites. Mos­quitoes were collected from the field and reared in an insectray. Susceptibility assays were carried out according to the WHO method. The laboratory reared susceptible Beech-Lab strain was used for comparison. Data were analyzed using Probit analysis to determine LC50 and LC90 values.Results: Susceptibility of An. stephensi to temephos indicated that the LC50 ranged from 0.0022 mg/l to 0.0141 mg/l. Although all field strains were susceptible to temephos, considerable variations in temephos resistance ratios of field strains were noticed from all the localities studied in comparison with the susceptible strain. A low level of resistance ratio was noticed in An. stephensi populations except for the Chabahar strain (RR= 4.27 fold. All field-collected An. stephensi populations exhibited homogeneity to the larvicide except for Bandar Abbas and Hormoodar village strains (P> 0.05%.Conclusion: Due to intensive use of temephos in the neighboring countries and occurrence of resistant to this insec­ticide in the main malaria vector in the region, insecticide resistance gene may evolve in the populations of An. stephensi. If temephos be applied as a larvicide it should be used judiciously for resistance management, as rotation strategy

  17. The role of reactive oxygen species on Plasmodium melanotic encapsulation in Anopheles gambiae.

    Science.gov (United States)

    Kumar, Sanjeev; Christophides, George K; Cantera, Rafael; Charles, Bradley; Han, Yeon Soo; Meister, Stephan; Dimopoulos, George; Kafatos, Fotis C; Barillas-Mury, Carolina

    2003-11-25

    Malaria transmission depends on the competence of some Anopheles mosquitoes to sustain Plasmodium development (susceptibility). A genetically selected refractory strain of Anopheles gambiae blocks Plasmodium development, melanizing, and encapsulating the parasite in a reaction that begins with tyrosine oxidation, and involves three quantitative trait loci. Morphological and microarray mRNA expression analysis suggest that the refractory and susceptible strains have broad physiological differences, which are related to the production and detoxification of reactive oxygen species. Physiological studies corroborate that the refractory strain is in a chronic state of oxidative stress, which is exacerbated by blood feeding, resulting in increased steady-state levels of reactive oxygen species, which favor melanization of parasites as well as Sephadex beads. PMID:14623973

  18. Integrated genetic map of Anopheles gambiae: use of RAPD polymorphisms for genetic, cytogenetic and STS landmarks.

    Science.gov (United States)

    Dimopoulos, G; Zheng, L; Kumar, V; della Torre, A; Kafatos, F C; Louis, C

    1996-06-01

    Randomly amplified polymorphic DNA (RAPD) markers have been integrated in the genetic and cytogenetic maps of the malaria vector mosquito, Anopheles gambiae. Fifteen of these markers were mapped by recombination, relative to microsatellite markers that had been mapped previously. Thirty-four gel-purified RAPD bands were cloned and sequenced, generating sequence tagged sites (STSs) that can be used as entry points to the A. gambiae genome. Thirty one of these STSs were localized on nurse cell polytene chromosomes through their unique hybridization signal in in situ hybridization experiments. Five STSs map close to the breakpoints of polymorphic inversions, which are notable features of the Anopheles genome. The usefulness and limitations of this integrated mosquito map are discussed. PMID:8725241

  19. Ecology of Anopheles Stephensi in a Malarious Area, Southeast of Iran

    OpenAIRE

    Norair Piazak; Minoo Mashayekhi; Ezatoddin Javadian; Hamideh Edalat; Mohammad Reza Abai; Mohammad Ali Oshaghi; Hassan Vatandoost; Ahmad Mehravaran; Ahmad Ali Hanafi-Bojd

    2012-01-01

    District of Jiroft is situated in south-east of Iran which is one of the malarious regions. Anopheles stephensi is considered as one of the main malaria vector in this region. Ecology of this species was studied in the area to understand its vector behavior for implementation of effective vector control measures. Different methods like total catch, pit shelter, night bite collection on human and animal, larval dipping methods were used for species identification, seasonal activity, anthropoph...

  20. Invasion of Wolbachia into Anopheles and Other Insect Germlines in an Ex vivo Organ Culture System

    OpenAIRE

    Hughes, Grant L.; Andrew D Pike; Ping Xue; Jason L Rasgon

    2012-01-01

    The common bacterial endosymbiont Wolbachia manipulates its host's reproduction to promote its own maternal transmission, and can interfere with pathogen development in many insects making it an attractive agent for the control of arthropod-borne disease. However, many important species, including Anopheles mosquitoes, are uninfected. Wolbachia can be artificially transferred between insects in the laboratory but this can be a laborious and sometimes fruitless process. We used a simple ex viv...

  1. Olfaction in the malaria mosquito Anopheles gambiae : Electrophysiology and identification of kairomones

    OpenAIRE

    Meijerink, J

    1999-01-01

    Female mosquitoes of the species Anopheles gambiae Giles sensu stricto are important vectors of human malaria in Africa. It is generally assumed that they locate their human host by odours. These odours are detected by olfactory receptor neurons situated within cuticular extensions on the antenna. These cuticular extensions, called sensilla, contain numerous pores through which the odours can enter the sensillum and reach the olfactory receptor neuron membrane. Despite the fact that these mos...

  2. Comparison of the functional features of the pump organs of Anopheles sinensis and Aedes togoi

    OpenAIRE

    Young-Ran Ha; Seung-Chul Lee; Seung-Jun Seo; Jeongeun Ryu; Dong-Kyu Lee; Sang-Joon Lee

    2015-01-01

    Mosquitoes act as vectors for severe tropical diseases. Mosquito-borne diseases are affected by various factors such as environmental conditions, host body susceptibility, and mosquito feeding behavior. Among these factors, feeding behavior is affected by the feeding pump system located inside the mosquito head and also depends on the species of mosquito. Therefore, the 3D morphological structures of the feeding pumps of Aedes togoi and Anopheles sinensis were comparatively investigated using...

  3. Rhodopsin coexpression in UV photoreceptors of Aedes aegypti and Anopheles gambiae mosquitoes

    OpenAIRE

    Hu, Xiaobang; Leming, Matthew T; Whaley, Michelle A.; O'Tousa, Joseph E.

    2014-01-01

    Differential rhodopsin gene expression within specialized R7 photoreceptor cells divides the retinas of Aedes aegypti and Anopheles gambiae mosquitoes into distinct domains. The two species express the rhodopsin orthologs Aaop8 and Agop8, respectively, in a large subset of these R7 photoreceptors that function as ultraviolet receptors. We show here that a divergent subfamily of mosquito rhodopsins, Aaop10 and Agop10, is coexpressed in these R7 photoreceptors. The properties of the A. aegypti ...

  4. Larvicidal Effects of a Neem (Azadirachta indica) Oil Formulation on the Malaria Vector Anopheles Gambiae.

    OpenAIRE

    Knols Bart GJ; Okumu Fredros O; Fillinger Ulrike

    2007-01-01

    Abstract Background Larviciding is a key strategy used in many vector control programmes around the world. Costs could be reduced if larvicides could be manufactured locally. The potential of natural products as larvicides against the main African malaria vector, Anopheles gambiae s.s was evaluated. Methods To assess the larvicidal efficacy of a neem (Azadirachta indica) oil formulation (azadirachtin content of 0.03% w/v) on An. gambiae s.s., larvae were exposed as third and fourth instars to...

  5. Anopheles gambiae mosquito isolated neurons : a new biological model for optimizing insecticide/repellent efficacy

    OpenAIRE

    Lavialle-Defaix, C.; Apaire-Marchais, V; Legros, C.; Pennetier, Cédric; Mohamed, A; P. Licznar; Corbel, Vincent; Lapied, B

    2011-01-01

    To understand better the mode of action of insecticides and repellents used in vector-borne diseases control, we developed a new biological model based on mosquito neurons isolated from adults Anopheles gambiae heads. This cellular model is well adapted to multidisciplinary approaches: electrophysiology, pharmacology, molecular biology and biochemical assays. Using RT-PCR, we demonstrated that isolated neurons express the nicotinic acetylcholine receptor subunit alpha 1 (Ag alpha 1 nAchR), tw...

  6. Mosquito repellent potential of Pithecellobium dulce leaf and seed against malaria vector Anopheles stephensi (Diptera: Culicidae)

    OpenAIRE

    Mohan Rajeswary; Marimuthu Govindarajan

    2016-01-01

    Objective: To determine the repellent properties of hexane, benzene, ethyl acetate, chloroform and methanol extract of Pithecellobium dulce (P. dulce) leaf and seed against Anopheles stephensi (An. stephensi). Methods: Repellent activity assay was carried out in a net cage (45 cm × 30 cm × 25 cm) containing 100 blood starved female mosquitoes of An. stephensi. This assay was carried out in the laboratory conditions according to the WHO 2009 protocol. Plant crude extracts of P. ...

  7. Extensive circadian and light regulation of the transcriptome in the malaria mosquito Anopheles gambiae

    OpenAIRE

    Rund, Samuel SC; James E. Gentile; Duffield, Giles E.

    2013-01-01

    Background Mosquitoes exhibit 24 hr rhythms in flight activity, feeding, reproduction and development. To better understand the molecular basis for these rhythms in the nocturnal malaria vector Anopheles gambiae, we have utilized microarray analysis on time-of-day specific collections of mosquitoes over 48 hr to explore the coregulation of gene expression rhythms by the circadian clock and light, and compare these with the 24 hr rhythmic gene expression in the diurnal Aedes aegypti dengue vec...

  8. Development of sporogonic cycle of Plasmodium vivax in experimentally infected Anopheles albimanus mosquitoes

    OpenAIRE

    Martha L. Salas; Romero, Jackeline F.; Yesid Solarte; Victor Olano; Myriam A. Herrera; Sócrates Herrera

    1994-01-01

    The sporogonic cycle of Plasmodium vivax was established and maintained under laboratory conditions in two different strains of Anopheles albimanus mosquitoes using as a parasite source blood from human patients or from Aotus monkeys infected with the VCC-2 P.vivax colombian isolate. Both the Tecojate strain isolate from Guatemala and the Cartagena strain from the colombian Pacific coast were susceptible to infections with P.vivax. A higher percentage of Cartagena mosquitoes was infected per ...

  9. Biochemical Characterization of Anopheles gambiae SRPN6, a Malaria Parasite Invasion Marker in Mosquitoes

    OpenAIRE

    Chunju An; Yasuaki Hiromasa; Xin Zhang; Scott Lovell; Michal Zolkiewski; John M Tomich; Kristin Michel

    2012-01-01

    Serine proteinase inhibitors of the serpin family are well known as negative regulators of hemostasis, thrombolysis and innate immune responses. Additionally, non-inhibitory serpins serve functions as chaperones, hormone transporters, or anti-angiogenic factors. In the African malaria mosquito, Anopheles gambiae s.s., at least three serpins (SRPNs) are implicated in the innate immune response against malaria parasites. Based on reverse genetic and cell biological analyses, AgSRPN6 limits para...

  10. The JNK Pathway Is a Key Mediator of Anopheles gambiae Antiplasmodial Immunity

    OpenAIRE

    Garver, Lindsey S.; de Almeida Oliveira, Giselle; Barillas-Mury, Carolina

    2013-01-01

    The innate immune system of Anopheles gambiae mosquitoes limits Plasmodium infection through multiple molecular mechanisms. For example, midgut invasion by the parasite triggers an epithelial nitration response that promotes activation of the complement-like system. We found that suppression of the JNK pathway, by silencing either Hep, JNK, Jun or Fos expression, greatly enhanced Plasmodium infection; while overactivating this cascade, by silencing the suppressor Puckered, had the opposite ef...

  11. A mosquito lipoxin/lipocalin complex mediates innate immune priming in Anopheles gambiae

    OpenAIRE

    Ramirez, Jose Luis; de Almeida Oliveira, Giselle; Calvo, Eric; Dalli, Jesmond; Colas, Romain A.; Serhan, Charles N.; Ribeiro, Jose M.; Barillas-Mury, Carolina

    2015-01-01

    Exposure of Anopheles gambiae mosquitoes to Plasmodium infection enhances the ability of their immune system to respond to subsequent infections. However, the molecular mechanism that allows the insect innate immune system to ‘remember' a previous encounter with a pathogen has not been established. Challenged mosquitoes constitutively release a soluble haemocyte differentiation factor into their haemolymph that, when transferred into Naive mosquitoes, also induces priming. Here we show that t...

  12. A Peroxidase/Dual Oxidase System Modulates Midgut Epithelial Immunity in Anopheles gambiae

    OpenAIRE

    Kumar, Sanjeev; Molina-Cruz, Alvaro; Gupta, Lalita; Rodrigues, Janneth; Barillas-Mury, Carolina

    2010-01-01

    Extracellular matrices in diverse biological systems are crosslinked by dityrosine covalent bonds catalyzed by the peroxidase/oxidase system. We show that the Immunomodulatory Peroxidase (IMPer), an enzyme secreted by the mosquito Anopheles gambiae midgut, and dual oxidase (Duox) form a dityrosine network that decreases gut permeability to immune elicitors and protects the microbiota by preventing activation of epithelial immunity. It also provides a suitable environment for malaria parasites...

  13. The STAT pathway mediates late phase immunity against Plasmodium in the mosquito Anopheles gambiae

    OpenAIRE

    Gupta, Lalita; Molina-Cruz, Alvaro; Kumar, Sanjeev; Rodrigues, Janneth; Dixit, Rajnikant; Zamora, Rodolfo E.; Barillas-Mury, Carolina

    2009-01-01

    The STAT family of transcription factors activate expression of immune system genes in vertebrates. The ancestral STAT gene (AgSTAT-A) appears to have duplicated in the mosquito Anopheles gambiae, giving rise to a second intronless STAT gene (AgSTAT-B), which we show regulates AgSTAT-A expression in adult females. AgSTAT-A participates in the transcriptional activation of nitric oxide synthase (NOS) in response to bacterial and plasmodial infection. Activation of this pathway, however, is not...

  14. Genome expression analysis of Anopheles gambiae: Responses to injury, bacterial challenge, and malaria infection

    OpenAIRE

    Dimopoulos, George; Christophides, George K.; Meister, Stephan; SCHULTZ, JÖRG; White, Kevin P.; Barillas-Mury, Carolina; Kafatos, Fotis C.

    2002-01-01

    The complex gene expression responses of Anopheles gambiae to microbial and malaria challenges, injury, and oxidative stress (in the mosquito and/or a cultured cell line) were surveyed by using cDNA microarrays constructed from an EST-clone collection. The expression profiles were broadly subdivided into induced and down-regulated gene clusters. Gram+ and Gram− bacteria and microbial elicitors up-regulated a diverse set of genes, many belonging to the immunity class, and the response to malar...

  15. Imidacloprid and Thiamethoxam Induced Mutations in Internal Transcribed Spacer 2 (ITS2) of Anopheles stephensi

    OpenAIRE

    Bhinder, Preety; Chaudhry, Asha; Barna, Bhupinder; Kaur, Satvinderjeet

    2012-01-01

    The present article deals with the polymerase chain reaction (PCR)-based genotoxicity evaluation of neonicotinoid pesticides, imidacloprid and thiamethoxam, by using the genome of a mosquito Anopheles stephensi taken as an experimental model. After treatment of the second instar larvae with LC20 of the pesticides for 24 h, the induced nucleotide sequence variations in the internal transcribed spacer 2 (ITS2) of freshly hatched unfed control and treated individuals was studied from the sequenc...

  16. Energy-state dependent responses of Anopheles gambiae to an unobtainable host

    OpenAIRE

    Zappia, Simon Pierre William

    2011-01-01

    Understanding how blood-seeking behavior changes with different energy levels in the malaria mosquito Anopheles gambiae (Diptera: Culicidae), when confronted with an unobtainable blood-host, is of interest for vector control strategies. I used a straight-tube olfactometer to mimic a domicile containing (i) a simulated blood-host (human foot smell) protected by either a plain bednet or a DEET impregnated net and (ii) a sugar source (honey scent) some distance away. I manipulated the mosquito’s...

  17. The role of cow urine in the oviposition site preference of culicine and Anopheles mosquitoes

    OpenAIRE

    Kweka Eliningaya J; Owino Eunice A; Mwang'onde Beda J; Mahande Aneth M; Nyindo Mramba; Mosha Franklin

    2011-01-01

    Abstract Background Chemical and behavioural ecology of mosquitoes plays an important role in the development of chemical cue based vector control. To date, studies available have focused on evaluating mosquito attractants and repellents of synthetic and human origins. This study, however, was aimed at seasonal evaluation of the efficiency of cow urine in producing oviposition cues to Anopheles gambiae s.l. and Culex quinquefasciatus in both laboratory and field conditions. Methods Ovipositio...

  18. Chemical composition and insecticidal activity of plant essential oils from Benin against Anopheles gambiae (Giles)

    OpenAIRE

    Bossou, Annick; Mangelinckx, Sven; Yedomonhan, Hounnankpon; Boko, Pelagie M; Akogbeto, Martin C; De Kimpe, Norbert; Avlessi, Felicien; Sohounhloue, Dominique CK

    2013-01-01

    Background Insecticide resistance in sub-Saharan Africa and especially in Benin is a major public health issue hindering the control of the malaria vectors. Each Anopheles species has developed a resistance to one or several classes of the insecticides currently in use in the field. Therefore, it is urgent to find alternative compounds to conquer the vector. In this study, the efficacies of essential oils of nine plant species, which are traditionally used to avoid mosquito bites in Benin, we...

  19. Mosquito repellent action of Blumea lacera (Asteraceae) against Anopheles stephensi and Culex quinquefasciatus.

    OpenAIRE

    Singh, S.P.; MITTAL, P.K.

    2014-01-01

    Petroleum ether extract of Blumea lacera was screened under laboratory conditions for repellent activity against mosquito vector Anopheles stephensi Liston and Culex quinquefasciatus Say (Diptera: Culicidae). The repellent activity of Blumea lacera extract was tested against mosquitoes in comparison with the DEET, which was used as a positive control. Results obtained from the laboratory experiment showed that the extract was effective against mosquito vectors even at a low dose. A direct rel...

  20. Cloning and molecular characterization of two invertebrate-type lysozymes from Anopheles gambiae

    OpenAIRE

    Paskewitz, S M; Li, B.; Kajla, M. K.

    2008-01-01

    We sequenced and characterized two novel invertebrate-type lysozymes from the mosquito Anopheles gambiae. Alignment and phylogenetic analysis of these and a number of related insect proteins identified through bioinformatics strategies showed a high degree of conservation of this protein family throughout the Class Insecta. Expression profiles were examined for the two mosquito genes through semiquantitative and real-time PCR analysis. Lys i-1 transcripts were found in adult females in the fa...

  1. Change in composition of the Anopheles gambiae complex and its possible implications for the transmission of malaria and lymphatic filariasis in north-eastern Tanzania

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    Derua Yahya A

    2012-06-01

    Full Text Available Abstract Background A dramatic decline in the incidence of malaria due to Plasmodium falciparum infection in coastal East Africa has recently been reported to be paralleled (or even preceded by an equally dramatic decline in malaria vector density, despite absence of organized vector control. As part of investigations into possible causes for the change in vector population density, the present study analysed the Anopheles gambiae s.l. sibling species composition in north-eastern Tanzania. Methods The study was in two parts. The first compared current species complex composition in freshly caught An. gambiae s.l. complex from three villages to the composition reported from previous studies carried out 2–4 decades ago in the same villages. The second took advantage of a sample of archived dried An. gambiae s.l. complex specimens collected regularly from a fourth study village since 2005. Both fresh and archived dried specimens were identified to sibling species of the An. gambiae s.l. complex by PCR. The same specimens were moreover examined for Plasmodium falciparum and Wuchereria bancrofti infection by PCR. Results As in earlier studies, An. gambiae s.s., Anopheles merus and Anopheles arabiensis were identified as sibling species found in the area. However, both study parts indicated a marked change in sibling species composition over time. From being by far the most abundant in the past An. gambiae s.s. was now the most rare, whereas An. arabiensis had changed from being the most rare to the most common. P. falciparum infection was rarely detected in the examined specimens (and only in An. arabiensis whereas W. bancrofti infection was prevalent and detected in all three sibling species. Conclusion The study indicates that a major shift in An. gambiae s.l. sibling species composition has taken place in the study area in recent years. Combined with the earlier reported decline in overall malaria vector density, the study suggests that this

  2. Mathematical evaluation of community level impact of combining bed nets and indoor residual spraying upon malaria transmission in areas where the main vectors are Anopheles arabiensis mosquitoes

    Directory of Open Access Journals (Sweden)

    Okumu Fredros O

    2013-01-01

    Full Text Available Abstract Background Indoor residual insecticide spraying (IRS and long-lasting insecticide treated nets (LLINs are commonly used together even though evidence that such combinations confer greater protection against malaria than either method alone is inconsistent. Methods A deterministic model of mosquito life cycle processes was adapted to allow parameterization with results from experimental hut trials of various combinations of untreated nets or LLINs (Olyset®, PermaNet 2.0®, Icon Life® nets with IRS (pirimiphos methyl, lambda cyhalothrin, DDT, in a setting where vector populations are dominated by Anopheles arabiensis, so that community level impact upon malaria transmission at high coverage could be predicted. Results Intact untreated nets alone provide equivalent personal protection to all three LLINs. Relative to IRS plus untreated nets, community level protection is slightly higher when Olyset® or PermaNet 2.0® nets are added onto IRS with pirimiphos methyl or lambda cyhalothrin but not DDT, and when Icon Life® nets supplement any of the IRS insecticides. Adding IRS onto any net modestly enhances communal protection when pirimiphos methyl is sprayed, while spraying lambda cyhalothrin enhances protection for untreated nets but not LLINs. Addition of DDT reduces communal protection when added to LLINs. Conclusions Where transmission is mediated primarily by An. arabiensis, adding IRS to high LLIN coverage provides only modest incremental benefit (e.g. when an organophosphate like pirimiphos methyl is used, but can be redundant (e.g. when a pyrethroid like lambda cyhalothin is used or even regressive (e.g. when DDT is used for the IRS. Relative to IRS plus untreated nets, supplementing IRS with LLINs will only modestly improve community protection. Beyond the physical protection that intact nets provide, additional protection against transmission by An. arabiensis conferred by insecticides will be remarkably small, regardless of

  3. Larvicidal and pupicidal activity of spinosad against the malarial vector Anopheles stephensi

    Institute of Scientific and Technical Information of China (English)

    Kolanthasamy Prabhu; Kadarkarai Murugan; Arjunan Nareshkumar; Subramanian Bragadeeswaran

    2011-01-01

    Objective:To investigate the larvicidal and pupicidal activity of spinosad againstAnopheles stephensi Listen.Methods: Spinosad from the actinomycete,Saccharopolyspora spinosa was tested againstAnopheles stephensi at different concentrations (0.01, 0.02, 0.04, 0.06 and0.08ppm.), and against first to fourth instar larvae and pupae.Results: The larval mortality ranged from36.1±1.7 in (0.01 ppm) to 79.3±1.8 (0.08 ppm) the first instar larva. The LC50andLC90values of first, second, third and fourth instar larva were0.001, 0.031, 0.034, 0.036and0.0113, 0.102, 0.111, 0.113, respectively. The pupal mortality ranged from33.0±2.0 (0.01 ppm) to 80.0±0.9 (0.08 ppm). The LC50 andLC90values were0.028 and 0.1020, respectively. The reduction percentage ofAnopheles larvae was82.7%, 91.4% and96.0% after 24, 48, 72 hours, respectively, while more than80% reduction was observed after3 weeks.Conclusions:In the present study spinosad effectively caused mortality of mosquito larvae in both the laboratory and field trial. It is predicted that spinosad is likely to be an effective larvicide for treatment of mosquito breeding sites.

  4. Thermal behaviour of Anopheles stephensi in response to infection with malaria and fungal entomopathogens

    Directory of Open Access Journals (Sweden)

    Read Andrew F

    2009-04-01

    Full Text Available Abstract Background Temperature is a critical determinant of the development of malaria parasites in mosquitoes, and hence the geographic distribution of malaria risk, but little is known about the thermal preferences of Anopheles. A number of other insects modify their thermal behaviour in response to infection. These alterations can be beneficial for the insect or for the infectious agent. Given current interest in developing fungal biopesticides for control of mosquitoes, Anopheles stephensi were examined to test whether mosquitoes showed thermally-mediated behaviour in response to infection with fungal entomopathogens and the rodent malaria, Plasmodium yoelii. Methods Over two experiments, groups of An. stephensi were infected with one of three entomopathogenic fungi, and/or P. yoelii. Infected and uninfected mosquitoes were released on to a thermal gradient (14 – 38°C for "snapshot" assessments of thermal preference during the first five days post-infection. Mosquito survival was monitored for eight days and, where appropriate, oocyst prevalence and intensity was assessed. Results and conclusion Both infected and uninfected An. stephensi showed a non-random distribution on the gradient, indicating some capacity to behaviourally thermoregulate. However, chosen resting temperatures were not altered by any of the infections. There is thus no evidence that thermally-mediated behaviours play a role in determining malaria prevalence or that they will influence the performance of fungal biopesticides against adult Anopheles.

  5. [The Anopheles fauna and the transmission of human malaria in Kinshasa (Zaire)].

    Science.gov (United States)

    Karch, S; Asidi, N; Manzambi, Z M; Salaun, J J

    1992-01-01

    A longitudinal epidemiological study of malaria and its vectors was conducted in Kinshasa. 264 night-bite collections on human bait (1,056 man nights) and 384 collections of the house-resting fauna were carried out from April 1989 to October 1990. The anophelian fauna was identified and inventoried, 7 Anopheles species were found: Anopheles gambiae, An. funestus, An. paludis, An. hancocki, An. counstani, An. brunnipes, and An. nili. A single species, An. gambiae s. l. is responsible for the transmission of malaria, it represents 93.27% of the anopheline fauna. The average number of anophele bites man day was 16.28 bites/man/night, it varied between 1 b/m/n in urban area to 26.05 b/m/n in semi-rural area. The average of the sporozoite index for An. gambiae was 3.3%, but it varied from 0% in the urban area to 6.52% in the semi-rural area. The entomological inoculation rate (h) was 197 infective bites per year. This rate fluctuated from 1 infective bite each 128 nights in urban area to 1.7 infective night-bite in semi-rural area. Other epidemiological index were also determined: the level of daily survival rate (p = 8.75 days), the vectorial capacity of 17.97 and the Macdonald's stability 3.5 bites on man taken by a vector during its entire lifetime.

  6. New selenoproteins identified in silico from the genome of Anopheles gambiae

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Selenoprotein is biosynthesized by the incorporation of selenocysteine into proteins,where the TGA codon in the open reading frame does not act as a stop signal but is translated into selenocysteine.The dual functions of TGA result in mis-annotation or lack of selenoproteins in the sequenced genomes of many species.Available computational tools fail to correctly predict selenoproteins.Thus,we devel-oped a new method to identify selenoproteins from the genome of Anopheles gambiae computationally.Based on released genomic information,several programs were edited with PERL language to identify selenocysteine insertion sequence(SECIS)element,the coding potential of TGA codons,and cys-teine-containing homologs of selenoprotein genes.Our results showed that 11365 genes were termi-nated with TGA codons,918 of which contained SECIS elements.Similarity search revealed that 58 genes contained Sec/Cys pairs and similar flanking regions around in-frame TGA codons.Finally,7 genes were found to fully meet requirements for selenoproteins,although they have not been anno-tated as selenoproteins in NCBI databases.Deduced from their basic properties,the newly found se-lenoproteins in the genome of Anopheles gambiae are possibly related to in vivo oxidation tolerance and protein regulation in order to interfere with anopheles’ vectorial capacity of Plasmodium.This study may also provide theoretical bases for the prevention of malaria from anopheles transmission.

  7. Prevalence of anopheles (Diptera: Culicidae) during sunset in areas of the Itaipu Hydroelectric Power Plant in Guaira County, State of Parana, Brazil; Prevalencia de anofelinos (Diptera: Culicidae) no crepusculo vespertino em areas da Usina Hidreletrica de Itaipu, no Municipio de Guaira, Estado do Parana, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Anthony Erico; Mello, Rubens Pinto de; Lopes, Catarina Macedo; Alencar, Jeronimo; Gentile, Carla [Fundacao Inst. Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil). Dept. de Entomologia. Lab. de Diptera

    1997-11-01

    Systematic collections of anophelines were conducted from November 1995 to August 1995 from 18:00 to 20:00 hr using Shannon traps and human-bait along the lake margin which forms the Itaipu Hydroelectric Reservoir, State of Parana, Brazil. Species prevalence was studied at 15 min intervals. Anopheles albitarsis sensu latu and An. galvaoi, were the most frequently collected mosquitoes. All Anopheles species populations peaked between 18:45 and 19:30 hr. The observations illustrate the existence of haematophagic activity cycle during the early evening hours: exogenous stimulus (the beginning of sunset) Shannon trap (light attraction) human bait (haematophagy) rest and digestion exogenous stimulus Shannon trap or surrounding vegetation. The greater abundance of An. albitarsis collected in human-bait and Shannon trap suggests it may be a potential malaria vector in the region. (author) 20 refs.

  8. Observations on sporozoite detection in naturally infected sibling species of the Anopheles culicifacies complex and variant of Anopheles stephensi in India

    Indian Academy of Sciences (India)

    Susanta Kumar Ghosh; Satyanarayan Tiwari; Kamaraju Raghavendra; Tiruchinapalli Sundaraj; Aditya Prasad Dash

    2008-09-01

    Sporozoites were detected in naturally infected sibling species of the primary rural vector Anopheles culicifacies complex in two primary health centres (PHCs) and a variant of the urban vector Anopheles stephensi in Mangalore city, Karnataka, south India while carrying out malaria outbreak investigations from 1998–2006. Sibling species of An. culicifacies were identified based on the banding patterns on ovarian polytene chromosomes, and variants of An. stephensi were identified based on the number of ridges on the egg floats. Sporozoites were detected in the salivary glands by the dissection method. Of the total 334 salivary glands of An. culicifacies dissected, 17 (5.08%) were found to be positive for sporozoites. Of the 17 positive samples, 11 were suitable for sibling species analysis; 10 were species A (an efficient vector) and 1 was species B (a poor vector). Out of 46 An. stephensi dissected, one was sporozoite positive and belonged to the type form (an efficient vector). In malaria epidemiology this observation is useful for planning an effective vector control programme, because each sibling species/variant differs in host specificity, susceptibility to malarial parasites, breeding habitats and response to insecticides.

  9. PCR-based methods for the detection of L1014 kdr mutation in Anopheles culicifacies sensu lato

    Directory of Open Access Journals (Sweden)

    Dash Aditya P

    2009-07-01

    Full Text Available Abstract Background Anopheles culicifacies s.l., a major malaria vector in India, has developed widespread resistance to DDT and is becoming resistant to pyrethroids–the only insecticide class recommended for the impregnation of bed nets. Knock-down resistance due to a point mutation in the voltage gated sodium channel at L1014 residue (kdr is a common mechanism of resistance to DDT and pyrethroids. The selection of this resistance may pose a serious threat to the success of the pyrethroid-impregnated bed net programme. This study reports the presence of kdr mutation (L1014F in a field population of An. culicifacies s.l. and three new PCR-based methods for kdr genotyping. Methods The IIS4-IIS5 linker to IIS6 segments of the para type voltage gated sodium channel gene of DDT and pyrethroid resistant An. culicifacies s.l. population from the Surat district of India was sequenced. This revealed the presence of an A-to-T substitution at position 1014 leading to a leucine-phenylalanine mutation (L1014F in a few individuals. Three molecular methods viz. Allele Specific PCR (AS-PCR, an Amplification Refractory Mutation System (ARMS and Primer Introduced Restriction Analysis-PCR (PIRA-PCR were developed and tested for kdr genotyping. The specificity of the three assays was validated following DNA sequencing of the samples genotyped. Results The genotyping of this An. culicifacies s.l. population by the three PCR based assays provided consistent result and were in agreement with DNA sequencing result. A low frequency of the kdr allele mostly in heterozygous condition was observed in the resistant population. Frequencies of the different genotypes were in Hardy-Weinberg equilibrium. Conclusion The Leu-Phe mutation, which generates the kdr phenotype in many insects, was detected in a pyrethroid and DDT resistant An. culicifacies s.l. population. Three PCR-based methods were developed for kdr genotyping. All the three assays were specific. The ARMS method

  10. Toxicity of essential oil from Indian borage on the larvae of the African malaria vector mosquito, Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    Kweka Eliningaya J

    2012-12-01

    Full Text Available Abstract Background Essential oils are currently studied for the control of different disease vectors, because of their efficacy on targeted organisms. In the present investigation, the larvicidal potential of essential oil extracted from Indian borage (Plectranthus amboinicus was studied against the African anthropophagic malaria vector mosquito, Anopheles gambiae. The larvae of An. gambiae s.s laboratory colony and An. gambiae s.l of wild populations were assayed and the larval mortality was observed at 12, 24 and 48 h after exposure period with the concentrations of 3.125, 6.25, 12.5, 25, 50 and 100 ppm. Findings Larval mortality rates of the essential oil was entirely time and dose dependent. The LC50 values of the laboratory colony were 98.56 (after 12h 55.20 (after 24 h and 32.41 ppm (after 48 h and the LC90 values were 147.40 (after 12h, 99.09 (after 24 h and 98.84 ppm (after 48 h. The LC50 and LC90 values of the wild population were 119.52, 179.85 (after 12h 67.53, 107.60 (after 24 h and 25.51, 111.17 ppm (after 48 h respectively. The oil showed good larvicidal potential after 48 h of exposure period against An. gambiae. The essential oil of Indian borage is a renowned natural source of larvicides for the control of the African malaria vector mosquito, An. gambiae. Conclusion The larvicidal efficacy shown by plant extracts against An. gambiae should be tested in semi field and small scale trials for effective compounds to supplement the existing larval control tools.

  11. Identification of a Bacillus thuringiensis Cry11Ba toxin-binding aminopeptidase from the mosquito, Anopheles quadrimaculatus

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    Abdullah Mohd

    2006-05-01

    Full Text Available Abstract Background Aminopeptidase N (APN type proteins isolated from several species of lepidopteran insects have been implicated as Bacillus thuringiensis (Bt toxin-binding proteins (receptors for Cry toxins. We examined brush border membrane vesicle (BBMV proteins from the mosquito Anopheles quadrimaculatus to determine if APNs from this organism would bind mosquitocidal Cry toxins that are active to it. Results A 100-kDa protein with APN activity (APNAnq 100 was isolated from the brush border membrane of Anopheles quadrimaculatus. Native state binding analysis by surface plasmon resonance shows that APNAnq 100 forms tight binding to a mosquitocidal Bt toxin, Cry11Ba, but not to Cry2Aa, Cry4Ba or Cry11Aa. Conclusion An aminopeptidase from Anopheles quadrimaculatus mosquitoes is a specific binding protein for Bacillus thuringiensis Cry11Ba.

  12. Description of Anopheles gabonensis, a new species potentially involved in rodent malaria transmission in Gabon, Central Africa.

    Science.gov (United States)

    Rahola, Nil; Makanga, Boris; Yangari, Patrick; Jiolle, Davy; Fontenille, Didier; Renaud, François; Ollomo, Benjamin; Ayala, Diego; Prugnolle, Franck; Paupy, Christophe

    2014-12-01

    The genus Anopheles includes mosquito vectors of human malaria and arboviruses. In sub-Saharan Africa, the anopheline fauna is rich of nearly 150 species, few of which are anthropophilic and capable of transmitting pathogens to humans. Some of the remaining species are found in forests far from human environments and are vectors of wildlife pathogens. The diversity and the biology of these species have yet to be fully described. As a contribution to furthering knowledge of sylvan Anophelinae, using morphological and molecular tools we describe a new Anopheles species collected in Gabon (Central Africa), which we have named Anopheles gabonensis n. sp. We also molecularly screened this species to detect infections by Plasmodium parasites. The results showed the species to have been infected by Plasmodium vinckei, a rodent parasite. We discuss the role of An. gabonensis n. sp. in the transmission of P. vinckei in the rainforest areas of Central Africa and its potential to transfer pathogens to humans.

  13. The insecticide resistance status of malaria vectors in the Mekong region

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    Denis Leen

    2008-06-01

    Full Text Available Abstract Background Knowledge on insecticide resistance in target species is a basic requirement to guide insecticide use in malaria control programmes. Malaria transmission in the Mekong region is mainly concentrated in forested areas along the country borders, so that decisions on insecticide use should ideally be made at regional level. Consequently, cross-country monitoring of insecticide resistance is indispensable to acquire comparable baseline data on insecticide resistance. Methods A network for the monitoring of insecticide resistance, MALVECASIA, was set up in the Mekong region in order to assess the insecticide resistance status of the major malaria vectors in Cambodia, Laos, Thailand, and Vietnam. From 2003 till 2005, bioassays were performed on adult mosquitoes using the standard WHO susceptibility test with diagnostic concentrations of permethrin 0.75% and DDT 4%. Additional tests were done with pyrethroid insecticides applied by the different national malaria control programmes. Results Anopheles dirus s.s., the main vector in forested malaria foci, was susceptible to permethrin. However, in central Vietnam, it showed possible resistance to type II pyrethroids. In the Mekong delta, Anopheles epiroticus was highly resistant to all pyrethroid insecticides tested. It was susceptible to DDT, except near Ho Chi Minh City where it showed possible DDT resistance. In Vietnam, pyrethroid susceptible and tolerant Anopheles minimus s.l. populations were found, whereas An. minimus s.l. from Cambodia, Laos and Thailand were susceptible. Only two An. minimus s.l. populations showed DDT tolerance. Anopheles vagus was found resistant to DDT and to several pyrethroids in Vietnam and Cambodia. Conclusion This is the first large scale, cross-country survey of insecticide resistance in Anopheles species in the Mekong Region. A unique baseline data on insecticide resistance for the Mekong region is now available, which enables the follow-up of trends

  14. "Behaviour changes in Permethrin-resistant strain of Anopheles Stephensi "

    Directory of Open Access Journals (Sweden)

    Vatandoost H

    2000-09-01

    Full Text Available Behaviour studies indicated that the permethrin resistant strin of An. Stephensi was 3-fold resistant to knock-down compared with the susceptible strain. The resistant strain was however 3-fold less irritable to permethrin and less responsive than the susceptible strain to the movement of an aspirator. If reduced irritability and reduced responsiveness to catch are consequences of the changes in the nervous system, then such a form of resistance may be disadvantageous to mosquitoes in natural populations.

  15. Review of Temephos Discriminating Concentration for Monitoring the Susceptibility of Anopheles labranchiae (Falleroni, 1926), Malaria Vector in Morocco

    OpenAIRE

    Chandre, F; Ameur, B; Herrak, T.; E. Adlaoui; Elkohli, M.; Faraj, C.

    2010-01-01

    In Morocco, the resistance monitoring of Anopheles labranchiae larvae to temephos is done using discriminating concentration of 0.125 mg, which is half of the WHO recommended dose for Anopheles. However, this dosage seemed to be too high to allow an early detection of the resistance and its revision was found necessary. The present study was carried out during May-June 2008 and 2009 in nine provinces from the north-west of the country. The aim was to determine the lethal concentrations LC100 ...

  16. Towards a sterile insect technique field release of Anopheles arabiensis mosquitoes in Sudan: Irradiation, transportation, and field cage experimentation

    Directory of Open Access Journals (Sweden)

    Malcolm Colin A

    2008-04-01

    Full Text Available Abstract Background The work described in this article forms part of a study to suppress a population of the malaria vector Anopheles arabiensis in Northern State, Sudan, with the Sterile Insect Technique. No data have previously been collected on the irradiation and transportation of anopheline mosquitoes in Africa, and the first series of attempts to do this in Sudan are reported here. In addition, experiments in a large field cage under near-natural conditions are described. Methods Mosquitoes were irradiated in Khartoum and transported as adults by air to the field site earmarked for future releases (400 km from the laboratory. The field cage was prepared for experiments by creating resting sites with favourable conditions. The mating and survival of (irradiated laboratory males and field-collected males was studied in the field cage, and two small-scale competition experiments were performed. Results Minor problems were experienced with the irradiation of insects, mostly associated with the absence of a rearing facility in close proximity to the irradiation source. The small-scale transportation of adult mosquitoes to the release site resulted in minimal mortality ( Conclusion It is concluded that although conditions are challenging, there are no major obstacles associated with the small-scale irradiation and transportation of insects in the current setting. The field cage is suitable for experiments and studies to test the competitiveness of irradiated males can be pursued. The scaling up of procedures to accommodate much larger numbers of insects needed for a release is the next challenge and recommendations to further implementation of this genetic control strategy are presented.

  17. Evaluation of Endod (Phytolacca dodecandra: Phytolaccaceae) as a Larvicide Against Anopheles arabiensis, the Principal Vector of Malaria in Ethiopia.

    Science.gov (United States)

    Getachew, Dejene; Balkew, Meshesha; Gebre-Michael, Teshome

    2016-06-01

    Malaria control methods rely mostly on adult mosquito control using insecticide-treated nets and indoor residual spraying with insecticides. Plants such as endod (Phytolacca dodecandra) can potentially be used for the control of mosquito larvae as a supplement to adult control methods. Following the discovery of endod, a molluscicide plant, more than 5 decades ago in Ethiopia, subsequent studies have shown that its potency can further be increased by simple procedures such as aging endod berry powder in water. This study was conducted to evaluate the killing effect of fresh and aged endod solution against 4th-stage larvae of Anopheles arabiensis. Laboratory-reared An. arabiensis larvae exposed to different concentrations of endod preparation using distilled or spring water had 50% lethal concentration (LC50)  =  49.6 ppm and 90% lethal concentration (LC90)  =  234 ppm for fresh and LC50  =  36.4 ppm and LC90  =  115.7 ppm for the aged endod solution in distilled water against the laboratory population. Against field-collected larvae of the same species, aged preparations in habitat water resulted in higher LC50 (472.7 ppm) and LC90 (691 ppm) values, with only a slight improvement over fresh preparations in habitat water (LC50  =  456.2 ppm; LC90  =  896.1 ppm). In general, although aged preparations of endod required lower concentrations than fresh to kill at least 90% of the larvae, these concentrations were much higher (12-70×) than that required for schistosome-transmitting snails. PMID:27280350

  18. DNA Barcodes indicate members of the Anopheles fluviatilis (Diptera: Culicidae) species complex to be conspecific in India.

    Science.gov (United States)

    Pradeep Kumar, N; Krishnamoorthy, N; Sahu, S S; Rajavel, A R; Sabesan, S; Jambulingam, P

    2013-05-01

    Anopheles fluviatilis, a major vector of malaria in India has been described as a complex of three sibling species members, named as S, T and U, based on variations in chromosomal inversions. Also, ribosomal DNA markers (repetitive Internal Transcribed Spacer 2 (ITS2) and 28S D3 region) were described to differentiate these three sibling species members. However, controversies prevail on the genetic isolation status of these cryptic species. Hence, we evaluated this taxonomic incongruence employing DNA barcoding, the well established methodology for species identification, using 60 An. fluviatilis sensu lato specimens, collected from two malaria endemic eastern states of India. These specimens were also subjected to sibling species characterization by ITS2 and D3 DNA markers. The former marker identified 31 specimens among these as An. fluviatilis S and 21 as An. fluviatilis T. Eight specimens amplified DNA fragments specific for both S and T. The D3 marker characterized 39 specimens belonging to species S and 21 to species T. Neither marker identified species U. Neighbor Joining analysis of mitochondrial cytochrome c oxidase gene 1 sequences (the DNA barcode) categorized all the 60 specimens into a single operational taxonomic unit, their Kimura 2 parameter (K2P) genetic variability being only 0.8%. The genetic differentiation (FST ) and gene flow (Nm ) estimates were 0.00799 and 62.07, respectively, indicating these two 'species' (S & T) as genetically con-specific intermixing populations with negligible genetic differentiation. Earlier investigations have refuted the existence of species U. Also, this study demonstrated that An. fluviatilis and the closely related An. minimus could be taxonomically differentiated by the DNA Barcode approach (K2P = 5.0%). PMID:23398631

  19. Electroantennogram, flight orientation and oviposition responses of Anopheles stephensi and Aedes aegypti to a fatty acid ester-propyl octadecanoate.

    Science.gov (United States)

    Seenivasagan, Thangaraj; Sharma, Kavita R; Prakash, Shri

    2012-10-01

    Studies were carried out to evaluate the role of a C(21)-fatty acid ester; propyl octadecanoate (PO) for olfaction-mediated behavioral responses of urban malaria vector, Anopheles stephensi and dengue vector, Aedes aegypti mosquitoes using electroantennogram (EAG), flight orientation and oviposition experiments. Dose dependent electrophysiological responses were recorded for PO from the antenna of both mosquito species in which 10(-5) g elicited significant EAG response. An. stephensi exhibited 2.4, 4.2 and 5.5 fold increased EAG response compared to control, while Ae. aegypti showed 1.9, 4.6 and 5.8 fold EAG responses respectively at 10(-7) g, 10(-6) g and 10(-5) g doses. In the Y-tube olfactometer, 77-80% gravid females of An. stephensi, and 64-77% of Ae. aegypti were caught in the chambers releasing 10(-6) g and 10(-5) g plume of PO. The synthetic fatty acid ester loaded onto an effervescent tablet at 0.1 mg/L, 1 mg/L and 10 mg/L elicited increased ovipositional responses from gravid mosquitoes compared to control. The oviposition activity indices (OAI) of An. stephensi females were +0.40, +0.51 and +0.58, whereas the OAI for Ae. aegypti females were +0.05, +0.36 and +0.57 respectively in 0.1, 1, 10 mg/L of PO; indicated concentration dependent increased egg deposition. Similarly, in the residual activity studies, oviposition substrates treated with PO on effervescent tablet at 1mg/L and 10mg/L received significantly increased egg deposition by gravid females of both mosquito species for up to 1 week compared to control substrates. PO can potentially be used in ovitraps to monitor An. stephensi and Ae. aegypti populations in the vector surveillance programs.

  20. Synergy in efficacy of fungal entomopathogens and permethrin against West African insecticide-resistant Anopheles gambiae mosquitoes.

    Directory of Open Access Journals (Sweden)

    Marit Farenhorst

    Full Text Available BACKGROUND: Increasing incidences of insecticide resistance in malaria vectors are threatening the sustainable use of contemporary chemical vector control measures. Fungal entomopathogens provide a possible additional tool for the control of insecticide-resistant malaria mosquitoes. This study investigated the compatibility of the pyrethroid insecticide permethrin and two mosquito-pathogenic fungi, Beauveria bassiana and Metarhizium anisopliae, against a laboratory colony and field population of West African insecticide-resistant Anopheles gambiae s.s. mosquitoes. METHODOLOGY/FINDINGS: A range of fungus-insecticide combinations was used to test effects of timing and sequence of exposure. Both the laboratory-reared and field-collected mosquitoes were highly resistant to permethrin but susceptible to B. bassiana and M. anisopliae infection, inducing 100% mortality within nine days. Combinations of insecticide and fungus showed synergistic effects on mosquito survival. Fungal infection increased permethrin-induced mortality rates in wild An. gambiae s.s. mosquitoes and reciprocally, exposure to permethrin increased subsequent fungal-induced mortality rates in both colonies. Simultaneous co-exposure induced the highest mortality; up to 70.3+/-2% for a combined Beauveria and permethrin exposure within a time range of one gonotrophic cycle (4 days. CONCLUSIONS/SIGNIFICANCE: Combining fungi and permethrin induced a higher impact on mosquito survival than the use of these control agents alone. The observed synergism in efficacy shows the potential for integrated fungus-insecticide control measures to dramatically reduce malaria transmission and enable control at more moderate levels of coverage even in areas where insecticide resistance has rendered pyrethroids essentially ineffective.

  1. Synergy between repellents and non-pyrethroid insecticides strongly extends the efficacy of treated nets against Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    N'Guessan Raphaël

    2007-03-01

    Full Text Available Abstract Background To manage the kdr pyrethroid-resistance in Anopheline malaria vectors, new compounds or new strategies are urgently needed. Recently, mixing repellents (DEET and a non-pyrethroid insecticide (propoxur was shown to be as effective as deltamethrin, a standard pyrethroid, under laboratory conditions, because of a strong synergy between the two compounds. In the present study, the interactions between two repellents (DEET and KBR 3023 and a non-pyrethroid insecticide (pyrimiphos methyl or PM on netting were investigated. The residual efficacy and the inhibition of blood feeding conferred by these mixtures were assessed against Anopheles gambiae mosquitoes. Methods DEET and KBR 3023 were mixed with pyrimiphos methyl (PM, a organophosphate (OP insecticide. The performance of mono- and bi-impregnated nets against adult mosquitoes was assessed using a miniaturized, experimental hut system (laboratory tunnel tests that allows expression of behavioural responses to insecticide, particularly the mortality and blood feeding effects. Results Both mixtures (PM+DEET and PM+KBR3023 induced 95% mortality for more than two months compared with less than one week for each compound used alone, then reflecting a strong synergy between the repellents and PM. A similar trend was observed with the blood feeding rates, which were significantly lower for the mixtures than for each component alone. Conclusion Synergistic interactions between organophosphates and repellents may be of great interest for vector control as they may contribute to increase the residual life of impregnated materials and improve the control of pyrethroid-resistance mosquitoes. These results prompt the need to evaluate the efficacy of repellent/non-pyrethroid insecticide mixtures against field populations of An. gambiae showing high level of resistance to Ops and pyrethroids.

  2. Susceptibility of Anopheles stephensi to Plasmodium gallinaceum: a trait of the mosquito, the parasite, and the environment.

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    Jen C C Hume

    Full Text Available BACKGROUND: Vector susceptibility to Plasmodium infection is treated primarily as a vector trait, although it is a composite trait expressing the joint occurrence of the parasite and the vector with genetic contributions of both. A comprehensive approach to assess the specific contribution of genetic and environmental variation on "vector susceptibility" is lacking. Here we developed and implemented a simple scheme to assess the specific contributions of the vector, the parasite, and the environment to "vector susceptibility." To the best of our knowledge this is the first study that employs such an approach. METHODOLOGY/PRINCIPAL FINDINGS: We conducted selection experiments on the vector (while holding the parasite "constant" and on the parasite (while holding the vector "constant" to estimate the genetic contributions of the mosquito and the parasite to the susceptibility of Anopheles stephensi to Plasmodium gallinaceum. We separately estimated the realized heritability of (i susceptibility to parasite infection by the mosquito vector and (ii parasite compatibility (transmissibility with the vector while controlling the other. The heritabilities of vector and the parasite were higher for the prevalence, i.e., fraction of infected mosquitoes, than the corresponding heritabilities of parasite load, i.e., the number of oocysts per mosquito. CONCLUSIONS: The vector's genetics (heritability comprised 67% of "vector susceptibility" measured by the prevalence of mosquitoes infected with P. gallinaceum oocysts, whereas the specific contribution of parasite genetics (heritability to this trait was only 5%. Our parasite source might possess minimal genetic diversity, which could explain its low heritability (and the high value of the vector. Notably, the environment contributed 28%. These estimates are relevant only to the particular system under study, but this experimental design could be useful for other parasite-host systems. The prospects and

  3. Expression Profiles and RNAi Silencing of Inhibitor of Apoptosis Transcripts in Aedes, Anopheles, and Culex Mosquitoes (Diptera: Culicidae).

    Science.gov (United States)

    Puglise, Jason M; Estep, Alden S; Becnel, James J

    2016-03-01

    Effective mosquito control is vital to curtail the devastating health effects of many vectored diseases. RNA interference (RNAi)-mediated control of mosquitoes is an attractive alternative to conventional chemical pesticides. Previous studies have suggested that transcripts for inhibitors of apoptosis (IAPs) may be good RNAi targets. To revisit and extend previous reports, we examined the expression of Aedes aegypti (L.) IAPs (AaeIAPs) 1, 2, 5, 6, 9, and a viral IAP-associated factor (vIAF) as well as Anopheles quadrimaculatus Say and Culex quinquefasciatus Say IAP1 homologs (AquIAP1 and CquIAP1) in adult females. Expression profiles of IAPs suggested that some older female mosquitoes had significantly higher IAP mRNA levels when compared to the youngest ones. Minor differences in expression of AaeIAPs were observed in mosquitoes that imbibed a bloodmeal, but the majority of the time points (up to 48 h) were not significantly different. Although in vitro experiments with the Ae. aegypti Aag-2 cell line demonstrated that the various AaeIAPs could be effectively knocked down within one day after dsRNA treatment, only Aag-2 cells treated with dsIAP1 displayed apoptotic morphology. Gene silencing and mortality were also evaluated after topical application and microinjection of the same dsRNAs into female Ae. aegypti. In contrast to previous reports, topical administration of dsRNA against AaeIAP1 did not yield a significant reduction in gene expression or increased mortality. Knockdown of IAP1 and other IAPs by microinjection did not result in significant mortality. In toto, our findings suggest that IAPs may not be suitable RNAi targets for controlling adult mosquito populations.

  4. Behavioural responses of Anopheles gambiae sensu stricto M and S molecular form larvae to an aquatic predator in Burkina Faso

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    Gimonneau Geoffrey

    2012-03-01

    Full Text Available Abstract Background Predation of aquatic immature stages has been identified as a major evolutionary force driving habitat segregation and niche partitioning in the malaria mosquito Anopheles gambiae sensu stricto in the humid savannahs of Burkina Faso, West Africa. Here, we explored behavioural responses to the presence of a predator in wild populations of the M and S molecular forms of An. gambiae that typically breed in permanent (e.g., rice field paddies and temporary (e.g., road ruts water collections. Methods Larvae used in these experiments were obtained from eggs laid by wild female An. gambiae collected from two localities in south-western Burkina Faso during the 2008 rainy season. Single larvae were observed in an experimental arena, and behavioural traits were recorded and quantified a in the absence of a predator and b in the presence of a widespread mosquito predator, the backswimmer Anisops jaczewskii. Differences in the proportion of time allocated to each behaviour were assessed using Principal Component Analysis and Multivariate Analysis of Variance. Results The behaviour of M and S form larvae was found to differ significantly; although both forms mainly foraged at the water surface, spending 60-90% of their time filtering water at the surface or along the wall of the container, M form larvae spent on average significantly more time browsing at the bottom of the container than S form larvae (4.5 vs. 1.3% of their overall time, respectively; P P P P Conclusions Behavioural differences between larvae of the M and S form of An. gambiae in response to an acute predation risk is likely to be a reflection of different trade-offs between foraging and predator vigilance that might be of adaptive value in contrasting aquatic ecosystems. Future studies should explore the relevance of these findings under the wide range of natural settings where both forms co-exist in Africa.

  5. Effect of three larval diets on larval development and male sexual performance of Anopheles gambiae s.s.

    Science.gov (United States)

    Yahouédo, Gildas A; Djogbénou, Luc; Saïzonou, Jacques; Assogba, Bénoît S; Makoutodé, Michel; Gilles, Jeremie R L; Maïga, Hamidou; Mouline, Karine; Soukou, Bhonna K; Simard, Frédéric

    2014-04-01

    Population replacement/elimination strategies based on mass-release of sterile or otherwise genetically modified (male) mosquitoes are being considered in order to expand the malaria vector control arsenal on the way to eradication. A challenge in this context, is to produce male mosquitoes that will be able to compete and mate with wild females more efficiently than their wild counterparts, i.e. high fitness males. This study explored the effect of three larval food diets developed by the International Atomic Energy Agency on the overall fitness and mating performance of male Anopheles gambiae s.s. mosquitoes (Kisumu strain). Larval development (pupation and emergence rate, development time) was monitored, and adult wing length and energy reserves at emergence (i.e. lipids, sugars, glycogen and proteins) were measured. Male sexual performance was assessed through an insemination test whereby one male and 10 virgin females were maintained together in the same cage in order to record the number of inseminated females per 24h. Our results show that males reared on Diets 2 and 3 performed best during larval development. Males provided with treatment 2.2 had a shorter development time and performed best in insemination tests. However, these males had the lowest overall lifespan, suggesting a trade-off between longevity and sexual performances which needs to be taken into consideration when planning release. The results from this work were discussed in the context of sterile insect techniques or genetic control methods which is today one of the strategy in the overall mosquito control and elimination efforts. PMID:24291460

  6. PCR detection of malaria parasites in desiccated Anopheles mosquitoes is uninhibited by storage time and temperature

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    Rider Mark A

    2012-06-01

    Full Text Available Abstract Background Reliable methods to preserve mosquito vectors for malaria studies are necessary for detecting Plasmodium parasites. In field settings, however, maintaining a cold chain of storage from the time of collection until laboratory processing, or accessing other reliable means of sample preservation is often logistically impractical or cost prohibitive. As the Plasmodium infection rate of Anopheles mosquitoes is a central component of the entomological inoculation rate and other indicators of transmission intensity, storage conditions that affect pathogen detection may bias malaria surveillance indicators. This study investigated the effect of storage time and temperature on the ability to detect Plasmodium parasites in desiccated Anopheles mosquitoes by real-time polymerase chain reaction (PCR. Methods Laboratory-infected Anopheles stephensi mosquitoes were chloroform-killed and stored over desiccant for 0, 1, 3, and 6 months while being held at four different temperatures: 28, 37, -20 and -80°C. The detection of Plasmodium DNA was evaluated by real-time PCR amplification of a 111 base pair region of block 4 of the merozoite surface protein. Results Varying the storage time and temperature of desiccated mosquitoes did not impact the sensitivity of parasite detection. A two-way factorial analysis of variance suggested that storage time and temperature were not associated with a loss in the ability to detect parasites. Storage of samples at 28°C resulted in a significant increase in the ability to detect parasite DNA, though no other positive associations were observed between the experimental storage treatments and PCR amplification. Conclusions Cold chain maintenance of desiccated mosquito samples is not necessary for real-time PCR detection of parasite DNA. Though field-collected mosquitoes may be subjected to variable conditions prior to molecular processing, the storage of samples over an inexpensive and logistically

  7. Vector capacity of Anopheles sinensis in malaria outbreak areas of central China

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    Pan Jia-Yun

    2012-07-01

    Full Text Available Abstract Background Both falciparum and vivax malaria were historically prevalent in China with high incidence. With the control efforts, the annual incidence in the whole country has reduced to 0.0001% except in some areas in the southern borders after 2000. Despite this, the re-emergence or outbreak of malaria was unavoidable in central China during 2005–2007. In order to understand the role of the vector in the transmission of malaria during the outbreak period, the vector capacity of An. sinensis in Huanghuai valley of central China was investigated. Findings The study was undertaken in two sites, namely Huaiyuan county of Anhui province and Yongcheng county of Henan province. In each county, malaria cases were recorded for recent years, and transmission risk factors for each study village including anti-mosquito facilities and total number of livestock were recorded by visiting each household in the study sites. The specimens of mosquitoes were collected in two villages, and population density and species in each study site were recorded after the identification of different species, and the blood-fed mosquitoes were tested by ring precipitation test. Finally, various indicators were calculated to estimate vector capacity or dynamics, including mosquito biting rate (MBR, human blood index (HBI, and the parous rates (M. Finally, the vector capacity, as an important indicator of malaria transmission to predict the potential recurrence of malaria, was estimated and compared in each study site. About 93.0% of 80 households in Huaiyuan and 89.3% of 192 households in Yongcheng had anti-mosquito facilities. No cattle or pigs were found, only less than 10 sheep were found in each study village. A total of 94 and 107 Anopheles spp. mosquitos were captured in two study sites, respectively, and all of An. sinensis were morphologically identified. It was found that mosquito blood-feeding peak was between 9:00 pm and 12:00 pm. Man biting rate of

  8. Larvicidal activity of extracts from three Plumbago spp against Anopheles gambiae

    OpenAIRE

    Barasa M Maniafu; Lwande Wilber; Ndiege, Isaiah O.; Cornelius C Wanjala; Teresa Ayuko Akenga

    2009-01-01

    Three Plumbago spp have been tested for mosquito larvicidal activity. The crude extracts exhibiting the highest larvicidal activity against Anopheles gambiae were hexane (LC50 = 6.4 μg/mL) and chloroform (LC50 = 6.7 μg/mL) extracts from Plumbago zeylanica Linn, chloroform (LC50 = 6.7 ug/mL) extract from Plumbago stenophylla Bull and ethyl acetate (LC50 = 4.1 μg/mL) extract from Plumbago dawei Rolfe. These LC50 values were within 95% confidence limits. 5-hydroxy-2-methyl-1,4-nap...

  9. Effect of ivermectin on the larvae of Anopheles gambiae and Culex quinquefasciatus

    DEFF Research Database (Denmark)

    Derua, Yahya A.; Malongo, Bernard B.; Simonsen, Paul E.

    2016-01-01

    Background: Ivermectin is used extensively globally for treatment of helminthic and ectoparasitic infections in animals and humans. The effect of excreted ivermectin on non-target organisms in aquatic and terrestrial environments has been increasingly reported. Due to its low water solubility...... and adsorption to sediments, the ivermectin exposure-risk to aquatic organisms dwelling in different strata of water bodies varies. This study assessed the survival of larvae of Anopheles gambiae Giles and Culex quinquefasciatus Say, when exposed to low concentrations of ivermectin under laboratory conditions...

  10. Insecticidal activity of the essential oil of Thymus transcaspicus against Anopheles stephensi

    Institute of Scientific and Technical Information of China (English)

    Leila Dargahi; Kamal Razavi-Azarkhiavi; Mohammad Ramezani; Mohammad Reza Abaee; Javad Behravan

    2014-01-01

    Objective:To investigate the insecticidal activity of the essential oil of Thymus transcaspicus (T. transcaspicus) against Anopheles stephensi (An. stephensi). Methods:An. stephensi were exposed to 31, 63, 125 and 250 µg/L of essential oil of T. transcaspicus for 24 h. Results:The most toxicity was observed at 250 µg/L of essential oil with the LC50 values of 134.1 µg/L after 24 h. Conclusions:The essential oil of T. transcaspicus exhibited strong insecticidal activity against An. stephensi which can be attributed to its constituent especially carvacrol and thymol phenols.

  11. Evaluation of a eucalyptus-based repellent against Anopheles spp. in Tanzania.

    Science.gov (United States)

    Trigg, J K

    1996-06-01

    A eucalyptus-based insect repellent (PMD) with the principal active ingredient p-menthane-3,8-diol was evaluated in the field in comparison with deet. In human landing catches in Tanzania, 3 formulations of PMD were tested against Anopheles gambiae and An. funestus. Repellents, applied to the legs and feet at doses chosen as used in practice, gave complete protection from biting for between 6 and 7.75 h, depending upon the formulation type, with no significant difference between PMD and deet in terms of efficacy and duration of protection. PMID:8827599

  12. A peroxidase/dual oxidase system modulates midgut epithelial immunity in Anopheles gambiae.

    Science.gov (United States)

    Kumar, Sanjeev; Molina-Cruz, Alvaro; Gupta, Lalita; Rodrigues, Janneth; Barillas-Mury, Carolina

    2010-03-26

    Extracellular matrices in diverse biological systems are cross-linked by dityrosine covalent bonds catalyzed by the peroxidase/oxidase system. We show that a peroxidase, secreted by the Anopheles gambiae midgut, and dual oxidase form a dityrosine network that decreases gut permeability to immune elicitors. This network protects the microbiota by preventing activation of epithelial immunity. It also provides a suitable environment for malaria parasites to develop within the midgut lumen without inducing nitric oxide synthase expression. Disruption of this barrier results in strong and effective pathogen-specific immune responses. PMID:20223948

  13. Immune factor Gambif1, a new rel family member from the human malaria vector, Anopheles gambiae.

    OpenAIRE

    Barillas-Mury, C; Charlesworth, A.; Gross, I; Richman, A; Hoffmann, J A; Kafatos, F C

    1996-01-01

    A novel rel family member, Gambif1 (gambiae immune factor 1), has been cloned from the human malaria vector, Anopheles gambiae, and shown to be most similar to Drosophila Dorsal and Dif. Gambif1 protein is translocated to the nucleus in fat body cells in response to bacterial challenge, although the mRNA is present at low levels at all developmental stages and is not induced by infection. DNA binding activity to the kappaB-like sites in the A.gambiae Defensin and the Drosophila Diptericin and...

  14. The JAK-STAT Pathway Controls Plasmodium vivax Load in Early Stages of Anopheles aquasalis Infection

    OpenAIRE

    Bahia, Ana C; Marina S Kubota; Antonio J Tempone; Helena R. C. Araújo; Bruno A M Guedes; Orfanó, Alessandra S.; Wanderli P Tadei; Ríos-Velásquez, Claudia M.; Han, Yeon S.; SECUNDINO Nágila F.C.; Barillas-Mury, Carolina; Pimenta, Paulo F. P.; Traub-Csekö, Yara M.

    2011-01-01

    Malaria affects 300 million people worldwide every year and 450,000 in Brazil. In coastal areas of Brazil, the main malaria vector is Anopheles aquasalis, and Plasmodium vivax is responsible for the majority of malaria cases in the Americas. Insects possess a powerful immune system to combat infections. Three pathways control the insect immune response: Toll, IMD, and JAK-STAT. Here we analyze the immune role of the A. aquasalis JAK-STAT pathway after P. vivax infection. Three genes, the tran...

  15. The JAK-STAT pathway controls Plasmodium vivax load in early stages of Anopheles aquasalis infection.

    OpenAIRE

    Bahia, Ana C; Marina S Kubota; Antonio J Tempone; Helena R. C. Araújo; Bruno A M Guedes; Orfanó, Alessandra S.; Wanderli P Tadei; Ríos-Velásquez, Claudia M.; Han, Yeon S.; SECUNDINO Nágila F.C.; Carolina Barillas-Mury; Pimenta, Paulo F. P.; Traub-Csekö, Yara M.

    2011-01-01

    Malaria affects 300 million people worldwide every year and 450,000 in Brazil. In coastal areas of Brazil, the main malaria vector is Anopheles aquasalis, and Plasmodium vivax is responsible for the majority of malaria cases in the Americas. Insects possess a powerful immune system to combat infections. Three pathways control the insect immune response: Toll, IMD, and JAK-STAT. Here we analyze the immune role of the A. aquasalis JAK-STAT pathway after P. vivax infection. Three genes, the tran...

  16. A Peroxidase/Dual Oxidase System Modulates Midgut Epithelial Immunity in Anopheles gambiae

    Science.gov (United States)

    Kumar, Sanjeev; Molina-Cruz, Alvaro; Gupta, Lalita; Rodrigues, Janneth; Barillas-Mury, Carolina

    2012-01-01

    Extracellular matrices in diverse biological systems are crosslinked by dityrosine covalent bonds catalyzed by the peroxidase/oxidase system. We show that the Immunomodulatory Peroxidase (IMPer), an enzyme secreted by the mosquito Anopheles gambiae midgut, and dual oxidase (Duox) form a dityrosine network that decreases gut permeability to immune elicitors and protects the microbiota by preventing activation of epithelial immunity. It also provides a suitable environment for malaria parasites to develop within the midgut lumen without inducing nitric oxide synthase expression. Disruption of this barrier results in strong and effective pathogen-specific immune responses. PMID:20223948

  17. Gene expression patterns associated with blood-feeding in the malaria mosquito Anopheles gambiae

    OpenAIRE

    Hogan James R; Lobo Neil F; Harker Brent W; Hillenmeyer Maureen E; Kern Marcia K; Hong Young S; Dana Ali N; Romans Patricia; Collins Frank H

    2005-01-01

    Abstract Background Blood feeding, or hematophagy, is a behavior exhibited by female mosquitoes required both for reproduction and for transmission of pathogens. We determined the expression patterns of 3,068 ESTs, representing ~2,000 unique gene transcripts using cDNA microarrays in adult female Anopheles gambiae at selected times during the first two days following blood ingestion, at 5 and 30 min during a 40 minute blood meal and at 0, 1, 3, 5, 12, 16, 24 and 48 hours after completion of t...

  18. Chemical composition and insecticidal activity of plant essential oils from Benin against Anopheles gambiae (Giles)

    Science.gov (United States)

    2013-01-01

    Background Insecticide resistance in sub-Saharan Africa and especially in Benin is a major public health issue hindering the control of the malaria vectors. Each Anopheles species has developed a resistance to one or several classes of the insecticides currently in use in the field. Therefore, it is urgent to find alternative compounds to conquer the vector. In this study, the efficacies of essential oils of nine plant species, which are traditionally used to avoid mosquito bites in Benin, were investigated. Methods Essential oils of nine plant species were extracted by hydrodistillation, and their chemical compositions were identified by GC-MS. These oils were tested on susceptible “kisumu” and resistant “ladji-Cotonou” strains of Anopheles gambiae, following WHO test procedures for insecticide resistance monitoring in malaria vector mosquitoes. Results Different chemical compositions were obtained from the essential oils of the plant species. The major constituents identified were as follows: neral and geranial for Cymbopogon citratus, Z-carveol, E-p-mentha-1(7),8-dien-2-ol and E-p-mentha-2,8-dienol for Cymbopogon giganteus, piperitone for Cymbopogon schoenanthus, citronellal and citronellol for Eucalyptus citriodora, p-cymene, caryophyllene oxide and spathulenol for Eucalyptus tereticornis, 3-tetradecanone for Cochlospermum tinctorium and Cochlospermum planchonii, methyl salicylate for Securidaca longepedunculata and ascaridole for Chenopodium ambrosioides. The diagnostic dose was 0.77% for C. citratus, 2.80% for E. tereticornis, 3.37% for E. citriodora, 4.26% for C. ambrosioides, 5.48% for C. schoenanthus and 7.36% for C. giganteus. The highest diagnostic doses were obtained with S. longepedunculata (9.84%), C. tinctorium (11.56%) and C. planchonii (15.22%), compared to permethrin 0.75%. A. gambiae cotonou, which is resistant to pyrethroids, showed significant tolerance to essential oils from C. tinctorium and S. longepedunculata as expected but was

  19. Short report : Development of a molecular assay to detect predation on Anopheles gambiae complex larval stages

    OpenAIRE

    Schielke, E.; Costantini, Carlo; Carchini, G.; Sagnon, N.; J. Powell; Caccone, A

    2007-01-01

    We developed a molecular assay to detect predation on Anopheles gambiae sensu lato (s.l.) mosquitoes. This intergenic spacer ribosomal DNA polymerase chain reaction assay and restriction enzyme analysis uses An. gambiae-specific primers to detect mosquito DNA in the DNA extracts from whole invertebrate predators, which enables identification of species (An. gambiae s.s. versus An. arabiensis) and molecular forms (M versus S in An. gambiae s.s.). We show that An. gambiae s.l. DNA can be detect...

  20. Successful field trial of attractive toxic sugar bait (ATSB plant-spraying methods against malaria vectors in the Anopheles gambiae complex in Mali, West Africa

    Directory of Open Access Journals (Sweden)

    Doumbia Seydou

    2010-07-01

    Full Text Available Abstract Background Based on highly successful demonstrations in Israel that attractive toxic sugar bait (ATSB methods can decimate local populations of mosquitoes, this study determined the effectiveness of ATSB methods for malaria vector control in the semi-arid Bandiagara District of Mali, West Africa. Methods Control and treatment sites, selected along a road that connects villages, contained man-made ponds that were the primary larval habitats of Anopheles gambiae and Anopheles arabiensis. Guava and honey melons, two local fruits shown to be attractive to An. gambiae s.l., were used to prepare solutions of Attractive Sugar Bait (ASB and ATSB that additionally contained boric acid as an oral insecticide. Both included a color dye marker to facilitate determination of mosquitoes feeding on the solutions. The trial was conducted over a 38-day period, using CDC light traps to monitor mosquito populations. On day 8, ASB solution in the control site and ATSB solution in the treatment site were sprayed using a hand-pump on patches of vegetation. Samples of female mosquitoes were age-graded to determine the impact of ATSB treatment on vector longevity. Results Immediately after spraying ATSB in the treatment site, the relative abundance of female and male An. gambiae s.l. declined about 90% from pre-treatment levels and remained low. In the treatment site, most females remaining after ATSB treatment had not completed a single gonotrophic cycle, and only 6% had completed three or more gonotrophic cycles compared with 37% pre-treatment. In the control site sprayed with ASB (without toxin, the proportion of females completing three or more gonotrophic cycles increased from 28.5% pre-treatment to 47.5% post-treatment. In the control site, detection of dye marker in over half of the females and males provided direct evidence that the mosquitoes were feeding on the sprayed solutions. Conclusion This study in Mali shows that even a single application of

  1. The paradoxical population genetics of Plasmodium falciparum.

    Science.gov (United States)

    Hartl, Daniel L; Volkman, Sarah K; Nielsen, Kaare M; Barry, Alyssa E; Day, Karen P; Wirth, Dyann F; Winzeler, Elizabeth A

    2002-06-01

    Among the leading causes of death in African children is cerebral malaria caused by the parasitic protozoan Plasmodium falciparum. Endemic forms of this disease are thought to have originated in central Africa 5000-10000 years ago, coincident with the innovation of slash-and-burn agriculture and the diversification of the Anopheles gambiae complex of mosquito vectors. Population genetic studies of P. falciparum have yielded conflicting results. Some evidence suggests that today's population includes multiple ancient lineages pre-dating human speciation. Other evidence suggests that today's population derives from only one, or a small number, of these ancient lineages. Resolution of this issue is important for the evaluation of the long-term efficacy of drug and immunological control strategies. PMID:12036741

  2. Karakteristik Habitat Larva Anopheles spp. di Desa Sungai Nyamuk, Daerah Endemik Malaria di Kabupaten Nunukan, Kalimantan Utara

    Directory of Open Access Journals (Sweden)

    Sugiarto Sugiarto

    2016-07-01

    Full Text Available A research about Habitat Characteristics of Anopheles spp. larvae was done in Sungai Nyamuk Village, Nunukan District, North Kalimantan Province from August 2010 to January 2012. This research aims to analyse the characteristics of breeding places of Anopheles spp. The larvae taken from various types of habitat with detention and maintained until it was developed into mosquitoes, then later identified. The results showed that there are four types of potential breeding places of Anopheles spp. ie lagoon, ditches, fish ponds and marshes. Anopheles types that are found consist of five species, namely An. vagus, An. subpictus, An. sundaicus, An. indefinitus dan An. peditaeniatus. Types of potential breeding places are dominated by the unused fish pond, with the substrate in the form of mud and water is not flowing, located around settlements surrounded by grasses, shrubs and trees. Breeding places contains of aquatic plants such as grasses and moss. Predators are found in the form of a dragonfly nymph, crustaceans, tadpoles and small fish. Early malaria vector control at the level of the larvae is a critical point of the success of malaria elimination programs in endemic areas.

  3. Electrophysiological responses of gustatory receptor neurons on the labella of the common malaria mosquito Anopheles quadrimaculatus Say (Diptera: Culicidae)

    Science.gov (United States)

    We recorded electrical responses from sensory cells associated with gustatory sensilla on the labella of female Anopheles quadrimaculatus to salt, sucrose, quinine (a feeding deterrent) and the insect repellent, N,N-diethyl-3-methylbenzamide (DEET). A salt-sensitive cell responded to increasing con...

  4. First report of Metarhizium anisopliae IP 46 pathogenicity in adult Anopheles gambiae s.s. and An. arabiensis (Diptera; Culicidae)

    NARCIS (Netherlands)

    Mnyone, L.L.; Russell, T.L.; Lyimo, I.N.; Lwetoijera, D.W.; Kirby, M.J.; Luz, C.

    2009-01-01

    The entomopathogenic fungus Metarhizium anisopliae isolate IP 46, originating from a soil sample collected in 2001 in the Cerrado of Central Brazil, was tested for its ability to reduce the survival of adult male and female Anopheles gambiae s.s. and An. arabiensis mosquitoes. A 6-h exposure to the

  5. Effect of Bacillus sphaericus Neide on Anopheles (Diptera: Culicidae and associated insect fauna in fish ponds in the Amazon

    Directory of Open Access Journals (Sweden)

    Francisco Augusto da Silva Ferreira

    2015-09-01

    Full Text Available ABSTRACTWe analyzed the effects of Bacillus sphaericus on Anopheles larvae and on the associated insect fauna in fish farming ponds. Five breeding sites in the peri-urban area of the city of Manaus, AM, Brazil, were studied. Seven samples were collected from each breeding site and B. sphaericus was applied and reapplied after 15 days. The samples were made at 24 h before application, 24 h post-application and 5 and 15 days post-application. We determined abundance, larval reduction and larval density for Anopheles, and abundance, richness, Shannon diversity index and classified according to the functional trophic groups for associated insect fauna. A total of 904 Anopheles larvae were collected and distributed into five species. Density data and larval reduction demonstrated the rapid effect of the biolarvicide 24 h after application. A total of 4874 associated aquatic insects belonging to six orders and 23 families were collected. Regression analysis of diversity and richness indicated that the application of the biolarvicide had no influence on these indices and thus no effect on the associated insect fauna for a period of 30 days. B. sphaericus was found to be highly effective against the larvae of Anopheles, eliminating the larvae in the first days after application, with no effect on the associated insect fauna present in the fish ponds analyzed.

  6. Shift in species composition in the Anopheles gambiae complex after implementation of long-lasting insecticidal nets in Dielmo, Senegal.

    Science.gov (United States)

    Sougoufara, S; Harry, M; Doucouré, S; Sembène, P M; Sokhna, C

    2016-09-01

    Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are the cornerstones of malaria vector control. However, the effectiveness of these control tools depends on vector ecology and behaviour, which also largely determine the efficacy of certain Anopheles mosquitoes (Diptera: Culicidae) as vectors. Malaria vectors in sub-Saharan Africa are primarily species of the Anopheles gambiae complex, which present intraspecific differences in behaviour that affect how they respond to vector control tools. The focus of this study is the change in species composition in the An. gambiae complex after the implementation of LLINs in Dielmo, Senegal. The main findings referred to dramatic decreases in the proportions of Anopheles coluzzii and An. gambiae after the introduction of LLINs, and an increase in the proportion of Anopheles arabiensis. Two years after LLINs were first introduced, An. arabiensis remained the most prevalent species and An. gambiae had begun to rebound. This indicated a need to develop additional vector control tools that can target the full range of malaria vectors. PMID:27058993

  7. Differential attractiveness of humans to the African malaria vector Anopheles gambiae Giles - Effects of host characteristics and parasite infection

    NARCIS (Netherlands)

    Mukabana, W.R.

    2002-01-01

    The results of a series of studies designed to understand the principal factors that determine the differential attractiveness of humans to the malaria vector Anopheles gambiae are described in this thesis. Specific

  8. Toxicity of six plant extracts and two pyridine alkaloids from Ricinus communis against the malaria vector Anopheles gambiae

    Science.gov (United States)

    The African malaria vector, Anopheles gambiae s.s., is known to feed selectively on certain plants for sugar sources. However, the adaptive significance of this behavior especially on how the extracts of such plants impact on the fitness of this vector has not been explored. This study determined th...

  9. Extent of digestion affects the success of amplifying human DNA from blood meals of Anopheles gambiae (Diptera: Culicidae)

    NARCIS (Netherlands)

    Mukabana, W.R.; Takken, W.; Seda, P.; Killeen, G.F.; Hawley, W.A.; Knols, B.G.J.

    2002-01-01

    The success of distinguishing blood meal sources of Anopheles gambiae Giles through deoxyribonucleic acid (DNA) profiling was investigated by polymerase chain reaction (PCR) amplification at the TC-11 and VWA human short tandem repeats (STR) loci. Blood meal size and locus had no significant effect

  10. Peculiar liquid-feeding and pathogen transmission behavior of Aedes togoi and comparison with Anopheles sinensis

    Science.gov (United States)

    Lee, Sang Joon; Kang, Dooho; Lee, Seung Chul; Ha, Young-Ran

    2016-02-01

    Female mosquitoes transmit various diseases as vectors during liquid-feeding. Identifying the determinants of vector efficiency is a major scientific challenge in establishing strategies against these diseases. Infection rate and transmission efficiency are interconnected with the mosquito-induced liquid-feeding flow as main indexes of vector efficiency. However, the relationship between liquid-feeding characteristics and pathogen remains poorly understood. The liquid-feeding behavior of Aedes togoi and Anopheles sinensis was comparatively investigated in conjunction with vector efficiency via micro-particle image velocimetry. The flow rates and ratio of the ejection volume of Aedes togoi were markedly higher than those of Anophels sinensis. These differences would influence pathogen re-ingestion. Wall shear stresses of these mosquito species were also clearly discriminatory affecting the infective rates of vector-borne diseases. The variations in volume of two pump chambers and diameter of proboscis of these mosquito species were compared to determine the differences in the liquid-feeding process. Liquid-feeding characteristics influence vector efficiency; hence, this study can elucidate the vector efficiency of mosquitoes and the vector-pathogen interactions and contribute to the development of strategies against vector-borne diseases.

  11. Indirect evidence that agricultural pesticides select for insecticide resistance in the malaria vector Anopheles gambiae.

    Science.gov (United States)

    Luc, Djogbénou S; Benoit, Assogba; Laurette, Djossou; Michel, Makoutode

    2016-06-01

    We investigated the possible relationship between the agricultural use of insecticides and the emergence of insecticide resistance. Bioassays were conducted using simulated mosquito larval habitats and well known Anopheles gambiae strains. Soil samples were collected from vegetable production areas in Benin, including one site with insecticide use, one site where insecticides had not been used for two months, and a third where insecticides had not been used. Pupation and emergence rates were very low in pyrethroid-susceptible strains when exposed to soil that had been recently exposed to insecticides. Pupation and emergence rates in strains with the kdr mutation alone or both the kdr and Ace-1 mutations were much higher. Overall, strains with the kdr mutation survived at higher rates compared to that without kdr mutation. Although this study is observational, we provide indirect evidence indicating that soils from agricultural areas contain insecticide residues that can play a role in the emergence of insecticide resistance in Anopheles. This aspect should be taken into account to better utilize the insecticide in the context of integrated pest management programs.

  12. Ecology of Anopheles dthali Patton in Bandar Abbas District, Hormozgan Province, Southern Iran

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    H Vatandoost

    2007-05-01

    Full Text Available Ecology of Anopheles dthali was studied in Bandar Abbas County, where there is indigenous malaria. Anopheles dthali plays as a secondary malaria vector in the region. It is active throughout the year in mountainous area with two peaks of activity, whereas in coastal area it has one peak. There is no report of hibernation or aestivation for this species in the re¬gion. Precipitin tests on specimens from different parts showed that 15.6-20.8% were positive for human blood. This species usually rests outdoors. It has different larval habitats. Insecticides susceptibility tests on adult females exhibited susceptibil¬ity to all insecticides recommended by WHO. LT50 for the currently used insecticide, lambda-cyhalothrin, is measured less than one minute. The irritability tests to pyrethroid insecticides, showed that permethrin and lambda-cyhalothrin had more irritancy compared to deltamethrin and cyfluthrin. Larval bioassay using malathion, chlorpyrifos, temephos and fenithrothion did not show any sing of resistance to these larvicides at the diagnostic dose. It is recommended that all the decision makers should consider the results of our study for any vector control measures in the region.

  13. Ecology of Anopheles dthali Patton in Bandar Abbas District, Hormozgan Province, Southern Iran

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    H Vatandoost

    2007-06-01

    Full Text Available Ecology of Anopheles dthali was studied in Bandar Abbas County, where there is indigenous malaria. Anopheles dthali plays as a secondary malaria vector in the region. It is active throughout the year in mountainous area with two peaks of activity, whereas in coastal area it has one peak. There is no report of hibernation or aestivation for this species in the re¬gion. Precipitin tests on specimens from different parts showed that 15.6-20.8% were positive for human blood. This species usually rests outdoors. It has different larval habitats. Insecticides susceptibility tests on adult females exhibited susceptibil¬ity to all insecticides recommended by WHO. LT50 for the currently used insecticide, lambda-cyhalothrin, is measured less than one minute. The irritability tests to pyrethroid insecticides, showed that permethrin and lambda-cyhalothrin had more irritancy compared to deltamethrin and cyfluthrin. Larval bioassay using malathion, chlorpyrifos, temephos and fenithrothion did not show any sing of resistance to these larvicides at the diagnostic dose. It is recommended that all the decision makers should consider the results of our study for any vector control measures in the region.

  14. Unassisted isolated-pair mating of Anopheles gambiae (Diptera: Culicidae) mosquitoes.

    Science.gov (United States)

    Benedict, Mark Q; Rafferty, Cristina S

    2002-11-01

    Female Anopheles mosquitoes usually mate only once, but mating is seldom seen in small containers containing only one female and male. Therefore, matings are often performed among many adults in large cages or by forced copulation. Isolated-pair mating of Anopheles gambiae G3 strain-derived mosquitoes without forced copulation in small vials is described. We observed that the experimental variables eye color and male number were significant factors in the mating frequency. Females mated more frequently when three males were present over only one male. White-eyed females were more likely to be mated than wild-eyed females, but wild males mated more frequently than did white-eyed males. Experiments were also conducted to determine when mating was occurring by using wild-eye-color mosquitoes in isolated pairs. Almost no matings were observed before day 6 rather than the frequencies typically observed after 1-2 d in standard large-cage matings among large numbers of adults.

  15. BEBERAPA ASPEK BIONOMIK ANOPHELES SP DI KABUPATEN SUMBA TENGAH, PROVINSI NUSA TENGGARA TIMUR

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    Ni Wayan Dewi Adyana

    2012-07-01

    Full Text Available Research Some Aspects of Anopheles sp Bionomik in Central Sumba Regency, Province of East Nusa Tenggara. Committed in the territory Maradesa Health Center. Data were collected by catching adult mosquitoes by using bait People inside and outside the home, a collection of breaks in the wall and at home, continued with larval surveys in all potential breeding places.  The results showed that the biting behavior tends eksofagik found on An. kochi, An. aconitus and An.barbirostris with bite density peaks in An. aconitus (0.6 persons/hour with a biting peak at 20:00 to 21:00. Behavior tends eksofilik break in An. kochi, An. aconitus, An. tesselatus, An. barbirostris, An. vagus, An.flavirostris, An. maculatus and An. indefinitus with the highest density in An.aconitus (0.9 persons/hour at 1:00 a.m. to 2:00 a.m. Anopheles larvae breeding places found in the small hole in the ground, creek, wetland, non-permanent irrigation, water reservoirs in the vegetable garden, ditches, puddles, swamps, springs, with species that are found as An.kochi, An.aconitus, An. tesselatus, An. barbirostris, An. vagus, An. flavirostris, An. maculatus, An. indefinitus and An. annullaris

  16. Identification of four evolutionarily related G protein-coupled receptors from the malaria mosquito Anopheles gambiae

    DEFF Research Database (Denmark)

    Belmont, Martin; Cazzamali, Giuseppe; Williamson, Michael;

    2006-01-01

    The mosquito Anopheles gambiae is an important vector for malaria, which is one of the most serious human parasitic diseases in the world, causing up to 2.7 million deaths yearly. To contribute to our understanding of A. gambiae and to the transmission of malaria, we have now cloned four evolutio......The mosquito Anopheles gambiae is an important vector for malaria, which is one of the most serious human parasitic diseases in the world, causing up to 2.7 million deaths yearly. To contribute to our understanding of A. gambiae and to the transmission of malaria, we have now cloned four...... evolutionarily related G protein-coupled receptors (GPCRs) from this mosquito and expressed them in Chinese hamster ovary cells. After screening of a library of thirty-three insect or other invertebrate neuropeptides and eight biogenic amines, we could identify (de-orphanize) three of these GPCRs as...... relationship to the A. gambiae and other insect AKH receptors suggested that it is a receptor for an AKH-like peptide. This is the first published report on evolutionarily related AKH, corazonin, and CCAP receptors in mosquitoes....

  17. FAUNA ANOPHELES DI DAERAH PANTAI BEKAS HUTAN MANGROVE KECAMATAN PADANG CERMIN KABUPATEN LAMPUNG SELATAN

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    N. Sushanti Idris-Idram

    2012-09-01

    Full Text Available Intensive mosquito collections were carried out in two villages in subdistrict of Padangcermin during 1992-1993. The method of mosquito collections consisted of night landing on man indoor and outdoor, night resting indoor and outdoor around cattle shelters, light trap in cattle shelters, daytime resting indoor and outdoor, as well as larvae collections to identify anophelines breeding sites. Sixteen anophelines i.e. Anopheles sundaicus, An. subpictus, An. vagus, An. indefinitus, An. nigerrimus, An. peditaeniatus, An. kochi, An. barbirostris, An. bambumbrosus, An. annularis, An. separatus, An. tesselatus, An. aconitus, An. umbrosus, An. leucosphyrus and An. letifer were collected. Among these mosquitos, An. sundaicus was found predominant, followed by An. vagus and An. subpictus. Other species were collected in small numbers. The behavior of Anopheles sundaicus, An. subpictus and An. vagus were exophagic and endophilic. The larvae of An. sundaicus was found only in brackish standing water such as abandoned shrimp ponds, An. subpictus in brackish standing water as well as fresh standing water, while An. vagus was found only in fresh standing water. Breeding sites of An. sundaicus was characterized by pond with floating algae while An. subpictus and An. vagus were not depending on vegetation.

  18. A natural Anopheles-associated Penicillium chrysogenum enhances mosquito susceptibility to Plasmodium infection

    Science.gov (United States)

    Angleró-Rodríguez, Yesseinia I.; Blumberg, Benjamin J.; Dong, Yuemei; Sandiford, Simone L.; Pike, Andrew; Clayton, April M.; Dimopoulos, George

    2016-01-01

    Whereas studies have extensively examined the ability of bacteria to influence Plasmodium infection in the mosquito, the tripartite interactions between non-entomopathogenic fungi, mosquitoes, and Plasmodium parasites remain largely uncharacterized. Here we report the isolation of a common mosquito-associated ascomycete fungus, Penicillium chrysogenum, from the midgut of field-caught Anopheles mosquitoes. Although the presence of Pe. chrysogenum in the Anopheles gambiae midgut does not affect mosquito survival, it renders the mosquito significantly more susceptible to Plasmodium infection through a secreted heat-stable factor. We further provide evidence that the mechanism of the fungus-mediated modulation of mosquito susceptibility to Plasmodium involves an upregulation of the insect’s ornithine decarboxylase gene, which sequesters arginine for polyamine biosynthesis. Arginine plays an important role in the mosquito’s anti-Plasmodium defense as a substrate of nitric oxide production, and its availability therefore has a direct impact on the mosquito’s susceptibility to the parasite. While this type of immunomodulatory mechanism has already been demonstrated in other host-pathogen interaction systems, this is the first report of a mosquito-associated fungus that can suppress the mosquito’s innate immune system in a way that would favor Plasmodium infection and possibly malaria transmission. PMID:27678168

  19. Comparative evaluation of systemic drugs for their effects against Anopheles gambiae.

    Science.gov (United States)

    Butters, Matthew P; Kobylinski, Kevin C; Deus, Kelsey M; da Silva, Ines Marques; Gray, Meg; Sylla, Massamba; Foy, Brian D

    2012-01-01

    Laboratory and field studies have shown that ivermectin, a drug that targets invertebrate ligand-gated ion channels (LGICs), is potently active against Anopheles spp. mosquitoes at concentrations present in human blood after standard drug administrations; thus ivermectin holds promise as a mass human-administered endectocide that could help suppress malaria parasite transmission. We evaluated other systemic LGIC-targeting drugs for their activities against the African malaria vector Anopheles gambiae using in vitro blood feeding assays. Eprinomectin, selamectin, moxidectin, and N-tert-butyl nodulisporamide were evaluated as potentially systemic drugs having similar modes of action to ivermectin; all primarily are agonists of invertebrate glutamate-gated chloride ion channels. Additionally, nitenpyram and spinosad were evaluated as systemic drugs that primarily work as agonists of nicotinic acetylcholine receptor channels. Only eprinomectin killed An. gambiae at concentrations that were comparable to ivermectin. At sub-lethal doses, nitenpyram and moxidectin marginally affected mosquito re-blood feeding ability. The macrocyclic lactones, particularly eprinomectin, caused significantly increased knockdown and significantly inhibited recovery in blood fed females. These data are a first step in evaluating drugs that might be eventually combined with, or substituted for ivermectin for future malaria parasite transmission control. PMID:22019935

  20. Entomological indices of Anopheles gambiae sensu lato at a rural community in south-west Nigeria

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    M.A.E. Noutcha

    2009-02-01

    Full Text Available Background & objectives: Investigations were conducted to obtain key entomological indices of Anopheles gambiae s.l. at Igbo-Ora, a rural community in south-west Nigeria. Methods: Mosquitoes were caught daily for a week from rooms where tenants had slept the previous night in each of the four months June, July (2001, and August, September (2002. Anopheles gambiae s.l. sibling species were PCR-identified, the blood meal origin was determined by direct ELISA, and the circumsporozoite antigen by sandwich ELISA. Mean weekly rates were calculated. Results: The mean human biting rates were 0.90 and 1.6 in 2001 and 2002 respectively. The mean weekly anthropophilic rates for An. gambiae s.l. were 82 and 86% in 2001 and 2002 respectively; they were high in An. gambiae s.s., An. arabiensis and non-identified species in the complex. The mean weekly circumsporozoite rates were 6.70% in 2001 and 6.30% in 2002. The mean weekly entomological inoculation rates (EIR were 4.95 and 5.05 in 2001 and 2002 respectively; the seasonal (6-month rates were high: 128.7 in 2001 and 131.3 in 2002, compared to data from other rural communities on the continent. Interpretation & conclusion: The implications of these findings on the role of An. gambiae s.l. in the holoendemicity of malaria at Igbo-Ora are discussed.

  1. Incomplete concerted evolution and reproductive isolation at the rDNA locus uncovers nine cryptic species within Anopheles longirostris from Papua New Guinea

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    Cooper Robert D

    2010-12-01

    Full Text Available Abstract Background Nuclear ribosomal DNA (rDNA genes and transcribed spacers are highly utilized as taxonomic markers in metazoans despite the lack of a cohesive understanding of their evolution. Here we follow the evolution of the rDNA second internal transcribed spacer (ITS2 and the mitochondrial DNA cytochrome oxidase I subunit in the malaria mosquito Anopheles longirostris from Papua New Guinea (PNG. This morphospecies inhabits a variety of ecological environments indicating that it may comprise a complex of morphologically indistinguishable species. Using collections from over 70 sites in PNG, the mtDNA was assessed via direct DNA sequencing while the ITS2 was assessed at three levels - crude sequence variation through restriction digest, intragenomic copy variant organisation (homogenisation through heteroduplex analysis and DNA sequencing via cloning. Results Genetic evaluation of over 300 individuals revealed that A. longirostris comprises eight ITS2 PCR-RFLP genotypes and nine ITS2 heteroduplex genotypes showing distinct copy variant organization profiles after PCR amplification. Seven of these nine genotypes were found to be sympatric with other genotypes. Phylogenetic analysis of cloned ITS2 PCR products and mtDNA COI confirmed all nine clades with evidence of reproductive isolation at the rDNA locus. Compensatory base changes in the ITS2 secondary structure or in pseudoknots were absent when closely related species were assessed. Individuals from each ITS2 genotype showed the same copy variant heteroduplex profile suggesting that the rDNA array is fixed within each genotype. Conclusion The centromere-proximal position of the rDNA array in Anopheles mosquitoes has probably reduced interchromosomal recombination leaving intrachromosomal events responsible for the observed pattern of concerted evolution we see in these mosquitoes. The stability of these intragenomic ITS2 copy variants within individuals and interbreeding populations

  2. Mosquitocidal activity of Polygala arvensis Willd against Aedes aegypti (Linn., Anopheles stephensi (Liston. and Culex quinquefasciatus (Say. (Diptera: Culicidae

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    M. Deepa

    2014-12-01

    Full Text Available To determine the larvicidal, ovicidal and repellent activities of benzene and methanol extract of Polygala arvensis against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus Twenty five 3rd instar larvae of selected mosquitoes species were exposed to various concentrations (60-300 ppm and were assayed in the laboratory by using the protocol of WHO 2005; the 24 h LC50 values of the P. Arvensis leaf extract was determined following Probit analysis. The ovicidal activity was determined against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus exposed to variousconcentrations were tested under laboratory conditions and the hatch rates were assessed 120hrs post treatment. The repellent efficacy was determined against selected mosquitoes at three concentrations viz., 1.0, 2.0 and 3.0 mg/cm2 under the laboratory conditions. The LC50 and LC90 values of benzene and methanol extract of P. arvensis against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus larvae in 24 h were 75.32, 88.26, 82.46, 58.21, 46.37, 42.68 and 260.48, 275.26, 251.39, 208.45, 189.82 and 130.44 ppm, respectively. It has been noticed that the higher concentrations of P. arvensis extractspossesses strong ovicidal activity at 200 ppm concentration against Ae. aegypti, An. stephensi and C. quinquefasciatus, no egg hatchability was recorded. In the same way, methanol extracts showed maximum ovicidal activity followed by benzene extract against selected vector mosquitoes. In repellent activity, among two extracts tested P. arvensis methanol extract had strong repellent action against selected mosquitoes as it provided 100% protection against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus for 280min. From the results it can be concluded the P. arvensis extract was an excellent potential for controlling Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus mosquitoes.

  3. A Study of the Essential Oils of Four Sudanese Accessions of Basil (Ocimum basilicum L. Against Anopheles Mosquito Larvae

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    Azhari H. Nour

    2009-01-01

    Full Text Available Problem statement: Certain basil essential oils were claimed to have a larvicidal activity towards mosquito's larvae. To test this claim the essential oils of four accessions of basil grown in Sudan were selected and tested for Anopheles larvae. Malaria is the major health problem in the Sudan and the whole country is now considered endemic, with varying degrees, about 35,000 deaths every year due to malaria. Anopheles mosquito is the major vector of malaria disease in Sudan. Search for larvicidal active compound(s is one of several attempts to fine effective and affordable ways to control this mosquito. To determine the toxic effects of basil essential oils extracted by steam distillation against Anopheles larvae. Approach: For the larvicidal bioassay, three concentrations (100, 300, 500 ppm of essential oil solutions of four basil accessions were prepared; 1 mL of ethanol was used to solubilize the oil in water (999 mL. In each concentration of oil solution were inserted 20 larvae (third instars. A set of controls using 0.1% ethanol and untreated sets of larvae in (tap water, were also run for comparison. Data were evaluated through regression analysis, from the regression line; the LC50 values were read. The active ingredients were separated and/ or identified by TLC, IR and GC-MS. Results: Larvicidal activity of the essential oils is varied, lasted for about 9 h and thereafter decreased, LC50 values ranging from 190-300 ppm. Linalool, geraniol and eugenol are active components of basil essential oil against Anopheles larvae. Two accessions were caused 100% mortality at a concentration range 300-500 ppm for 3 h. Conclusion: These results indicated that basil essential oils have larvicidal activity towards Anopheles larvae. Therefore, could be affordable way to control this mosquito.

  4. Fine pathogen discrimination within the APL1 gene family protects Anopheles gambiae against human and rodent malaria species.

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    Christian Mitri

    2009-09-01

    Full Text Available Genetically controlled resistance of Anopheles gambiae mosquitoes to Plasmodium falciparum is a common trait in the natural population, and a cluster of natural resistance loci were mapped to the Plasmodium-Resistance Island (PRI of the A. gambiae genome. The APL1 family of leucine-rich repeat (LRR proteins was highlighted by candidate gene studies in the PRI, and is comprised of paralogs APL1A, APL1B and APL1C that share > or =50% amino acid identity. Here, we present a functional analysis of the joint response of APL1 family members during mosquito infection with human and rodent Plasmodium species. Only paralog APL1A protected A. gambiae against infection with the human malaria parasite P. falciparum from both the field population and in vitro culture. In contrast, only paralog APL1C protected against the rodent malaria parasites P. berghei and P. yoelii. We show that anti-P. falciparum protection is mediated by the Imd/Rel2 pathway, while protection against P. berghei infection was shown to require Toll/Rel1 signaling. Further, only the short Rel2-S isoform and not the long Rel2-F isoform of Rel2 confers protection against P. falciparum. Protection correlates with the transcriptional regulation of APL1A by Rel2-S but not Rel2-F, suggesting that the Rel2-S anti-parasite phenotype results at least in part from its transcriptional control over APL1A. These results indicate that distinct members of the APL1 gene family display a mutually exclusive protective effect against different classes of Plasmodium parasites. It appears that a gene-for-pathogen-class system orients the appropriate host defenses against distinct categories of similar pathogens. It is known that insect innate immune pathways can distinguish between grossly different microbes such as Gram-positive bacteria, Gram-negative bacteria, or fungi, but the function of the APL1 paralogs reveals that mosquito innate immunity possesses a more fine-grained capacity to distinguish between

  5. Detection of the East and West African kdr mutation in Anopheles gambiae and Anopheles arabiensis from Uganda using a new assay based on FRET/Melt Curve analysis

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    Backeljau Thierry

    2006-02-01

    Full Text Available Abstract Background Appropriate monitoring of vector resistance to insecticides is an integral component of planning and evaluation of insecticide use in malaria control programmes. The malaria vectors Anopheles gambiae s.s. and Anopheles arabiensis have developed resistance to pyrethroid insecticides as a result of a mechanism conferring reduced nervous system sensitivity, better known as knockdown resistance (kdr. In An. gambiae s.s. and An. arabiensis, two different substitutions in the para-type sodium channel, a L1014F substitution common in West Africa and a L1014S replacement found in Kenya, are linked with kdr. Two different allele-specific polymerase chain reactions (AS-PCR are needed to detect these known kdr mutations. However, these AS-PCR assays rely on a single nucleotide polymorphism mismatch, which can result in unreliable results. Methods Here, a new assay for the detection of knockdown resistance in An. gambiae s.s. and An. arabiensis based on Fluorescence Resonance Energy Transfer/Melt Curve analysis (FRET/MCA is presented and compared with the existing assays. Results The new FRET/MCA method has the important advantage of detecting both kdr alleles in one assay. Moreover, results show that the FRET/MCA is more reliable and more sensitive than the existing AS-PCR assays and is able to detect new genotypes. By using this technique, the presence of the East African kdr mutation (L1014S is shown for the first time in An. arabiensis specimens from Uganda. In addition, a new kdr genotype is reported in An. gambiae s.s. from Uganda, where four An. gambiae s.s. mosquitoes possess both, the West (L1014F and East (L1014S African kdr allele, simultaneously. Conclusion The presence of both kdr mutations in the same geographical region shows the necessity of a reliable assay that enables to detect both mutations in one single assay. Hence, this new assay based on FRET/MCA will improve the screening of the kdr frequencies in An. gambiae s

  6. Diversity and transmission competence in lymphatic filariasis vectors in West Africa, and the implications for accelerated elimination of Anopheles-transmitted filariasis

    OpenAIRE

    de Souza Dziedzom K; Koudou Benjamin; Kelly-Hope Louise A; Wilson Michael D; Bockarie Moses J; Boakye Daniel A

    2012-01-01

    Abstract Lymphatic Filariasis (LF) is targeted for elimination by the Global Programme for the Elimination of Lymphatic Filariasis (GPELF). The strategy adopted is based on the density dependent phenomenon of Facilitation, which hypothesizes that in an area where the vector species transmitting Wuchereria bancrofti are Anopheles mosquitoes, it is feasible to eliminate LF using Mass Drug Administration (MDA) because of the inability of Anopheles species to transmit low-density microfilaraemia....

  7. The relationship between wing length, blood meal volume, and fecundity for seven colonies of Anopheles species housed at the Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.

    Science.gov (United States)

    Phasomkusolsil, Siriporn; Pantuwattana, Kanchana; Tawong, Jaruwan; Khongtak, Weeraphan; Kertmanee, Yossasin; Monkanna, Nantaporn; Klein, Terry A; Kim, Heung-Chul; McCardle, Patrick W

    2015-12-01

    Established colonies of Anopheles campestris, Anopheles cracens, Anopheles dirus, Anopheles kleini, Anopheles minimus, Anopheles sawadwongporni, and Anopheles sinensis are maintained at the Armed Forces Research Institute of Medical Sciences (AFRIMS). Females were provided blood meals on human blood containing citrate as an anticoagulant using an artificial membrane feeder. The mean wing length, used as an estimate of body size, for each species was compared to blood-feeding duration (time), blood meal volume, and numbers of eggs oviposited. Except for An. campestris and An. cracens, there were significant interspecies differences in wing length. The mean blood meal volumes (mm(3)) of An. kleini and An. sinensis were significantly higher than the other 5 species. For all species, the ratios of unfed females weights/blood meal volumes were similar (range: 0.76-0.88), except for An. kleini (1.08) and An. cracens (0.52), that were significantly higher and lower, respectively. Adult females were allowed to feed undisturbed for 1, 3, and 5min intervals before blood feeding was interrupted. Except for An. campestris and An. sawadwongporni, the number of eggs oviposited were significantly higher for females that fed for 3min when compared to those that only fed for 1min. This information is critical to better understand the biology of colonized Anopheles spp. and their role in the transmission of malaria parasites as they relate to the relative size of adult females, mean volumes of blood of engorged females for each of the anopheline species, and the effect of blood feeding duration on specific blood meal volumes and fecundity.

  8. Development of a Gravid Trap for Collecting Live Malaria Vectors Anopheles gambiae s.l.

    Science.gov (United States)

    Dugassa, Sisay; Lindh, Jenny M.; Oyieke, Florence; Mukabana, Wolfgang R.; Lindsay, Steven W.; Fillinger, Ulrike

    2013-01-01

    Background Effective malaria vector control targeting indoor host-seeking mosquitoes has resulted in fewer vectors entering houses in many areas of sub-Saharan Africa, with the proportion of vectors outdoors becoming more important in the transmission of this disease. This study aimed to develop a gravid trap for the outdoor collection of the malaria vector Anopheles gambiae s.l. based on evaluation and modification of commercially available gravid traps. Methods Experiments were implemented in an 80 m2 semi-field system where 200 gravid Anopheles gambiae s.s. were released nightly. The efficacy of the Box, CDC and Frommer updraft gravid traps was compared. The Box gravid trap was tested to determine if the presence of the trap over water and the trap’s sound affected catch size. Mosquitoes approaching the treatment were evaluated using electrocuting nets or detergents added to the water in the trap. Based on the results, a new gravid trap (OviART trap) that provided an open, unobstructed oviposition site was developed and evaluated. Results Box and CDC gravid traps collected similar numbers (relative rate (RR) 0.8, 95% confidence interval (CI) 0.6–1.2; p = 0.284), whereas the Frommer trap caught 70% fewer mosquitoes (RR 0.3, 95% CI 0.2–0.5; p < 0.001). The number of mosquitoes approaching the Box trap was significantly reduced when the trap was positioned over a water-filled basin compared to an open pond (RR 0.7 95% CI 0.6–0.7; p < 0.001). This effect was not due to the sound of the trap. Catch size increased by 60% (RR 1.6, 1.2–2.2; p = 0.001) with the new OviART trap. Conclusion Gravid An. Gambiae s.s. females were visually deterred by the presence of the trapping device directly over the oviposition medium. Based on these investigations, an effective gravid trap was developed that provides open landing space for egg-laying Anopheles. PMID:23861952

  9. Development of a gravid trap for collecting live malaria vectors Anopheles gambiae s.l.

    Directory of Open Access Journals (Sweden)

    Sisay Dugassa

    Full Text Available BACKGROUND: Effective malaria vector control targeting indoor host-seeking mosquitoes has resulted in fewer vectors entering houses in many areas of sub-Saharan Africa, with the proportion of vectors outdoors becoming more important in the transmission of this disease. This study aimed to develop a gravid trap for the outdoor collection of the malaria vector Anopheles gambiae s.l. based on evaluation and modification of commercially available gravid traps. METHODS: Experiments were implemented in an 80 m(2 semi-field system where 200 gravid Anopheles gambiae s.s. were released nightly. The efficacy of the Box, CDC and Frommer updraft gravid traps was compared. The Box gravid trap was tested to determine if the presence of the trap over water and the trap's sound affected catch size. Mosquitoes approaching the treatment were evaluated using electrocuting nets or detergents added to the water in the trap. Based on the results, a new gravid trap (OviART trap that provided an open, unobstructed oviposition site was developed and evaluated. RESULTS: Box and CDC gravid traps collected similar numbers (relative rate (RR 0.8, 95% confidence interval (CI 0.6-1.2; p = 0.284, whereas the Frommer trap caught 70% fewer mosquitoes (RR 0.3, 95% CI 0.2-0.5; p < 0.001. The number of mosquitoes approaching the Box trap was significantly reduced when the trap was positioned over a water-filled basin compared to an open pond (RR 0.7 95% CI 0.6-0.7; p < 0.001. This effect was not due to the sound of the trap. Catch size increased by 60% (RR 1.6, 1.2-2.2; p = 0.001 with the new OviART trap. CONCLUSION: Gravid An. Gambiae s.s. females were visually deterred by the presence of the trapping device directly over the oviposition medium. Based on these investigations, an effective gravid trap was developed that provides open landing space for egg-laying Anopheles.

  10. A spatial individual-based model predicting a great impact of copious sugar sources and resting sites on survival of Anopheles gambiae and malaria parasite transmission

    Science.gov (United States)

    Zhu, Lin; Qualls, Whitney A.; Marshall, John M; Arheart, Kris L.; DeAngelis, Don; McManus, John W.; Traore, Sekou F.; Doumbia, Seydou; Schlein, Yosef; Muller, Gunter C.; Beier, John C.

    2015-01-01

    BackgroundAgent-based modelling (ABM) has been used to simulate mosquito life cycles and to evaluate vector control applications. However, most models lack sugar-feeding and resting behaviours or are based on mathematical equations lacking individual level randomness and spatial components of mosquito life. Here, a spatial individual-based model (IBM) incorporating sugar-feeding and resting behaviours of the malaria vector Anopheles gambiae was developed to estimate the impact of environmental sugar sources and resting sites on survival and biting behaviour.MethodsA spatial IBM containing An. gambiae mosquitoes and humans, as well as the village environment of houses, sugar sources, resting sites and larval habitat sites was developed. Anopheles gambiae behaviour rules were attributed at each step of the IBM: resting, host seeking, sugar feeding and breeding. Each step represented one second of time, and each simulation was set to run for 60 days and repeated 50 times. Scenarios of different densities and spatial distributions of sugar sources and outdoor resting sites were simulated and compared.ResultsWhen the number of natural sugar sources was increased from 0 to 100 while the number of resting sites was held constant, mean daily survival rate increased from 2.5% to 85.1% for males and from 2.5% to 94.5% for females, mean human biting rate increased from 0 to 0.94 bites per human per day, and mean daily abundance increased from 1 to 477 for males and from 1 to 1,428 for females. When the number of outdoor resting sites was increased from 0 to 50 while the number of sugar sources was held constant, mean daily survival rate increased from 77.3% to 84.3% for males and from 86.7% to 93.9% for females, mean human biting rate increased from 0 to 0.52 bites per human per day, and mean daily abundance increased from 62 to 349 for males and from 257 to 1120 for females. All increases were significant (P Survival was greater when sugar sources were randomly distributed

  11. Abiotic and biotic factors associated with the presence of Anopheles arabiensis immatures and their abundance in naturally occurring and man-made aquatic habitats

    Directory of Open Access Journals (Sweden)

    Gouagna Louis

    2012-07-01

    Full Text Available Abstract Background Anopheles arabiensis (Diptera: Culicidae is a potential malaria vector commonly present at low altitudes in remote areas in Reunion Island. Little attention has been paid to the environmental conditions driving larval development and abundance patterns in potential habitats. Two field surveys were designed to determine whether factors that discriminate between aquatic habitats with and without An. arabiensis larvae also drive larval abundance, comparatively in man-made and naturally occurring habitats. Methods In an initial preliminary survey, a representative sample of aquatic habitats that would be amenable to an intensive long-term study were selected and divided into positive and negative sites based on the presence or absence of Anopheles arabiensis larvae. Subsequently, a second survey was prompted to gain a better understanding of biotic and abiotic drivers of larval abundance, comparatively in man-made and naturally occurring habitats in the two studied locations. In both surveys, weekly sampling was performed to record mosquito species composition and larval density within individual habitats, as well as in situ biological characteristics and physico-chemical properties. Results Whilst virtually any stagnant water body could be a potential breeding ground for An. arabiensis, habitats occupied by their immatures had different structural and biological characteristics when compared to those where larvae were absent. Larval occurrence seemed to be influenced by flow velocity, macrofauna diversity and predation pressure. Interestingly, the relative abundance of larvae in man-made habitats (average: 0.55 larvae per dip, 95%CI [0.3–0.7] was significantly lower than that recorded in naturally occurring ones (0.74, 95%CI [0.5–0.8]. Such differences may be accounted for in part by varying pressures that could be linked to a specific habitat. Conclusions If the larval ecology of An. arabiensis is in general very complex

  12. Anopheles culicifacies breeding in Sri Lanka and options for control through water management

    DEFF Research Database (Denmark)

    Konradsen, F; Matsuno, Y; Amerasinghe, F P;

    1998-01-01

    This paper assesses the options for control of malaria vectors through different water management practices in a natural stream in Sri Lanka. The association between water level in the stream and breeding of the immature stages of the primary vector Anopheles culicifacies was investigated and the...... a high degree of support from the local community is essential and consultation between government departments needed....... that by regulating the water level above 20 cm in the stream throughout the dry season the breeding of A. culicifacies could be significantly reduced. The intervention would have only limited impact on the water lost for agriculture and the management input would be minimal. However, for the intervention to work...

  13. Larvicidal activity of extracts from three Plumbago spp against Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    Barasa M Maniafu

    2009-09-01

    Full Text Available Three Plumbago spp have been tested for mosquito larvicidal activity. The crude extracts exhibiting the highest larvicidal activity against Anopheles gambiae were hexane (LC50 = 6.4 μg/mL and chloroform (LC50 = 6.7 μg/mL extracts from Plumbago zeylanica Linn, chloroform (LC50 = 6.7 ug/mL extract from Plumbago stenophylla Bull and ethyl acetate (LC50 = 4.1 μg/mL extract from Plumbago dawei Rolfe. These LC50 values were within 95% confidence limits. 5-hydroxy-2-methyl-1,4-naphthoquinone (plumbagin 1 (LC50 = 1.9 μg/mL and β-sitosterol 2 were characterised from ethyl acetate extract of root bark of P. dawei, a native medicinal plant growing in Kenya, based on spectral analysis and comparisons with data in literature.

  14. Anopheles barbirostris Confirmation as Malaria Vector in Waikabubak through the Detection of Circumsporozoit Protein

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    Yuneu Yuliasih

    2012-06-01

    Full Text Available Anopheline species confirmed as malaria vector if the salivary gland contained sporozoites. One of the method to confirmed it was through an Enzyme-Linked Immunosorbent Assay (ELISA. The aim of this study was to investigate the presence of circum sporozoite protein (CSP in the mosquito of Anopheles barbirostris with ELISA method. The study was conducted in malaria endemic area named Modu Waimaringu Village, Waikabubak District, Sumba Barat Regency in March 2011. The study design was cross-sectional study, mosquito for the ELISA test were collected only from animal bait. ELISA method examination used on An. barbirostris body parts (i.e. the head-thorax where sporozoites of P. falciparum or P. Vivax possibly be found. The results showed that 40 samples of An. barbirostris mosquitoes which acquired from the mosquite bait in Modu Waimaringu Village was negative (100%. It means that there was no CSP found and An. barbirostris was not a malaria vector in the area

  15. Avoidance Behavior to Essential Oils by Anopheles minimus, a Malaria Vector in Thailand.

    Science.gov (United States)

    Nararak, Jirod; Sathantriphop, Sunaiyana; Chauhan, Kamal; Tantakom, Siripun; Eiden, Amanda L; Chareonviriyaphap, Theeraphap

    2016-03-01

    Essential oils extracted from 4 different plant species--citronella (Cymbopogon nardus), hairy basil (Ocimum americanum), sweet basil (Ocimum basilicum), and vetiver (Vetiveria zizanioides)-were investigated for their irritant and repellent activities against Anopheles minimus, using an excito-repellency test system. Pure essential oils were used in absolute ethanol at the concentrations of 0.5%, 1%, 2.5%, and 5% (v/v) compared with deet. At the lowest concentration of 0.5%, hairy basil displayed the best irritant and repellent effects against An. minimus. Citronella and vetiver at 1-5% showed strong irritant effects with>80% escape, while repellent effects of both oils were observed at 1% and 2.5% citronella (73-89% escape) and at 5% vetiver (83.9% escape). Sweet basil had only moderate irritant action at 5% concentration (69.6% escape) and slightly repellent on test mosquitoes (mosquito repellent products for protection against An. minimus. PMID:27105214

  16. Mosquito repellent action of Blumea lacera (Asteraceae against Anopheles stephensi and Culex quinquefasciatus.

    Directory of Open Access Journals (Sweden)

    S.P. Singh

    2014-03-01

    Full Text Available Petroleum ether extract of Blumea lacera was screened under laboratory conditions for repellent activity against mosquito vector Anopheles stephensi Liston and Culex quinquefasciatus Say (Diptera: Culicidae. The repellent activity of Blumea lacera extract was tested against mosquitoes in comparison with the DEET, which was used as a positive control. Results obtained from the laboratory experiment showed that the extract was effective against mosquito vectors even at a low dose. A direct relationship was observed with concentrations of Blumea lacera extract and the repellent activity. Percent repellency obtained at 6% concentration of theextract against An. stephensi and Cx. quinquefasciatus were 97and 98% at 0 hour and 78.8 and 76.2% after 6 hrs. DEET-2% however showed 100% repellency against An. stephensi and against Cx. quinquefasciatus up to 4 hours and 1 hour, respectively. These results show that Blumea lacera extract has the potential as an effective mosquito repellent.

  17. [The mosquitocidal efficacy of microcapsules of alpha-cypermethrin against Anopheles sinensis].

    Science.gov (United States)

    Pan, K Y; Ye, B H; Zhi, C L

    1994-01-01

    The efficacy of spraying of alpha-cypermethrin microcapsule for the control of Anopheles sinensis was investigated when alpha-cypermethrin microcapsule was sprayed at 0.5 g/m2, the KT50 was 7.9 min and a 100% of 24 hours' mortality of An. sinensis, the efficacy being similar to that of the emulsion. 180 days after spray, the KT50 was 28.2 min, the 24 hours' mortality was 85.7%, the residual efficacy was 3 times over that of the emulsion. In the mimic field experiment, similar results were obtained. In the field trial, the residual efficacy of the alpha-cypermethrin microcapsule was 5.9 times that of the emulsion. Alpha-cypermethrin microcapsules is recommended as a good formulation of mosquitocide for mosquito control, considering its mosquitocidal efficacy and residual efficacy.

  18. Larvicidal activity of oak Quercus infectoria Oliv. (Fagaceae) gall extracts against Anopheles stephensi Liston.

    Science.gov (United States)

    Aivazi, Ali-Ashraf; Vijayan, V A

    2009-06-01

    There is a growing interest in the use of botanical insecticides to reduce the use of synthetic pesticides in order to avoid environmental side effects. Anopheles stephensi is the primary vector of urban malaria, an endemic disease in India. So, an effort to assay An. stephensi larvae with gall extracts of Quercus infectoria was made under laboratory conditions at Mysore. Ethyl-acetate extract was found to be the most effective of all the five extracts tested for larvicidal activity against the fourth instar larvae, with LC(50) of 116.92 ppm followed by gallotannin, n-butanol, acetone, and methanol with LC(50) values of 124.62, 174.76, 299.26, and 364.61 ppm, respectively. The efficacy in killing mosquito larvae may make this plant promising for the development of new botanical larvicide. PMID:19148681

  19. Larvicidal activity of oak Quercus infectoria Oliv. (Fagaceae) gall extracts against Anopheles stephensi Liston.

    Science.gov (United States)

    Aivazi, Ali-Ashraf; Vijayan, V A

    2009-06-01

    There is a growing interest in the use of botanical insecticides to reduce the use of synthetic pesticides in order to avoid environmental side effects. Anopheles stephensi is the primary vector of urban malaria, an endemic disease in India. So, an effort to assay An. stephensi larvae with gall extracts of Quercus infectoria was made under laboratory conditions at Mysore. Ethyl-acetate extract was found to be the most effective of all the five extracts tested for larvicidal activity against the fourth instar larvae, with LC(50) of 116.92 ppm followed by gallotannin, n-butanol, acetone, and methanol with LC(50) values of 124.62, 174.76, 299.26, and 364.61 ppm, respectively. The efficacy in killing mosquito larvae may make this plant promising for the development of new botanical larvicide.

  20. Development of sporogonic cycle of Plasmodium vivax in experimentally infected Anopheles albimanus mosquitoes

    Directory of Open Access Journals (Sweden)

    Martha L. Salas

    1994-01-01

    Full Text Available The sporogonic cycle of Plasmodium vivax was established and maintained under laboratory conditions in two different strains of Anopheles albimanus mosquitoes using as a parasite source blood from human patients or from Aotus monkeys infected with the VCC-2 P.vivax colombian isolate. Both the Tecojate strain isolate from Guatemala and the Cartagena strain from the colombian Pacific coast were susceptible to infections with P.vivax. A higher percentage of Cartagena mosquitoes was infected per trial, however the Tecojate strain developed higher sporozoite loads. Intravenous inoculation of Aotus monkeys with sporozoites obtained from both anopheline strains resulted in successful blood infections. Animals infected with sporozoites from the Tecojate strain presented a patent period of 21-32 days whereas parasitemia appeared between days 19-53 in monkeys infected with sporozites from Cartagena strain.

  1. Development of sporogonic cycle of Plasmodium vivax in experimentally infected Anopheles albimanus mosquitoes.

    Science.gov (United States)

    Salas, M L; Romero, J F; Solarte, Y; Olano, V; Herrera, M A; Herrera, S

    1994-01-01

    The sporogonic cycle of Plasmodium vivax was established and maintained under laboratory conditions in two different strains of Anopheles albimanus mosquitoes using as a parasite source blood from human patients or from Aotus monkeys infected with the VCC-2 P.vivax colombian isolate. Both the Tecojate strain isolate from Guatemala and the Cartagena strain from the colombian Pacific coast were susceptible to infections with P.vivax. A higher percentage of Cartagena mosquitoes was infected per trial, however the Tecojate strain developed higher sporozoite loads. Intravenous inoculation of Aotus monkeys with sporozoites obtained from both anopheline strains resulted in successful blood infections. Animals infected with sporozoites from the Tecojate strain presented a patent period of 21-32 days whereas parasitemia appeared between days 19-53 in monkeys infected with sporozites from Cartagena strain. PMID:7565121

  2. Anopheles gambiae eicosanoids modulate Plasmodium berghei survival from oocyst to salivary gland invasion

    Directory of Open Access Journals (Sweden)

    Susana Ramos

    2014-08-01

    Full Text Available Eicosanoids affect the immunity of several pathogen/insect models, but their role on the Anopheles gambiae response to Plasmodium is still unknown. Plasmodium berghei-infected mosquitoes were injected with an eicosanoid biosynthesis inhibitor, indomethacin (IN, or a substrate, arachidonic acid (AA, at day 7 or day 12 post-infection (p.i.. Salivary gland invasion was evaluated by sporozoite counts at day 21 p.i. IN promoted infection upon sporozoite release from oocysts, but inhibited infection when sporozoites were still maturing within the oocysts, as observed by a reduction in the number of sporozoites reaching the salivary glands. AA treatment had the opposite effect. We show for the first time that An. gambiae can modulate parasite survival through eicosanoids by exerting an antagonistic or agonistic effect on the parasite, depending on its stage of development.

  3. “Highly evolvable malaria vectors: the genomes of 16 Anopheles mosquitoes”

    Science.gov (United States)

    Neafsey, Daniel E.; Waterhouse, Robert M.; Abai, Mohammad R.; Aganezov, Sergey S.; Alekseyev, Max A.; Allen, James E.; Amon, James; Arcà, Bruno; Arensburger, Peter; Artemov, Gleb; Assour, Lauren A.; Basseri, Hamidreza; Berlin, Aaron; Birren, Bruce W.; Blandin, Stephanie A.; Brockman, Andrew I.; Burkot, Thomas R.; Burt, Austin; Chan, Clara S.; Chauve, Cedric; Chiu, Joanna C.; Christensen, Mikkel; Costantini, Carlo; Davidson, Victoria L.M.; Deligianni, Elena; Dottorini, Tania; Dritsou, Vicky; Gabriel, Stacey B.; Guelbeogo, Wamdaogo M.; Hall, Andrew B.; Han, Mira V.; Hlaing, Thaung; Hughes, Daniel S.T.; Jenkins, Adam M.; Jiang, Xiaofang; Jungreis, Irwin; Kakani, Evdoxia G.; Kamali, Maryam; Kemppainen, Petri; Kennedy, Ryan C.; Kirmitzoglou, Ioannis K.; Koekemoer, Lizette L.; Laban, Njoroge; Langridge, Nicholas; Lawniczak, Mara K.N.; Lirakis, Manolis; Lobo, Neil F.; Lowy, Ernesto; MacCallum, Robert M.; Mao, Chunhong; Maslen, Gareth; Mbogo, Charles; McCarthy, Jenny; Michel, Kristin; Mitchell, Sara N.; Moore, Wendy; Murphy, Katherine A.; Naumenko, Anastasia N.; Nolan, Tony; Novoa, Eva M.; O'Loughlin, Samantha; Oringanje, Chioma; Oshaghi, Mohammad A.; Pakpour, Nazzy; Papathanos, Philippos A.; Peery, Ashley N.; Povelones, Michael; Prakash, Anil; Price, David P.; Rajaraman, Ashok; Reimer, Lisa J.; Rinker, David C.; Rokas, Antonis; Russell, Tanya L.; Sagnon, N'Fale; Sharakhova, Maria V.; Shea, Terrance; Simão, Felipe A.; Simard, Frederic; Slotman, Michel A.; Somboon, Pradya; Stegniy, Vladimir; Struchiner, Claudio J.; Thomas, Gregg W.C.; Tojo, Marta; Topalis, Pantelis; Tubio, José M.C.; Unger, Maria F.; Vontas, John; Walton, Catherine; Wilding, Craig S.; Willis, Judith H.; Wu, Yi-Chieh; Yan, Guiyun; Zdobnov, Evgeny M.; Zhou, Xiaofan; Catteruccia, Flaminia; Christophides, George K.; Collins, Frank H.; Cornman, Robert S.; Crisanti, Andrea; Donnelly, Martin J.; Emrich, Scott J.; Fontaine, Michael C.; Gelbart, William; Hahn, Matthew W.; Hansen, Immo A.; Howell, Paul I.; Kafatos, Fotis C.; Kellis, Manolis; Lawson, Daniel; Louis, Christos; Luckhart, Shirley; Muskavitch, Marc A.T.; Ribeiro, José M.; Riehle, Michael A.; Sharakhov, Igor V.; Tu, Zhijian; Zwiebel, Laurence J.; Besansky, Nora J.

    2015-01-01

    Variation in vectorial capacity for human malaria among Anopheles mosquito species is determined by many factors, including behavior, immunity, and life history. To investigate the genomic basis of vectorial capacity and explore new avenues for vector control, we sequenced the genomes of 16 anopheline mosquito species from diverse locations spanning ~100 million years of evolution. Comparative analyses show faster rates of gene gain and loss, elevated gene shuffling on the X chromosome, and more intron losses, relative to Drosophila. Some determinants of vectorial capacity, such as chemosensory genes, do not show elevated turnover, but instead diversify through protein-sequence changes. This dynamism of anopheline genes and genomes may contribute to their flexible capacity to take advantage of new ecological niches, including adapting to humans as primary hosts. PMID:25554792

  4. A mosquito lipoxin/lipocalin complex mediates innate immune priming in Anopheles gambiae.

    Science.gov (United States)

    Ramirez, Jose Luis; de Almeida Oliveira, Giselle; Calvo, Eric; Dalli, Jesmond; Colas, Romain A; Serhan, Charles N; Ribeiro, Jose M; Barillas-Mury, Carolina

    2015-01-01

    Exposure of Anopheles gambiae mosquitoes to Plasmodium infection enhances the ability of their immune system to respond to subsequent infections. However, the molecular mechanism that allows the insect innate immune system to 'remember' a previous encounter with a pathogen has not been established. Challenged mosquitoes constitutively release a soluble haemocyte differentiation factor into their haemolymph that, when transferred into Naive mosquitoes, also induces priming. Here we show that this factor consists of a Lipoxin/Lipocalin complex. We demonstrate that innate immune priming in mosquitoes involves a persistent increase in expression of Evokin (a lipid carrier of the lipocalin family), and in their ability to convert arachidonic acid to lipoxins, predominantly Lipoxin A4. Plasmodium ookinete midgut invasion triggers immune priming by inducing the release of a mosquito lipoxin/lipocalin complex. PMID:26100162

  5. Genome expression analysis of Anopheles gambiae: responses to injury, bacterial challenge, and malaria infection.

    Science.gov (United States)

    Dimopoulos, George; Christophides, George K; Meister, Stephan; Schultz, Jörg; White, Kevin P; Barillas-Mury, Carolina; Kafatos, Fotis C

    2002-06-25

    The complex gene expression responses of Anopheles gambiae to microbial and malaria challenges, injury, and oxidative stress (in the mosquito and/or a cultured cell line) were surveyed by using cDNA microarrays constructed from an EST-clone collection. The expression profiles were broadly subdivided into induced and down-regulated gene clusters. Gram+ and Gram- bacteria and microbial elicitors up-regulated a diverse set of genes, many belonging to the immunity class, and the response to malaria partially overlapped with this response. Oxidative stress activated a distinctive set of genes, mainly implicated in oxidoreductive processes. Injury up- and down-regulated gene clusters also were distinctive, prominently implicating glycolysis-related genes and citric acid cycle/oxidative phosphorylation/redox-mitochondrial functions, respectively. Cross-comparison of in vivo and in vitro responses indicated the existence of tightly coregulated gene groups that may correspond to gene pathways. PMID:12077297

  6. Energy metabolism affects susceptibility of Anopheles gambiae mosquitoes to Plasmodium infection.

    Science.gov (United States)

    Oliveira, Jose Henrique M; Gonçalves, Renata L S; Oliveira, Giselle A; Oliveira, Pedro L; Oliveira, Marcus F; Barillas-Mury, Carolina

    2011-06-01

    Previous studies showed that Anopheles gambiae L3-5 females, which are refractory (R) to Plasmodium infection, express higher levels of genes involved in redox-metabolism and mitochondrial respiration than susceptible (S) G3 females. Our studies revealed that R females have reduced longevity, faster utilization of lipid reserves, impaired mitochondrial state-3 respiration, increased rate of mitochondrial electron leak and higher expression levels of several glycolytic enzyme genes. Furthermore, when state-3 respiration was reduced in S females by silencing expression of the adenine nucleotide translocator (ANT), hydrogen peroxide generation was higher and the mRNA levels of lactate dehydrogenase increased in the midgut, while the prevalence and intensity of Plasmodium berghei infection were significantly reduced. We conclude that there are broad metabolic differences between R and S An. gambiae mosquitoes that influence their susceptibility to Plasmodium infection. PMID:21320598

  7. A mosquito lipoxin/lipocalin complex mediates innate immune priming in Anopheles gambiae

    Science.gov (United States)

    Ramirez, Jose Luis; de Almeida Oliveira, Giselle; Calvo, Eric; Dalli, Jesmond; Colas, Romain A.; Serhan, Charles N.; Ribeiro, Jose M.; Barillas-Mury, Carolina

    2015-01-01

    Exposure of Anopheles gambiae mosquitoes to Plasmodium infection enhances the ability of their immune system to respond to subsequent infections. However, the molecular mechanism that allows the insect innate immune system to ‘remember' a previous encounter with a pathogen has not been established. Challenged mosquitoes constitutively release a soluble haemocyte differentiation factor into their haemolymph that, when transferred into Naive mosquitoes, also induces priming. Here we show that this factor consists of a Lipoxin/Lipocalin complex. We demonstrate that innate immune priming in mosquitoes involves a persistent increase in expression of Evokin (a lipid carrier of the lipocalin family), and in their ability to convert arachidonic acid to lipoxins, predominantly Lipoxin A4. Plasmodium ookinete midgut invasion triggers immune priming by inducing the release of a mosquito lipoxin/lipocalin complex. PMID:26100162

  8. Susceptibility of Anopheles maculipennis to different classes of insecticides in West Azarbaijan Province, Northwestern Iran

    Institute of Scientific and Technical Information of China (English)

    Ali; Reza; Chavshin; Farrokh; Dabiri; Hassan; Vatandoost; Mulood; Mohammadi; Bavani

    2015-01-01

    Objective: To determine the susceptibility status of Anopheles maculipennis(An. maculipennis) against the major insecticides used in the health sectors in West Azarbaijan Province, Northwestern Iran.Methods: Unfed 3-5 days old adult females of An. maculipennis were collected across the West Azarbaijan Province and were subjected to evaluation of their susceptibility following World Health Organization recommended protocol against six insecticides(permethrin, deltamethrin, propoxur, bendiocarb, malathion and dieldrin) belonging to four different classes. Results: In this study, 916 specimens of An. maculipennis were examined against the insecticides which indicated that An. maculipennis was tolerant to permethrin, deltamethrin and dielderin, but displayed resistance against propoxur, bendiocarb and malathion. Conclusions: The pattern of resistance in An. maculipennis could be attributed to the agricultural landscapes, agricultural pesticides used and the exposure of the mosquitoes to insecticides. Logical cooperation is needed between the agriculture and health sectors to ensure the judicious use of pesticides in each sector and the management of probable resistance.

  9. RESISTANCE OF ANOPHELES STEPHENSI LISTON TO MALATHION IN THE PROVICE OF FARS, SOUTHERN IRAN

    Directory of Open Access Journals (Sweden)

    N.Eshghy

    1985-08-01

    Full Text Available Anopheles Stephensi is an important malaria vector in southern Iran. This species developed resistance to DDT in 1975 and subsequently to dieldrin in 1960. Since 1968 this species has been under pressure of malathin house sprayin. 50% w.d.p. , 2g/m2, 1-2 rounds per year. Susceptibility tests carried out with malathion impregnated papers during 1979 showed that An.stephensi has acquired resistant to malathion too. With regard to the 0.1% propoxur, a study was carried out to obtain base-line data in the localities under routine observations and also the discriminating dosage that could kill 100% of An.stephensi. The objective of the present paper is to summarize and discuss briefly the field investigations concerning insecticide resistance in An.stephensi.

  10. Genetic Study of Propoxur Resistance—A Carbamate Insecticide in the Malaria Mosquito, Anopheles stephensi Liston

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    D. Sanil

    2010-01-01

    Full Text Available Anopheles stephensi Liston (Diptera: Culicidae is the urban vector of malaria in the Indian subcontinent and several countries of the Middle East. The genetics of propoxur resistance (pr in An. stephensi larvae was studied to determine its mode of inheritance. A diagnostic dose of 0.01 mg/L as recommended by WHO was used to establish homozygous resistant and susceptible strains. Reciprocal crosses between the resistant and susceptible strains showed an F1 generation of incomplete dominance. The progenies of backcrosses to susceptible parents were in 1 : 1 ratio of the same phenotypes as the parents and hybrids involved. The dosage mortality (d-m lines were constructed for each one of the crosses, and the degree of dominance was calculated. It is concluded that propoxur resistance in An. stephensi larvae is due to monofactorial inheritance with incomplete dominance and is autosomal in nature.

  11. PROPOXUR SELECTION OF THE ADULTS OF ANOPHELES STEPHENSI FROM MINAB, SOUTH OF IRAN

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    H. Edalat

    1997-10-01

    Full Text Available Anopheles stephensi is the main malaria vector in south of Iran. It has been known to be resistant to DDT, malathion and dieldrin. After appearance of resistance the area was treated with propoxur, at the rate of 2 g/m2 twice a year for 14 successive years. This species is still susceptible to propoxur. In order to forecast the possibility of development of propoxur resistance in An.stephensi, the females of this species were put under the pressure of propoxur for 14 generations in 1988. Fourteen generations of propoxur selection on the adult females of An.stephensi resulted in an increase in LT60 from 8.5 min to 24.30 minutes, i.e. 2.86 fold increase in tolerance.

  12. Systematic studies on Anopheles galvaoi Causey, Deane & Deane from the subgenus Nysssorhynchus blanchard (Diptera: Culicidae

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    Maria Anice Mureb Sallum

    2002-12-01

    Full Text Available Anopheles galvaoi, a member of the subgenus Nyssorhynchus, is redescribed based on morphological characters of the adults male and female, fourth-instar larva and pupa. Female, male genitalia, larval and pupal stages are illustrated. Data about medical importance, bionomics, and distribution are given based on literature records. Adult female of An. galvaoi can be easily misidentified as An. benarrochi Gabaldón and An. aquasalis Curry. A few characters are indicated for identifying female and immatures of An. galvaoi. Phylogenetic relationships among An. galvaoi and six other species of the Oswaldoi Subgroup are estimated using COII mtDNA and ITS2 rDNA gene sequences. Lectotype of An. galvaoi, an adult female from Rio Branco, State of Acre, is invalidated.

  13. The genetics of inviability and male sterility in hybrids between Anopheles gambiae and An. arabiensis.

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    Slotman, M; Della Torre, A; Powell, J R

    2004-05-01

    Male hybrids between Anopheles gambiae and An. arabiensis suffer from hybrid sterility, and inviability effects are sometimes present as well. We examined the genetic basis of these reproductive barriers between the two species, using 21 microsatellite markers. Generally, recessive inviability effects were found on the X chromosome of gambiae that are incompatible with at least one factor on each arabiensis autosome. Inviability is complete when the gambiae and arabiensis inviability factors are hemi- or homozygous. Using a QTL mapping approach, regions that contribute to male hybrid sterility were also identified. The X chromosome has a disproportionately large effect on male hybrid sterility. Additionally, several moderate-to-large autosomal QTL were found in both species. The effect of these autosomal QTL is contingent upon the presence of an X chromosome from the other species. Substantial regions of the autosomes do not contribute markedly to male hybrid sterility. Finally, no evidence for epistatic interactions between conspecific sterility loci was found.

  14. Molecular typing of bacteria of the genus Asaia in malaria vector Anopheles arabiensis Patton, 1905

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    S. Epis

    2012-08-01

    Full Text Available The acetic acid bacterium Asaia spp. was successfully detected in Anopheles arabiensis Patton, 1905, one of the major vector of human malaria in Sub-Saharan Africa. A collection of 45 Asaia isolates in cellfree media was established from 20 individuals collected from the field in Burkina Faso. 16S rRNA universal polymerase chain reaction (PCR and specific qPCR, for the detection of Asaia spp. were performed in order to reveal the presence of different bacterial taxa associated with this insect. The isolates were typed by internal transcribed spacer-PCR, BOX-PCR, and randomly amplified polymorphic DNA-PCR, proved the presence of different Asaia in A. arabiensis.

  15. Molecular taxonomy provides new insights into anopheles species of the neotropical arribalzagia series.

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    Giovan F Gómez

    Full Text Available Phylogenetic analysis of partial mitochondrial cytochrome oxidase c subunit I (COI and nuclear internal transcribed spacer 2 (ITS2 sequences were used to evaluate initial identification and to investigate phylogenetic relationships of seven Anopheles morphospecies of the Arribalzagia Series from Colombia. Phylogenetic trees recovered highly supported clades for An. punctimaculas.s., An. calderoni, An. malefactor s.l., An. neomaculipalpus, An. apicimacula s.l., An. mattogrossensis and An. peryassui. This study provides the first molecular confirmation of An. malefactorfrom Colombia and discovered conflicting patterns of divergence for the molecular markers among specimens from northeast and northern Colombia suggesting the presence of two previously unrecognized Molecular Operational Taxonomic Units (MOTUs. Furthermore, two highly differentiated An. apicimacula MOTUs previously found in Panama were detected. Overall, the combined molecular dataset facilitated the detection of known and new Colombian evolutionary lineages, and constitutes the baseline for future research on their bionomics, ecology and potential role as malaria vectors.

  16. Development of a molecular assay to detect predation on Anopheles gambiae complex larval stages.

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    Schielke, Erika; Costantini, Carlo; Carchini, Gianmaria; Sagnon, N'falé; Powell, Jeffrey; Caccone, Adalgisa

    2007-09-01

    We developed a molecular assay to detect predation on Anopheles gambiae sensu lato (s.l.) mosquitoes. This intergenic spacer ribosomal DNA polymerase chain reaction assay and restriction enzyme analysis uses An. gambiae-specific primers to detect mosquito DNA in the DNA extracts from whole invertebrate predators, which enables identification of species (An. gambiae s.s. versus An. arabiensis) and molecular forms (M versus S in An. gambiae s.s.). We show that An. gambiae s.l. DNA can be detected after ingestion by members of the families Lestidae (order Odonata) after four hours, Libellulidae (order Odonata) after six hours, and Notonectidae (order Hemiptera) after 24 hours. This method is an improvement over previously published methods because of ease of execution and increased time of detection after ingestion. PMID:17827361

  17. [Historical review of the distribution of Anopheles (Nyssorhynchus) darlingi (Diptera: Culicidae) in the Peruvian Amazon].

    Science.gov (United States)

    Fernández, Roberto; Vera, Hubert; Calderón, Guillermo

    2014-04-01

    Anopheles (Nyssorhynchus) darlingi has been reported since 1931 in border areas of the department of Loreto, mainly along the borders with Brazil and Colombia. In 1994, during an outbreak of malaria, An. darlingi was found in neighboring towns to Iquitos. At present, its distribution has expanded considerably in Loreto. This paper reviews literature available for all possible information on the distribution of mosquitoes, particularly anopheline in the Amazon region of the country, with special emphasis on An darlingi. Entomological collections were also conducted in the departments of Madre de Dios and Ucayali in order to know and verify the distribution of An. darlingi. At present, the distribution of the species is confined to localities in southeastern Peru with Bolivia border towns, in a town near the Abujao River in the department of Ucayali, and widely in the northeastern region of the Amazon basin of Loreto in Peru. PMID:25123872

  18. Wash Resistance and Bioefficacy of Alpha-cypermethrin Long Lasting Impregnated Nets (LLIN-Interceptor(® against Anopheles stephensi using Tunnel Test.

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    Hassan Vatandoost

    2013-06-01

    Full Text Available The Long-lasing insecticide impregnated nets (LLINs is considered as an effective tools for malaria vector control. The aim of this study was to evaluate the residual efficacy of alpha-cypermethrin long lasting impregnated nets (LLIN-Interceptor(® against Anopheles stephensi using tunnel test.The wash-resistance of Interceptor(® nets were assessed under laboratory conditions using tunnel test. Females of An. stephensi were released into the tunnel and then they were provided blood meals from guinea pigs. Bed nets were washed according to the standard procedure up to 20 times. The bioefficacy indicators such as inhibition of bloodmeal from experimental animal, knockdown, irritancy rate, survival rate, entry index and mortality were calculated.It induced 90-100% mortalities in the population of An. stephensi up to 15 washes. The KT50 values reduced from 73.47 to 26.30 minutes in unwashed in comparison to one washed, respectively. The mean of mortality rate of blood-feeding inhibition and entry indexes was reached to 91.6%±2.8, 87.0±3.4 and 24.9±2.8 respectively after 20 washing.This net could provide a good personal protection against malaria vectors and could induce relatively high mortality, inhibit the blood-feeding as well as reduce the entry rates of female mosquitoes even after several washes.

  19. Wash Resistance and Bioefficacy of Alpha-cypermethrin Long Lasting Impregnated Nets (LLIN-Interceptor® against Anopheles stephensi using Tunnel Test

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    Hassan Vatandoost

    2013-03-01

    Full Text Available Background: The Long-lasing insecticide impregnated nets (LLINs is considered as an effective tools for malaria vector control. The aim of this study was to evaluate the residual efficacy of alpha-cypermethrin long lasting im­pregnated nets (LLIN-Interceptor® against Anopheles stephensi using tunnel test.Methods: The wash-resistance of Interceptor® nets were assessed under laboratory conditions using tunnel test. Females of An. stephensi were released into the tunnel and then they were provided blood meals from guinea pigs. Bed nets were washed according to the standard procedure up to 20 times. The bioefficacy indicators such as inhi­bition of bloodmeal from experimental animal, knockdown, irritancy rate, survival rate, entry index and mortality were calculated.Results: It induced 90–100% mortalities in the population of An. stephensi up to 15 washes. The KT50 values re­duced from 73.47 to 26.30 minutes in unwashed in comparison to one washed, respectively. The mean of mortality rate of blood-feeding inhibition and entry indexes was reached to 91.6%±2.8, 87.0±3.4 and 24.9±2.8 respectively after 20 washing.Conclusion: This net could provide a good personal protection against malaria vectors and could induce relatively high mortality, inhibit the blood-feeding as well as reduce the entry rates of female mosquitoes even after several washes.

  20. Chemical composition and larvicidal activity of the essential oil of Plectranthus amboinicus (Lour.) Spreng against Anopheles stephensi: a malarial vector mosquito.

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    Senthilkumar, Annadurai; Venkatesalu, Venugopalan

    2010-10-01

    Essential oil of Plectranthus amboinicus was studied for its chemical composition and larvicidal potential against the malarial vector mosquito Anopheles stephensi. Totally 26 compounds were identified by GC and GC-MS. The major chemical compounds were carvacrol (28.65%) followed by thymol (21.66%), α-humulene (9.67%), undecanal (8.29%), γ-terpinene (7.76%), ρ-cymene (6.46%), caryophyllene oxide (5.85%), α-terpineol (3.28%) and β-selinene (2.01%). The larvicidal assay was conducted to record the LC(50) and LC(90) values and the larval mortality was observed after 12 and 24 h of exposure period. The LC(50) values of the oil were 33.54 (after 12 h) and 28.37 ppm (after 24 h). The LC(90) values of the oil were 70.27 (after 12 h) and 59.38 ppm (after 24 h). The results of the present study showed that the essential oil of P. amboinicus is one of the inexpensive and eco-friendly sources of natural mosquito larvicidal agent to control/reduce the population of malarial vector mosquito. PMID:20668876

  1. Green-synthesised nanoparticles from Melia azedarach seeds and the cyclopoid crustacean Cyclops vernalis: an eco-friendly route to control the malaria vector Anopheles stephensi?

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    Anbu, Priya; Murugan, Kadarkarai; Madhiyazhagan, Pari; Dinesh, Devakumar; Subramaniam, Jayapal; Panneerselvam, Chellasamy; Suresh, Udaiyan; Alarfaj, Abdullah A; Munusamy, Murugan A; Higuchi, Akon; Hwang, Jiang-Shiou; Kumar, Suresh; Nicoletti, Marcello; Benelli, Giovanni

    2016-09-01

    The impact of green-synthesised mosquitocidal nanoparticles on non-target aquatic predators is poorly studied. In this research, we proposed a single-step method to synthesise silver nanoparticles (Ag NP) using the seed extract of Melia azedarach. Ag NP were characterised using a variety of biophysical methods, including UV-vis spectrophotometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. In laboratory assays on Anopheles stephensi, Ag NP showed LC50 ranging from 2.897 (I instar larvae) to 14.548 ppm (pupae). In the field, the application of Ag NP (10 × LC50) lead to complete elimination of larval populations after 72 h. The application of Ag NP in the aquatic environment did not show negative adverse effects on predatory efficiency of the mosquito natural enemy Cyclops vernalis. Overall, this study highlights the concrete possibility to employ M. azedarach-synthesised Ag NP on young instars of malaria vectors.

  2. The Influence of Insecticide Resistance, Age, Sex, and Blood Feeding Frequency on Thermal Tolerance of Wild and Laboratory Phenotypes of Anopheles funestus (Diptera: Culicidae).

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    Lyons, C L; Oliver, S V; Hunt, R H; Coetzee, M

    2016-03-01

    Resistance to insecticides is a global phenomenon and is increasing at an unprecedented rate. How resistant and susceptible strains of malaria vectors might differ in terms of life history and basic biology is often overlooked, despite the potential importance of such information in light of changing climates. Here, we investigated the upper thermal limits (ULT50) of wild and laboratory strains of Anopheles funestus Giles mosquitoes, including resistance status, sex, age, and blood feeding status as potential factors influencing ULT50. No significant differences in ULT50 were observed between strains displaying different resistance patterns, nor was there a significant difference between wild and laboratory strains. In some instances, strains showed a senescence response, displaying decreased ULT50 with an increase in age, and differences between males and females (females displaying higher ULT50 than males). Blood feeding did not seem to influence ULT50 in any way. For An. funestus, it seems evident that there is no cost to resistance despite what is displayed in other anopheline species. This could have significant impacts for vector control, with resistant populations of An. funestus performing just as well, if not better, than susceptible strains, especially under changing environmental conditions such as those expected to occur with climate change. PMID:26718714

  3. Spatial and sex-specific dissection of the Anopheles gambiae midgut transcriptome

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    Mahairaki Vassiliki

    2007-01-01

    Full Text Available Abstract Background The midgut of hematophagous insects, such as disease transmitting mosquitoes, carries out a variety of essential functions that mostly relate to blood feeding. The midgut of the female malaria vector mosquito Anopheles gambiae is a major site of interactions between the parasite and the vector. Distinct compartments and cell types of the midgut tissue carry out specific functions and vector borne pathogens interact and infect different parts of the midgut. Results A microarray based global gene expression approach was used to compare transcript abundance in the four major female midgut compartments (cardia, anterior, anterior part of posterior and posterior part of posterior midgut and between the male and female Anopheles gambiae midgut. Major differences between the female and male midgut gene expression relate to digestive processes and immunity. Each compartment has a distinct gene function profile with the posterior midgut expressing digestive enzyme genes and the cardia and anterior midgut expressing high levels of antimicrobial peptide and other immune gene transcripts. Interestingly, the cardia expressed several known anti-Plasmodium factors. A parallel peptidomic analysis of the cardia identified known mosquito antimicrobial peptides as well as several putative short secreted peptides that are likely to represent novel antimicrobial factors. Conclusion The A. gambiae sex specific midgut and female midgut compartment specific transcriptomes correlates with their known functions. The significantly greater functional diversity of the female midgut relate to hematophagy that is associated with digestion and nutrition uptake as well as exposes it to a variety of pathogens, and promotes growth of its endogenous microbial flora. The strikingly high proportion of immunity related factors in the cardia tissue most likely serves the function to increase sterility of ingested sugar and blood. A detailed characterization of the

  4. Observations on the swarming and mating behaviour of Anopheles funestus from southern Mozambique

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    Thompson R

    2003-02-01

    Full Text Available Abstract Background Control of malaria by the release of genetically modified mosquitoes refractory to transmission is now becoming a possibility. In many areas of Africa, Anopheles gambiae is found together with an equally important vector, An. funestus. Given their sympatry and the likelihood of a similar mating period some aspects of the mating behaviour of An. gambiae s.l. and An. funestus are likely to differ. We therefore attempted to characterise the swarming behaviour of An. funestus and to determine if any aspects of the observed behaviour differed from that recorded for the M form of An. gambiae from São Tomé. Methods In March – May 2002 the swarming, mating, house exiting and resting behaviour of Anopheles funestus was studied by direct observation in Mozambique. Swarming males and insects in copula were collected by sweep net. Wing lengths of males collected resting, exiting houses, swarming and mating were measured and the wingbeat frequency distribution of individual insects, in free flight confined inside netting covered paper cups, was also determined. Results Mono-specific swarms occurred at sunset in relatively open areas close to houses used for resting. Mating pairs were seen 11 ± 3.7 min after the start of swarming. The number of total pairs observed being inversely proportional to the time difference between the start of swarming and the first pairing. The great majority of females mated before feeding. Male or female size did not appear to affect mating success or other behaviours. During the study, ambient temperatures decreased and female, but not male, wing size increased. At 516 Hz, the flight tone of female An. funestus was similar to the 497 Hz of the local An. gambiae. Males dispersed if light or dark artificial horizontal markers were placed underneath naturally occurring swarms. Conclusion Differential response to markers would be sufficient for swarming in An. funestus and An. gambiae s.l. to occur in

  5. Polymorphisms in Anopheles gambiae immune genes associated with natural resistance to Plasmodium falciparum.

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    Caroline Harris

    Full Text Available Many genes involved in the immune response of Anopheles gambiae, the main malaria vector in Africa, have been identified, but whether naturally occurring polymorphisms in these genes underlie variation in resistance to the human malaria parasite, Plasmodium falciparum, is currently unknown. Here we carried out a candidate gene association study to identify single nucleotide polymorphisms (SNPs associated with natural resistance to P. falciparum. A. gambiae M form mosquitoes from Cameroon were experimentally challenged with three local wild P. falciparum isolates. Statistical associations were assessed between 157 SNPs selected from a set of 67 A. gambiae immune-related genes and the level of infection. Isolate-specific associations were accounted for by including the effect of the isolate in the analysis. Five SNPs were significantly associated to the infection phenotype, located within or upstream of AgMDL1, CEC1, Sp PPO activate, Sp SNAKElike, and TOLL6. Low overall and local linkage disequilibrium indicated high specificity in the loci found. Association between infection phenotype and two SNPs was isolate-specific, providing the first evidence of vector genotype by parasite isolate interactions at the molecular level. Four SNPs were associated to either oocyst presence or load, indicating that the genetic basis of infection prevalence and intensity may differ. The validity of the approach was verified by confirming the functional role of Sp SNAKElike in gene silencing assays. These results strongly support the role of genetic variation within or near these five A. gambiae immune genes, in concert with other genes, in natural resistance to P. falciparum. They emphasize the need to distinguish between infection prevalence and intensity and to account for the genetic specificity of vector-parasite interactions in dissecting the genetic basis of Anopheles resistance to human malaria.

  6. Inducible peroxidases mediate nitration of anopheles midgut cells undergoing apoptosis in response to Plasmodium invasion.

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    Kumar, Sanjeev; Gupta, Lalita; Han, Yeon Soo; Barillas-Mury, Carolina

    2004-12-17

    Plasmodium berghei invasion of Anopheles stephensi midgut cells causes severe damage, induces expression of nitric-oxide synthase, and leads to apoptosis. The present study indicates that invasion results in tyrosine nitration, catalyzed as a two-step reaction in which nitric-oxide synthase induction is followed by increased peroxidase activity. Ookinete invasion induced localized expression of peroxidase enzymes, which catalyzed protein nitration in vitro in the presence of nitrite and H(2)O(2). Histochemical stainings revealed that when a parasite migrates laterally and invades more than one cell, the pattern of induced peroxidase activity is similar to that observed for tyrosine nitration. In Anopheles gambiae, ookinete invasion elicited similar responses; it induced expression of 5 of the 16 peroxidase genes predicted by the genome sequence and decreased mRNA levels of one of them. One of these inducible peroxidases has a C-terminal oxidase domain homologous to the catalytic moiety of phagocyte NADPH oxidase and could provide high local levels of superoxide anion (O(2)), that when dismutated would generate the local increase in H(2)O(2) required for nitration. Chemically induced apoptosis of midgut cells also activated expression of four ookinete-induced peroxidase genes, suggesting their involvement in general apoptotic responses. The two-step nitration reaction provides a mechanism to precisely localize and circumscribe the toxic products generated by defense reactions involving nitration. The present study furthers our understanding of the biochemistry of midgut defense reactions to parasite invasion and how these may influence the efficiency of malaria transmission by anopheline mosquitoes. PMID:15456781

  7. Anopheles midgut epithelium evades human complement activity by capturing factor H from the blood meal.

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    Ayman Khattab

    2015-02-01

    Full Text Available Hematophagous vectors strictly require ingesting blood from their hosts to complete their life cycles. Exposure of the alimentary canal of these vectors to the host immune effectors necessitates efficient counteractive measures by hematophagous vectors. The Anopheles mosquito transmitting the malaria parasite is an example of hematophagous vectors that within seconds can ingest human blood double its weight. The innate immune defense mechanisms, like the complement system, in the human blood should thereby immediately react against foreign cells in the mosquito midgut. A prerequisite for complement activation is that the target cells lack complement regulators on their surfaces. In this work, we analyzed whether human complement is active in the mosquito midgut, and how the mosquito midgut cells protect themselves against complement attack. We found that complement remained active for a considerable time and was able to kill microbes within the mosquito midgut. However, the Anopheles mosquito midgut cells were not injured. These cells were found to protect themselves by capturing factor H, the main soluble inhibitor of the alternative complement pathway. Factor H inhibited complement on the midgut cells by promoting inactivation of C3b to iC3b and preventing the activity of the alternative pathway amplification C3 convertase enzyme. An interference of the FH regulatory activity by monoclonal antibodies, carried to the midgut via blood, resulted in increased mosquito mortality and reduced fecundity. By using a ligand blotting assay, a putative mosquito midgut FH receptor could be detected. Thereby, we have identified a novel mechanism whereby mosquitoes can tolerate human blood.

  8. Functional characterization of the NF-κB transcription factor gene REL2 from Anopheles gambiae

    Institute of Scientific and Technical Information of China (English)

    NGO T. HOA; LIANGBIAO ZHENG

    2007-01-01

    The REL2 gene plays an important role in innate immunity against both Gram (+) and Gram (-) bacteria and malaria parasites in Anopheles gambiae, the main vector of malaria in Africa. Through alternative splicing, REL2 produces two protein products, REL2F (with a Rel-homology domain as well as an inhibitory ankyrin repeat region) and REL2S (without the ankyrin repeats). In the immune-competent cell line Sua1B from An. Gambiae, REL2 has been shown to be a key regulator for cecropin A (or CEC1). The high level expression of CEC1 in Sua1B was postulated to be the result of constitutive activation of REL2F. Here we showed that REL2F is indeed processed, albeit at a low level, in the Sua1B cell line. The primary cleavage requires residue 678 (an aspartic acid). Proteolytic cleavage of REL2F can be enhanced by challenge with bacteria Escherichia coli and Bacillus subtilis, but not with fungus Beauveria bassiana. The inducible cleavage can be substantially reduced by RNA interference against PGRP-LC and CASPL1. Over-expression of REL2S or a constitutively active form of REL2F (REL2F380C or REL2F678) in An. Gambiae cell line can further increase expression of CEC1 and other antimicrobial peptide genes. Over-expression of these constitutive active proteins in an immune na?ve cell line, MSQ43, from Anopheles stephensi, results in even more dramatic increased expression of antimicrobial peptides.

  9. Living at the edge: biogeographic patterns of habitat segregation conform to speciation by niche expansion in Anopheles gambiae

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    Costantini Carlo

    2009-05-01

    Full Text Available Abstract Background Ongoing lineage splitting within the African malaria mosquito Anopheles gambiae is compatible with ecological speciation, the evolution of reproductive isolation by divergent natural selection acting on two populations exploiting alternative resources. Divergence between two molecular forms (M and S identified by fixed differences in rDNA, and characterized by marked, although incomplete, reproductive isolation is occurring in West and Central Africa. To elucidate the role that ecology and geography play in speciation, we carried out a countrywide analysis of An. gambiae M and S habitat requirements, and that of their chromosomal variants, across Burkina Faso. Results Maps of relative abundance by geostatistical interpolators produced a distinct pattern of distribution: the M-form dominated in the northernmost arid zones, the S-form in the more humid southern regions. Maps of habitat suitability, quantified by Ecological Niche Factor Analysis based on 15 eco-geographical variables revealed less contrast among forms. M was peculiar as it occurred proportionally more in habitat of marginal quality. Measures of ecological niche breadth and overlap confirmed the mismatch between the fundamental and realized patterns of habitat occupation: forms segregated more than expected from the extent of divergence of their environmental envelope – a signature of niche expansion. Classification of chromosomal arm 2R karyotypes by multilocus genetic clustering identified two clusters loosely corresponding to molecular forms, with 'mismatches' representing admixed individuals due to shared ancestral polymorphism and/or residual hybridization. In multivariate ordination space, these karyotypes plotted in habitat of more marginal quality compared to non-admixed, 'typical', karyotypes. The distribution of 'typical' karyotypes along the main eco-climatic gradient followed a consistent pattern within and between forms, indicating an adaptive role

  10. Multiple Insecticide Resistance in the Malaria Vector Anopheles funestus from Northern Cameroon Is Mediated by Metabolic Resistance Alongside Potential Target Site Insensitivity Mutations

    Science.gov (United States)

    Menze, Benjamin D.; Riveron, Jacob M.; Ibrahim, Sulaiman S.; Irving, Helen; Antonio-Nkondjio, Christophe; Awono-Ambene, Parfait H.; Wondji, Charles S.

    2016-01-01

    Background Despite the recent progress in establishing the patterns of insecticide resistance in the major malaria vector Anopheles funestus, Central African populations of this species remain largely uncharacterised. To bridge this important gap and facilitate the implementation of suitable control strategies against this vector, we characterised the resistance patterns of An. funestus population from northern Cameroon. Methods and Findings Collection of indoor-resting female mosquitoes in Gounougou (northern Cameroon) in 2012 and 2015 revealed a predominance of An. funestus during dry season. WHO bioassays performed using F1 An. funestus revealed that the population was multiple resistant to several insecticide classes including pyrethroids (permethrin, deltamethrin, lambda-cyhalothrin and etofenprox), carbamates (bendiocarb) and organochlorines (DDT and dieldrin). However, a full susceptibility was observed against the organophosphate malathion. Bioassays performed with 2015 collection revealed that resistance against pyrethroids and DDT is increasing. PBO synergist assays revealed a significant recovery of susceptibility for all pyrethroids but less for DDT. Analysis of the polymorphism of a portion of the voltage-gated sodium channel gene (VGSC) revealed the absence of the L1014F/S kdr mutation but identified 3 novel amino acid changes I877L, V881L and A1007S. However, no association was established between VGSC polymorphism and pyrethroid/DDT resistance. The DDT resistant 119F-GSTe2 allele (52%) and the dieldrin resistant 296S-RDL allele (45%) were detected in Gounougou. Temporal analysis between 2006, 2012 and 2015 collections revealed that the 119F-GSTe2 allele was relatively stable whereas a significant decrease is observed for 296S-RDL allele. Conclusion This multiple resistance coupled with the temporal increased in resistance intensity highlights the need to take urgent measures to prolong the efficacy of current insecticide-based interventions against

  11. First report on co-occurrence knockdown resistance mutations and susceptibility to beta-cypermethrin in Anopheles sinensis from Jiangsu Province, China.

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    Wei-Long Tan

    Full Text Available The increasing prevalence of insecticide resistance in Anopheles sinensis, a major vector of malaria in Jiangsu province in eastern China, threatens to compromise the successful use of insecticides in malaria control strategies. It is therefore vital to understand the insecticide resistance status of An. sinensis in the region. This study examined the nucleotide diversity of the para-sodium channel and knockdown resistance (kdr in five field populations of adult An. sinensis mosquitoes collected in Jiangsu province, identifying the L1014F and L1014C substitutions for the first time. Competitive polymerase chain reaction (PCR amplification of specific allele (cPASA and polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP for resistance diagnosis were developed and validated. Comparing the results with direct sequencing revealed that the PCR-RFLP method was more sensitive and specific whereas the cPASA method was more convenient and suitable. The significant positive correlation between kdr allele frequency and bioassay-based resistance phenotype demonstrates that the frequency of L1014F and L1014C substitutions in the kdr gene provides a useful molecular marker for monitoring beta-cypermethrin resistance in natural populations of An. sinensis. Our results point to the L1014F substitution as the key mutation associated with beta-cypermethrin resistance. The high resistance and mutation frequency detected in the five populations also suggest cross-resistance with other pyrethroids may occur in An. sinensis, highlighting the need for further surveys to map insecticide resistance in China and the adoption of a rational management of insecticide application for resistance management and mosquito vector control.

  12. Repeated landmass reformation limits diversification in the widespread littoral zone mosquito Anopheles sundaicus sensu lato in the Indo-Oriental Region.

    Science.gov (United States)

    Zarowiecki, Magdalena; Linton, Yvonne-Marie; Post, Rory J; Bangs, Michael J; Htun, Pe Than; Hlaing, Thaung; Seng, Chang Moh; Baimai, Visut; Ding, Trung Ho; Sochantha, Tho; Walton, Catherine

    2014-05-01

    Southeast Asia harbours abundant biodiversity, hypothesized to have been generated by Pliocene and Pleistocene climatic and environmental change. Vicariance between the island of Borneo, the remaining Indonesian archipelago and mainland Southeast Asia caused by elevated sea levels during interglacial periods has been proposed to lead to diversification in the littoral zone mosquito Anopheles (Cellia) sundaicus (Rodenwaldt) sensu lato. To test this biogeographical hypothesis, we inferred the population history and assessed gene flow of A. sundaicus s.l. sampled from 18 populations across its pan-Asian species range, using sequences from mitochondrial cytochrome c oxidase subunit 1 (CO1), the internal transcribed spacer 2 (ITS2) and the mannose phosphate isomerase (Mpi) gene. A hypothesis of ecological speciation for A. sundaicus involving divergent adaptation to brackish and freshwater larval habitats was also previously proposed, based on a deficiency of heterozygotes for Mpi allozyme alleles in sympatry. This hypothesis was not supported by Mpi sequence data, which exhibited no fixed differences between brackish and freshwater larval habitats. Mpi and CO1 supported the presence of up to eight genetically distinct population groupings. Counter to the hypothesis of three allopatric species, divergence was often no greater between Borneo, Sumatra/Java and the Southeast Asian mainland than it was between genetic groupings within these landmasses. An isolation-with-migration (IM) model indicates recurrent gene flow between the current major landmasses. Such gene flow would have been possible during glacial periods when the current landmasses merged, presenting opportunities for dispersal along expanding and contracting coastlines. Consequently, Pleistocene climatic variation has proved a homogenizing, rather than diversifying, force for A. sundaicus diversity. PMID:24750501

  13. Is the current decline in malaria burden in sub-Saharan Africa due to a decrease in vector population?

    DEFF Research Database (Denmark)

    Meyrowitsch, Dan Wolf; Pedersen, Erling Møller; Alifrangis, Michael;

    2011-01-01

    ) and between 2003 and 2009 (2nd period), mosquitoes were collected weekly in 50 households using CDC light traps. Data on rainfall were obtained from the nearby climate station and was used to analyze the association between monthly rainfall and malaria mosquito populations. RESULTS: The average number...... of Anopheles gambiae and Anopheles funestus per trap decreased by 76.8% and 55.3%, respectively over the 1st period, and by 99.7% and 99.8% over the 2nd period. During the last year of sampling (2009), the use of 2368 traps produced a total of only 14 Anopheline mosquitoes. With the exception of the decline...... in An. gambiae during the 1st period, the results did not reveal any statistical association between mean trend in monthly rainfall and declining malaria vector populations. CONCLUSION: A longitudinal decline in the density of malaria mosquito vectors was seen during both study periods despite...

  14. The bionomics of the malaria vector Anopheles farauti in Northern Guadalcanal, Solomon Islands: issues for successful vector control

    OpenAIRE

    Bugoro, Hugo; Hii, Jeffery L; Butafa, Charles; Iro’ofa, Charlie; Apairamo, Allen; Robert D Cooper; Chen, Cheng-Chen; Russell, Tanya L

    2014-01-01

    Background The north coast of Guadalcanal has some of the most intense malaria transmission in the Solomon Islands. And, there is a push for intensified vector control in Guadalcanal, to improve the livelihood of residents and to minimize the number of cases, which are regularly exported to the rest of the country. Therefore, the bionomics of the target vector, Anopheles farauti, was profiled in 2007–08; which was after 20 years of limited surveillance during which time treated bed nets (ITNs...

  15. A Possible Mechanism for the Suppression of Plasmodium berghei Development in the Mosquito Anopheles gambiae by the Microsporidian Vavraia culicis

    OpenAIRE

    Bargielowski, Irka; Koella, Jacob C

    2009-01-01

    Background Microsporidian parasites of mosquitoes offer a possible way of controlling malaria, as they impede the development of Plasmodium parasites within the mosquito. The mechanism involved in this interference process is unknown. Methodology We evaluated the possibility that larval infection by a microsporidian primes the immune system of adult mosquitoes in a way that enables a more effective anti-Plasmodium response. To do so, we infected 2-day old larvae of the mosquito Anopheles gamb...

  16. Mosquito Larvicidal Potential of Gossypium hirsutum (Bt cotton) Leaves Extracts against Aedes aegypti and Anopheles stephensi larvae.

    OpenAIRE

    Patil, Chandrashekhar D; Hemant P Borase; Salunkhe, Rahul B; Rahul K Suryawanshi; Narkhade, Chandrakant P; Salunke, Bipinchandra K.; Satish V Patil

    2014-01-01

    Background: We aimed to extract the ingredients from leaves of Gossypium hirsutum (Bt cotton) using different solvents and evaluate for potential use to control different larval stages of mosquito species, Aedes aegypti and Anopheles stephensi. Methods: Qualitative and quantitative estimation of ingredients from Go. hirsutum (Bt) plant extract was carried out and their inhibitory action against mosquito larvae was determined using mosquito larvicidal assay. Results: LC50 values of water, etha...

  17. Larvicidal and repellent properties of Adansonia digitata against medically important human malarial vector mosquito Anopheles stephensi (Diptera: Culicidae)

    OpenAIRE

    K. Krishnappa , K. Elumalai , S. Dhanasekaran & J. Gokulakrishnan

    2012-01-01

    Background & objectives: Development of plant-based alternative compounds for mosquito control has gainedimportance now-a-days, in view of increasing resistance in mosquito vectors to existing insecticides. The larvicidaland repellent activities of benzene, chloroform, hexane and methanol leaf extracts of Indian medicinal plant,Adansonia digitata were investigated against malarial vector, Anopheles stephensi.Methods: In all, 25 III instar larvae of An. stephensi were exposed to various concen...

  18. Baseline Susceptibility of Different Geographical Strains of Anopheles stephensi (Diptera: Culicidae) to Temephos in Malarious Areas of Iran

    OpenAIRE

    Aboozar Soltani; Hassan Vatandoost; Mohammad Ali Oshaghi; Ahmad Ali Enayati; Ahmad Raeisi; Mohammad Reza Eshraghian; Mohammad Mehdi Soltan-Dallal; Ahmad Ali Hanafi-Bojd; Mohammad Reza Abai; Fatemeh Rafi

    2013-01-01

    Background: Malaria still remains a public health problem in Iran. There are different vector control interventions such as insecticide spraying. The present study was carried out to determine the susceptibility status of Anopheles stephensi larvae to temephos as a national plan for monitoring and mapping of insecticide resistance Methods: Eight different localities in two main malarious provinces were determined as field collecting sites. Mosquitoes were collected from the field and reared i...

  19. Life-table studies revealed significant effects of deforestation on the development and survivorship of Anopheles minimus larvae

    OpenAIRE

    Wang, Xiaoming; Zhou, Guofa; Zhong, Daibin; Wang, Xiaoling; Ying WANG; Yang, Zhaoqing; Cui, Liwang; Yan, Guiyun

    2016-01-01

    Background Many developing countries are experiencing rapid ecological changes such as deforestation and shifting agricultural practices. These environmental changes may have an important consequence on malaria due to their impact on vector survival and reproduction. Despite intensive deforestation and malaria transmission in the China-Myanmar border area, the impact of deforestation on malaria vectors in the border area is unknown. Methods We conducted life table studies on Anopheles minimus...

  20. Remotely-sensed land use patterns and the presence of Anopheles larvae (Diptera: Culicidae) in Sukabumi, West Java, Indonesia.

    Science.gov (United States)

    Stoops, Craig A; Gionar, Yoyo R; Shinta; Sismadi, Priyanto; Rachmat, Agus; Elyazar, Iqbal F; Sukowati, Supratman

    2008-06-01

    Land use patterns and the occurrence of Anopheles species larvae were studied in Sukabumi District, West Java, Indonesia, from October 2004 to September 2005. Two land use maps derived using remote sensing were used. One map derived from Quickbird satellite images of 150 km2 of the Simpenan and Ciemas subdistricts (106 degrees 27' 53"-106 degrees 38' 38" E and 6 degrees 59' 59"-7 degrees 8' 46" S) in Sukabumi and one using ASTER images covering 4,000 km2 of Sukabumi District from 106 degrees 22' 15"-107 degrees 4' 1" E and 6 degrees 42' 50" - 7 degrees 26' 13" S. There was a total of 11 Anopheles spp. collected from 209 sampling locations in the area covered by the Quickbird image and a total of 15 Anopheles spp. collected from 1,600 sampling locations in the area covered by the ASTER map. For the area covered by the land use maps, ten species were found to have statistically positive relationships between land use class and species presence: Anopheles aconitus, An. annularis, An. barbirostris. An. flavirostris, An. insulaeflorum, An. kochi, An. maculatus, An. subpictus, An. sundaicus, and An. vagus. Quickbird and ASTER satellite images both produced land maps that were adequate for predicting species presence in an area. The land use classes associated with malaria vector breeding were rice paddy (An. aconitus, An. subpictus), plantation located near or adjacent to human settlements (An. maculatus), bush/shrub (An. aconitus, An. maculatus, An. sundaicus), bare land, and water body land use on the coast located < or = 250 m of the beach (An. sundaicus). Understanding the associations of habitat and species in one area, predictions of species presence or absence can be made prior to a ground survey allowing for accurate vector survey and control planning.

  1. An Epithelial Serine Protease, AgESP, Is Required for Plasmodium Invasion in the Mosquito Anopheles gambiae

    OpenAIRE

    Rodrigues, Janneth; Oliveira, Giselle A.; Kotsyfakis, Michalis; Dixit, Rajnikant; Molina-Cruz, Alvaro; Jochim, Ryan; Barillas-Mury, Carolina

    2012-01-01

    Background Plasmodium parasites need to cross the midgut and salivary gland epithelia to complete their life cycle in the mosquito. However, our understanding of the molecular mechanism and the mosquito genes that participate in this process is still very limited. Methodology/Principal Findings We identified an Anopheles gambiae epithelial serine protease (AgESP) that is constitutively expressed in the submicrovillar region of mosquito midgut epithelial cells and in the basal side of the sali...

  2. Molecular interactions between Anopheles stephensi midgut cells and Plasmodium berghei: the time bomb theory of ookinete invasion of mosquitoes

    OpenAIRE

    Han, Yeon Soo; Thompson, Joanne; Kafatos, Fotis C.; Barillas-Mury, Carolina

    2000-01-01

    We present a detailed analysis of the interactions between Anopheles stephensi midgut epithelial cells and Plasmodium berghei ookinetes during invasion of the mosquito by the parasite. In this mosquito, P.berghei ookinetes invade polarized columnar epithelial cells with microvilli, which do not express high levels of vesicular ATPase. The invaded cells are damaged, protrude towards the midgut lumen and suffer other characteristic changes, including induction of nitric oxide synthase (NOS) exp...

  3. Feeding and indoor resting behaviour of the mosquito Anopheles longipalpis in an area of hyperendemic malaria transmission in southern Zambia

    OpenAIRE

    Kent, R.J.; Coetzee, M.; Mharakurwa, S.; Norris, D. E.

    2006-01-01

    Anopheles longipalpis (Theobald) (Diptera: Culicidae) is a predominantly zoophilic mosquito that has not been implicated in malaria transmission. However, this species was collected indoors with An. funestus s.l. in southern Zambia, where transmission of Plasmodium falciparum is hyperendemic, and we initially misidentified it morphologically and molecularly as An. funestus s.l. The indoor resting density and blood-feeding behaviour of An. longipalpis were investigated during the 2004 – 05 and...

  4. Composition, abundance and aspects of temporal variation in the distribution of Anopheles species in an area of Eastern Amazonia

    Directory of Open Access Journals (Sweden)

    Ledayane Mayana Costa Barbosa

    2014-06-01

    Full Text Available Introduction The diverse and complex environmental conditions of the Amazon Basin favor the breeding and development of Anopheles species. This study aimed to describe the composition, abundance and temporal frequency of Anopheles species and to correlate these factors with precipitation, temperature and relative humidity. Methods The study was conducted in the District of Coração, State of Amapá, Brazil. Samples were collected monthly during three consecutive nights, from 6:00 PM to 10:00 PM, from December 2010 to November 2011. In addition, four 12-hour collections (i.e., 6:00 PM to 6:00 AM were performed during this period. Results A total of 1,230 Anopheles specimens were collected. In the monthly collections, Anopheles darlingi was the predominant species, followed by An. braziliensis and An. albitarsis s.l., whereas An. darlingi, An. peryassui and An. braziliensis were the most frequent species collected in the 12-hour collections. The greatest number of anophelines was collected in September (the dry season. The highest frequency of anophelines was observed for An. darlingi during September, when there were the least rainfalls of the year, along with lower relative humidity and higher temperatures. There was little variation in the abundance of this species in other months, with the exception of slight increases in February, July and August. Conclusions The major malaria vectors, An. darlingi and An. albitarsis s.l. (likely An. marajoara, were the most abundant species collected in the study area. Consequently, prevention and control measures should be taken to prevent malaria outbreaks in the District of Coração.

  5. Effect of larval environment on some life history parameters in anopheles gambiae s.s. (diptera:culicidae))

    OpenAIRE

    Jannat, Khandaker Noore

    2010-01-01

    The effects of larval density, nutrition and cannibalism risk on some life history parameters of Anopheles gambiae larvae were evaluated in the laboratory. Adult body size was inversely correlated with larval density whereas larval mortality and mean age at pupation varied across experiments. When density increased, the secondary sex ratio shifted toward female bias. Effects of different types of nutrition on larval life were compared by providing larvae with algae Chaetophora sp., fish food ...

  6. Scanning electron microscopic (Sem studies on fourth instar larva and pupa of Anopheles (Cellia stephensi Liston (Anophelinae: Culicidae

    Directory of Open Access Journals (Sweden)

    Jagbir Singh Kirti

    2014-12-01

    Full Text Available Anopheles (Cellia stephensi Liston is a major vector species of malaria in Indian subcontinent. Taxonomists have worked on its various morphological aspects and immature stages to explore additional and new taxonomic attributes. Scanning electron microscopic (SEM studies have been conducted on the fourth instar larva and pupa of An. stephensi to find additional taxonomic features for the first time from Punjab state.

  7. The Role of Oxidative Stress in the Longevity and Insecticide Resistance Phenotype of the Major Malaria Vectors Anopheles arabiensis and Anopheles funestus.

    Directory of Open Access Journals (Sweden)

    Shüné V Oliver

    Full Text Available Oxidative stress plays numerous biological roles, both functional and pathological. The role of oxidative stress in various epidemiologically relevant biological traits in Anopheles mosquitoes is not well established. In this study, the effects of oxidative stress on the longevity and insecticide resistance phenotype in the major malaria vector species An. arabiensis and An. funestus were examined. Responses to dietary copper sulphate and hydrogen peroxide were used as proxies for the oxidative stress phenotype by determining the effect of copper on longevity and hydrogen peroxide lethal dose. Glutathione peroxidase and catalase activities were determined colorimetrically. Oxidative burden was quantified as protein carbonyl content. Changes in insecticide resistance phenotype were monitored by WHO bioassay. Insecticide resistant individuals showed an increased capacity for coping with oxidative stress, mediated by increased glutathione peroxidase and catalase activity. This effect was observed in both species, as well as in laboratory strains and F1 individuals derived from wild-caught An. funestus mothers. Phenotypic capacity for coping with oxidative stress was greatest in strains with elevated Cytochrome P450 activity. Synergism of oxidative stress defence enzymes by dietary supplementation with haematin, 3-Amino-1, 2, 4-triazole and Sodium diethyldithiocarbamate significantly increased pyrethroid-induced mortality in An. arabiensis and An. funestus. It is therefore concluded that defence against oxidative stress underlies the augmentation of the insecticide resistance phenotype associated with multiple blood-feeding. This is because multiple blood-feeding ultimately leads to a reduction of oxidative stress in insecticide resistant females, and also reduces the oxidative burden induced by DDT and pyrethroids, by inducing increased glutathione peroxidase activity. This study highlights the importance of oxidative stress in the longevity and

  8. Larvicidal potential of carvacrol and terpinen-4-ol from the essential oil of Origanum vulgare (Lamiaceae) against Anopheles stephensi, Anopheles subpictus, Culex quinquefasciatus and Culex tritaeniorhynchus (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, Marimuthu; Rajeswary, Mohan; Hoti, S L; Benelli, Giovanni

    2016-02-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. However, the use of synthetic insecticides to control Culicidae may lead to resistance, high operational costs and adverse non-target effects. Nowadays, plant-borne mosquitocides may serve as suitable alternative in the fight against mosquito vectors. In this study, the mosquito larvicidal activity of Origanum vulgare (Lamiaceae) leaf essential oil (EO) and its major chemical constituents was evaluated against the malaria vectors Anopheles stephensi and An. subpictus, the filariasis vector Culex quinquefasciatus and the Japanese encephalitis vector Cx. tritaeniorhynchus. The chemical composition of the EO was analyzed by gas chromatography-mass spectroscopy. GC-MS revealed that the essential oil of O. vulgare contained 17 compounds. The major chemical components were carvacrol (38.30%) and terpinen-4-ol (28.70%). EO had a significant toxic effect against early third-stage larvae of An. stephensi, An. subpictus, Cx. quinquefasciatus and Cx. tritaeniorhynchus, with LC50 values of 67.00, 74.14, 80.35 and 84.93 μg/ml. The two major constituents extracted from the O. vulgare EO were tested individually for acute toxicity against larvae of the four mosquito vectors. Carvacrol and terpinen-4-ol appeared to be most effective against An. stephensi (LC50=21.15 and 43.27 μg/ml, respectively) followed by An. subpictus (LC50=24.06 and 47.73 μg/ml), Cx. quinquefasciatus (LC50=26.08 and 52.19 μg/ml) and Cx. tritaeniorhynchus (LC50=27.95 and 54.87 μg/ml). Overall, this research adds knowledge to develop newer and safer natural larvicides against malaria, filariasis and Japanese encephalitis mosquito vectors. PMID:26850541

  9. Characterization of the Rel2-regulated transcriptome and proteome of Anopheles stephensi identifies new anti-Plasmodium factors.

    Science.gov (United States)

    Pike, Andrew; Vadlamani, Alekhya; Sandiford, Simone L; Gacita, Anthony; Dimopoulos, George

    2014-09-01

    Mosquitoes possess an innate immune system that is capable of limiting infection by a variety of pathogens, including the Plasmodium spp. parasites responsible for human malaria. The Anopheles immune deficiency (IMD) innate immune signaling pathway confers resistance to Plasmodium falciparum. While some previously identified Anopheles anti-Plasmodium effectors are regulated through signaling by Rel2, the transcription factor of the IMD pathway, many components of this defense system remain uncharacterized. To begin to better understand the regulation of immune effector proteins by the IMD pathway, we used oligonucleotide microarrays and iTRAQ to analyze differences in mRNA and protein expression, respectively, between transgenic Anopheles stephensi mosquitoes exhibiting blood meal-inducible overexpression of an active recombinant Rel2 and their wild-type conspecifics. Numerous genes were differentially regulated at both the mRNA and protein levels following induction of Rel2. While multiple immune genes were up-regulated, a majority of the differentially expressed genes have no known immune function in mosquitoes. Selected up-regulated genes from multiple functional categories were tested for both anti-Plasmodium and anti-bacterial action using RNA interference (RNAi). Based on our experimental findings, we conclude that increased expression of the IMD immune pathway-controlled transcription factor Rel2 affects the expression of numerous genes with diverse functions, suggesting a broader physiological impact of immune activation and possible functional versatility of Rel2. Our study has also identified multiple novel genes implicated in anti-Plasmodium defense. PMID:24998399

  10. Life-table analysis of Anopheles malaria vectors: generational mortality as tool in mosquito vector abundance and control studies

    Directory of Open Access Journals (Sweden)

    Godwin Ray Anugboba Okogun

    2005-06-01

    Full Text Available Background & objectives: Vector control will for sometime remain a primary weapon in the waragainst vector borne diseases. Malaria is of paramount importance in this with its associated highmorbidity and mortality especially in sub-Saharan Africa. This study on generational mortality associatedfactors in Anopheles mosquitoes life-table analysis was designed to investigate the fecundity,levels of mortality and mortality associated factors at the aquatic stages of anopheline malaria vectors.Methods: Mortality associated factors were investigated at the eggs, I and II instar larval, III and IVinstar larval and pupal stages of two anopheline species— Anopheles pseudopunctipennis (Theobaldand An. gambiae life-cycles in screen cages. Adult male and female mosquitoes were membrane filterfedand algae in culture medium formed the bulk of food substances for the larval stage. Environmentaltemperature of culture media, pH and some associated physio-chemical factors were also determined.Results: Results showed significant mortality rates at various aquatic stages. Infertility, cannibalismand environmental factors were the major factors responsible for mortality at the egg, larval and pupalstages respectively.Interpretation & conclusion: The aquatic stages of Anopheles mosquito mortality factor K and themortality factors at the various stages investigated k1, k2, k3 and k4 are discussed. Our recommendationsinclude further studies on the possible genetic modification of predacious An. pseudopunctipennislarvae and/or its modification for the production of sterile/infertile eggs as possible alternativesin the reduction and control of anopheline malaria burden.

  11. Unexpected diversity of Anopheles species in Eastern Zambia: implications for evaluating vector behavior and interventions using molecular tools.

    Science.gov (United States)

    Lobo, Neil F; St Laurent, Brandyce; Sikaala, Chadwick H; Hamainza, Busiku; Chanda, Javan; Chinula, Dingani; Krishnankutty, Sindhu M; Mueller, Jonathan D; Deason, Nicholas A; Hoang, Quynh T; Boldt, Heather L; Thumloup, Julie; Stevenson, Jennifer; Seyoum, Aklilu; Collins, Frank H

    2015-12-09

    The understanding of malaria vector species in association with their bionomic traits is vital for targeting malaria interventions and measuring effectiveness. Many entomological studies rely on morphological identification of mosquitoes, limiting recognition to visually distinct species/species groups. Anopheles species assignments based on ribosomal DNA ITS2 and mitochondrial DNA COI were compared to morphological identifications from Luangwa and Nyimba districts in Zambia. The comparison of morphological and molecular identifications determined that interpretations of species compositions, insecticide resistance assays, host preference studies, trap efficacy, and Plasmodium infections were incorrect when using morphological identification alone. Morphological identifications recognized eight Anopheles species while 18 distinct sequence groups or species were identified from molecular analyses. Of these 18, seven could not be identified through comparison to published sequences. Twelve of 18 molecularly identified species (including unidentifiable species and species not thought to be vectors) were found by PCR to carry Plasmodium sporozoites - compared to four of eight morphological species. Up to 15% of morphologically identified Anopheles funestus mosquitoes in insecticide resistance tests were found to be other species molecularly. The comprehension of primary and secondary malaria vectors and bionomic characteristics that impact malaria transmission and intervention effectiveness are fundamental in achieving malaria elimination.

  12. Physiological correlates of ecological divergence along an urbanization gradient: differential tolerance to ammonia among molecular forms of the malaria mosquito Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    Tene Fossog Billy

    2013-01-01

    Full Text Available Abstract Background Limitations in the ability of organisms to tolerate environmental stressors affect their fundamental ecological niche and constrain their distribution to specific habitats. Evolution of tolerance, therefore, can engender ecological niche dynamics. Forest populations of the afro-tropical malaria mosquito Anopheles gambiae have been shown to adapt to historically unsuitable larval habitats polluted with decaying organic matter that are found in densely populated urban agglomerates of Cameroon. This process has resulted in niche expansion from rural to urban environments that is associated with cryptic speciation and ecological divergence of two evolutionarily significant units within this taxon, the molecular forms M and S, among which reproductive isolation is significant but still incomplete. Habitat segregation between the two forms results in a mosaic distribution of clinally parapatric patches, with the M form predominating in the centre of urban agglomerates and the S form in the surrounding rural localities. We hypothesized that development of tolerance to nitrogenous pollutants derived from the decomposition of organic matter, among which ammonia is the most toxic to aquatic organisms, may affect this pattern of distribution and process of niche expansion by the M form. Results Acute toxicity bioassays indicated that populations of the two molecular forms occurring at the extremes of an urbanization gradient in Yaounde, the capital of Cameroon, differed in their response to ammonia. The regression lines best describing the dose-mortality profile differed in the scale of the explanatory variable (ammonia concentration log-transformed for the S form and linear for the M form, and in slope (steeper for the S form and shallower for the M form. These features reflected differences in the frequency distribution of individual tolerance thresholds in the two populations as assessed by probit analysis, with the M form exhibiting

  13. A new mtDNA COI gene lineage closely related to Anopheles janconnae of the Albitarsis complex in the Caribbean region of Colombia

    Directory of Open Access Journals (Sweden)

    Lina A Gutiérrez

    2010-12-01

    Full Text Available An understanding of the taxonomic status and vector distribution of anophelines is crucial in controlling malaria. Previous phylogenetic analyses have supported the description of six species of the Neotropical malaria vector Anopheles (Nyssorhynchus albitarsis s.l. (Diptera: Culicidae: An. albitarsis, Anopheles deaneorum, Anopheles marajoara, Anopheles oryzalimnetes, Anopheles janconnae and An. albitarsis F. To evaluate the taxonomic status of An. albitarsis s.l. mosquitoes collected in various localities in the Colombian Caribbean region, specimens were analyzed using the complete mitochondrial DNA cytochrome oxidase I (COI gene, the ribosomal DNA (rDNA internal transcribed spacer 2 (ITS2 region and partial nuclear DNA white gene sequences. Phylogenetic analyses of the COI gene sequences detected a new lineage closely related to An. janconnae in the Caribbean region of Colombia and determined its position relative to the other members of the complex. However, the ITS2 and white gene sequences lacked sufficient resolution to support a new lineage closely related to An. janconnae or the An. janconnae clade. The possible involvement of this new lineage in malaria transmission in Colombia remains unknown, but its phylogenetic closeness to An. janconnae, which has been implicated in local malaria transmission in Brazil, is intriguing.

  14. Anopheles culicifacies breeding in brackish waters in Sri Lanka and implications for malaria control

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    Surendran Sinnathamby N

    2010-04-01

    Full Text Available Abstract Background Anopheles culicifacies is the major vector of both falciparum and vivax malaria in Sri Lanka, while Anopheles subpictus and certain other species function as secondary vectors. In Sri Lanka, An. culicifacies is present as a species complex consisting of species B and E, while An. subpictus exists as a complex of species A-D. The freshwater breeding habit of An. culicifacies is well established. In order to further characterize the breeding sites of the major malaria vectors in Sri Lanka, a limited larval survey was carried out at a site in the Eastern province that was affected by the 2004 Asian tsunami. Methods Anopheline larvae were collected fortnightly for six months from a brackish water body near Batticaloa town using dippers. Collected larvae were reared in the laboratory and the emerged adults were identified using standard keys. Sibling species status was established based on Y-chromosome morphology for An. culicifacies larvae and morphometric characteristics for An. subpictus larvae and adults. Salinity, dissolved oxygen and pH were determined at the larval collection site. Results During a six month study covering dry and wet seasons, a total of 935 anopheline larvae were collected from this site that had salinity levels up to 4 parts per thousand at different times. Among the emerged adult mosquitoes, 661 were identified as An. culicifacies s.l. and 58 as An. subpictus s.l. Metaphase karyotyping of male larvae showed the presence of species E of the Culicifacies complex, and adult morphometric analysis the presence of species B of the Subpictus complex. Both species were able to breed in water with salinity levels up to 4 ppt. Conclusions The study demonstrates the ability of An. culicifacies species E, the major vector of falciparum and vivax malaria in Sri Lanka, to oviposit and breed in brackish water. The sibling species B in the An. subpictus complex, a well-known salt water breeder and a secondary malaria

  15. Analysis of two novel midgut-specific promoters driving transgene expression in Anopheles stephensi mosquitoes.

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    Tony Nolan

    Full Text Available BACKGROUND: Tissue-specific promoters controlling the expression of transgenes in Anopheles mosquitoes represent a valuable tool both for studying the interaction between these malaria vectors and the Plasmodium parasites they transmit and for novel malaria control strategies based on developing Plasmodium-refractory mosquitoes by expressing anti-parasitic genes. With this aim we have studied the promoter regions of two genes from the most important malaria vector, Anopheles gambiae, whose expression is strongly induced upon blood feeding. RESULTS: We analysed the A. gambiae Antryp1 and G12 genes, which we have shown to be midgut-specific and maximally expressed at 24 hours post-bloodmeal (PBM. Antryp1, required for bloodmeal digestion, encodes one member of a family of 7 trypsin genes. The G12 gene, of unknown function, was previously identified in our laboratory in a screen for genes induced in response to a bloodmeal. We fused 1.1 kb of the upstream regions containing the putative promoter of these genes to reporter genes and transformed these into the Indian malaria vector A. stephensi to see if we could recapitulate the expression pattern of the endogenous genes. Both the Antryp1 and G12 upstream regions were able to drive female-predominant, midgut-specific expression in transgenic mosquitoes. Expression of the Antryp1-driven reporter in transgenic A. stephensi lines was low, undetectable by northern blot analysis, and failed to fully match the induction kinetics of the endogenous Antryp1 gene in A. gambiae. This incomplete conservation of expression suggests either subtle differences in the transcriptional machinery between A. stephensi and A. gambiae or that the upstream region chosen lacked all the control elements. In contrast, the G12 upstream region was able to faithfully reproduce the expression profile of the endogenous A. gambiae gene, showing female midgut specificity in the adult mosquito and massive induction PBM, peaking at 24

  16. Effect of discriminative plant-sugar feeding on the survival and fecundity of Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    Jackson Robert R

    2007-08-01

    Full Text Available Abstract Background A previous study showed for Anopheles gambiae s.s. a gradation of feeding preference on common plant species growing in a malaria holoendemic area in western Kenya. The present follow-up study determines whether there is a relationship between the mosquito's preferences and its survival and fecundity. Methods Groups of mosquitoes were separately given ad libitum opportunity to feed on five of the more preferred plant species (Hamelia patens, Parthenium hysterophorus, Ricinus communis, Senna didymobotrya, and Tecoma stans and one of the less preferred species (Lantana camara. The mosquitoes were monitored daily for survival. Sugar solution (glucose 6% and water were used as controls. In addition, the fecundity of mosquitoes on each plant after (i only one blood meal (number of eggs oviposited, and (ii after three consecutive blood meals (proportion of females ovipositing, number of eggs oviposited and hatchability of eggs, was determined. The composition and concentration of sugar in the fed-on parts of each plant species were determined using gas chromatography. Using SAS statistical package, tests for significant difference of the fitness values between mosquitoes exposed to different plant species were conducted. Results and Conclusion Anopheles gambiae that had fed on four of the five more preferred plant species (T. stans, S. didymobotrya, R. communis and H. patens, but not P. hysterophorus lived longer and laid more eggs after one blood meal, when compared with An. gambiae that had fed on the least preferred plant species L. camara. When given three consecutive blood-meals, the percentage of females that oviposited, but not the number of eggs laid, was significantly higher for mosquitoes that had previously fed on the four more preferred plant species. Total sugar concentration in the preferred plant parts was significantly correlated with survival and with the proportion of females that laid eggs. This effect was

  17. The role of cow urine in the oviposition site preference of culicine and Anopheles mosquitoes

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    Kweka Eliningaya J

    2011-09-01

    Full Text Available Abstract Background Chemical and behavioural ecology of mosquitoes plays an important role in the development of chemical cue based vector control. To date, studies available have focused on evaluating mosquito attractants and repellents of synthetic and human origins. This study, however, was aimed at seasonal evaluation of the efficiency of cow urine in producing oviposition cues to Anopheles gambiae s.l. and Culex quinquefasciatus in both laboratory and field conditions. Methods Oviposition response evaluation in laboratory conditions was carried out in mosquito rearing cages. The oviposition substrates were located in parallel or in diagonal positions inside the cage. Urine evaluation against gravid females of An. arabiensis and Cx. quinquefasciatus was carried out at Day 1, Day 3 and Day 7. Five millilitres (mls of cow urine was added to oviposition substrate while de-chlorinated water was used as a control. In field experiments, 500 mls of cow urine was added in artificial habitats with 2500 mls of de-chlorinated water and 2 kgs of soil. The experiment was monitored for thirty consecutive days, eggs were collected daily from the habitats at 7.00 hrs. Data analysis was performed using parametric and non-parametric tests for treatments and controls while attraction of the oviposition substrate in each species was presented using Oviposition Activity Index (OAI. Results The OAI was positive with ageing of cattle urine in culicine species in both laboratory and field experiments. The OAI for anopheline species was positive with fresh urine. The OAI during the rainy season was positive for all species tested while in the dry season the OAI for culicine spp and Anopheles gambiae s.l., changed with time from positive to negative values. Based on linear model analysis, seasons and treatments had a significant effect on the number of eggs laid in habitats, even though the number of days had no effect. Conclusion Oviposition substrates treated with

  18. Three years of insecticide resistance monitoring in Anopheles gambiae in Burkina Faso: resistance on the rise?

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    Badolo Athanase

    2012-07-01

    Full Text Available Abstract Background and methods A longitudinal Anopheles gambiae s.l. insecticide-resistance monitoring programme was established in four sentinel sites in Burkina Faso. For three years, between 2008 and 2010, WHO diagnostic dose assays were used to measure the prevalence of resistance to all the major classes of insecticides at the beginning and end of the malaria transmission season. Species identification and genotyping for target site mutations was also performed and the sporozoite rate in adults determined. Results At the onset of the study, resistance to DDT and pyrethroids was already prevalent in An. gambiae s.l. from the south-west of the country but mosquitoes from the two sites in central Burkina Faso were largely susceptible. Within three years, DDT and permethrin resistance was established in all four sites. Carbamate and organophosphate resistance remains relatively rare and largely confined to the south-western areas although a small number of bendiocarb survivors were found in all sites by the final round of monitoring. The ace-1R target site resistance allele was present in all localities and its frequency exceeded 20% in 2010 in two of the sites. The frequency of the 1014F kdr mutation increased throughout the three years and by 2010, the frequency of 1014F in all sites combined was 0.02 in Anopheles arabiensis, 0.56 in An. gambiae M form and 0.96 in An. gambiae S form. This frequency did not differ significantly between the sites. The 1014S kdr allele was only found in An. arabiensis but its frequency increased significantly throughout the study (P = 0.0003 and in 2010 the 1014S allele frequency was 0.08 in An. arabiensis. Maximum sporozoite rates (12% were observed in Soumousso in 2009 and the difference between sites is significant for each year. Conclusion Pyrethroid and DDT resistance is now established in An. gambiae s.l. throughout Burkina Faso. Results from diagnostic dose assays are highly variable within and

  19. Spatial and temporal distribution of the malaria mosquito Anopheles arabiensis in northern Sudan: influence of environmental factors and implications for vector control

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    Malcolm Colin A

    2009-06-01

    Full Text Available Abstract Background Malaria is an important public health problem in northern Sudan, but little is known about the dynamics of its transmission. Given the characteristic low densities of Anopheles arabiensis and the difficult terrain in this area, future vector control strategies are likely to be based on area-wide integrated pest management (AW-IPM that may include the sterile insect technique (SIT. To support the planning and implementation of future AW-IPM activities, larval surveys were carried out to provide key data on spatial and seasonal dynamics of local vector populations. Methods Monthly cross-sectional larval surveys were carried out between March 2005 and May 2007 in two localities (Dongola and Merowe adjacent to the river Nile. A stratified random sampling strategy based on the use of Remote Sensing (RS, Geographical Information Systems (GIS and the Global Positioning System (GPS was used to select survey locations. Breeding sites were mapped using GPS and data on larval density and breeding site characteristics were recorded using handheld computers. Bivariate and multivariate logistic regression models were used to identify breeding site characteristics associated with increased risk of presence of larvae. Seasonal patterns in the proportion of breeding sites positive for larvae were compared visually to contemporaneous data on climate and river height. Results Of a total of 3,349 aquatic habitats sampled, 321 (9.6% contained An. arabiensis larvae. The frequency with which larvae were found varied markedly by habitat type. Although most positive sites were associated with temporary standing water around the margins of the main Nile channel, larvae were also found at brickworks and in areas of leaking pipes and canals – often far from the river. Close to the Nile channel, a distinct seasonal pattern in larval populations was evident and appeared to be linked to the rise and fall of the river level. These patterns were not

  20. Biting behaviour of Anopheles funestus populations in Mutare and Mutasa districts, Manicaland province, Zimbabwe: Implications for the malaria control programme

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    Shadreck Sande

    2016-01-01

    Interpretation & conclusion: The present work highlighted important information on the host-seeking behaviour, blood meal sources and infection rates in An. funestus. The information would be helpful in improving the vector control strategies.

  1. Historical applications of induced sterilisation in field populations of mosquitoes

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    Knols Bart GJ

    2009-11-01

    Full Text Available Abstract Research on sterile mosquito technology from 1955 to the 1980s provided a substantial body of knowledge on propagation and release of sterile mosquitoes. Radiation sterilisation and chemosterilisation have been used effectively to induce dominant lethality and thereby sterilise important mosquito vectors in the laboratory. Experimental releases of chemosterilised males provided complete control of Anopheles albimanus in a small breeding population (14-15 sq km in El Salvador. Releases of radiation sterilised males failed to control either Aedes aegypti or Anopheles quadrimaculatus in the USA. Releases of radiation-sterilised and chemosterilised male Culex quinquefasciatus in the USA and India were successful in some instances. Development of genetic sexing systems for Anopheles and improved physical separation methods for Culex have made it possible to rear and release males almost exclusively (> 99% minimizing the release of potential vectors, the females. Factors that affected efficacy in some field programmes included reduction of competitiveness by radiation, immigration of fertilized females from outside the release zones, and inability of laboratory-bred males to perform in the wild. Despite significant progress, institutional commitments to carry the process further were generally lacking in the late 1970s and until recently. Now, with renewed interest and support for further assessment of this technology, this paper summarizes the current knowledge base, prioritizes some areas of investigation, and challenges scientists and administrators to maintain an awareness of progress, remain realistic about the interpretation of new findings, and make decisions about the sterile insect technique on the basis of informed scientific documentation. Areas recommended for priority research status include the establishment of genetic sexing mechanisms that can be transferred to other mosquito species, re-examination of radiation sterilisation

  2. Signatures of aestivation and migration in Sahelian malaria mosquito populations.

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    Dao, A; Yaro, A S; Diallo, M; Timbiné, S; Huestis, D L; Kassogué, Y; Traoré, A I; Sanogo, Z L; Samaké, D; Lehmann, T

    2014-12-18

    During the long Sahelian dry season, mosquito vectors of malaria are expected to perish when no larval sites are available; yet, days after the first rains, mosquitoes reappear in large numbers. How these vectors persist over the 3-6-month long dry season has not been resolved, despite extensive research for over a century. Hypotheses for vector persistence include dry-season diapause (aestivation) and long-distance migration (LDM); both are facets of vector biology that have been highly controversial owing to lack of concrete evidence. Here we show that certain species persist by a form of aestivation, while others engage in LDM. Using time-series analyses, the seasonal cycles of Anopheles coluzzii, Anopheles gambiae sensu stricto (s.s.), and Anopheles arabiensis were estimated, and their effects were found to be significant, stable and highly species-specific. Contrary to all expectations, the most complex dynamics occurred during the dry season, when the density of A. coluzzii fluctuated markedly, peaking when migration would seem highly unlikely, whereas A. gambiae s.s. was undetected. The population growth of A. coluzzii followed the first rains closely, consistent with aestivation, whereas the growth phase of both A. gambiae s.s. and A. arabiensis lagged by two months. Such a delay is incompatible with local persistence, but fits LDM. Surviving the long dry season in situ allows A. coluzzii to predominate and form the primary force of malaria transmission. Our results reveal profound ecological divergence between A. coluzzii and A. gambiae s.s., whose standing as distinct species has been challenged, and suggest that climate is one of the selective pressures that led to their speciation. Incorporating vector dormancy and LDM is key to predicting shifts in the range of malaria due to global climate change, and to the elimination of malaria from Africa. PMID:25470038

  3. Comprehensive genetic dissection of the hemocyte immune response in the malaria mosquito Anopheles gambiae.

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    Fabrizio Lombardo

    2013-01-01

    Full Text Available Reverse genetics in the mosquito Anopheles gambiae by RNAi mediated gene silencing has led in recent years to an advanced understanding of the mosquito immune response against infections with bacteria and malaria parasites. We developed RNAi screens in An. gambiae hemocyte-like cells using a library of double-stranded RNAs targeting 109 genes expressed highly or specifically in mosquito hemocytes to identify novel regulators of the hemocyte immune response. Assays included phagocytosis of bacterial bioparticles, expression of the antimicrobial peptide CEC1, and basal and induced expression of the mosquito complement factor LRIM1. A cell viability screen was also carried out to assess dsRNA cytotoxicity and to identify genes involved in cell growth and survival. Our results identify 22 novel immune regulators, including proteins putatively involved in phagosome assembly and maturation (Ca²⁺ channel, v-ATPase and cyclin-dependent protein kinase, pattern recognition (fibrinogen-domain lectins and Nimrod, immune modulation (peptidase and serine protease homolog, immune signaling (Eiger and LPS-induced factor, cell adhesion and communication (Laminin B1 and Ninjurin and immune homeostasis (Lipophorin receptor. The development of robust functional cell-based assays paves the way for genome-wide functional screens to study the mosquito immune response to infections with human pathogens.

  4. Preferencias alimenticias del Anopheles pseudopunctipennis y A. triannulatus en el Perú

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    Manuel Acosta

    1960-01-01

    Full Text Available Mediante la prueba serológica de las pricipitinas, entre agosto y noviembre, 1958, se ha tratado de determinar las preferencias alimenticias del Anopheles pseudopunctipennis y del A. triannulatus en varias localidades peruanas, con los siguientes resultados: 1. En una serie, con insectos procedentes de dos regiones geográficas diferentes y usando sueros inmunes correspondientes a la especie humana y a varios animales inferiores, se obtuvo: a que el A. pseudopunctipennis no presenta comportamiento uniforme en cuanto a su alimentación en el hombre; y b que los animales inferiores sobre los que se alimenta con mayor frecuencia son la vaca y el perro. 2. En otra serie, en la que se usó tan sólo el suero anti-hombre, se verificó que el A. pseudopunctipennis había ingerido sangre humana entre el 87.3 y 100.0 por ciento. 3. En 0.5 por ciento de 977 especímenes del A. triannulatus se puso de manifiesto la presencia de sangre humana. 4. Se discute las circunstancias que condicionarían la preferencia que los insectos estudiados suelen mostrar en cuanto a sus huéspedes.

  5. Molecular taxonomy of Anopheles (Nyssorhynchus) benarrochi (Diptera: Culicidae) and malaria epidemiology in southern Amazonian Peru.

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    Conn, Jan E; Moreno, Marta; Saavedra, Marlon; Bickersmith, Sara A; Knoll, Elisabeth; Fernandez, Roberto; Vera, Hubert; Burrus, Roxanne G; Lescano, Andres G; Sanchez, Juan Francisco; Rivera, Esteban; Vinetz, Joseph M

    2013-02-01

    Anopheline specimens were collected in 2011 by human landing catch, Shannon and CDC traps from the malaria endemic localities of Santa Rosa and San Pedro in Madre de Dios Department, Peru. Most specimens were either Anopheles (Nyssorhynchus) benarrochi B or An. (Nys.) rangeli, confirmed by polymerase chain reaction-restriction fragment length polymorphism-internal transcribed spacer 2 (PCR-RFLP-ITS2) and, for selected individuals, ITS2 sequences. A few specimens from Lupuna, Loreto Department, northern Amazonian Peru, were also identified as An. benarrochi B. A statistical parsimony network using ITS2 sequences confirmed that all Peruvian An. benarrochi B analyzed were identical to those in GenBank from Putumayo, southern Colombia. Sequences of the mtDNA COI BOLD region of specimens from all three Peruvian localities were connected using a statistical parsimony network, although there were multiple mutation steps between northern and southern Peruvian sequences. A Bayesian inference of concatenated Peruvian sequences of ITS2 + COI detected a single clade with very high support for all An. benarrochi B except one individual from Lupuna that was excluded. No samples were positive for Plasmodium by CytB-PCR.

  6. The role of proboscis of the malaria vector mosquito Anopheles stephensi in host-seeking behavior

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    Yoshimura Aya

    2011-01-01

    Full Text Available Abstract Background The proboscis is an essential head appendage in insects that processes gustatory code during food intake, particularly useful considering that blood-sucking arthropods routinely reach vessels under the host skin using this proboscis as a probe. Results Here, using an automated device able to quantify CO2-activated thermo (35°C-sensing behavior of the malaria vector Anopheles stephensi, we uncovered that the protruding proboscis of mosquitoes contributes unexpectedly to host identification from a distance. Ablation experiments indicated that not only antennae and maxillary palps, but also proboscis were required for the identification of pseudo-thermo targets. Furthermore, the function of the proboscis during this behavior can be segregated from CO2 detection required to evoke mosquito activation, suggesting that the proboscis of mosquitoes divide the proboscis into a "thermo-antenna" in addition to a "thermo-probe". Conclusions Our findings support an emerging view with a possible role of proboscis as important equipment during host-seeking, and give us an insight into how these appendages likely evolved from a common origin in order to function as antenna organs.

  7. Partial genomic organization of ribosomal protein S7 gene from malaria vector Anopheles stephensi

    Institute of Scientific and Technical Information of China (English)

    RAJNIKANT DIXIT; SARITA DIXIT; UPAL ROY; YOGESH S.SHOUCHE; SURENDRA GAKHAR

    2007-01-01

    In this study, we describe the partial genomic organization of ribosomal protein S7 gene isolated from the mosquito Anopheles stephensi. Initially a 558 bp partial cDNA sequence was amplified as precursor mRNA sequence containing 223 bp long intron. 5' and 3' end sequences were recovered using end specific rapid amplification of cDNA ends (RACE) polymerase chain reaction. The full-length cDNA sequence was 914 nucleotide long with an open reading frame capable of encoding 192 amino acid long protein with calculated molecular mass of 22174 Da and a pI point of 9.94. Protein homology search revealed >75% identity to other insect's S7 ribosomal proteins. Analysis of sequence alignment revealed several highly conserved domains, one of which is related to nuclear localization signal (NLS) region of human rpS7. Interestingly, intron nucleotide sequence comparison with A. gambiae showed a lesser degree of conservation as compared to coding and untranslated regions. Like this, early studies on the genomic organization and cDNA/Expressed sequence tag analysis (EST) could help in genome annotation ofA. stephensi, and would be likely to be sequenced in the future.

  8. The spatial distribution of Anopheles gambiae sensu stricto and An. arabiensis (Diptera: Culicidae in Mali

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    N. Sogoba

    2007-05-01

    Full Text Available Variations in the biology and ecology and the high level of genetic polymorphism of malaria vectors in Africa highlight the value of mapping their spatial distribution to enhance successful implementation of integrated vector management. The objective of this study was to collate data on the relative frequencies of Anopheles gambiae s.s. and An. arabiensis mosquitoes in Mali, to assess their association with climate and environmental covariates, and to produce maps of their spatial distribution. Bayesian geostatistical logistic regression models were fitted to identify environmental determinants of the relative frequencies of An. gambiae s.s. and An. arabiensis species and to produce smooth maps of their geographical distribution. The frequency of An. arabiensis was positively associated with the normalized difference vegetation index, the soil water storage index, the maximum temperature and the distance to water bodies. It was negatively associated with the minimum temperature and rainfall. The predicted map suggests that, in West Africa, An. arabiensis is concentrated in the drier savannah areas, while An. gambiae s.s. prefers the southern savannah and land along the rivers, particularly the inner delta of Niger. Because the insecticide knockdown resistance (kdr gene is reported only in An. gambiae s.s. in Mali, the maps provide valuable information for vector control. They may also be useful for planning future implementation of malaria control by genetically manipulated mosquitoes.

  9. Larvicidal effects of a neem (Azadirachta indica oil formulation on the malaria vector Anopheles gambiae

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    Knols Bart GJ

    2007-05-01

    Full Text Available Abstract Background Larviciding is a key strategy used in many vector control programmes around the world. Costs could be reduced if larvicides could be manufactured locally. The potential of natural products as larvicides against the main African malaria vector, Anopheles gambiae s.s was evaluated. Methods To assess the larvicidal efficacy of a neem (Azadirachta indica oil formulation (azadirachtin content of 0.03% w/v on An. gambiae s.s., larvae were exposed as third and fourth instars to a normal diet supplemented with the neem oil formulations in different concentrations. A control group of larvae was exposed to a corn oil formulation in similar concentrations. Results Neem oil had an LC50 value of 11 ppm after 8 days, which was nearly five times more toxic than the corn oil formulation. Adult emergence was inhibited by 50% at a concentration of 6 ppm. Significant reductions on growth indices and pupation, besides prolonged larval periods, were observed at neem oil concentrations above 8 ppm. The corn oil formulation, in contrast, produced no growth disruption within the tested range of concentrations. Conclusion Neem oil has good larvicidal properties for An. gambiae s.s. and suppresses successful adult emergence at very low concentrations. Considering the wide distribution and availability of this tree and its products along the East African coast, this may prove a readily available and cheap alternative to conventional larvicides.

  10. Mosquito repellent potential of Pithecellobium dulce leaf and seed against malaria vector Anopheles stephensi (Diptera: Culicidae

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    Mohan Rajeswary

    2016-03-01

    Full Text Available Objective: To determine the repellent properties of hexane, benzene, ethyl acetate, chloroform and methanol extract of Pithecellobium dulce (P. dulce leaf and seed against Anopheles stephensi (An. stephensi. Methods: Repellent activity assay was carried out in a net cage (45 cm × 30 cm × 25 cm containing 100 blood starved female mosquitoes of An. stephensi. This assay was carried out in the laboratory conditions according to the WHO 2009 protocol. Plant crude extracts of P. dulce were applied at 1.0, 2.5, and 5.0 mg/cm2 separately in the exposed fore arm of study subjects. Ethanol was used as the sole control. Results: In this study, the applied plant crude extracts were observed to protect against mosquito bites. There were no allergic reactions experienced by the study subjects. The repellent activity of the extract was dependent on the concentration of the extract. Among the tested solvents, the leaf and seed methanol extract showed the maximum efficacy. The highest concentration of 5.0 mg/cm2 leaf and seed methanol extract of P. dulce provided over 180 min and 150 min protection, respectively. Conclusions: Crude extracts of P. dulce exhibit the potential for controlling malaria vector mosquito An. stephensi.

  11. Some ecological attributes of malarial vector Anopheles superpictus Grassi in endemic foci in southeastern Iran

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    Jalil Nejati; Hasan Vatandoost; Mohammad Ali Oshghi; Masud Salehi; Ehssan Mozafari; Seyed Hasan Moosa-Kazemi

    2013-01-01

    Objective:To determine the bionomics and susceptibility status of the malarial vector Anopheles superpictus (An. superpictus) to different insecticides in the Sistan-Baluchestan province which has the highest malarial prevalence in Iran. Methods:Different sampling methods, in addition to scoring abdominal conditions, were used to define the seasonal activity and endo/exophilic behavior of this species. In addition, the standard WHO susceptibility tests were applied on adult field strains. Results: Most adult mosquitoes were collected from outdoor shelters. The peak of seasonal activity of An. superpictus occurred at the end of autumn. Most larvae were collected from natural and permanent breeding places with full sunlight and no vegetation. Blood feeding activities occurred around midnight. Compared with the abdominal conditions of adult mosquitoes collected indoors, the abdominal conditions of adult mosquitoes collected outdoors were gravid and semigravid. This species was suspected to be resistant to DDT, but was susceptible to other insecticides. Conclusions:An. superpictus was present in almost all outdoor shelters, and the ratios of gravid, semigravid/unfed, and freshly fed confirmed that this species had a higher tendency to rest outdoors than indoors. This behavior can protect An. superpictus from indoor residual spraying in this malarious area. To the best of our knowledge, this is the first report on the susceptibility status of An. superpictus in Southeastern Iran. We do not suggest the use of DDT for indoor residual spraying in southeast Iran.

  12. [Anopheles cruzii larvae found in bromelias in an urban area on the Brazilian coast].

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    Marques, Gisela R A M; Forattini, Oswaldo Paulo

    2009-04-01

    The occurrence of Anopheles (Kerteszia) cruzii larvae is reported for the first time in bromelias on the ground located in an urban area within the municipality of Ilha Bela, on the northern coast of the State of São Paulo. From March 1998 to July 1999 312 immature forms of An. cruzii were captured, being that 8.6% of them were in bromelias in the urban environment, 40.1% in periurban bromelias and 51.3% in the forest. The average number of bromelias containing An. cruzii was 4.0% of the total investigated. The positive rate in the periurban and forested environments presented similar values. The presence of An. cruzii is probably due to their having been present previously in the forest, together with the frequent presence of these breeding places, food sources and appropriate shelter in the urban area. This set of factors makes it necessary to warn against the possibility of transferring infections from one environment to the other.

  13. Larvicidal effects of endophytic and basidiomycete fungus extracts on Aedes and Anopheles larvae (Diptera, Culicidae

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    Augusto Bucker

    2013-08-01

    Full Text Available Introduction In vitro bioassays were performed to access the larvicidal activity of crude extracts from the endophytic fungus Pestalotiopsis virgulata (Melanconiales, Amphisphaeriaceae and the saprophytic fungus Pycnoporus sanguineus (Basidiomycetes, Polyporaceae against the mosquitoes Aedes aegypti and Anopheles nuneztovari. Methods The extracts were tested at concentrations of 100, 200, 300, 400 and 500ppm. Ethyl acetate mycelia (EAM extracts and liquid culture media (LCM from Pe. virgulata and Py. sanguineus were tested against third instar larvae of Ae. aegypti and An. nuneztovari. Results The larvicidal activity of the EAM extracts from Pe. virgulata against Ae. aegypti had an LC50=101.8ppm, and the extract from the basidiomycete fungus Py. sanguineus had an LC50=156.8ppm against the Ae. aegypti larvae. The Pe. virgulata extract had an LC50=16.3ppm against the An. nuneztovari larvae, and the Py. sanguineus extract had an LC50=87.2ppm against these larvae. Conclusions These results highlight the larvicidal effect of EAM extracts from the endophyte Pe. virgulata against the two larval mosquitoes tested. Thus, Pe. virgulata and Py. sanguineus have the potential for the production of bioactive substances against larvae of these two tropical disease vectors, with An. nuneztovari being more susceptible to these extracts.

  14. Larvicidal potential of essential oils against Musca domestica and Anopheles stephensi.

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    Chauhan, Nitin; Malik, Anushree; Sharma, Satyawati; Dhiman, R C

    2016-06-01

    The larvicidal activity of Mentha piperita, Cymbopogan citratus (lemongrass), Eucalyptus globulus and Citrus sinensis (orange) essential oils and their combinations was evaluated against Musca domestica (housefly) and Anopheles stephensi (mosquitoes) through contact toxicity assay. Among all the tested essential oils/combinations, Me. piperita was found to be the most effective larvicidal agent against Mu. domestica and An. stephensi with LC50 values of 0.66 μl/cm(2) and 44.66 ppm, respectively, after 48 h. The results clearly highlighted that the addition of mentha oil to other oils (1:1 ratio) improved their larvicidal activity. The order of effectiveness of essential oils/combinations indicated that the pattern for An. stephensi follows the trend as mentha > mentha + lemongrass > lemongrass > mentha + eucalyptus > eucalyptus > mentha + orange > orange and for Mu. domestica as mentha > mentha + lemongrass > lemongrass > mentha + orange > orange > mentha + eucalyptus > eucalyptus. The images obtained from scanning electron microscopy (SEM) analysis indicated the toxic effect of Me. piperita as the treated larvae were observed to be dehydrated and deformed. This study demonstrates the effectiveness of tested essential oils/combinations against the larval stages of Mu. domestica and An. stephensi and has the potential for development of botanical formulations.

  15. Larvicidal activity of essential oil and methanol extract of Nepeta menthoides against malaria vector Anopheles stephensi

    Institute of Scientific and Technical Information of China (English)

    Khanavi Mahnaz; Fallah Alireza; Vatandoost Hassan; Sedaghat Mahdi; Abai Mohammad Reza; Hadjiakhoondi Abbas

    2012-01-01

    Objective: To investigate the larvicidal activity of essential oil and methanol extract of theNepeta menthoides (N. menthoides) against main malaria vector, Anopheles stephensi (An. stephensi). Methods: The essential oil of plant was obtained by Clevenger type apparatus and the methanol extract was supplied with Percolation method. Larvicidal activity was tested by WHO method. Twenty five fourth-instar larvae of An. stephensi were used in the larvicidal assay and four replicates were tested for each concentration. Five different concentrations of the oil and extract were tested for calculation of LC50 and LC90 values. Results: The LC50 and LC90 values were determined by probit analysis. LC50 was 69.5 and 234.3 ppm and LC90 was 175.5 and 419.9 ppm for the extract and essential oil respectively. Conclusions: According to the results of this study methanolic extract of plant exhibited more larvicidal activity than essential oil. This could be useful for investigation of new natural larvicidal compounds.

  16. Screening of selected ethnomedicinal plants from South Africa for larvicidal activity against the mosquito Anopheles arabiensis

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    Maharaj Rajendra

    2012-09-01

    Full Text Available Abstract Background This study was initiated to establish whether any South African ethnomedicinal plants (indigenous or exotic, that have been reported to be used traditionally to repel or kill mosquitoes, exhibit effective mosquito larvicidal properties. Methods Extracts of a selection of plant taxa sourced in South Africa were tested for larvicidal properties in an applicable assay. Thirty 3rd instar Anopheles arabiensis larvae were exposed to various extract types (dichloromethane, dichloromethane/methanol (1:1, methanol and purified water of each species investigated. Mortality was evaluated relative to the positive control Temephos (Mostop; Agrivo, an effective emulsifiable concentrate larvicide. Results Preliminary screening of crude extracts revealed substantial variation in toxicity with 24 of the 381 samples displaying 100% larval mortality within the seven day exposure period. Four of the high activity plants were selected and subjected to bioassay guided fractionation. The results of the testing of the fractions generated identified one fraction of the plant, Toddalia asiatica as being very potent against the An. arabiensis larvae. Conclusion The present study has successfully identified a plant with superior larvicidal activity at both the crude and semi pure fractions generated through bio-assay guided fractionation. These results have initiated further research into isolating the active compound and developing a malaria vector control tool.

  17. Larvicidal activity of metabolites from the endophytic Podospora sp. against the malaria vector Anopheles gambiae.

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    Matasyoh, Josphat C; Dittrich, Birger; Schueffler, Anja; Laatsch, Hartmut

    2011-03-01

    In a screening for natural products with mosquito larvicidal activities, the endophytic fungus Podospora sp. isolated from the plant Laggera alata (Asteraceae) was conspicuous. Two xanthones, sterigmatocystin (1) and secosterigmatocystin (2), and an anthraquinone derivative (3) 13-hydroxyversicolorin B were isolated after fermentation on M(2) medium. These compounds were characterised using spectroscopic and X-ray analysis and examined against third instar larvae of Anopheles gambiae. The results demonstrated that compound 1 was the most potent one with LC(50) and LC(90) values of 13.3 and 73.5 ppm, respectively. Over 95% mortality was observed at a concentration 100 ppm after 24 h. These results compared farvorably with the commercial larvicide pylarvex® that showed 100% mortality at the same concentration. Compound 3 was less potent and had an LC(50) of 294.5 ppm and over 95% mortality was achieved at a concentration of 1,000 ppm. Secosterigmatocystin (2) revealed relatively weak activity and therefore LC values were not determined.

  18. Life on the edge: African malaria mosquito (Anopheles gambiae s. l.) larvae are amphibious

    Science.gov (United States)

    Miller, James R.; Huang, Juan; Vulule, John; Walker, Edward D.

    2007-03-01

    Anopheles gambiae s.l. is the main vector of malaria in Sub-Saharan Africa. Here, an estimated 1 million people die every year from this disease. Despite considerable research on An. gambiae that increasingly explores sub-organismal phenomena, important facets of the field biology of this deadly insect are yet being discovered. In the current study, we used simple observational tools to reveal that the habitat of larval An. gambiae is not limited within the boundaries of temporary mud puddles, as has been the accepted generalization. Thus, control tactics aimed at immatures must consider zones larger than puddles per se. In fact, eggs are more likely to be found outside than inside puddles. Eggs can develop and larvae can emerge on mud. Larvae are then capable of three distinct modes of terrestrial displacement (two active and one passive), whereby, they can reach standing water. On mud bearing a film of water, larvae actively displace backwards by sinusoidal undulations shown to be only a slight variation of the swimming motor program. On drying mud, larvae switch to a slower and forward form of active locomotion resembling that of a crawling caterpillar. During rains, small larvae may be passively displaced by flowing rainwater so as to be deposited into puddles. These capabilities for being amphibious, along with very rapid growth and development, help explain how An. gambiae thrives in a highly uncertain and often hostile larval environment.

  19. Chromosomal inversions among insecticide-resistant strains of Anopheles stephensi Liston, a malaria mosquito.

    Science.gov (United States)

    Shetty, N J; Hariprasad, T P N; Sanil, D; Zin, T

    2013-11-01

    Polytene chromosomes were prepared from the ovarian nurse cells of semi-gravid females of ten insecticide-resistant strains of Anopheles stephensi. Altogether, 16 heterozygous paracentric inversions, namely b/+ (11D-16C) in alphamethrin; i/+ (14B-18A) and h/+ (27B-28A) in DDT; j/+ (14A-16B) in chlorpyrifos; k/+ (11D-16B) in cyfluthrin; l/+ (11A-16C) in deltamethrin; m/+ (14B-15C) and e/+ (32A-33B) in bifenthrin; n/+ (12D-14B), f/+ (33A-36A) and g/+ (33C-34A) in propoxur; o/+ (11A-12D), h/+ (37A-37C) and i/+ (31C-32C) in temephos; d/+ (33D-35C) in carbofuran and a/+ (41C-43B) in neem strains, were reported. No inversions were observed in X chromosome so far. The frequency of inversions in different insecticides was found to be highest in the 2R arm, followed by the 3R arm. Such inversions were not reported in the corresponding susceptible strains or in the parental stocks. PMID:23982309

  20. A user-friendly software to easily count Anopheles egg batches

    Directory of Open Access Journals (Sweden)

    Mollahosseini Ali

    2012-06-01

    Full Text Available Abstract Background Studies on malaria vector ecology and development/evaluation of vector control strategies often require measures of mosquito life history traits. Assessing the fecundity of malaria vectors can be carried out by counting eggs laid by Anopheles females. However, manually counting the eggs is time consuming, tedious, and error prone. Methods In this paper we present a newly developed software for high precision automatic egg counting. The software written in the Java programming language proposes a user-friendly interface and a complete online manual. It allows the inspection of results by the operator and includes proper tools for manual corrections. The user can in fact correct any details on the acquired results by a mouse click. Time saving is significant and errors due to loss of concentration are avoided. Results The software was tested over 16 randomly chosen images from 2 different experiments. The results show that the proposed automatic method produces results that are close to the ground truth. Conclusions The proposed approaches demonstrated a very high level of robustness. The adoption of the proposed software package will save many hours of labor to the bench scientist. The software needs no particular configuration and is freely available for download on: http://w3.ualg.pt/∼hshah/eggcounter/.

  1. Suboptimal Larval Habitats Modulate Oviposition of the Malaria Vector Mosquito Anopheles coluzzii.

    Directory of Open Access Journals (Sweden)

    Eunho Suh

    Full Text Available Selection of oviposition sites by gravid females is a critical behavioral step in the reproductive cycle of Anopheles coluzzii, which is one of the principal Afrotropical malaria vector mosquitoes. Several studies suggest this decision is mediated by semiochemicals associated with potential oviposition sites. To better understand the chemosensory basis of this behavior and identify compounds that can modulate oviposition, we examined the generally held hypothesis that suboptimal larval habitats give rise to semiochemicals that negatively influence the oviposition preference of gravid females. Dual-choice bioassays indicated that oviposition sites conditioned in this manner do indeed foster significant and concentration dependent aversive effects on the oviposition site selection of gravid females. Headspace analyses derived from aversive habitats consistently noted the presence of dimethyl disulfide (DMDS, dimethyl trisulfide (DMTS and 6-methyl-5-hepten-2-one (sulcatone each of which unitarily affected An. coluzzii oviposition preference. Electrophysiological assays across the antennae, maxillary palp, and labellum of gravid An. coluzzii revealed differential responses to these semiochemicals. Taken together, these findings validate the hypothesis in question and suggest that suboptimal environments for An. coluzzii larval development results in the release of DMDS, DMTS and sulcatone that impact the response valence of gravid females.

  2. Laser dosimetry for disabling anopheles stephensi mosquitoes in-flight (Conference Presentation)

    Science.gov (United States)

    Keller, Matthew D.; Norton, Bryan J.; Rutschman, Phil; Farrar, David J.; Marvit, Maclen; Makagon, Artyom

    2016-03-01

    The Photonic Fence is a system designed to detect mosquitoes and other pestilent flying insects in an active region and to apply lethal doses of laser light to them. Previously, we determined lethal fluence levels for a variety of lasers and pulse conditions on anesthetized Anopheles stephensi mosquitoes. In this work, similar studies were performed while the bugs were freely flying within transparent cages. Dose-response curves were created for various beam diameter, pulse width, and power conditions at 455 nm, 532 nm, 1064nm, and 1540 nm wavelengths. Besides mortality outcomes, the flight behavior of the bugs and the performance of the tracking system were monitored for consistency and to ensure that they had no impact on the mortality outcomes. As in anesthetized experiments, the visible wavelengths required significantly less fluence than near infrared wavelengths to reliably disable bugs. For the visible wavelengths, lethal fluence values were generally equivalent to those found in anesthetized dosing, while near infrared wavelengths required approximately twice the fluence compared with anesthetized experiments. The performance of the optical tracking system remained highly stable throughout the experiments, and it was found not to influence mortality results for pulse widths up to 25 ms. In general, keeping energy constant while decreasing power and increasing pulse width reduced mortality levels. The results of this study further affirm the practicality of using optical approaches to protect people and crops from flying insects.

  3. Suitability of monotypic and mixed diets for Anopheles hermsi larval development.

    Science.gov (United States)

    Beasley, Donald A; Walton, William E

    2016-06-01

    The developmental time and survival to eclosion of Anopheles hermsi Barr & Guptavanij fed monotypic and mixed diets of ten food types were examined in laboratory studies. Larvae fed monotypic diets containing animal detritus (freeze-dried rotifers, freeze-dried Daphnia pulicaria, and TetraMin® fish food flakes) and the mixotrophic protistan Cryptomonas ovata developed faster and survived better than larvae that were fed other monotypic diets. Survival to adulthood of larvae fed several concentrations of the diatom Planothidium (=Achnanthes) lanceolatum was poor (diet. Larvae fed monotypic diets containing prokaryotes (bacteria [Bacillus cereus] and cyanobacteria [Oscillatoria prolifera]) and brewer's yeast (Saccharomyces cerevisiae) failed to survive beyond the 1(st) and 2(nd) instar, respectively. Larvae fed only chlorophytes, single-celled Chlamydomonas reinhardtii and filamentous Spirogyra communis, failed to complete larval development, regardless of the concentration tested. Cohorts fed a combination of food types (mixed diets) usually developed better than cohorts fed monotypic diets. Food types that failed to support complete development when fed alone often facilitated development to adulthood when fed in combination with food types containing >1% C20 polyunsaturated fatty acids as total fat, but regardless of essential fatty acid content, algae that produced mucilage and filaments that sank out of the feeding zone were poor quality diets.

  4. Functional characterization of PGRP-LC1 of Anopheles gambiae through deletion and RNA interference

    Institute of Scientific and Technical Information of China (English)

    Yang Chen; Erjun Ling; Zhihui Weng

    2009-01-01

    Peptidoglycan recognition proteins (PGRP) play an important role in innate immunity in insects through the activation of the Imd pathway, which has been shown to be required in the antibacterial response in insects and in the limitation of the number of Plasmodium berghei oocysts developing in mosquito midgut. The LC1gene of the PRGP family in Anopheles gambiae produces many products through alternative splicing. In this work, we demonstrate that PGRP-LC1a alone is sufficient to activate the Imd pathway in the A. gambiae L3-5 cell line through a combination of terminal or internal deletions, and RNA interference against endogenous PGRP-LC products. In the absence of endogenous PGRP-LC proteins, the integrity of the cytoplasmic domain is necessary for LC1 a function, while that of the extracellular domain is not. Moreover, the shorter the extracellular domain, the higher the activity for LC1a. However, the removal of either the cytoplasmic or the extracellular PGRP-binding domain has little impact on the activity of LC1a in the presence of endogenous PGRP-LC proteins.

  5. Efficacy of three insect repellents against the malaria vector Anopheles arabiensis.

    Science.gov (United States)

    Govere, J; Durrheim, D N; Baker, L; Hunt, R; Coetzee, M

    2000-12-01

    Three commercial repellents marketed in South Africa: Bio-Skincare (BSC, oils of coconut, jojoba, rapeseed and vitamin E), Mosiguard towelletes with 0.574 g quwenling (p-menthane-3,8-diol, PMD) and the standard deet (15% diethyl-3-methylbenzamide, Tabard lotion), were compared against a laboratory colony of the mosquito Anopheles arabiensis Patton (Diptera: Culicidae), the predominant malaria vector in South Africa. Human forearms were treated with 1.2 g BSC, 0.8 g PMD towelette or 0.5 g deet and exposed to 200 hungry An. arabiensis females for 1 min, at intervals of 1-6 h post-treatment. Tests were conducted by three adult male volunteers (aged 30-45 years, crossover controlled test design for 3 consecutive days), using their left arm for treatment and right arm for untreated control. Biting rates averaged 39-52 bites/min on untreated arms. All three repellents provided complete protection against An. arabiensis for up to 3-4 h post-application; deet and PMD gave 90-100% protection up to 5-6h, but BSC declined to only 52% protection 6h post-treatment. These results are interpreted to show that all three repellent products give satisfactory levels of personal protection against An. arabiensis for 4-5 h, justifying further evaluation in the field. PMID:11129710

  6. Characterization of Anopheles gambiae Transglutaminase 3 (AgTG3) and Its Native Substrate Plugin*

    Science.gov (United States)

    Le, Binh V.; Nguyen, Jennifer B.; Logarajah, Shankar; Wang, Bo; Marcus, Jacob; Williams, Hazel P.; Catteruccia, Flaminia; Baxter, Richard H. G.

    2013-01-01

    Male Anopheles mosquitoes coagulate their seminal fluids via cross-linking of a substrate, called Plugin, by the seminal transglutaminase AgTG3. Formation of the “mating plug” by cross-linking Plugin is necessary for efficient sperm storage by females. AgTG3 has a similar degree of sequence identity (∼30%) to both human Factor XIII (FXIII) and tissue transglutaminase 2 (hTG2). Here we report the solution structure and in vitro activity for the cross-linking reaction of AgTG3 and Plugin. AgTG3 is a dimer in solution and exhibits Ca2+-dependent nonproteolytic activation analogous to cytoplasmic FXIII. The C-terminal domain of Plugin is predominantly α-helical with extended tertiary structure and oligomerizes in solution. The specific activity of AgTG3 was measured as 4.25 × 10−2 units mg−1. AgTG3 is less active than hTG2 assayed using the general substrate TVQQEL but has 8–10× higher relative activity when Plugin is the substrate. Mass spectrometric analysis of cross-linked Plugin detects specific peptides including a predicted consensus motif for cross-linking by AgTG3. These results support the development of AgTG3 inhibitors as specific and effective chemosterilants for A. gambiae. PMID:23288850

  7. The STAT pathway mediates late phase immunity against Plasmodium in the mosquito Anopheles gambiae

    Science.gov (United States)

    Gupta, Lalita; Molina-Cruz, Alvaro; Kumar, Sanjeev; Rodrigues, Janneth; Dixit, Rajnikant; Zamora, Rodolfo E.; Barillas-Mury, Carolina

    2009-01-01

    The STAT family of transcription factors activate expression of immune system genes in vertebrates. The ancestral STAT gene (AgSTAT-A) appears to have duplicated in the mosquito Anopheles gambiae, giving rise to a second intronless STAT gene (AgSTAT-B), which we show regulates AgSTAT-A expression in adult females. AgSTAT-A participates in the transcriptional activation of nitric oxide synthase (NOS) in response to bacterial and plasmodial infection. Activation of this pathway, however, is not essential for mosquitoes to survive a bacterial challenge. AgSTAT-A silencing reduces the number of early Plasmodium oocysts in the midgut, but nevertheless enhances the overall infection by increasing oocyst survival. Silencing of SOCS, a STAT suppressor, has the opposite effect, reducing Plasmodium infection by increasing NOS expression. Chemical inhibition of mosquito NOS activity after oocyte formation increases oocyte survival. Thus, the AgSTAT-A pathway mediates a late phase anti-plasmodial response that reduces oocyst survival in An. gambiae. PMID:19454353

  8. Immune factor Gambif1, a new rel family member from the human malaria vector, Anopheles gambiae.

    Science.gov (United States)

    Barillas-Mury, C; Charlesworth, A; Gross, I; Richman, A; Hoffmann, J A; Kafatos, F C

    1996-09-01

    A novel rel family member, Gambif1 (gambiae immune factor 1), has been cloned from the human malaria vector, Anopheles gambiae, and shown to be most similar to Drosophila Dorsal and Dif. Gambif1 protein is translocated to the nucleus in fat body cells in response to bacterial challenge, although the mRNA is present at low levels at all developmental stages and is not induced by infection. DNA binding activity to the kappaB-like sites in the A.gambiae Defensin and the Drosophila Diptericin and Cecropin promoters is also induced in larval nuclear extracts following infection. Gambif1 has the ability to bind to kappaB-like sites in vitro. Co-transfection assays in Drosophila mbn-2 cells show that Gambif1 can activate transcription by interacting with the Drosophila Diptericin regulatory elements, but is not functionally equivalent to Dorsal in this assay. Gambif1 protein translocation to the nucleus and the appearance of kappaB-like DNA binding activity can serve as molecular markers of activation of the immune system and open up the possibility of studying the role of defence reactions in determining mosquito susceptibility/refractoriness to malaria infection. PMID:8887560

  9. Comparative genome and proteome analysis of Anopheles gambiae and Drosophila melanogaster.

    Science.gov (United States)

    Zdobnov, Evgeny M; von Mering, Christian; Letunic, Ivica; Torrents, David; Suyama, Mikita; Copley, Richard R; Christophides, George K; Thomasova, Dana; Holt, Robert A; Subramanian, G Mani; Mueller, Hans-Michael; Dimopoulos, George; Law, John H; Wells, Michael A; Birney, Ewan; Charlab, Rosane; Halpern, Aaron L; Kokoza, Elena; Kraft, Cheryl L; Lai, Zhongwu; Lewis, Suzanna; Louis, Christos; Barillas-Mury, Carolina; Nusskern, Deborah; Rubin, Gerald M; Salzberg, Steven L; Sutton, Granger G; Topalis, Pantelis; Wides, Ron; Wincker, Patrick; Yandell, Mark; Collins, Frank H; Ribeiro, Jose; Gelbart, William M; Kafatos, Fotis C; Bork, Peer

    2002-10-01

    Comparison of the genomes and proteomes of the two diptera Anopheles gambiae and Drosophila melanogaster, which diverged about 250 million years ago, reveals considerable similarities. However, numerous differences are also observed; some of these must reflect the selection and subsequent adaptation associated with different ecologies and life strategies. Almost half of the genes in both genomes are interpreted as orthologs and show an average sequence identity of about 56%, which is slightly lower than that observed between the orthologs of the pufferfish and human (diverged about 450 million years ago). This indicates that these two insects diverged considerably faster than vertebrates. Aligned sequences reveal that orthologous genes have retained only half of their intron/exon structure, indicating that intron gains or losses have occurred at a rate of about one per gene per 125 million years. Chromosomal arms exhibit significant remnants of homology between the two species, although only 34% of the genes colocalize in small "microsyntenic" clusters, and major interarm transfers as well as intra-arm shuffling of gene order are detected. PMID:12364792

  10. The JNK pathway is a key mediator of Anopheles gambiae antiplasmodial immunity.

    Directory of Open Access Journals (Sweden)

    Lindsey S Garver

    Full Text Available The innate immune system of Anopheles gambiae mosquitoes limits Plasmodium infection through multiple molecular mechanisms. For example, midgut invasion by the parasite triggers an epithelial nitration response that promotes activation of the complement-like system. We found that suppression of the JNK pathway, by silencing either Hep, JNK, Jun or Fos expression, greatly enhanced Plasmodium infection; while overactivating this cascade, by silencing the suppressor Puckered, had the opposite effect. The JNK pathway limits infection via two coordinated responses. It induces the expression of two enzymes (HPx2 and NOX5 that potentiate midgut epithelial nitration in response to Plasmodium infection and regulates expression of two key hemocyte-derived immune effectors (TEP1 and FBN9. Furthermore, the An. gambiae L3-5 strain that has been genetically selected to be refractory (R to Plasmodium infection exhibits constitutive overexpression of genes from the JNK pathway, as well as midgut and hemocyte effector genes. Silencing experiments confirmed that this cascade mediates, to a large extent, the drastic parasite elimination phenotype characteristic of this mosquito strain. In sum, these studies revealed the JNK pathway as a key regulator of the ability of An. gambiae mosquitoes to limit Plasmodium infection and identified several effector genes mediating these responses.

  11. The STAT pathway mediates late-phase immunity against Plasmodium in the mosquito Anopheles gambiae.

    Science.gov (United States)

    Gupta, Lalita; Molina-Cruz, Alvaro; Kumar, Sanjeev; Rodrigues, Janneth; Dixit, Rajnikant; Zamora, Rodolfo E; Barillas-Mury, Carolina

    2009-05-01

    The STAT family of transcription factors activates expression of immune system genes in vertebrates. The ancestral STAT gene (AgSTAT-A) appears to have duplicated in the mosquito Anopheles gambiae, giving rise to a second intronless STAT gene (AgSTAT-B), which we show regulates AgSTAT-A expression in adult females. AgSTAT-A participates in the transcriptional activation of nitric oxide synthase (NOS) in response to bacterial and plasmodial infection. Activation of this pathway, however, is not essential for mosquitoes to survive a bacterial challenge. AgSTAT-A silencing reduces the number of early Plasmodium oocysts in the midgut, but nevertheless enhances the overall infection by increasing oocyst survival. Silencing of SOCS, a STAT suppressor, has the opposite effect, reducing Plasmodium infection by increasing NOS expression. Chemical inhibition of mosquito NOS activity after oocyte formation increases oocyte survival. Thus, the AgSTAT-A pathway mediates a late-phase antiplasmodial response that reduces oocyst survival in A. gambiae. PMID:19454353

  12. The JNK pathway is a key mediator of Anopheles gambiae antiplasmodial immunity.

    Science.gov (United States)

    Garver, Lindsey S; de Almeida Oliveira, Giselle; Barillas-Mury, Carolina

    2013-01-01

    The innate immune system of Anopheles gambiae mosquitoes limits Plasmodium infection through multiple molecular mechanisms. For example, midgut invasion by the parasite triggers an epithelial nitration response that promotes activation of the complement-like system. We found that suppression of the JNK pathway, by silencing either Hep, JNK, Jun or Fos expression, greatly enhanced Plasmodium infection; while overactivating this cascade, by silencing the suppressor Puckered, had the opposite effect. The JNK pathway limits infection via two coordinated responses. It induces the expression of two enzymes (HPx2 and NOX5) that potentiate midgut epithelial nitration in response to Plasmodium infection and regulates expression of two key hemocyte-derived immune effectors (TEP1 and FBN9). Furthermore, the An. gambiae L3-5 strain that has been genetically selected to be refractory (R) to Plasmodium infection exhibits constitutive overexpression of genes from the JNK pathway, as well as midgut and hemocyte effector genes. Silencing experiments confirmed that this cascade mediates, to a large extent, the drastic parasite elimination phenotype characteristic of this mosquito strain. In sum, these studies revealed the JNK pathway as a key regulator of the ability of An. gambiae mosquitoes to limit Plasmodium infection and identified several effector genes mediating these responses. PMID:24039583

  13. The JNK Pathway Is a Key Mediator of Anopheles gambiae Antiplasmodial Immunity

    Science.gov (United States)

    Garver, Lindsey S.; de Almeida Oliveira, Giselle; Barillas-Mury, Carolina

    2013-01-01

    The innate immune system of Anopheles gambiae mosquitoes limits Plasmodium infection through multiple molecular mechanisms. For example, midgut invasion by the parasite triggers an epithelial nitration response that promotes activation of the complement-like system. We found that suppression of the JNK pathway, by silencing either Hep, JNK, Jun or Fos expression, greatly enhanced Plasmodium infection; while overactivating this cascade, by silencing the suppressor Puckered, had the opposite effect. The JNK pathway limits infection via two coordinated responses. It induces the expression of two enzymes (HPx2 and NOX5) that potentiate midgut epithelial nitration in response to Plasmodium infection and regulates expression of two key hemocyte-derived immune effectors (TEP1 and FBN9). Furthermore, the An. gambiae L3–5 strain that has been genetically selected to be refractory (R) to Plasmodium infection exhibits constitutive overexpression of genes from the JNK pathway, as well as midgut and hemocyte effector genes. Silencing experiments confirmed that this cascade mediates, to a large extent, the drastic parasite elimination phenotype characteristic of this mosquito strain. In sum, these studies revealed the JNK pathway as a key regulator of the ability of An. gambiae mosquitoes to limit Plasmodium infection and identified several effector genes mediating these responses. PMID:24039583

  14. Swarming and mating activity of Anopheles gambiae mosquitoes in semi-field enclosures.

    Science.gov (United States)

    Achinko, D; Thailayil, J; Paton, D; Mireji, P O; Talesa, V; Masiga, D; Catteruccia, F

    2016-03-01

    Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) is the major Afro-tropical vector of malaria. Novel strategies proposed for the elimination and eradication of this mosquito vector are based on the use of genetic approaches, such as the sterile insect technique (SIT). These approaches rely on the ability of released males to mate with wild females, and depend on the application of effective protocols to assess the swarming and mating behaviours of laboratory-reared insects prior to their release. The present study evaluated whether large semi-field enclosures can be utilized to study the ability of males from a laboratory colony to respond to natural environmental stimuli and initiate normal mating behaviour. Laboratory-reared males exhibited spatiotemporally consistent swarming behaviour within the study enclosures. Swarm initiation, peak and termination time closely tracked sunset. Comparable insemination rates were observed in females captured in copula in the semi-field cages relative to females in small laboratory cages. Oviposition rates after blood feeding were also similar to those observed in laboratory settings. The data suggest that outdoor enclosures are suitable for studying swarming and mating in laboratory-bred males in field-like settings, providing an important reference for future studies aimed at assessing the comparative mating ability of strains for SIT and other vector control strategies. PMID:26508420

  15. Carbamate and Pyrethroid Resistance in the Akron Strain of Anopheles gambiae

    Science.gov (United States)

    Mutunga, James M.; Anderson, Troy D.; Craft, Derek T.; Gross, Aaron D.; Swale, Daniel R.; Tong, Fan; Wong, Dawn M.; Carlier, Paul R.; Bloomquist, Jeffrey R.

    2015-01-01

    Insecticide resistance in the malaria vector, Anopheles gambiae is a serious problem, epitomized by the multi-resistant Akron strain, originally isolated in the country of Benin. Here we report resistance in this strain to pyrethroids and DDT (13-fold to 35-fold compared to the susceptible G3 strain), but surprisingly little resistance to etofenprox, a compound sometimes described as a “pseudo-pyrethroid.” There was also strong resistance to topically-applied commercial carbamates (45-fold to 81-fold), except for the oximes aldicarb and methomyl. Biochemical assays showed enhanced cytochrome P450 monooxygenase and carboxylesterase activity, but not that of glutathione-S-transferase. A series of substituted α,α,α,-trifluoroacetophenone oxime methylcarbamates were evaluated for enzyme inhibition potency and toxicity against G3 and Akron mosquitoes. The compound bearing an unsubstituted phenyl ring showed the greatest toxicity to mosquitoes of both strains. Low cross resistance in Akron was retained by all analogs in the series. Kinetic analysis of acetylcholinesterase activity and its inhibition by insecticides in the G3 strain showed inactivation rate constants greater than that of propoxur, and against Akron enzyme inactivation rate constants similar to that of aldicarb. However, inactivation rate constants against recombinant human AChE were essentially identical to that of the G3 strain. Thus, the acetophenone oxime carbamates described here, though potent insecticides that control resistant Akron mosquitoes, require further structural modification to attain acceptable selectivity and human safety. PMID:26047119

  16. Suitability of monotypic and mixed diets for Anopheles hermsi larval development.

    Science.gov (United States)

    Beasley, Donald A; Walton, William E

    2016-06-01

    The developmental time and survival to eclosion of Anopheles hermsi Barr & Guptavanij fed monotypic and mixed diets of ten food types were examined in laboratory studies. Larvae fed monotypic diets containing animal detritus (freeze-dried rotifers, freeze-dried Daphnia pulicaria, and TetraMin® fish food flakes) and the mixotrophic protistan Cryptomonas ovata developed faster and survived better than larvae that were fed other monotypic diets. Survival to adulthood of larvae fed several concentrations of the diatom Planothidium (=Achnanthes) lanceolatum was poor (Chlamydomonas reinhardtii and filamentous Spirogyra communis, failed to complete larval development, regardless of the concentration tested. Cohorts fed a combination of food types (mixed diets) usually developed better than cohorts fed monotypic diets. Food types that failed to support complete development when fed alone often facilitated development to adulthood when fed in combination with food types containing >1% C20 polyunsaturated fatty acids as total fat, but regardless of essential fatty acid content, algae that produced mucilage and filaments that sank out of the feeding zone were poor quality diets. PMID:27232128

  17. Segmental duplication implicated in the genesis of inversion 2Rj of Anopheles gambiae.

    Directory of Open Access Journals (Sweden)

    Mamadou B Coulibaly

    Full Text Available The malaria vector Anopheles gambiae maintains high levels of inversion polymorphism that facilitate its exploitation of diverse ecological settings across tropical Africa. Molecular characterization of inversion breakpoints is a first step toward understanding the processes that generate and maintain inversions. Here we focused on inversion 2Rj because of its association with the assortatively mating Bamako chromosomal form of An. gambiae, whose distinctive breeding sites are rock pools beside the Niger River in Mali and Guinea. Sequence and computational analysis of 2Rj revealed the same 14.6 kb insertion between both breakpoints, which occurred near but not within predicted genes. Each insertion consists of 5.3 kb terminal inverted repeat arms separated by a 4 kb spacer. The insertions lack coding capacity, and are comprised of degraded remnants of repetitive sequences including class I and II transposable elements. Because of their large size and patchwork composition, and as no other instances of these insertions were identified in the An. gambiae genome, they do not appear to be transposable elements. The 14.6 kb modules inserted at both 2Rj breakpoint junctions represent low copy repeats (LCRs, also called segmental duplications that are strongly implicated in the recent (approximately 0.4N(e generations origin of 2Rj. The LCRs contribute to further genome instability, as demonstrated by an imprecise excision event at the proximal breakpoint of 2Rj in field isolates.

  18. Isolation of Bacillus sphaericus from Lombok Island, Indonesia, and Their Toxicity against Anopheles aconitus.

    Science.gov (United States)

    Suryadi, Bambang Fajar; Yanuwiadi, Bagyo; Ardyati, Tri; Suharjono

    2015-01-01

    Malaria is endemic to Lombok Island, Indonesia. One approach to suppress malaria spread is to eliminate a