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Sample records for anopheles gambiae diptera

  1. 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.

  2. Multiple insecticide resistance in Anopheles gambiae (Diptera: Culicidae) from Pointe Noire, Republic of the Congo.

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    Koekemoer, Lizette L; Spillings, Belinda L; Christian, Riann N; Lo, Te-Chang M; Kaiser, Maria L; Norton, Ryan A I; Oliver, Shune V; Choi, Kwang S; Brooke, Basil D; Hunt, Richard H; Coetzee, Maureen

    2011-08-01

    Successful implementation of an integrated vector control program will rely on availability of accurate vector information in the specific location. However, such information can be limited in some countries. The aim of this study was to obtain baseline vector information from Pointe Noire on the Congo coast (Republic of the Congo). Field sampling was conducted during April 2009 in the village of Boutoto and its surrounds, close to the city of Pointe Noire. Anopheles gambiae sensu lato mosquitoes were collected resting indoors. Samples were analyzed for insecticide susceptibility, species identification, and Plasmodium sporozoite infection. Molecular and biochemical assays were conducted to characterize insecticide resistance mechanisms. The malaria vector A. gambiae S-form was the only mosquito species identified, and it had a high Plasmodium falciparum infection rate (9.6%). Multiple insecticide resistance was detected in this population with full susceptibility to only one insecticide class, the organophosphates. Dieldrin and DDT resistance was mainly attributed to target-site resistance (the Rdl and L1014F/L1014S kdr mutations respectively), whereas pyrethroid resistance was mainly attributed to P450 metabolic enzyme-mediated detoxification in addition to kdr. The role of various insecticide resistance mechanisms revealed a complex association between metabolic detoxification and reduced target-site sensitivity. PMID:21417925

  3. 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

  4. Predators of Anopheles gambiae sensu lato (Diptera: Culicidae) larvae in wetlands, western Kenya: confirmation by polymerase chain reaction method.

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    Ohba, Shin-Ya; Kawada, Hitoshi; Dida, Gabriel O; Juma, Duncan; Sonye, Gorge; Minakawa, Noboru; Takagi, Masahiro

    2010-09-01

    Polymerase chain reaction analysis was performed to determine whether mosquito predators in wetland habitats feed on Anopheles gambiae sensu lato (s.l.) larvae. Aquatic mosquito predators were collected from six wetlands near Lake Victoria in Mbita, Western Kenya. This study revealed that the whole positive rate of An. gambiae s.l. from 330 predators was 54.2%. The order of positive rate was the highest in Odonata (70.2%), followed by Hemiptera (62.8%), Amphibia (41.7%), and Coleoptera (18%). This study demonstrates that the polymerase chain reaction method can determine whether aquatic mosquito predators feed on An. gambiae s.l. larvae if the predators have undigested An. gambiae s.l. in their midgut or stomach. PMID:20939371

  5. Predators of Anopheles gambiae sensu lato (Diptera: Culicidae) Larvae in Wetlands, Western Kenya: Confirmation by Polymerase Chain Reaction Method

    OpenAIRE

    Ohba, Shin-ya; Kawada, Hitoshi; Dida, Gabriel O; Juma, Duncan; SONYE, GORGE; Minakawa, Noboru; Takagi, Masahiro

    2010-01-01

    Polymerase chain reaction analysis was performed to determine whether mosquito predators in wetland habitats feed on Anopheles gambiae sensu lato (s.l.) larvae. Aquatic mosquito predators were collected from six wetlands near Lake Victoria in Mbita, Western Kenya. This study revealed that the whole positive rate of An. gambiae s.l. from 330 predators was 54.2%. The order of positive rate was the highest in Odonata (70.2%), followed by Hemiptera (62.8%), Amphibia (41.7%), and Coleoptera (18%)....

  6. Predators of Anopheles gambiae sensu lato (Diptera: Culicidae) larvae in Wetlands, Western Kenya: Confirmation by polymerase chain reaction method

    OpenAIRE

    Ohba, Shin-ya; Kawada, Hitoshi; Dida, Gabriel O; Juma, Duncan; SONYE, GORGE; Minakawa, Noboru; Takagi, Masahiro

    2010-01-01

    Polymerase chain reaction analysis was performed to determine whether mosquito predators in wetland habitats feed on Anopheles gambiae sensu lato (s.l.) larvae. Aquatic mosquito predators were collected from six wetlands near Lake Victoria in Mbita, Western Kenya. This study revealed that the whole positive rate of An. gambiae s.l. from 330 predators was 54.2%. The order of positive rate was the highest in Odonata (70.2%), followed by Hemiptera (62.8%), Amphibia (41.7%), and Coleoptera (18%)....

  7. 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 ...

  8. Insecticide susceptibility of Anopheles coluzzii and Anopheles gambiae mosquitoes in Ibadan, South-West Nigeria

    OpenAIRE

    Okorie, Patricia N.; Ademowo, George O.; Irving, Helen; Kelly-Hope, Louise A; Wondji, Charles S

    2014-01-01

    The emergence of insecticide resistance in Anopheles mosquitoes has great implications for malaria control in Nigeria. This study aimed to determine the dynamics of insecticide susceptibility levels and frequency of knockdown resistance (kdr) mutations (L1014F) in wild Anopheles coluzzii Coetzee & Wilkerson sp. n. and An. gambiae Giles ( (Diptera: Culicidae) from Ojoo and Bodija areas of Ibadan, South-West, Nigeria. Insecticide susceptibility to pyrethroids, organophosphates, carbamates and o...

  9. First report of Metarhizium anisopliae IP 46 pathogenicity in adult Anopheles gambiae s.s. and An. arabiensis (Diptera; Culicidae

    Directory of Open Access Journals (Sweden)

    Lyimo Issa N

    2009-12-01

    Full Text Available Abstract 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 fungus coated on test paper at a concentration of 3.3 × 106 conidia cm-2 reduced the daily survival of both mosquito species (HR = 3.14, p An. gambiae s.s relative to An. arabiensis (HR = 1.38, p 95% of mosquito cadavers in the treatment groups. The results indicate that M. anisopliae IP 46 has the potential to be a bio-control agent for African malaria vector species, and is a suitable candidate for further research and development.

  10. Identification, characterisation, and function of adipokinetic hormones and receptor in the African malaria mosquito, "Anopheles Gambiae" (Diptera)

    OpenAIRE

    Kaufmann, Christian; Betschart, Bruno

    2007-01-01

    En utilisant la bioinformatique et la biologie moléculaire, nous avons pu identifier chez le principal vecteur africain de la malaria, le moustique, Anopheles gambiae deux hormones adipokinétiques (AKHs): l'octapeptide, Anoga-AKH-I (pQLTFTPAWa) et le décapeptide, Anoga-AKH-II, (pQVTFSRDWNAa). La fonction principale des AKHs est d’induire une hyperlipémie (effet d’adipokinétique), ainsi qu’une hypertrehalosémie et une hyperprolinémie. En tant que membres de la famille des AKH, les deux neurope...

  11. Repellent activities of stereoisomers of p-menthane-3,8-diols against Anopheles gambiae (Diptera: Culicidae).

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    Barasa, Stephen S; Ndiege, Isaiah O; Lwande, Wilber; Hassanali, Ahmed

    2002-09-01

    Four stereoisomers of p-menthane-3,8-diol, which make up the natural product obtained from Eucalyptus citriodora, were synthesized through stereoselective procedures. Repellency assays showed that all the four were equally active against Anopheles gambiae s.s. Racemic blends and the diastereoisomeric mixture of all the four isomers were also equally repellent. 1-alpha-terpeneol, with a single hydroxyl function at C-8 and unsaturation at C-8, and menthol, with a single hydroxyl function at C-3, were not repellent. The practical implication of these results is discussed. PMID:12349856

  12. Susceptibility of Anopheles gambiae sensu lato (Diptera:Culicidae to permethrin, deltamethrin and bendiocarb in Ibadan city, Southwest Nigeria

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    Kolade Tahiru Ibrahim

    2013-01-01

    Full Text Available This study was carried out to assess the resistance/susceptibility level of An.gambiae s.l, a major malaria vector in Ibadan metropolis, south west Nigeria, to two classes of insecticides approved by World Health Organization (WHO for vector control. Anopheles larvae were collected from two communities (Ojoo and Bodija within the metropolis and reared to adults. Two to three-day old, non-engorged female mosquitoes were exposed to discriminating dosages of 0.05% deltamethrin, 0.75% permethrin and 0.1% bendiocarb using WHO protocols and susceptibility test kits. Knockdown effect was recorded every 10 min and mortality scored 24 h after exposure. Species identification was by morphological characteristics only. The study revealed that the major malaria vector in Nigeria, An.gambiae s.l,An.gambiae s.l, were susceptible (mortality rate of 98.8% to deltamethrin in Ojoo community, while Bodija recorded marginal susceptibility (87.5%. Both sites showed reduced susceptibility to permethrin and resistance to bendiocarb with 24 h post exposure mortalities ranging from 83.5% to 87.7% and 70.0% and 52.5%, respectively. The median knockdown time (KDT50 from 22-44.2 min for the pyrethroids (permethrin and deltamethrin, while that of carbamates (bendiocarb range from 35.2 to 49.5 min. Resistance recorded in the field populations of An.gambiae s.l in Ibadan to bendiocarb was not observed in same population exposed to the pyrethroids (deltamethrin and permethrin but with differential susceptibility. Therefore Bendiocarb may not be suitable as alternatives to mitigate pyrethroid resistance. A rationalised use of these insecticides coupled with regular monitoring of resistance status is essential to improve and evaluate the efficacy of the current vector control tools (ITN and IRS.

  13. Effect of temperature on the development of the aquatic stages of Anopheles gambiae sensu stricto (Diptera: Culicidae).

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    Bayoh, M N; Lindsay, S W

    2003-10-01

    Global warming may affect the future pattern of many arthropod-borne diseases, yet the relationship between temperature and development has been poorly described for many key vectors. Here the development of the aquatic stages of Africa's principal malaria vector, Anopheles gambiae s.s. Giles, is described at different temperatures. Development time from egg to adult was measured under laboratory conditions at constant temperatures between 10 and 40 degrees C. Rate of development from one immature stage to the next increased at higher temperatures to a peak around 28 degrees C and then declined. Adult development rate was greatest between 28 and 32 degrees C, although adult emergence was highest between 22 and 26 degrees C. No adults emerged below 18 degrees C or above 34 degrees C. Non-linear models were used to describe the relationship between developmental rate and temperature, which could be used for developing process-based models of malaria transmission. The utility of these findings is demonstrated by showing that a map where the climate is suitable for the development of aquatic stages of A. gambiae s.s. corresponded closely with the best map of malaria risk currently available for Africa. PMID:14641976

  14. Orientation of Anopheles gambiae (Diptera: Culicidae) to Plant-Host Volatiles in a Novel Diffusion-Cage Olfactometer.

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    Otienoburu, Philip E; Nikbakhtzadeh, Mahmood R; Foster, Woodbridge A

    2016-01-01

    A novel diffusion-cage olfactometer tested the responses of Anopheles gambiae Giles to plant volatiles. Green-leaf volatiles are often released from cut or injured plant tissue and may alter the headspace of plants used in olfactometer assays. The diffusion-cage olfactometer is designed for use with whole, intact plants, hence giving a more realistic behavioral assay. Its simple plastic construction, ease of assembly, and accommodation to whole plants makes it a useful tool for measuring mosquito orientation to plant volatiles within large enclosures. We compared its performance to that of the more commonly used T-tube wind-tunnel olfactometer, by testing the orientation of mosquitoes to volatiles of a few prevalent plants of eastern Africa reportedly utilized by An. gambiae for sugar: Parthenium hysterophorus (Asteraceae), Ricinus communis (Euphorbiaceae), Lantana camara (Verbenaceae), and Senna occidentalis (Fabaceae). Results indicate that the diffusion-cage olfactometer is an effective alternative to conventional wind-tunnel olfactometers, to test mosquito orientation to plant volatiles under seminatural conditions. PMID:26502752

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

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    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. PMID:26336230

  16. Larvicidal potential of some plants from West Africa against Culex quinquefasciatus (Say and Anopheles gambiae Giles (Diptera: Culicidae

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    Alain Azokou

    2013-04-01

    Full Text Available Background & objectives: Mosquitoes increased resistance to insecticides, and environmental concerns about the use of insecticides, pose a major challenge in the search for new molecules to deplete and incapacitate mosquito populations. Plants are the valuable source as practices consisting in exploiting plant materials as repellents, and are still in wide use throughout developing countries. The aim of the present study was to screen plants from Cτte d'Ivoire for larvicidal activity against mosquitoes. Methods: Resistant and sensitive larvae (III and IV instar of Anopheles gambiae and Culex quinquefasciatus were exposed to crude ethanol extracts (90% of 45 plants and viability observed after 30 min, 6, 12 and 24 h postincubation. After partition of active extracts, each fraction (hexane and chloroform washed with NaCl 1%, tannins and aqueous was tested using the same protocol at various concentrations (1000– 31.2 ppm. Results: Of 49 extracts tested, 7 exhibited high potential (LC50 = 80 to 370 ppm against resistant and sensitive III and IV instar larvae of An. gambiae and Cx. quinquefasciatus. These extracts were from Cissus populnea, Cochlospermum planchonii, Heliotropium indicum, Phyllanthus amarus, Vitex grandifolia and Alchornea cordifolia. However, three most active plant species (LC50 = 80– 180 ppm were Cs. populnea, Cm. planchonii and P. amarus Their hexane and chloroform fractions showed high larvicidal activity. Conclusion: This study demonstrated that plants from Cτte d'Ivoire have a real potential for malaria, yellow fever, filarial and dengue vector control. Those could be used as sources or provide lead compounds for the development of safe plant-based biocides.

  17. The SNMP/CD36 gene family in Diptera, Hymenoptera and Coleoptera: Drosophila melanogaster, D. pseudoobscura, Anopheles gambiae, Aedes aegypti, Apis mellifera, and Tribolium castaneum.

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    Nichols, Zachary; Vogt, Richard G

    2008-04-01

    Sensory neuron membrane proteins (SNMPs) are membrane bound proteins initially identified in olfactory receptor neurons of Lepidoptera and are thought to play a role in odor detection; SNMPs belong to a larger gene family characterized by the human protein CD36. We have identified 12-14 candidate SNMP/CD36 homologs from each of the genomes of Drosophila melanogaster, D. pseudoobscura, Anopheles gambiae and Aedes aegypti (Diptera), eight candidate homologs from Apis mellifera (Hymenoptera), and 15 from Tribolium castaneum (Coleoptera). Analysis (sequence similarity and intron locations) suggests that the insect SNMP/CD36 genes fall into three major groups. Group 1 includes the previously characterized D. melanogaster emp (epithelial membrane protein). Group 2 includes the previously characterized D. melanogaster croquemort, ninaD, santa maria, and peste. Group 3 genes include the SNMPs, which fall into two subgroups referred to as SNMP1 and SNMP2. D. melanogaster SNMP1 (CG7000) shares both significant sequence similarity and five of its six intron insertion sites with the lepidopteran Bombyx mori SNMP1. The topological conservation of this gene family within the three major holometabolous lineages indicates that it predates the coleopteran and hymenoptera/dipera/lepidoptera split 300+ million years ago. The current state of knowledge of the characterized insect members of this gene family is discussed. PMID:18342246

  18. Synergism between ammonia, lactic acid and carboxylic acids as kairomones in the host-seeking behaviour of the malaria mosquito Anopheles gambiae sensu stricto (Diptera: Culicidae)

    NARCIS (Netherlands)

    Smallegange, R.C.; Qiu, Y.T.; Loon, van J.J.A.; Takken, W.

    2005-01-01

    Host odours play a major role in the orientation and host location of blood-feeding mosquitoes. Anopheles gambiae Giles sensu stricto, which is the most important malaria vector in Africa, is a highly anthropophilic mosquito species, and the host-seeking behaviour of the females of this mosquito is

  19. Preliminary field testing of a long-lasting insecticide-treated hammock against Anopheles gambiae and Mansonia spp. (Diptera : Culicidae) in West Africa

    OpenAIRE

    Hougard, Jean-Marc; Martin, Thibaud; Guillet, Pierre; Coosemans, M.; ITOH, T.; Akogbéto, M.; Chandre, Fabrice

    2007-01-01

    The efficacy of an experimental long-lasting insecticide-treated ham mock (LLIH) with a long-lasting treated net used as a blanket and made of the same fabric (polyethylene) was tested in a concrete block experimental hut, against the malaria vector Anopheles gambiae s.l. and the arbovirus vectors and nuisance mosquitoes Mansonia africana (Theobald) and Alansonia uniformis (Theobald). The LLIH was treated with the pyrethroid insecticide permethrin. It was evaluated concurrently with ignited m...

  20. Optimization of breeding output for larval stage of Anopheles gambiae (Diptera: Culicidae): prospects for the creation and maintenance of laboratory colony from wild isolates

    OpenAIRE

    Tchuinkam, T.; Mpoame, M.; Make-Mveinhya, B.; Simard, Frédéric; Lélé-Defo, E.; Zebazé-Togouet, S.; Tateng-Ngouateu, A.; Awono-Ambéné, H. P.; Antonio-Nkondjio, C.; Njiné, T.; Fontenille, Didier

    2011-01-01

    Domesticating anopheline species from wild isolates provides an important laboratory tool but requires detailed knowledge of their natural biology and ecology, especially the natural breeding habitats of immature stages. The aim of this study was to determine the optimal values of some parameters of Anopheles gambiae larval development, so as to design a standard rearing protocol of highland isolates, which would ensure: the biggest fourth instars, the highest pupae productivity, the shortest...

  1. Demasculinization of the Anopheles gambiae X chromosome

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    Magnusson Kalle

    2012-05-01

    Full Text Available Abstract Background In a number of organisms sex-biased genes are non-randomly distributed between autosomes and the shared sex chromosome X (or Z. Studies on Anopheles gambiae have produced conflicting results regarding the underrepresentation of male-biased genes on the X chromosome and it is unclear to what extent sexual antagonism, dosage compensation or X-inactivation in the male germline, the evolutionary forces that have been suggested to affect the chromosomal distribution of sex-biased genes, are operational in Anopheles. Results We performed a meta-analysis of sex-biased gene expression in Anopheles gambiae which provides evidence for a general underrepresentation of male-biased genes on the X-chromosome that increased in significance with the observed degree of sex-bias. A phylogenomic comparison between Drosophila melanogaster, Aedes aegypti and Culex quinquefasciatus also indicates that the Anopheles X chromosome strongly disfavours the evolutionary conservation of male-biased expression and that novel male-biased genes are more likely to arise on autosomes. Finally, we demonstrate experimentally that transgenes situated on the Anopheles gambiae X chromosome are transcriptionally silenced in the male germline. Conclusion The data presented here support the hypothesis that the observed demasculinization of the Anopheles X chromosome is driven by X-chromosome inactivation in the male germline and by sexual antagonism. The demasculinization appears to be the consequence of a loss of male-biased expression, rather than a failure in the establishment or the extinction of male-biased genes.

  2. 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...

  3. Transstadial and horizontal transfer of bacteria within a colony of Anopheles gambiae (Diptera: Culicidae) and oviposition response to bacteria-containing water.

    Science.gov (United States)

    Lindh, J M; Borg-Karlson, A-K; Faye, I

    2008-09-01

    In a paratransgenic approach, genetically modified bacteria are utilized to kill the parasite in the vector gut. A critical component for paratransgenics against malaria is how transgenic bacteria can be introduced and then kept in a mosquito population. Here, we investigated transstadial and horizontal transfer of bacteria within an Anopheles gambiae mosquito colony with the focus on spiked breeding sites as a possible means of introducing bacteria to mosquitoes. A Pantoea stewartii strain, previously isolated from An. gambiae, marked with a green fluorescent protein (GFP), was introduced to mosquitoes in different life stages. The following life stages or older mosquitoes in the case of adults were screened for bacteria in their guts. In addition to P. stewartii other bacteria were isolated from the guts: these were identified by 16S rRNA sequence analysis and temporal temperature gradient gel electrophoresis (TTGE). Bacteria were transferred from larvae to pupae but not from pupae to adults. The mosquitoes were able to take up bacteria from the water they emerged from and transfer the same bacteria to the water they laid eggs in. Elizabethkingia meningoseptica was more often isolated from adult mosquitoes than P. stewartii. A bioassay was used to examine An. gambiae oviposition responses towards bacteria-containing solutions. The volatiles emitted from the solutions were sampled by headspace-solid phase microextraction (SPME) and identified by gas chromatography and mass spectrometry (GC-MS) analysis. P. stewartii but not E. meningoseptica mediated a positive oviposition response. The volatiles emitted by P. stewartii include indole and 3-methyl-1-butanol, which previously have been shown to affect An. gambiae mosquito behaviour. E. meningoseptica emitted indole but not 3-methyl-1-butanol, when suspended in saline. Taken together, this indicates that it may be possible to create attractive breeding sites for distribution of genetically modified bacteria in the

  4. Brachiola gambiae sp n. the microsporidian parasite of Anopheles gambiae and A-melas in Liberia

    Czech Academy of Sciences Publication Activity Database

    Weiser, Jaroslav; Žižka, Zdeněk

    2004-01-01

    Roč. 43, č. 1 (2004), s. 73-80. ISSN 0065-1583 Institutional research plan: CEZ:AV0Z5007907 Keywords : Anopheles gambiae * Anopheles melas * Brachiola gambiae Subject RIV: EG - Zoology Impact factor: 0.986, year: 2004

  5. Optimization of breeding output for larval stage of Anopheles gambiae (Diptera: Culicidae): prospects for the creation and maintenance of laboratory colony from wild isolates.

    Science.gov (United States)

    Tchuinkam, T; Mpoame, M; Make-Mveinhya, B; Simard, F; Lélé-Defo, E; Zébazé-Togouet, S; Tateng-Ngouateu, A; Awono-Ambéné, H-P; Antonio-Nkondjio, C; Njiné, T; Fontenille, D

    2011-06-01

    Domesticating anopheline species from wild isolates provides an important laboratory tool but requires detailed knowledge of their natural biology and ecology, especially the natural breeding habitats of immature stages. The aim of this study was to determine the optimal values of some parameters of Anopheles gambiae larval development, so as to design a standard rearing protocol of highland isolates, which would ensure: the biggest fourth instars, the highest pupae productivity, the shortest duration of the larval stage and the best synchronization of pupation. The density of larvae, the size of breeding water and the quantity of food supplied were tested for their effect on larval growth. Moreover, three cheap foodstuffs were selected and tested for their capability to improve the breeding yield versus TetraMin® as the standard control. The larval density was a very sensitive parameter. Its optimal value, which was found to be ≈1 cm-2 surface area, yielded a daily pupation peak of 38.7% on day 8 post-oviposition, and a global pupae productivity of 78.7% over a duration range of three days. Anopheles gambiae's larval growth, survival and developmental synchronization were density-dependent, and this species responded to overcrowding by producing smaller fourth instars and fewer pupae, over elongated immature lifetime and duration range of pupae occurrence, as a consequence of intraspecific competition. While shallow breeding waters (water pollution level (which was assessed by the biological oxygen demand (BOD) and the chemical oxygen demand (COD)) up to a limit depending on the food quality, above which a rapid increase in larval mortality was recorded. The food quality that could substitute the manufactured baby fish food was obtained with weighed mixture of 1 wheat+1 shrimp+2 fish. On establishing an anopheline mosquito colony in the laboratory, special care should be taken to design and maintain the appropriate optimal values of larval density, water

  6. 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

  7. An expression map for Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    MacCallum Robert M

    2011-12-01

    Full Text Available Abstract Background Quantitative transcriptome data for the malaria-transmitting mosquito Anopheles gambiae covers a broad range of biological and experimental conditions, including development, blood feeding and infection. Web-based summaries of differential expression for individual genes with respect to these conditions are a useful tool for the biologist, but they lack the context that a visualisation of all genes with respect to all conditions would give. For most organisms, including A. gambiae, such a systems-level view of gene expression is not yet available. Results We have clustered microarray-based gene-averaged expression values, available from VectorBase, for 10194 genes over 93 experimental conditions using a self-organizing map. Map regions corresponding to known biological events, such as egg production, are revealed. Many individual gene clusters (nodes on the map are highly enriched in biological and molecular functions, such as protein synthesis, protein degradation and DNA replication. Gene families, such as odorant binding proteins, can be classified into distinct functional groups based on their expression and evolutionary history. Immunity-related genes are non-randomly distributed in several distinct regions on the map, and are generally distant from genes with house-keeping roles. Each immunity-rich region appears to represent a distinct biological context for pathogen recognition and clearance (e.g. the humoral and gut epithelial responses. Several immunity gene families, such as peptidoglycan recognition proteins (PGRPs and defensins, appear to be specialised for these distinct roles, while three genes with physically interacting protein products (LRIM1/APL1C/TEP1 are found in close proximity. Conclusions The map provides the first genome-scale, multi-experiment overview of gene expression in A. gambiae and should also be useful at the gene-level for investigating potential interactions. A web interface is available

  8. Genomic islands of speciation in Anopheles gambiae.

    Directory of Open Access Journals (Sweden)

    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

  9. 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...

  10. Identification of candidate volatiles that affect the behavioural response of the malaria mosquito Anopheles gambiae sensu stricto to an active kairomone blend: laboratory and semi-field assays

    NARCIS (Netherlands)

    Smallegange, R.C.; Bukovinszkine Kiss, G.; Otieno, B.; Mbadi, P.A.; Takken, W.; Mukabana, W.R.; Loon, van J.J.A.

    2012-01-01

    Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) is the most important vector of human malaria in sub-Saharan Africa, affecting the lives of millions of people. Existing tools such as insecticide-treated nets and indoor-residual sprays are not only effective, but also have limitations as a

  11. 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

  12. 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

  13. Studies of Anopheles gambiae s.l (Diptera: Culicidae exhibiting different vectorial capacities in lymphatic filariasis transmission in the Gomoa district, Ghana

    Directory of Open Access Journals (Sweden)

    Amuzu Hilaria

    2010-09-01

    Full Text Available Abstract Background Two lymphatic filariasis endemic communities Mampong and Hwida in Ghana have been regularly monitored for impact on transmission after annual mass drug administration (MDA with albendazole and ivermectin. After six MDAs even though the ABR for Mampong was 55883/person/year and that of Hwida was 2494/person/year, they both had ATPs of 15.21 infective larvae/person/year. Interestingly the human microfilaraemia levels had reduced significantly from 14% to 0% at Mampong and 12% to 3% at Hwida. In an attempt to understand this anomaly, we collected mosquitoes over a 5-month period using human landing catches to determine the species composition, the number of cibarial teeth, the lengths and widths of the cibarium and the cibarial dome of the vector populations. Results Out of 2553 mosquitoes caught at Mampong, 42.6% were An. gambiae s.l. All 280 identified further by PCR were An. gambiae s.s (275 M and 5 S molecular forms. At Hwida, 112 mosquitoes were obtained; 67 (59.8% were An. gambiae s.l, comprised of 40 (59.7% An. melas, 24 (35.8% An. gambiae s.s (17 and 5 M and S molecular forms respectively and 3 (4.5% unidentified. The mean number of teeth for An. melas was 14.1 (median = 14, range = 12-15, An. gambiae s.s., 15.7 (median = 15, range = 13-19 M form 15.5 (median = 15 range = 13-19 and S form 16 (median = 16, range 15-17. The observed differences in teeth numbers were significantly different between An. melas and An. gambiae s.s (p = 0.004, and the M form (p = 0.032 and the S form (p = 0.002. Conclusions In this study, An. gambiae s.s was the main vector at Mampong and was found to possess significantly more cibarial teeth than An. melas, the principal vector at Hwida. We postulate that the different impact observed after 6 MDAs may be due to An. gambiae s.s exhibiting 'facilitation' at Mampong and at Hwida An. melas the main vector exhibits 'limitation'. Thus it may be necessary to compliment MDA with vector control to

  14. 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...

  15. Molecular characterization of DDT resistance in Anopheles gambiae from Benin

    OpenAIRE

    Djègbè, Innocent; Agossa, Fiacre R; Jones, Christopher M.; Poupardin, Rodolphe; Cornelie, Sylvie; Akogbéto, Martin; Ranson, Hilary; Corbel, Vincent

    2014-01-01

    Background Insecticide resistance in the mosquito vector is the one of the main obstacles against effective malaria control. In order to implement insecticide resistance management strategies, it is important to understand the genetic factors involved. In this context, we investigated the molecular basis of DDT resistance in the main malaria vector from Benin. Methods Anopheles gambiae mosquitoes were collected from four sites across Benin and identified to species/molecular form. Mosquitoes ...

  16. Molecular characterization of DDT resistance in Anopheles gambiae from Benin

    OpenAIRE

    Djegbe, I.; Agossa, F. R.; Jones, C. M.; Poupardin, R; Cornélie, Sylvie; Akogbeto, M; Ranson, H.; Corbel, Vincent

    2014-01-01

    Background: Insecticide resistance in the mosquito vector is the one of the main obstacles against effective malaria control. In order to implement insecticide resistance management strategies, it is important to understand the genetic factors involved. In this context, we investigated the molecular basis of DDT resistance in the main malaria vector from Benin. Methods: Anopheles gambiae mosquitoes were collected from four sites across Benin and identified to species/molecular form. Mosquitoe...

  17. Frequent blood-feeding and restrictive sugar-feeding behavior enhance the malaria vector potential of Anopheles gambiae s.l. and An. funestus (Diptera:Culicidae) in western Kenya.

    Science.gov (United States)

    Beier, J C

    1996-07-01

    Natural blood-feeding and sugar-feeding behaviors were investigated for populations of Anopheles gambiae s.l. and An. funestus Giles at 2 sites in western Kenya. During peak levels of malaria parasite transmission, > 85% of 1,569 indoor-resting females contained fresh blood meals. Findings that up to 55.4% of blood-fed resting females and 72.0% of host-seeking females had either stage IV or V oocytes provided strong evidence that females were refeeding before oviposition. Such gonotrophic discordance was common throughout the year for both An. gambiae s.l. and An. funestus. Determinations of gonotrophic cycles for freshly blood-fed mosquitoes collected inside houses indicated that only 60.0% of 1,287 An. gambiae s.l. and 60.0% of 974 An. funestus oviposited eggs after a single blood meal. The timing of oviposition was irregular as indicated by relatively high coefficients of variation for An. gambiae s.l. (44.0%) and An. funestus (35.9%). Associated with frequent blood feeding was a surprisingly low rate of sugar feeding; only 6.3% of 1,183 indoor-resting and only 14.4% of 236 host-seeking anophelines were positive for fructose. Natural patterns of frequent blood feeding, year-round gonotrophic discordance, irregular oviposition cycles, and limited sugar feeding illustrate that anopheline mosquitoes have complex behavioral and physiologic means for adapting to their environment. In western Kenya, for example, adaptations for frequent blood feeding by An. gambiae s.l. and An. funestus potentiates their ability to transmit malaria parasites, well beyond that predicted by standard measures of vectorial capacity. PMID:8699456

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

    Directory of Open Access Journals (Sweden)

    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.

  19. 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

  20. Electroantennogram and behavioural responses of the malaria vector Anopheles gambiae to human-specific sweat components.

    Science.gov (United States)

    Costantini, C; Birkett, M A; Gibson, G; Ziesmann, J; Sagnon, N F; Mohammed, H A; Coluzzi, M; Pickett, J A

    2001-09-01

    Afrotropical malaria vectors of the Anopheles gambiae complex (Diptera: Culicidae), particularly An. gambiae sensu stricto, are attracted mainly to human hosts. A major source of human volatile emissions is sweat, from which key human-specific components are the carboxylic acids (E)- and (Z)-3-methyl-2-hexenoic acid and 7-octenoic acid. Electrophysiological studies on the antennae of An. gambiae s.s. showed selective sensitivity to these compounds, with a threshold at 10(-6) g comparable to that of known olfactory stimulants 1-octen-3-ol, p-cresol, isovaleric acid, and lower than threshold sensitivity to L-lactic acid and the synthetic mosquito repellent N,N-diethyltoluamide (DEET). A combination of the acids released at concentrations > 10(-5) g in wind tunnel bioassays significantly reduced the response to CO2, the major attractant released by human hosts, for strains of An. gambiae s.s. originating from East and West Africa. Field trials with odour-baited entry traps (OBETs) in Burkina Faso showed that 7-octenoic acid significantly increased (by 1.7-fold) the catch of females of An. gambiae sensu lato (comprising two sibling species: An. arabiensis Patton and An. gambiae s.s.) in OBETs baited with CO2, whereas combinations of the acids significantly reduced the catch in CO2-baited traps (by 2.1-fold) and in whole human odour-baited traps (by 1.5-fold). The pure (E) and (Z) geometric isomers of 3-methyl-2-hexenoic acid gave comparable results to the (EIZ) isomer mixture. These results provide the first experimental evidence that human-specific compounds affect the behaviour of highly anthropophilic An. gambiae s.l. mosquitoes. The compounds appear to inhibit the upwind flight' response to known long-range attractants, and may serve either to mask' the attractants present or, more probably, to 'arrest' upwind flight when mosquitoes arrive at a host under natural conditions. In the final approach to hosts, vectors are known to reduce their flight speed and increase

  1. A maleness gene in the malaria mosquito Anopheles gambiae.

    Science.gov (United States)

    Krzywinska, Elzbieta; Dennison, Nathan J; Lycett, Gareth J; Krzywinski, Jaroslaw

    2016-07-01

    The molecular pathways controlling gender are highly variable and have been identified in only a few nonmammalian model species. In many insects, maleness is conferred by a Y chromosome-linked M factor of unknown nature. We have isolated and characterized a gene, Yob, for the M factor in the malaria mosquito Anopheles gambiae Yob, activated at the beginning of zygotic transcription and expressed throughout a male's life, controls male-specific splicing of the doublesex gene. Silencing embryonic Yob expression is male-lethal, whereas ectopic embryonic delivery of Yob transcripts yields male-only broods. This female-killing property may be an invaluable tool for creation of conditional male-only transgenic Anopheles strains for malaria control programs. PMID:27365445

  2. Gene expression-based biomarkers for Anopheles gambiae age grading.

    Science.gov (United States)

    Wang, Mei-Hui; Marinotti, Osvaldo; Zhong, Daibin; James, Anthony A; Walker, Edward; Guda, Tom; Kweka, Eliningaya J; Githure, John; Yan, Guiyun

    2013-01-01

    Information on population age structure of mosquitoes under natural conditions is fundamental to the understanding of vectorial capacity and crucial for assessing the impact of vector control measures on malaria transmission. Transcriptional profiling has been proposed as a method for predicting mosquito age for Aedes and Anopheles mosquitoes, however, whether this new method is adequate for natural conditions is unknown. This study tests the applicability of transcriptional profiling for age-grading of Anopheles gambiae, the most important malaria vector in Africa. The transcript abundance of two An. gambiae genes, AGAP009551 and AGAP011615, was measured during aging under laboratory and field conditions in three mosquito strains. Age-dependent monotonic changes in transcript levels were observed in all strains evaluated. These genes were validated as age-grading biomarkers using the mark, release and recapture (MRR) method. The MRR method determined a good correspondence between actual and predicted age, and thus demonstrated the value of age classifications derived from the transcriptional profiling of these two genes. The technique was used to establish the age structure of mosquito populations from two malaria-endemic areas in western Kenya. The population age structure determined by the transcriptional profiling method was consistent with that based on mosquito parity. This study demonstrates that the transcription profiling method based on two genes is valuable for age determination of natural mosquitoes, providing a new approach for determining a key life history trait of malaria vectors. PMID:23936017

  3. Gene expression-based biomarkers for Anopheles gambiae age grading.

    Directory of Open Access Journals (Sweden)

    Mei-Hui Wang

    Full Text Available Information on population age structure of mosquitoes under natural conditions is fundamental to the understanding of vectorial capacity and crucial for assessing the impact of vector control measures on malaria transmission. Transcriptional profiling has been proposed as a method for predicting mosquito age for Aedes and Anopheles mosquitoes, however, whether this new method is adequate for natural conditions is unknown. This study tests the applicability of transcriptional profiling for age-grading of Anopheles gambiae, the most important malaria vector in Africa. The transcript abundance of two An. gambiae genes, AGAP009551 and AGAP011615, was measured during aging under laboratory and field conditions in three mosquito strains. Age-dependent monotonic changes in transcript levels were observed in all strains evaluated. These genes were validated as age-grading biomarkers using the mark, release and recapture (MRR method. The MRR method determined a good correspondence between actual and predicted age, and thus demonstrated the value of age classifications derived from the transcriptional profiling of these two genes. The technique was used to establish the age structure of mosquito populations from two malaria-endemic areas in western Kenya. The population age structure determined by the transcriptional profiling method was consistent with that based on mosquito parity. This study demonstrates that the transcription profiling method based on two genes is valuable for age determination of natural mosquitoes, providing a new approach for determining a key life history trait of malaria vectors.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  6. 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...

  7. 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 ...

  8. 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

  9. 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 ...

  10. 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...

  11. 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

  12. Inhibition of Anopheles gambiae Odorant Receptor Function by Mosquito Repellents*

    Science.gov (United States)

    Tsitoura, Panagiota; Koussis, Konstantinos; Iatrou, Kostas

    2015-01-01

    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 Ca2+-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

  13. 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...

  14. 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

  15. 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.

  16. Environmental factors associated with the malaria vectors Anopheles gambiae and Anopheles funestus in Kenya

    Directory of Open Access Journals (Sweden)

    Hemingway Janet

    2009-11-01

    Full Text Available Abstract Background The Anopheles gambiae and Anopheles funestus mosquito species complexes are the primary vectors of Plasmodium falciparum malaria in sub-Saharan Africa. To better understand the environmental factors influencing these species, the abundance, distribution and transmission data from a south-eastern Kenyan study were retrospectively analysed, and the climate, vegetation and elevation data in key locations compared. Methods Thirty villages in Malindi, Kilifi and Kwale Districts with data on An. gambiae sensu strict, Anopheles arabiensis and An. funestus entomological inoculation rates (EIRs, were used as focal points for spatial and environmental analyses. Transmission patterns were examined for spatial autocorrelation using the Moran's I statistic, and for the clustering of high or low EIR values using the Getis-Ord Gi* statistic. Environmental data were derived from remote-sensed satellite sources of precipitation, temperature, specific humidity, Normalized Difference Vegetation Index (NDVI, and elevation. The relationship between transmission and environmental measures was examined using bivariate correlations, and by comparing environmental means between locations of high and low clustering using the Mann-Whitney U test. Results Spatial analyses indicated positive autocorrelation of An. arabiensis and An. funestus transmission, but not of An. gambiae s.s., which was found to be widespread across the study region. The spatial clustering of high EIR values for An. arabiensis was confined to the lowland areas of Malindi, and for An. funestus to the southern districts of Kilifi and Kwale. Overall, An. gambiae s.s. and An. arabiensis had similar spatial and environmental trends, with higher transmission associated with higher precipitation, but lower temperature, humidity and NDVI measures than those locations with lower transmission by these species and/or in locations where transmission by An. funestus was high. Statistical

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

    OpenAIRE

    Ferguson Heather M; Lee Yoosook; Knols Bart GJ; Ng'habi Kija R; Lanzaro Gregory C

    2011-01-01

    Abstract 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 the two major and widespread malaria vectors in sub-Saharan Africa. Several studies have examined the ecology and population dynamics of these vectors. Ecological conditions along the Kilomb...

  18. Chloroquine mediated modulation of Anopheles gambiae gene expression.

    Directory of Open Access Journals (Sweden)

    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.

  19. 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

  20. 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

  1. 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.

  2. Anopheles gambiae exploits the treehole ecosystem in western Kenya: a new urban malaria risk?

    Science.gov (United States)

    Omlin, Francois X; Carlson, John C; Ogbunugafor, C Brandon; Hassanali, Ahmed

    2007-12-01

    At six sites in western Kenya, we explored the presence of Anopheles immature stages in treeholes. An. gambiae larvae were found in 19 species, 13 of which are exotic. The most common exotic species were Delonix regia, Jacaranda mimosipholia, and Eucalyptus citrodora. In Kisumu city, longitudinal assessments of 10 Flamboyant trees showed repeated presence of An. gambiae s.s. in treeholes with water. Production of Anopheles larvae did not correlate with habitat volume but with habitat height, showing a strong but statistically insignificant negative correlation. During a dry season, eggs recovered by rinsing dry treeholes hatched into 2.5 +/- 3.06 An. gambiae and 7.9 +/- 8.2 Aedes larvae. In cage experiments, An. gambiae s.s. laid more eggs in water originating from treeholes than in distilled or lake water, implying preference for ovipositing in this habitat. Our findings indicate that treeholes represent a hitherto unrecognized habitat for malaria vectors, which needs further studies. PMID:18165501

  3. 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.

  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. 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...

  6. Deforestation and Vectorial Capacity of Anopheles gambiae Giles Mosquitoes in Malaria Transmission, Kenya

    OpenAIRE

    Afrane, Yaw A; Little, Tom J.; Lawson, Bernard W; Githeko, Andrew K; Yan, Guiyun

    2008-01-01

    We investigated the effects of deforestation on microclimates and sporogonic development of Plasmodium falciparum parasites in Anopheles gambiae mosquitoes in an area of the western Kenyan highland prone to malaria epidemics. An. gambiae mosquitoes were fed with P. falciparum–infected blood through membrane feeders. Fed mosquitoes were placed in houses in forested and deforested areas in a highland area (1,500 m above sea level) and monitored for parasite development. Deforested sites had hig...

  7. A reliable morphological method to assess the age of male Anopheles gambiae

    OpenAIRE

    Killeen Gerry F; Ng'habi Kija R; Huho Bernadette J; Nkwengulila Gamba; Knols Bart GJ; Ferguson Heather M

    2006-01-01

    Abstract Background Release of genetically-modified (GM) or sterile male mosquitoes for malaria control is hampered by inability to assess the age and mating history of free-living male Anopheles. Methods Age and mating-related changes in the reproductive system of male Anopheles gambiae were quantified and used to fit predictive statistical models. These models, based on numbers of spermatocysts, relative size of sperm reservoir and presence/absence of a clear area around the accessory gland...

  8. A reliable morphological method to assess the age of male Anopheles gambiae

    OpenAIRE

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

    2006-01-01

    Background Release of genetically-modified (GM) or sterile male mosquitoes for malaria control is hampered by inability to assess the age and mating history of free-living male Anopheles. Methods Age and mating-related changes in the reproductive system of male Anopheles gambiae were quantified and used to fit predictive statistical models. These models, based on numbers of spermatocysts, relative size of sperm reservoir and presence/absence of a clear area around the accessory gla...

  9. 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...

  10. Development of a molecular assay to detect predation on Anopheles gambiae complex larval stages.

    Science.gov (United States)

    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

  11. Identification and Characterization of Two Novel RNA Viruses from Anopheles gambiae Species Complex Mosquitoes

    Science.gov (United States)

    Carissimo, Guillaume; Eiglmeier, Karin; Reveillaud, Julie; Holm, Inge; Diallo, Mawlouth; Diallo, Diawo; Vantaux, Amélie; Kim, Saorin; Ménard, Didier; Siv, Sovannaroth; Belda, Eugeni; Bischoff, Emmanuel; Antoniewski, Christophe; Vernick, Kenneth D.

    2016-01-01

    Mosquitoes of the Anopheles gambiae complex display strong preference for human bloodmeals and are major malaria vectors in Africa. However, their interaction with viruses or role in arbovirus transmission during epidemics has been little examined, with the exception of O’nyong-nyong virus, closely related to Chikungunya virus. Deep-sequencing has revealed different RNA viruses in natural insect viromes, but none have been previously described in the Anopheles gambiae species complex. Here, we describe two novel insect RNA viruses, a Dicistrovirus and a Cypovirus, found in laboratory colonies of An. gambiae taxa using small-RNA deep sequencing. Sequence analysis was done with Metavisitor, an open-source bioinformatic pipeline for virus discovery and de novo genome assembly. Wild-collected Anopheles from Senegal and Cambodia were positive for the Dicistrovirus and Cypovirus, displaying high sequence identity to the laboratory-derived virus. Thus, the Dicistrovirus (Anopheles C virus, AnCV) and Cypovirus (Anopheles Cypovirus, AnCPV) are components of the natural virome of at least some anopheline species. Their possible influence on mosquito immunity or transmission of other pathogens is unknown. These natural viruses could be developed as models for the study of Anopheles-RNA virus interactions in low security laboratory settings, in an analogous manner to the use of rodent malaria parasites for studies of mosquito anti-parasite immunity. PMID:27138938

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

    Directory of Open Access Journals (Sweden)

    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.

  13. 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.

  14. 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

  15. 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

  16. Role of Testis-Specific Gene Expression in Sex-Chromosome Evolution of Anopheles gambiae

    Science.gov (United States)

    Baker, Dean A.; Russell, Steven

    2011-01-01

    Gene expression in Anopheles gambiae shows a deficiency of testis-expressed genes on the X chromosome associated with an excessive movement of retrogene duplication. We suggest that the degeneration of sex chromosomes in this monandrous species is likely the result of pressures from X inactivation, dosage compensation, and sexual antagonism. PMID:21890740

  17. 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

  18. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  20. The distribution of insecticide resistance in Anopheles gambiae s.l. populations from Cameroon: an update.

    Science.gov (United States)

    Ndjemaï, Hamadou N M; Patchoké, Salomon; Atangana, Jean; Etang, Josiane; Simard, Fréderic; Bilong, Charles F Bilong; Reimer, Lisa; Cornel, Anthony; Lanzaro, Gregory C; Fondjo, Etienne

    2009-11-01

    Insecticides are a key component of vector-based malaria control programmes in Cameroon. As part of ongoing resistance surveillance efforts, Anopheles gambiae s.l. female mosquitoes were exposed to organochlorine (DDT), a carbamate (bendiocarb), an organophosphate (malathion), and three pyrethroids (deltamethrin, lambda-cyhalothrin and permethrin) in WHO bioassay test kits. Results indicated a higher level of resistance (reduced mortality and knockdown effect) to DDT and pyrethroids in populations of A. gambiae s.s. than in A. arabiensis. The West and East African knockdown resistance (kdr) mutations were found in both species but at much higher frequencies in A. gambiae s.s. The West Africa kdr mutant was also more frequent in the A. gambiae S form than in the M form. No resistance to bendiocarb and malathion was found. Carbamate and organophosphorous compounds could thus be used as alternatives in locations in Cameroon where pyrethroid-resistant populations are found. PMID:19155034

  1. 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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    Ferguson Heather M

    2011-10-01

    Full Text Available Abstract 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 the two major and widespread malaria vectors in sub-Saharan Africa. Several studies have examined the ecology and population dynamics of these vectors. Ecological conditions along the Kilombero valley in Tanzania influence the distribution and population density of these two vector species. It remains unclear whether the ecological diversity within the Kilombero valley has affected the population structure of An. gambiae s.l. populations. The goal of this study was to characterise the genetic structure of sympatric An. gambiae s.s and An. arabiensis populations along the Kilombero valley. Methodology Mosquitoes were collected from seven locations in Tanzania: six from the Kilombero valley and one outside the valley (~700 km away as an out-group. To archive a genome-wide coverage, 13 microsatellite markers from chromosomes X, 2 and 3 were used. Results High levels of genetic differentiation among An. arabiensis populations was observed, as opposed to An. gambiae s.s., which was genetically undifferentiated across the 6,650 km2 of the Kilombero valley landscape. It appears that genetic differentiation is not attributed to physical barriers or distance, but possibly by ecological diversification within the Kilombero valley. Genetic divergence among An. arabiensis populations (FST = 0.066 was higher than that of the well-known M and S forms of An. gambiae s. s. in West and Central Africa (FST = 0.035, suggesting that these populations are maintained by some level of reproductive isolation. Conclusion It was hypothesized that ecological diversification across the valley may be a driving force for observed An. arabiensis genetic divergence. The

  4. 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...

  5. 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

  6. 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

  7. 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

  8. 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 ...

  9. 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...

  10. The distribution of insecticide resistance in Anopheles gambiae s.l. populations from Cameroon: an update

    OpenAIRE

    Ndjemai, H. N. M.; Patchoke, S.; Atangana, J.; Etang, J.; Simard, Frédéric; Bilong, C. F. B.; Reimer, L.; Cornel, A.; Lanzaro, G.C.; Fondjo, E

    2009-01-01

    Insecticides are a key component of vector-based malaria control programmes in Cameroon. As part of ongoing resistance surveillance efforts, Anopheles gambiae s.l. female mosquitoes were exposed to organochlorine (DDT), a carbamate (bendiocarb), an organophosphate (malathion), and three pyrethroids (deltamethrin, lambda-cyhalothrin and permethrin) in WHO bioassay test kits. Results indicated a higher level of resistance (reduced mortality and knockdown effect) to DDT and pyrethroids in popula...

  11. 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...

  12. 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...

  13. A behavioral mechanism underlying ecological divergence in the malaria mosquito Anopheles gambiae

    OpenAIRE

    Gimonneau, Geoffrey; Bouyer, Jérémy; Morand, Serge; Besansky, Nora J.; Diabate, Abdoulaye; Simard, Frédéric

    2010-01-01

    Disruptive selection mediated by predation on aquatic immature stages has been proposed as a major force driving ecological divergence and fostering speciation between the M and S molecular forms of the African malaria mosquito, Anopheles gambiae. In the dry savannahs of West Africa where both molecular forms co-occur, the S form thrives in temporary pools filled with rainwater, whereas the M form preferentially breeds in permanent freshwater habitats where predator pressure is higher. Here, ...

  14. 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...

  15. Factors affecting the vectorial competence of Anopheles gambiae: a question of scale

    OpenAIRE

    Takken, W; Lindsay, S. W.

    2003-01-01

    Malaria transmission in Africa is without doubt governed by the existence of a group of highly efficient vectors, of which Anopheles gambiae Giles sensu stricto is predominant. The endophilic and anthropophagic behaviours of this mosquito create an intimate association between the human reservoir and insect vectors of malaria. In this paper several mosquito-related and environmental factors that modulate the transmission intensity of malaria in Africa are discussed, in order to illustrate the...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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 ...

  2. Multiple Origins of Knockdown Resistance Mutations in the Afrotropical Mosquito Vector Anopheles gambiae

    OpenAIRE

    Pinto, Joao; Lynd, Amy; Vicente, José L; Santolamazza, Federica; Randle, Nadine P.; Gentile, Gabriele; Moreno, Marta; Simard, Frédéric; Charlwood, Jaques Derek; Rosário, Virgilio E do; Caccone, Adalgisa; Torre, Alessandra della; Donelly, Martin J.

    2007-01-01

    How often insecticide resistance mutations arise in natural insect populations is a fundamental question for understanding the evolution of resistance and also for modeling its spread. Moreover, the development of resistance is regarded as a favored model to study the molecular evolution of adaptive traits. In the malaria vector Anopheles gambiae two point mutations (L1014F and L1014S) in the voltage-gated sodium channel gene, that confer knockdown resistance (kdr) to DDT and pyrethroid insec...

  3. 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.

  4. Multimodal pyrethroid resistance in malaria vectors, Anopheles gambiae s.s., Anopheles arabiensis, and Anopheles funestus s.s. in western Kenya.

    Science.gov (United States)

    Kawada, Hitoshi; Dida, Gabriel O; Ohashi, Kazunori; Komagata, Osamu; Kasai, Shinji; Tomita, Takashi; Sonye, George; Maekawa, Yoshihide; Mwatele, Cassian; Njenga, Sammy M; Mwandawiro, Charles; Minakawa, Noboru; Takagi, Masahiro

    2011-01-01

    Anopheles gambiae s.s., Anopheles arabiensis, and Anopheles funestus s.s. are the most important species for malaria transmission. Pyrethroid resistance of these vector mosquitoes is one of the main obstacles against effective vector control. The objective of the present study was to monitor the pyrethroid susceptibility in the 3 major malaria vectors in a highly malaria endemic area in western Kenya and to elucidate the mechanisms of pyrethroid resistance in these species. Gembe East and West, Mbita Division, and 4 main western islands in the Suba district of the Nyanza province in western Kenya were used as the study area. Larval and adult collection and bioassay were conducted, as well as the detection of point mutation in the voltage-gated sodium channel (1014L) by using direct DNA sequencing. A high level of pyrethroid resistance caused by the high frequency of point mutations (L1014S) was detected in An. gambiae s.s. In contrast, P450-related pyrethroid resistance seemed to be widespread in both An. arabiensis and An. funestus s.s. Not a single L1014S mutation was detected in these 2 species. A lack of cross-resistance between DDT and permethrin was also found in An. arabiensis and An. funestus s.s., while An. gambiae s.s. was resistant to both insecticides. It is noteworthy that the above species in the same area are found to be resistant to pyrethroids by their unique resistance mechanisms. Furthermore, it is interesting that 2 different resistance mechanisms have developed in the 2 sibling species in the same area individually. The cross resistance between permethrin and DDT in An. gambiae s.s. may be attributed to the high frequency of kdr mutation, which might be selected by the frequent exposure to ITNs. Similarly, the metabolic pyrethroid resistance in An. arabiensis and An. funestus s.s. is thought to develop without strong selection by DDT. PMID:21853038

  5. 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 ...

  6. 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

  7. Following in Soper's footsteps: northeast Brazil 63 years after eradication of Anopheles gambiae.

    Science.gov (United States)

    Killeen, Gerry F

    2003-10-01

    Sub-Saharan Africa has long suffered under the yoke of the Anopheles gambiae mosquito, but for northeast Brazil (figure 1) its arrival over 60 years ago was a new and horrifying experience. This African mosquito is an exceptionally effective malaria vector because it is well adapted to feeding upon people and to exploiting aquatic habitats associated with our daily activities. Anopheles gambiae sensu lato probably accounts for most of the world's malaria deaths and socioeconomic burden. Fortunately, the Brazilian experience had a happy ending. The prospect of A gambiae spreading across much of the Americas motivated a ruthlessly effective response that deserves a special and heroic place in the annals of public health. Building on the successes and infrastructure of the Yellow Fever Service for Aedes aegypti elimination, the Rockefeller Foundation and Brazilian government collaborated to form a new Malaria Service of the Northeast. This new entity rolled the invader back into oblivion with an aggressive eradication campaign, focusing primarily upon larviciding of all potential habitats. The driving force of this endeavour was an enigmatic man called Fred Soper whose sheer will and determination was a key element in this success, and a source of inspiration today (see Killeen GF, et al. Eradication of Anopheles gambiae from Brazil: lessons for malaria control in Africa? Lancet Infect Dis 2002; 2: 618-27). I recently took an opportunity to fulfil a long-held dream and follow in some of Soper's footsteps. Tired of gazing at yellowing maps like figure 1, I went to see the northeast of Brazil for myself. PMID:14522266

  8. A comprehensive gene expression atlas of sex- and tissue-specificity in the malaria vector, Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    Crisanti Andrea

    2011-06-01

    Full Text Available Abstract Background The mosquito, Anopheles gambiae, is the primary vector of human malaria, a disease responsible for millions of deaths each year. To improve strategies for controlling transmission of the causative parasite, Plasmodium falciparum, we require a thorough understanding of the developmental mechanisms, physiological processes and evolutionary pressures affecting life-history traits in the mosquito. Identifying genes expressed in particular tissues or involved in specific biological processes is an essential part of this process. Results In this study, we present transcription profiles for ~82% of annotated Anopheles genes in dissected adult male and female tissues. The sensitivity afforded by examining dissected tissues found gene activity in an additional 20% of the genome that is undetected when using whole-animal samples. The somatic and reproductive tissues we examined each displayed patterns of sexually dimorphic and tissue-specific expression. By comparing expression profiles with Drosophila melanogaster we also assessed which genes are well conserved within the Diptera versus those that are more recently evolved. Conclusions Our expression atlas and associated publicly available database, the MozAtlas (http://www.tissue-atlas.org, provides information on the relative strength and specificity of gene expression in several somatic and reproductive tissues, isolated from a single strain grown under uniform conditions. The data will serve as a reference for other mosquito researchers by providing a simple method for identifying where genes are expressed in the adult, however, in addition our resource will also provide insights into the evolutionary diversity associated with gene expression levels among species.

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

    Directory of Open Access Journals (Sweden)

    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. Environmental factors associated with the malaria vectors Anopheles gambiae and Anopheles funestus in Kenya

    OpenAIRE

    Hemingway Janet; Kelly-Hope Louise A; McKenzie F Ellis

    2009-01-01

    Abstract Background The Anopheles gambiae and Anopheles funestus mosquito species complexes are the primary vectors of Plasmodium falciparum malaria in sub-Saharan Africa. To better understand the environmental factors influencing these species, the abundance, distribution and transmission data from a south-eastern Kenyan study were retrospectively analysed, and the climate, vegetation and elevation data in key locations compared. Methods Thirty villages in Malindi, Kilifi and Kwale Districts...

  11. Remarkable diversity of intron-1 of the para voltage-gated sodium channel gene in an Anopheles gambiae/Anopheles coluzzii hybrid zone.

    OpenAIRE

    Santolamazza, F.; Caputo, B.; Nwakanma, DC; Fanello, C.; Petrarca, V.; Conway, DJ; Weetman, D; J. Pinto; Mancini, E.; della Torre, A.

    2015-01-01

    Background Genomic differentiation between Anopheles gambiae and Anopheles coluzzii - the major malaria vectors in sub-Saharan Africa - is localized into large “islands” toward the centromeres of chromosome-X and the two autosomes. Linkage disequilibrium between these genomic islands was first detected between species-specific polymorphisms within ribosomal DNA genes (IGS-rDNA) on the X-chromosome and a single variant at position 702 of intron 1 (Int-1702) of the para Voltage-Gated Sodium Cha...

  12. Gene Expression-Based Biomarkers for Anopheles gambiae Age Grading

    OpenAIRE

    Wang, Mei-Hui; Marinotti, Osvaldo; Zhong, Daibin; JAMES, ANTHONY A.; Walker, Edward; Guda, Tom; Kweka, Eliningaya J.; Githure, John; Yan, Guiyun

    2013-01-01

    Information on population age structure of mosquitoes under natural conditions is fundamental to the understanding of vectorial capacity and crucial for assessing the impact of vector control measures on malaria transmission. Transcriptional profiling has been proposed as a method for predicting mosquito age for Aedes and Anopheles mosquitoes, however, whether this new method is adequate for natural conditions is unknown. This study tests the applicability of transcriptional profiling for age...

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

    Directory of Open Access Journals (Sweden)

    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

  14. Multiple insecticide resistance in Anopheles gambiae s.l. populations from Burkina Faso, West Africa.

    Directory of Open Access Journals (Sweden)

    Moussa Namountougou

    Full Text Available Malaria control programs are being jeopardized by the spread of insecticide resistance in mosquito vector populations. The situation in Burkina Faso is emblematic with Anopheles gambiae populations showing high levels of resistance to most available compounds. Although the frequency of insecticide target-site mutations including knockdown resistance (kdr and insensitive acetylcholinesterase (Ace-1(R alleles has been regularly monitored in the area, it is not known whether detoxifying enzymes contribute to the diversity of resistance phenotypes observed in the field. Here, we propose an update on the phenotypic diversity of insecticide resistance in An. gambiae populations sampled from 10 sites in Burkina Faso in 2010. Susceptibility to deltamethrin, permethrin, DDT, bendiocarb and fenithrotion was assessed. Test specimens (N = 30 per locality were identified to species and molecular form and their genotype at the kdr and Ace-1 loci was determined. Detoxifying enzymes activities including non-specific esterases (NSEs, oxydases (cytochrome P450 and Glutathione S-Transferases (GSTs were measured on single mosquitoes (N = 50 from each test locality and compared with the An. gambiae Kisumu susceptible reference strain. In all sites, mosquitoes demonstrated multiple resistance phenotypes, showing reduced mortality to several insecticidal compounds at the same time, although with considerable site-to-site variation. Both the kdr 1014L and Ace-1(R 119S resistant alleles were detected in the M and the S forms of An. gambiae, and were found together in specimens of the S form. Variation in detoxifying enzyme activities was observed within and between vector populations. Elevated levels of NSEs and GSTs were widespread, suggesting multiple resistance mechanisms segregate within An. gambiae populations from this country. By documenting the extent and diversity of insecticide resistance phenotypes and the putative combination of their underlying

  15. 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

  16. 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.

  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. 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.

  19. 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...

  20. Anopheles gambiae heat shock protein cognate 70B impedes o'nyong-nyong virus replication

    OpenAIRE

    Higgs Stephen; Vanlandingham Dana L; Tsetsarkin Konstantin A; Hong Young S; Sim Cheolho; Collins Frank H

    2007-01-01

    Abstract Background Phylogenetic and functional analysis was conducted on an Anopheles gambiae gene, ENSANGG00000017398. Based on phylogenetic analysis, this gene belongs to the same lineage as Heat shock protein cognate 70-4 (Hsc70-4) in Drosophila. Accordingly, we propose to name this gene Heat shock protein cognate 70B (HSC70B). We previously reported that expression of HSC70B and other genes including elongation factor-1α (EF-1α) and the agglutinin attachment subunit (agglutinin) were up-...

  1. 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...

  2. 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

  3. 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

  4. 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......, showing that the receptor was quite selective for myosuppressin. These results also showed that the myosuppressin receptor needs a much larger portion than the C-terminal FLRFamide sequence for its activation. The insect myosuppressins are often grouped together with the insect FMRFamides under the name...

  5. 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

  6. 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

  7. Three years of insecticide resistance monitoring in Anopheles gambiae in Burkina Faso: resistance on the rise?

    Directory of Open Access Journals (Sweden)

    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

  8. Predation efficiency of Anopheles gambiae larvae by aquatic predators in western Kenya highlands

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    Nyindo Mramba

    2011-07-01

    Full Text Available Abstract Background The current status of insecticide resistance in mosquitoes and the effects of insecticides on non-target insect species have raised the need for alternative control methods for malaria vectors. Predation has been suggested as one of the important regulation mechanisms for malaria vectors in long-lasting aquatic habitats, but the predation efficiency of the potential predators is largely unknown in the highlands of western Kenya. In the current study, we examined the predation efficiency of five predators on Anopheles gambiae s.s larvae in 24 hour and semi- field evaluations. Methods Predators were collected from natural habitats and starved for 12 hours prior to starting experiments. Preliminary experiments were conducted to ascertain the larval stage most predated by each predator species. When each larval instar was subjected to predation, third instar larvae were predated at the highest rate. Third instar larvae of An. gambiae were introduced into artificial habitats with and without refugia at various larval densities. The numbers of surviving larvae were counted after 24 hours in 24. In semi-field experiments, the larvae were counted daily until they were all either consumed or had developed to the pupal stage. Polymerase chain reaction was used to confirm the presence of An. gambiae DNA in predator guts. Results Experiments found that habitat type (P P P P An. gambiae DNA was found in at least three out of ten midguts for all predator species. Gambusia affins was the most efficient, being three times more efficient than tadpoles. Conclusion These experiments provide insight into the efficiency of specific natural predators against mosquito larvae. These naturally occurring predators may be useful in biocontrol strategies for aquatic stage An. gambiae mosquitoes. Further investigations should be done in complex natural habitats for these predators.

  9. Ultrastructure of a microsporidium brachiola gambiae n.sp.parasitising a mosquito anopheles gamblae, a malaria vector

    Czech Academy of Sciences Publication Activity Database

    Weiser, Jaroslav; Žižka, Zdeněk

    - (2003), s. 35-36. ISSN 1214-021X. [Conference on Cell Biology /5./. České Budějovice, 08.09.2003-10.09.2003] Institutional research plan: CEZ:AV0Z5020903 Keywords : anopheles gambiae * malaria * vector Subject RIV: EE - Microbiology, Virology

  10. 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

  11. 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

  12. A reliable morphological method to assess the age of male Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    Killeen Gerry F

    2006-07-01

    Full Text Available Abstract Background Release of genetically-modified (GM or sterile male mosquitoes for malaria control is hampered by inability to assess the age and mating history of free-living male Anopheles. Methods Age and mating-related changes in the reproductive system of male Anopheles gambiae were quantified and used to fit predictive statistical models. These models, based on numbers of spermatocysts, relative size of sperm reservoir and presence/absence of a clear area around the accessory gland, were evaluated using an independent sample of mosquitoes whose status was blinded during the experiment. Results The number of spermatocysts in male testes decreased with age, and the relative size of their sperm reservoir increased. The presence of a clear area around accessory glands was also linked to age and mating status. A quantitative model was able to categorize males from the blind trial into age groups of young (≤ 4 days and old (> 4 days with an overall efficiency of 89%. Using the parameters of this model, a simple table was compiled that can be used to predict male age. In contrast, mating history could not be reliably assessed as virgins could not be distinguished from mated males. Conclusion Simple assessment of a few morphological traits which are easily collected in the field allows accurate age-grading of male An. gambiae. This simple, yet robust, model enables evaluation of demographic patterns and mortality in wild and released males in populations targeted by GM or sterile male-based control programmes.

  13. 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.

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

    Science.gov (United States)

    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

  15. 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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  18. 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.

  19. Visual and olfactory associative learning in the malaria vector Anopheles gambiae sensu stricto

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    Chilaka Nora

    2012-01-01

    Full Text Available Abstract Background Memory and learning are critical aspects of the ecology of insect vectors of human pathogens because of their potential effects on contacts between vectors and their hosts. Despite this epidemiological importance, there have been only a limited number of studies investigating associative learning in insect vector species and none on Anopheline mosquitoes. Methods A simple behavioural assays was developed to study visual and olfactory associative learning in Anopheles gambiae, the main vector of malaria in Africa. Two contrasted membrane qualities or levels of blood palatability were used as reinforcing stimuli for bi-directional conditioning during blood feeding. Results Under such experimental conditions An. gambiae females learned very rapidly to associate visual (chequered and white patterns and olfactory cues (presence and absence of cheese or Citronella smell with the reinforcing stimuli (bloodmeal quality and remembered the association for up to three days. Associative learning significantly increased with the strength of the conditioning stimuli used. Importantly, learning sometimes occurred faster when a positive reinforcing stimulus (palatable blood was associated with an innately preferred cue (such as a darker visual pattern. However, the use of too attractive a cue (e.g. Shropshire cheese smell was counter-productive and decreased learning success. Conclusions The results address an important knowledge gap in mosquito ecology and emphasize the role of associative memory for An. gambiae's host finding and blood-feeding behaviour with important potential implications for vector control.

  20. Immune factor Gambif1, a new rel family member from the human malaria vector, Anopheles gambiae.

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    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

  1. The JNK pathway is a key mediator of Anopheles gambiae antiplasmodial immunity.

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    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.

  2. The JNK pathway is a key mediator of Anopheles gambiae antiplasmodial immunity.

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    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

  3. 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

  4. 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.

  5. A splice variant of PGRP-LC required for expression of antimicrobial peptides in Anopheles gambiae

    Institute of Scientific and Technical Information of China (English)

    HUI LIN; LINGMIN ZHANG; CORALIA LUNA; NGO T.HOA; LIANGBIAO ZHENG

    2007-01-01

    Members of the peptidoglycan recognition protein (PGRP) family play essential roles in different manifestations of immune responses in insects. PGRP-LC, one of seven members of this family in the malaria vector Anopheles gambiae produced several spliced variants. Here we show that PGRP-LC, and not other members of the PGRP family nor the six members of the Gram-negative binding protein families, is required for the expression of antimicrobial peptide genes (such as CEC1 and GAM1) under the control of the Imd-Rel2 pathway in an A. gambiae cell line, 4a3A. PGRP-LC produces many splice variants that can be classified into three sub-groups (LC1, LC2 and LC3), based on the carboxyl terminal sequences. RNA interference against one LC1 sub-group resulted in dramatic reduction of CEC1 and GAM1. Over-expression of LC1 a and to a lesser extent LC3a (a member of the LC1 and LC3 sub-group, respectively) in the 4a3A cell line enhances the expression of CEC1 and GAM1. These results demonstrate that the LC1-subgroup splice variants are essential for the expression of CEC1 and GAM1 in A. gambiae cell line.

  6. 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

  7. 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

  8. 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

  9. Chromosome Inversions, Genomic Differentiation and Speciation in the African Malaria Mosquito Anopheles gambiae

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    Lee, Yoosook; Collier, Travis C.; Sanford, Michelle R.; Marsden, Clare D.; Fofana, Abdrahamane; Cornel, Anthony J.; Lanzaro, Gregory C.

    2013-01-01

    The African malaria vector, Anopheles gambiae, is characterized by multiple polymorphic chromosomal inversions and has become widely studied as a system for exploring models of speciation. Near complete reproductive isolation between different inversion types, known as chromosomal forms, has led to the suggestion that A. gambiae is in early stages of speciation, with divergence evolving in the face of considerable gene flow. We compared the standard chromosomal arrangement (Savanna form) with genomes homozygous for j, b, c, and u inversions (Bamako form) in order to identify regions of genomic divergence with respect to inversion polymorphism. We found levels of divergence between the two sub-taxa within some of these inversions (2Rj and 2Rb), but at a level lower than expected and confined near the inversion breakpoints, consistent with a gene flux model. Unexpectedly, we found that the majority of diverged regions were located on the X chromosome, which contained half of all significantly diverged regions, with much of this divergence located within exons. This is surprising given that the Bamako and Savanna chromosomal forms are both within the S molecular form that is defined by a locus near centromere of X chromosome. Two X-linked genes (a heat shock protein and P450 encoding genes) involved in reproductive isolation between the M and S molecular forms of A. gambiae were also significantly diverged between the two chromosomal forms. These results suggest that genes mediating reproductive isolation are likely located on the X chromosome, as is thought to be the case for the M and S molecular forms. We conclude that genes located on the sex chromosome may be the major force driving speciation between these chromosomal forms of A. gambiae. PMID:23526957

  10. Transcription profiling of a recently colonised pyrethroid resistant Anopheles gambiae strain from Ghana

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    Donnelly Martin J

    2007-01-01

    Full Text Available Abstract Background Mosquito resistance to the pyrethroid insecticides used to treat bednets threatens the sustainability of malaria control in sub-Saharan Africa. While the impact of target site insensitivity alleles is being widely discussed the implications of insecticide detoxification – though equally important – remains elusive. The successful development of new tools for malaria intervention and management requires a comprehensive understanding of insecticide resistance, including metabolic resistance mechanisms. Although three enzyme families (cytochrome P450s, glutathione S-transferases and carboxylesterases have been widely associated with insecticide detoxification the role of individual enzymes is largely unknown. Results Here, constitutive expression patterns of genes putatively involved in conferring pyrethroid resistance was investigated in a recently colonised pyrethroid resistant Anopheles gambiae strain from Odumasy, Southern Ghana. RNA from the resistant strain and a standard laboratory susceptible strain, of both sexes was extracted, reverse transcribed and labelled with either Cy3- or Cy5-dye. Labelled cDNA was co-hybridised to the detox chip, a custom-made microarray containing over 230 A. gambiae gene fragments predominantly from enzyme families associated with insecticide resistance. After hybridisation, Cy3- and Cy5-signal intensities were measured and compared gene by gene. In both females and males of the resistant strain the cytochrome P450s CYP6Z2 and CYP6M2 are highly over-expressed along with a member of the superoxide dismutase (SOD gene family. Conclusion These genes differ from those found up-regulated in East African strains of pyrethroid resistant A. gambiae and constitute a novel set of candidate genes implicated in insecticide detoxification. These data suggest that metabolic resistance may have multiple origins in A. gambiae, which has strong implications for the management of resistance.

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

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    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.

  12. The interplay between tubulins and P450 cytochromes during Plasmodium berghei invasion of Anopheles gambiae midgut.

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    Rute C Félix

    Full Text Available BACKGROUND: Plasmodium infection increases the oxidative stress inside the mosquito, leading to a significant alteration on transcription of Anopheles gambiae detoxification genes. Among these detoxification genes several P450 cytochromes and tubulins were differently expressed, suggesting their involvement in the mosquito's response to parasite invasion. P450 cytochromes are usually involved in the metabolism and detoxification of several compounds, but are also regulated by several pathogens, including malaria parasite. Tubulins are extremely important as components of the cytoskeleton, which rearrangement functions as a response to malaria parasite invasion. METHODOLOGY/PRINCIPAL FINDINGS: Gene silencing methods were used to uncover the effects of cytochrome P450 reductase, tubulinA and tubulinB silencing on the A. gambiae response to Plasmodium berghei invasion. The role of tubulins in counter infection processes was also investigated by inhibiting their effect. Colchicine, vinblastine and paclitaxel, three different tubulin inhibitors were injected into A. gambiae mosquitoes. Twenty-four hours post injection these mosquitoes were infected with P. berghei through a blood meal from infected CD1 mice. Cytochrome P450 gene expression was measured using RT-qPCR to detect differences in cytochrome expression between silenced, inhibited and control mosquitoes. Results showed that cytochrome P450 reductase silencing, as well as tubulin (A and B silencing and inhibition affected the efficiency of Plasmodium infection. Silencing and inhibition also affected the expression levels of cytochromes P450. CONCLUSIONS: Our results suggest the existence of a relationship between tubulins and P450 cytochromes during A. gambiae immune response to P. berghei invasion. One of the P450 cytochromes in this study, CYP6Z2, stands out as the potential link in this association. Further work is needed to fully understand the role of tubulin genes in the response to

  13. Chromosome inversions, genomic differentiation and speciation in the African malaria mosquito Anopheles gambiae.

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    Yoosook Lee

    Full Text Available The African malaria vector, Anopheles gambiae, is characterized by multiple polymorphic chromosomal inversions and has become widely studied as a system for exploring models of speciation. Near complete reproductive isolation between different inversion types, known as chromosomal forms, has led to the suggestion that A. gambiae is in early stages of speciation, with divergence evolving in the face of considerable gene flow. We compared the standard chromosomal arrangement (Savanna form with genomes homozygous for j, b, c, and u inversions (Bamako form in order to identify regions of genomic divergence with respect to inversion polymorphism. We found levels of divergence between the two sub-taxa within some of these inversions (2Rj and 2Rb, but at a level lower than expected and confined near the inversion breakpoints, consistent with a gene flux model. Unexpectedly, we found that the majority of diverged regions were located on the X chromosome, which contained half of all significantly diverged regions, with much of this divergence located within exons. This is surprising given that the Bamako and Savanna chromosomal forms are both within the S molecular form that is defined by a locus near centromere of X chromosome. Two X-linked genes (a heat shock protein and P450 encoding genes involved in reproductive isolation between the M and S molecular forms of A. gambiae were also significantly diverged between the two chromosomal forms. These results suggest that genes mediating reproductive isolation are likely located on the X chromosome, as is thought to be the case for the M and S molecular forms. We conclude that genes located on the sex chromosome may be the major force driving speciation between these chromosomal forms of A. gambiae.

  14. Influence of Land-use on the Fitness of Anopheles gambiae, the Principal Vector of Malaria in Nigeria

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    Israel Kayode Olayemi

    2009-02-01

    Full Text Available Background: Urbanization often results in profound environmental alterations that may promote the transmission of malaria. Though, land-use practices in urban areas have been linked with proliferations of suitable larval breeding habitats of malaria vectors, no attempt has been made to systematically investigate the influence of land-use practices on malaria transmission in Nigeria. Objectives: To elucidate the influence of land-use practices on larval development and adult body size of Anopheles gambiae (Diptera: Culicidae mosquitoes in Minna, Nigeria. Materials and Methods: Newly-hatched larvae of An. gmbiae mosquitoes were reared in semi-natural habitats stationed in five different sites, each representing the major land-use types in the area. The larvae were monitored daily for Duration of Immature Development (DID and Immature Survival Rate (ISR; while Wing Length (WL was used as an index of adult body size. Results: DID, ISR and WL varied significantly (P < 0.05 among the land-use categories; with lager numbers of bigger mosquitoes produced at a faster rate in the artificial than natural land-use sites. Water temperature for larval development was best in the Refuse Dump (RD site (mean = 28.11 ± 2.50oC and consequently the shortest DID (mean = 9.70 ± 0.74 days, as well as, the largest mosquitoes (mean WL = 3.10 ± 0.90 mm, were recorded in this land-use category. However, while ISR was highest (mean = 96.30 ± 2.78% in Farm Land (FL, the mosquitoes that emerged from this site were the smallest (mean WL = 1.96 ± 0.51mm. The Natural Vegetation (NV land-use category was the least productive, as the larvae took the longest time (13.29 ± 1.69 days to develop, and survived least (42.94 ± 7.50% in this site. Conclusion: The land-use practices in Minna enhanced the fitness of An. gambiae, and may increase the vectorial capacity of the species for malaria transmission in the area. Targeted larviciding interventions will greatly contribute to

  15. Activité larvicide sur Anopheles gambiae Giles et composition chimique des huiles essentielles extraites de quatre plantes cultivées au Cameroun

    OpenAIRE

    Tchoumbougnang F.; Dongmo PMJ.; Sameza ML.; Mbanjo EGN.; Fotso GBT.; Zollo PHA.; Menut C.

    2009-01-01

    Larvicidal activity against Anopheles gambiae Giles and chemical composition of essential oils from four plants cultivated in Cameroon. The chemical composition of the essential oils obtained by hydrodistillation of dry leaves from Cymbopogon citrates (DC.) Stapf, Ocimum canum Sims, Ocimum gratissimum L. var 'gratissimum' L. and Thymus vulgaris L. cultivated in Cameroon were analyzed and their larvicidal activity against fourth instar larvae of Anopheles gambiae Giles were determined. The yie...

  16. 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

  17. 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.

  18. 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...

  19. 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

  20. Reactive oxygen species detoxification by catalase is a major determinant of fecundity in the mosquito Anopheles gambiae

    OpenAIRE

    DeJong, Randall J.; Miller, Lisa M; Molina-Cruz, Alvaro; Gupta, Lalita; Kumar, Sanjeev; Barillas-Mury, Carolina

    2007-01-01

    The mosquito Anopheles gambiae is a primary vector of Plasmodium parasites in Africa. The effect of aging on reproductive output in A. gambiae females from three strains that differ in their ability to melanize Plasmodium and in their systemic levels of hydrogen peroxide (H2O2), a reactive oxygen species (ROS), was analyzed. The number of eggs oviposited after the first blood meal decreases with age in all strains; however, this decline was much more pronounced in the G3 (unselected) and R (r...

  1. 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.

  2. 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

  3. 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

  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. Morphological Differentiation May Mediate Mate-Choice between Incipient Species of Anopheles gambiae s.s.

    Science.gov (United States)

    Sanford, Michelle R.; Demirci, Berna; Marsden, Clare D.; Lee, Yoosook; Cornel, Anthony J.; Lanzaro, Gregory C.

    2011-01-01

    The M and S molecular forms of Anopheles gambiae s.s. have been considered incipient species for more than ten years, yet the mechanism underlying assortative mating of these incipient species has remained elusive. The discovery of the importance of harmonic convergence of wing beat frequency in mosquito mating and its relation to wing size have laid the foundation for exploring phenotypic divergence in wing size of wild populations of the two forms. In this study, wings from field collected mosquitoes were measured for wing length and wing width from two parts of the sympatric distribution, which differ with respect to the strength of assortative mating. In Mali, where assortative mating is strong, as evidenced by low rates of hybridization, mean wing lengths and wing widths were significantly larger than those from Guinea-Bissau. In addition, mean wing widths in Mali were significantly different between molecular forms. In Guinea-Bissau, assortative mating appears comparatively reduced and wing lengths and widths did not differ significantly between molecular forms. The data presented in this study support the hypothesis that wing beat frequency may mediate assortative mating in the incipient species of A. gambiae and represent the first documentation of a morphological difference between the M and S molecular forms. PMID:22132169

  6. Comprehensive genetic dissection of the hemocyte immune response in the malaria mosquito Anopheles gambiae.

    Directory of Open Access Journals (Sweden)

    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.

  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. 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

  9. Biochemical characterization of chitin synthase activity and inhibition in the African malaria mosquito, Anopheles gambiae

    Institute of Scientific and Technical Information of China (English)

    Xin Zhang; Kun Yan Zhu

    2013-01-01

    Chitin synthase (CHS) is an important enzyme catalyzing the formation of chitin polymers in all chitin containing organisms and a potential target site for insect pest control.However,our understanding of biochemical properties of insect CHSs has been very limited.We here report enzymatic and inhibitory properties of CHS prepared from the African malaria mosquito,Anopheles gambiae.Our study,which represents the first time to use a nonradioactive method to assay CHS activity in an insect species,determined the optimal conditions for measuring the enzyme activity,including pH,temperature,and concentrations of the substrate uridine diphosphate N-acetyl-D-glucosamine (UDPGlcNAc) and Mg++.The optimal pH was about 6.5-7.0,and the highest activity was detected at temperatures between 37℃ and 44℃.Dithithreitol is required to prevent melanization of the enzyme extract.CHS activity was enhanced at low concentration of GlcNAc,but inhibited at high concentrations.Proteolytic activation of the activity is significant both in the 500×g supernatant and the 40 000×g pellet.Our study revealed only slight in vitro inhibition ofA.gambiae CHS activity by diflubenzuron and nikkomycin Z at the highest concentration (2.5μmol/L) examined.There was no in vitro inhibition by polyoxin D at any concentration examined.Furthermore,we did not observe any in vivo inhibition of CHS activity by any of these chemicals at any concentration examined.Our results suggest that the inhibition of chitin synthesis by these chemicals is not due to direct inhibition of CHS in A.gambiae.

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

    Directory of Open Access Journals (Sweden)

    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.

  11. Reactive oxygen species modulate Anopheles gambiae immunity against bacteria and Plasmodium.

    Science.gov (United States)

    Molina-Cruz, Alvaro; DeJong, Randall J; Charles, Bradley; Gupta, Lalita; Kumar, Sanjeev; Jaramillo-Gutierrez, Giovanna; Barillas-Mury, Carolina

    2008-02-01

    The involvement of reactive oxygen species (ROS) in mosquito immunity against bacteria and Plasmodium was investigated in the malaria vector Anopheles gambiae. Strains of An. gambiae with higher systemic levels of ROS survive a bacterial challenge better, whereas reduction of ROS by dietary administration of antioxidants significantly decreases survival, indicating that ROS are required to mount effective antibacterial responses. Expression of several ROS detoxification enzymes increases in the midgut and fat body after a blood meal. Furthermore, expression of several of these enzymes increases to even higher levels when mosquitoes are fed a Plasmodium berghei-infected meal, indicating that the oxidative stress after a blood meal is exacerbated by Plasmodium infection. Paradoxically, a complete lack of induction of catalase mRNA and lower catalase activity were observed in P. berghei-infected midguts. This suppression of midgut catalase expression is a specific response to ookinete midgut invasion and is expected to lead to higher local levels of hydrogen peroxide. Further reduction of catalase expression by double-stranded RNA-mediated gene silencing promoted parasite clearance by a lytic mechanism and reduced infection significantly. High mosquito mortality is often observed after P. berghei infection. Death appears to result in part from excess production of ROS, as mortality can be decreased by oral administration of uric acid, a strong antioxidant. We conclude that ROS modulate An. gambiae immunity and that the mosquito response to P. berghei involves a local reduction of detoxification of hydrogen peroxide in the midgut that contributes to limit Plasmodium infection through a lytic mechanism. PMID:18065421

  12. 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. PMID:27232122

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

    Science.gov (United States)

    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

  14. 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

  15. Intraspecific chromosomal polymorphism in the Anopheles gambiae complex as a factor affecting malaria transmission in the Kisumu area of Kenya.

    Science.gov (United States)

    Petrarca, V; Beier, J C

    1992-02-01

    The paracentric inversion polymorphisms of Anopheles gambiae and An. arabiensis populations in the Kisumu area of western Kenya were studied in relation to parameters of Plasmodium falciparum transmission. Anopheles gambiae (n = 1,387) was polymorphic for inversions b on chromosomal arm 2R and a on arm 2L, with frequencies of the inverted arrangements of 17% and 43%, respectively. Anopheles arabiensis (n = 484) was polymorphic for inversion b on chromosomal arm 2R and a on 3R, with frequencies of the inverted arrangements of 58% and 5%, respectively. Observed karyotypic frequencies did not deviate from Hardy-Weinberg equilibrium, indicating a condition of panmixia (i.e., random mating) for both species. The overall degree of intraspecific polymorphism was low, confirming findings from other zones of East Africa. No significant differences in inversion frequencies of either An. gambiae or An. arabiensis were observed, either between collecting sites or between similar sampling periods of consecutive years. At the same time, a stable, significant two-fold difference in Plasmodium infection rates was detected among An. gambiae carriers of different inversion karyotypes on chromosome 2. A significant non-uniform distribution of human- and bovid-fed specimens was also detected among the carriers of different 2Rb inversion karyotypes in indoor resting An. arabiensis. Relationships among inversion karyotypes of the two major malaria vectors in the An. gambiae complex and key factors affecting malaria transmission intensity emphasize that intraspecific variation could contribute significantly to the diversity and stability of malaria vectorial systems in Africa. PMID:1539757

  16. 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...

  17. A comprehensive transcriptomic view of renal function in the malaria vector, Anopheles gambiae

    DEFF Research Database (Denmark)

    Overend, Gayle; Cabrero, Pablo; Halberg, Kenneth Agerlin;

    2015-01-01

    Renal function is essential to maintain homeostasis. This is particularly significant for insects that undergo complete metamorphosis; larval mosquitoes must survive a freshwater habitat whereas adults are terrestrial, and mature females must maintain ion and fluid homeostasis after blood feeding....... To investigate the physiological adaptations required for successful development to adulthood, we studied the Malpighian tubule transcriptome of Anopheles gambiae using Affymetrix arrays. We assessed transcription under several conditions; as third instar larvae, as adult males fed on sugar, as adult...

  18. An Epithelial Serine Protease, AgESP, Is Required for Plasmodium Invasion in the Mosquito Anopheles gambiae

    Czech Academy of Sciences Publication Activity Database

    Rodrigues, J.; Oliveira, G. A.; Kotsyfakis, Michalis; Dixit, R.; Molina-Cruz, A.; Jochim, R.; Barillas-Mury, C.

    2012-01-01

    Roč. 7, č. 4 (2012), e35210. E-ISSN 1932-6203 Institutional support: RVO:60077344 Keywords : malaria * mosquito * serine protease * sporozoites * ookinetes * gene silencing * midgut * salivary glands * Plasmodium falciparum * Anopheles gambiae Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.730, year: 2012 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0035210

  19. 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...

  20. 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...

  1. Crystal structure of a novel type of odorant binding protein from Anopheles gambiae, belonging to the C+ class

    OpenAIRE

    Lagarde, Amandine; Spinelli, Silvia; Qiao, Huili; Tegoni, Mariella; Pelosi, Paolo; Cambillau, Christian

    2011-01-01

    Anopheles gambiae (Agam) relies on its olfactory system to target human prey, leading eventually to injection of Plasmodium falciparum, the malaria vector. Odorant-binding proteins (OBPs) are the first line of proteins involved in odorant recognition. They interact with olfactory receptors and thus constitute an interesting target for insect control. We undertook a large-scale study of proteins belonging to the olfactory system of Agam with the aim of preventing insect bites by designing stro...

  2. Crystal structure of a novel type of odorant binding protein from Anopheles gambiae, belonging to the C+ class

    OpenAIRE

    2011-01-01

    Abstract Anopheles gambiae (Agam) relies on its olfactory system to target human prey, leading eventually to injection of Plasmodium falciparum, the malaria vector. Odorant-binding proteins (OBPs) are the first line of proteins involved in odorant recognition. They interact with olfactory receptors and thus constitute an interesting target for insect control. We undertook a large-scale study of proteins belonging to the olfactory system of Agam with the aim of preventing insect bit...

  3. Variation in susceptibility of African Plasmodium falciparum malaria parasites to TEP1 mediated killing in Anopheles gambiae mosquitoes

    OpenAIRE

    Maarten Eldering; Isabelle Morlais; Geert-Jan van Gemert; Marga van de Vegte-Bolmer; Wouter Graumans; Rianne Siebelink-Stoter; Martijn Vos; Luc Abate; Will Roeffen; Teun Bousema; Levashina, Elena A.; Sauerwein, Robert W.

    2016-01-01

    Anopheles gambiae s.s. mosquitoes are efficient vectors for Plasmodium falciparum, although variation exists in their susceptibility to infection. This variation depends partly on the thioester-containing protein 1 (TEP1) and TEP depletion results in significantly elevated numbers of oocysts in susceptible and resistant mosquitoes. Polymorphism in the Plasmodium gene coding for the surface protein Pfs47 modulates resistance of some parasite laboratory strains to TEP1-mediated killing. Here, w...

  4. A Serine Protease Homolog Negatively Regulates TEP1 Consumption in Systemic Infections of the Malaria Vector Anopheles gambiae

    OpenAIRE

    Yassine, Hassan; Kamareddine, Layla; Chamat, Soulaima; Christophides, George K.; Osta, Mike A.

    2014-01-01

    Clip domain serine protease homologs are widely distributed in insect genomes and play important roles in regulating insect immune responses, yet their exact functions remain poorly understood. Here, we show that CLIPA2, a clip domain serine protease homolog of Anopheles gambiae, regulates the consumption of the mosquito complement-like protein TEP1 during systemic bacterial infections. We provide evidence that CLIPA2 localizes to microbial surfaces in a TEP1-dependent manner whereby it negat...

  5. Water quality and immatures of the M and S forms of Anopheles gambiae s.s. and An. arabiensis in a Malian village

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    Touré Yeya T

    2006-04-01

    Full Text Available Abstract Introduction The associations between the immatures of Anopheles gambiae s.s. (Diptera: Culicidae, its M and S forms, and Anopheles arabiensis among and within larval breeding habitats in Banambani, Mali were investigated under varying conditions of water quality and rainfall. The intent was to elucidate on niche partitioning of these taxa. Methods Immatures of An. arabiensis, An. gambiae s.s., and its M and S forms were sampled every alternate day for a month in mid-rainy season from three sampling sites in each of the larval breeding habitats (rock pools, swamp, and puddles. Water quality was characterized by alkalinity, conductivity, dissolved oxygen (D.O., nitrate, orthophosphate, pH, temperature, total dissolved solids (TDS, and turbidity. A type 3 analysis of the GENMOD model was used to examine the associations between the proportional frequencies of young (first and second instar larvae and old (third and fourth instar larvae and pupae or total immatures of species or forms among sampling sites within and among larval breeding habitats during a category of rainfall as influenced by water quality. Results Of the 4,174 immatures sampled, 1,300 were molecularly identified to species and forms. Significant association between the proportional frequencies of young larvae of An. arabiensis, An. gambiae s.s., its M and S forms was found among sampling sites within habitats but not among larval breeding habitats. The proportional frequencies of young larvae of M and S forms varied daily perhaps due to recruitment, mortality, and dispersal within habitats. Conductivity and TDS had significant effects when the proportional frequencies of young larvae of M and S forms among sampling sites within habitats were significantly associated. Alkalinity, D.O., orthophosphate, pH, nitrate, temperature and turbidity had no effects on niche partitioning of species and forms among sampling sites within habitats. Rainfall did not affect the frequencies

  6. 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.

  7. 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

  8. Genetic variation of male reproductive success in a laboratory population of Anopheles gambiae

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    Voordouw Maarten J

    2007-07-01

    Full Text Available Abstract Background For Anopheline mosquitoes, the vectors of human malaria, genetic variation in male reproductive success can have important consequences for any control strategy based on the release of transgenic or sterile males. Methods A quantitative genetics approach was used to test whether there was a genetic component to variation in male reproductive success in a laboratory population of Anopheles gambiae. Swarms of full sibling brothers were mated with a fixed number of females and their reproductive success was measured as (1 proportion of ovipositing females, (2 proportion of ovipositing females that produced larvae, (3 proportion of females that produced larvae, (4 number of eggs laid per female, (5 number of larvae per ovipositing female and (6 number of larvae per female. Results The proportion of ovipositing females (trait 1 and the proportion of ovipositing females that produced larvae (trait 2 differed among full sib families, suggesting a genetic basis of mating success. In contrast, the other measures of male reproductive success showed little variation due to the full sib families, as their variation are probably mostly due to differences among females. While age at emergence and wing length of the males were also heritable, they were not associated with reproductive success. Larger females produced more eggs, but males did not prefer such partners. Conclusion The first study to quantify genetic variation for male reproductive success in A. gambiae found that while the initial stages of male reproduction (i.e. the proportion of ovipositing females and the proportion of ovipositing females that produced larvae had a genetic basis, the overall reproductive success (i.e. the mean number of larvae per female did not.

  9. 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.

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

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    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.

  11. Gene expression patterns associated with blood-feeding in the malaria mosquito Anopheles gambiae

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    Hogan James R

    2005-01-01

    Full Text Available 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 the blood meal and compared their expression to transcript levels in mosquitoes with access only to a sugar solution. Results In blood-fed mosquitoes, 413 unique transcripts, approximately 25% of the total, were expressed at least two-fold above or below their levels in the sugar-fed mosquitoes, at one or more time points. These differentially expressed gene products were clustered using k-means clustering into Early Genes, Middle Genes, and Late Genes, containing 144, 130, and 139 unique transcripts, respectively. Several genes from each group were analyzed by quantitative real-time PCR in order to validate the microarray results. Conclusion The expression patterns and annotation of the genes in these three groups (Early, Middle, and Late genes are discussed in the context of female mosquitoes' physiological responses to blood feeding, including blood digestion, peritrophic matrix formation, egg development, and immunity.

  12. Mapping the Anopheles gambiae Odorant Binding Protein 1 (AgamOBP1) using modeling techniques, site directed mutagenesis, circular dichroism and ligand binding assays

    OpenAIRE

    Rusconi, B.; Maranhao, A.C.; Fuhrer, J P; Krotee, P.; Choi, S. H.; Grun, F; Thireou, T; Dimitratos, S.D.; Woods, D F; Marinotti, O.; Walter, M.F.; Eliopoulos, E.

    2012-01-01

    The major malaria vector in Sub-Saharan Africa is the Anopheles gambiae mosquito. This species is a key target of malaria control measures. Mosquitoes find humans primarily through olfaction, yet the molecular mechanisms associated with host-seeking behavior remain largely unknown. To further understand the functionality of A. gambiae odorant binding protein 1 (AgamOBP1), we combined in silico protein structure modeling and site-directed mutagenesis to generate 16 AgamOBP1 protein analogues c...

  13. Effects of bed net use, female size, and plant abundance on the first meal choice (blood vs sugar) of the malaria mosquito Anopheles gambiae

    OpenAIRE

    Stone Chris M; Jackson Bryan T; Foster Woodbridge A

    2012-01-01

    Abstract Background The purpose of this study was to determine whether the sugar-or-blood meal choice of Anopheles gambiae females one day after emergence is influenced by blood-host presence and accessibility, nectariferous plant abundance, and female size. This tested the hypothesis that the initial meal of female An. gambiae is sugar, even when a blood host is available throughout the night, and, if not, whether the use of a bed net diverts mosquitoes to sugar sources. Methods Females and ...

  14. Select small core structure carbamates exhibit high contact toxicity to "carbamate-resistant" strain malaria mosquitoes, Anopheles gambiae (Akron.

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    Dawn M Wong

    Full Text Available Acetylcholinesterase (AChE is a proven target for control of the malaria mosquito (Anopheles gambiae. Unfortunately, a single amino acid mutation (G119S in An. gambiae AChE-1 (AgAChE confers resistance to the AChE inhibitors currently approved by the World Health Organization for indoor residual spraying. In this report, we describe several carbamate inhibitors that potently inhibit G119S AgAChE and that are contact-toxic to carbamate-resistant An. gambiae. PCR-RFLP analysis was used to confirm that carbamate-susceptible G3 and carbamate-resistant Akron strains of An. gambiae carry wild-type (WT and G119S AChE, respectively. G119S AgAChE was expressed and purified for the first time, and was shown to have only 3% of the turnover number (k(cat of the WT enzyme. Twelve carbamates were then assayed for inhibition of these enzymes. High resistance ratios (>2,500-fold were observed for carbamates bearing a benzene ring core, consistent with the carbamate-resistant phenotype of the G119S enzyme. Interestingly, resistance ratios for two oxime methylcarbamates, and for five pyrazol-4-yl methylcarbamates were found to be much lower (4- to 65-fold. The toxicities of these carbamates to live G3 and Akron strain An. gambiae were determined. As expected from the enzyme resistance ratios, carbamates bearing a benzene ring core showed low toxicity to Akron strain An. gambiae (LC(50>5,000 μg/mL. However, one oxime methylcarbamate (aldicarb and five pyrazol-4-yl methylcarbamates (4a-e showed good to excellent toxicity to the Akron strain (LC(50 = 32-650 μg/mL. These results suggest that appropriately functionalized "small-core" carbamates could function as a resistance-breaking anticholinesterase insecticides against the malaria mosquito.

  15. Identification and expression profiling of putative odorant-binding proteins in the malaria mosquitoes, Anopheles gambiae and A.arabiensis

    Institute of Scientific and Technical Information of China (English)

    LI; Zhengxi; Jing-Jiang; ZHOU; SHEN; Zuorui; Lin; FIELD

    2004-01-01

    Olfaction plays a major role in host-seeking behaviour of mosquitoes. An informatics-based genome-wide analysis of odorant-binding protein (OBP) homologues is undertaken,and 32 putative OBP genes in total in the whole genome sequences of Anopheles gambiae are identified. Tissue-specific expression patterns of all A. gambiae OBP candidates are determined by semi-quantitative Reverse Transcription (RT)-PCR using mosquito actin gene as internal expression control standard. The results showed that 20 OBP candidates had strong expression in mosquito olfactory tissues (female antennae), which indicate that OBPs may play an important role in regulating mosquito olfactory behaviours. Species-specific expression patterns of all putative anopheline OBPs are also studied in two of the most important malaria vectors in A. gambiae complex, i.e.A. gambiae and A. arabiensis, which found 12 of the putative OBP genes examined displayed species-differential expression patterns. The cumulative relative expression intensity of the OBPs in A. arabiensis antennae was higher than that in A. gambiae (the ratio is 1441.45:1314.12), which might be due to their different host preference behaviour. While A.gambiae is a highly anthropophilic mosquito, A. arabiensis is more opportunistic (varying from anthropophilic to zoophilic). So the latter should need more OBPs to support its host selection preference. Identification of mosquito OBPs and verification of their tissue- and species-specific expression patterns represent the first step towards further molecular analysis of mosquito olfactory mechanism, such as recombinant expression and ligand identification.

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

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    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.

  17. Outdoor host seeking behaviour of Anopheles gambiae mosquitoes following initiation of malaria vector control on Bioko Island, Equatorial Guinea

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    Reddy Vamsi P

    2011-07-01

    Full Text Available Abstract Background Indoor-based anti-vector interventions remain the preferred means of reducing risk of malaria transmission in malaria endemic areas around the world. Despite demonstrated success in reducing human-mosquito interactions, these methods are effective solely against endophilic vectors. It may be that outdoor locations serve as an important venue of host seeking by Anopheles gambiae sensu lato (s.l. mosquitoes where indoor vector suppression measures are employed. This paper describes the host seeking activity of anopheline mosquito vectors in the Punta Europa region of Bioko Island, Equatorial Guinea. In this area, An. gambiae sensu stricto (s.s. is the primary malaria vector. The goal of the paper is to evaluate the importance of An gambiae s.l. outdoor host seeking behaviour and discuss its implications for anti-vector interventions. Methods The venue and temporal characteristics of host seeking by anopheline vectors in a hyperendemic setting was evaluated using human landing collections conducted inside and outside homes in three villages during both the wet and dry seasons in 2007 and 2008. Additionally, five bi-monthly human landing collections were conducted throughout 2009. Collections were segregated hourly to provide a time distribution of host-seeking behaviour. Results Surprisingly high levels of outdoor biting by An. gambiae senso stricto and An. melas vectors were observed throughout the night, including during the early evening and morning hours when human hosts are often outdoors. As reported previously, An. gambiae s.s. is the primary malaria vector in the Punta Europa region, where it seeks hosts outdoors at least as much as it does indoors. Further, approximately 40% of An. gambiae s.l. are feeding at times when people are often outdoors, where they are not protected by IRS or LLINs. Repeated sampling over two consecutive dry-wet season cycles indicates that this result is independent of seasonality. Conclusions

  18. [Egg morphology as an indirect method to identify Anopheles benarrochi, Anopheles oswaldoi and Anopheles rangeli (Diptera: Culicidae)].

    Science.gov (United States)

    Estrada, Dora Amparo; Quiñoes, Martha L; Sierra, Diana Maria; Calle, David A; Ruiz, Fredy; Erazo, Holmes F; Linton, Yvonne-Marie

    2003-12-01

    In the Department of Putumayo in southern Colombia, malaria transmission has continued in the absence of the 4 traditional Latin American vector species--Anopheles darlingi, Anopheles nuneztovari, Anopheles albimanus or Anopheles trinkae. Human bait collections yielded Anopheles mosquitoes and a morphological variant of Anopheles benarrochi, the adult females of which can easily be misidentified as Anopheles oswaldoi. Species identification of females of Anopheles in the subgenus Nyssorhynchus is generally difficult due to overlapping morphological characters; therefore, progeny of field collected females were link-reared to assess species identity. Herein a robust method is presented to identify the species Anopheles benarrochi, Anopheles oswaldoi and Anopheles rangeli from southern Colombia, using the morphology of the eggs induced from wild-caught females. Eggs of A. rangeli and A. benarrochi were differentiated on the basis of the anterior crown. In A. rangeli, this feature is positioned apically with high walls. In A. benarrochi, anterior crown is positioned more ventrally with comparatively shorter walls. No crown is present in A. oswaldoi. These differences are clear with the aid of a dissecting microscope and make accurate species determination possible even in field conditions. Egg morphology is shown to be an accurate, albeit indirect, method for the taxonomic determination for the three southern Colombian species and may also be useful in other regions of Latin America where the morphological variant of A. benarrochi is sympatric with A. oswaldoi. PMID:14968916

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

    DEFF Research Database (Denmark)

    Derua, Yahya A; Alifrangis, Michael; Hosea, Kenneth M;

    2012-01-01

    . 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...... 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...

  20. 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...

  1. Some strains of Plasmodium falciparum, a human malaria parasite, evade the complement-like system of Anopheles gambiae mosquitoes

    OpenAIRE

    Molina-Cruz, Alvaro; DeJong, Randall J.; Ortega, Corrie; Haile, Ashley; Abban, Ekua; Rodrigues, Janneth; Jaramillo-Gutierrez, Giovanna; Barillas-Mury, Carolina

    2012-01-01

    Plasmodium falciparum lines differ in their ability to infect mosquitoes. The Anopheles gambiae L3-5 refractory (R) line melanizes most Plasmodium species, including the Brazilian P. falciparum 7G8 line, but it is highly susceptible to some African P. falciparum strains such as 3D7, NF54, and GB4. We investigated whether these lines differ in their ability to evade the mosquito immune system. Silencing key components of the mosquito complement-like system [thioester-containing protein 1 (TEP1...

  2. Anopheles gambiae Ag-STAT, a new insect member of the STAT family, is activated in response to bacterial infection.

    OpenAIRE

    Barillas-Mury, C; Han, Y S; Seeley, D; Kafatos, F C

    1999-01-01

    A new insect member of the STAT family of transcription factors (Ag-STAT) has been cloned from the human malaria vector Anopheles gambiae. The domain involved in DNA interaction and the SH2 domain are well conserved. Ag-STAT is most similar to Drosophila D-STAT and to vertebrate STATs 5 and 6, constituting a proposed ancient class A of the STAT family. The mRNA is expressed at all developmental stages, and the protein is present in hemocytes, pericardial cells, midgut, skeletal muscle and fat...

  3. Molecular Basis for Genetic Resistance of Anopheles gambiae to Plasmodium: Structural Analysis of TEP1 Susceptible and Resistant Alleles

    OpenAIRE

    Le, Binh V.; Williams, Marni; Logarajah, Shankar; Baxter, Richard H. G.

    2012-01-01

    Thioester-containing protein 1 (TEP1) is a central component in the innate immune response of Anopheles gambiae to Plasmodium infection. Two classes of TEP1 alleles, TEP1*S and TEP1*R, are found in both laboratory strains and wild isolates, related by a greater or lesser susceptibility, respectively to both P. berghei and P. falciparum infection. We report the crystal structure of the full-length TEP1*S1 allele which, while similar to the previously determined structure of full-length TEP1*R1...

  4. 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

  5. Bacteria- and IMD pathway-independent immune defenses against Plasmodium falciparum in Anopheles gambiae.

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    Benjamin J Blumberg

    Full Text Available The mosquito Anopheles gambiae uses its innate immune system to control bacterial and Plasmodium infection of its midgut tissue. The activation of potent IMD pathway-mediated anti-Plasmodium falciparum defenses is dependent on the presence of the midgut microbiota, which activate this defense system upon parasite infection through a peptidoglycan recognition protein, PGRPLC. We employed transcriptomic and reverse genetic analyses to compare the P. falciparum infection-responsive transcriptomes of septic and aseptic mosquitoes and to determine whether bacteria-independent anti-Plasmodium defenses exist. Antibiotic treated aseptic mosquitoes mounted molecular immune responses representing a variety of immune functions upon P. falciparum infection. Among other immune factors, our analysis uncovered a serine protease inhibitor (SRPN7 and Clip-domain serine protease (CLIPC2 that were transcriptionally induced in the midgut upon P. falciparum infection, independent of bacteria. We also showed that SRPN7 negatively and CLIPC2 positively regulate the anti-Plasmodium defense, independently of the midgut-associated bacteria. Co-silencing assays suggested that these two genes may function together in a signaling cascade. Neither gene was regulated, nor modulated, by infection with the rodent malaria parasite Plasmodium berghei, suggesting that SRPN7 and CLIPC2 are components of a defense system with preferential activity towards P. falciparum. Further analysis using RNA interference determined that these genes do not regulate the anti-Plasmodium defense mediated by the IMD pathway, and both factors act as agonists of the endogenous midgut microbiota, further demonstrating the lack of functional relatedness between these genes and the bacteria-dependent activation of the IMD pathway. This is the first study confirming the existence of a bacteria-independent, anti-P. falciparum defense. Further exploration of this anti-Plasmodium defense will help clarify

  6. Multicopper oxidase-3 is a laccase associated with the peritrophic matrix of Anopheles gambiae.

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    Minglin Lang

    Full Text Available The multicopper oxidase (MCO family of enzymes includes laccases, which oxidize a broad range of substrates including polyphenols and phenylendiamines; ferroxidases, which oxidize ferrous iron; and several other oxidases with specific substrates such as ascorbate, bilirubin or copper. The genome of Anopheles gambiae, a species of mosquito, encodes five putative multicopper oxidases. Of these five, only AgMCO2 has known enzymatic and physiological functions: it is a highly conserved laccase that functions in cuticle pigmentation and tanning by oxidizing dopamine and dopamine derivatives. AgMCO3 is a mosquito-specific gene that is expressed predominantly in adult midguts and Malpighian tubules. To determine its enzymatic function, we purified recombinant AgMCO3 and analyzed its activity. AgMCO3 oxidized hydroquinone (a p-diphenol, the five o-diphenols tested, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid (ABTS, and p-phenylenediamine, but not ferrous iron. The catalytic efficiencies of AgMCO3 were similar to those of cuticular laccases (MCO2 orthologs, except that AgMCO3 oxidized all of the phenolic substrates with similar efficiencies whereas the MCO2 isoforms were less efficient at oxidizing catechol or dopa. These results demonstrate that AgMCO3 can be classified as a laccase and suggest that AgMCO3 has a somewhat broader substrate specificity than MCO2 orthologs. In addition, we observed AgMCO3 immunoreactivity in the peritrophic matrix, which functions as a selective barrier between the blood meal and midgut epithelial cells, protecting the midgut from mechanical damage, pathogens, and toxic molecules. We propose that AgMCO3 may oxidize toxic molecules in the blood meal leading to detoxification or to cross-linking of the molecules to the peritrophic matrix, thus targeting them for excretion.

  7. The molecular evolution of four anti-malarial immune genes in the Anopheles gambiae species complex

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    Simard Frederic

    2008-03-01

    Full Text Available Abstract Background If the insect innate immune system is to be used as a potential blocking step in transmission of malaria, then it will require targeting one or a few genes with highest relevance and ease of manipulation. The problem is to identify and manipulate those of most importance to malaria infection without the risk of decreasing the mosquito's ability to stave off infections by microbes in general. Molecular evolution methodologies and concepts can help identify such genes. Within the setting of a comparative molecular population genetic and phylogenetic framework, involving six species of the Anopheles gambiae complex, we investigated whether a set of four pre-selected immunity genes (gambicin, NOS, Rel2 and FBN9 might have evolved under selection pressure imposed by the malaria parasite. Results We document varying levels of polymorphism within and divergence between the species, in all four genes. Introgression and the sharing of ancestral polymorphisms, two processes that have been documented in the past, were verified in this study in all four studied genes. These processes appear to affect each gene in different ways and to different degrees. However, there is no evidence of positive selection acting on these genes. Conclusion Considering the results presented here in concert with previous studies, genes that interact directly with the Plasmodium parasite, and play little or no role in defense against other microbes, are probably the most likely candidates for a specific adaptive response against P. falciparum. Furthermore, since it is hard to establish direct evidence linking the adaptation of any candidate gene to P. falciparum infection, a comparative framework allowing at least an indirect link should be provided. Such a framework could be achieved, if a similar approach like the one involved here, was applied to all other anopheline complexes that transmit P. falciparum malaria.

  8. The effect of aliphatic carboxylic acids on olfaction-based host-seeking of the malaria mosquito Anopheles gambiae sensu stricto

    NARCIS (Netherlands)

    Smallegange, R.C.; Qiu, Y.T.; Bukovinszkine-Kiss, G.; Loon, van J.J.A.; Takken, W.

    2009-01-01

    The role of aliphatic carboxylic acids in host-seeking response of the malaria mosquito Anopheles gambiae sensu stricto was examined both in a dual-choice olfactometer and with indoor traps. A basic attractive blend of ammonia + lactic acid served as internal standard odor. Single carboxylic acids w

  9. Sugar-fermenting yeast as an organic source of carbon dioxide to attract the malaria mosquito Anopheles gambiae

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    Spitzen Jeroen

    2010-10-01

    Full Text Available Abstract Background Carbon dioxide (CO2 plays an important role in the host-seeking process of opportunistic, zoophilic and anthropophilic mosquito species and is, therefore, commonly added to mosquito sampling tools. The African malaria vector Anopheles gambiae sensu stricto is attracted to human volatiles augmented by CO2. This study investigated whether CO2, usually supplied from gas cylinders acquired from commercial industry, could be replaced by CO2 derived from fermenting yeast (yeast-produced CO2. Methods Trapping experiments were conducted in the laboratory, semi-field and field, with An. gambiae s.s. as the target species. MM-X traps were baited with volatiles produced by mixtures of yeast, sugar and water, prepared in 1.5, 5 or 25 L bottles. Catches were compared with traps baited with industrial CO2. The additional effect of human odours was also examined. In the laboratory and semi-field facility dual-choice experiments were conducted. The effect of traps baited with yeast-produced CO2 on the number of mosquitoes entering an African house was studied in the MalariaSphere. Carbon dioxide baited traps, placed outside human dwellings, were also tested in an African village setting. The laboratory and semi-field data were analysed by a χ2-test, the field data by GLM. In addition, CO2 concentrations produced by yeast-sugar solutions were measured over time. Results Traps baited with yeast-produced CO2 caught significantly more mosquitoes than unbaited traps (up to 34 h post mixing the ingredients and also significantly more than traps baited with industrial CO2, both in the laboratory and semi-field. Adding yeast-produced CO2 to traps baited with human odour significantly increased trap catches. In the MalariaSphere, outdoor traps baited with yeast-produced or industrial CO2 + human odour reduced house entry of mosquitoes with a human host sleeping under a bed net indoors. Anopheles gambiae s.s. was not caught during the field trials

  10. 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

  11. Repellent, irritant and toxic effects of 20 plant extracts on adults of the malaria vector Anopheles gambiae mosquito.

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    Emilie Deletre

    Full Text Available Pyrethroid insecticides induce an excito-repellent effect that reduces contact between humans and mosquitoes. Insecticide use is expected to lower the risk of pathogen transmission, particularly when impregnated on long-lasting treated bednets. When applied at low doses, pyrethroids have a toxic effect, however the development of pyrethroid resistance in several mosquito species may jeopardize these beneficial effects. The need to find additional compounds, either to kill disease-carrying mosquitoes or to prevent mosquito contact with humans, therefore arises. In laboratory conditions, the effects (i.e., repellent, irritant and toxic of 20 plant extracts, mainly essential oils, were assessed on adults of Anopheles gambiae, a primary vector of malaria. Their effects were compared to those of DEET and permethrin, used as positive controls. Most plant extracts had irritant, repellent and/or toxic effects on An. gambiae adults. The most promising extracts, i.e. those combining the three types of effects, were from Cymbopogon winterianus, Cinnamomum zeylanicum and Thymus vulgaris. The irritant, repellent and toxic effects occurred apparently independently of each other, and the behavioural response of adult An. gambiae was significantly influenced by the concentration of the plant extracts. Mechanisms underlying repellency might, therefore, differ from those underlying irritancy and toxicity. The utility of the efficient plant extracts for vector control as an alternative to pyrethroids may thus be envisaged.

  12. Some strains of Plasmodium falciparum, a human malaria parasite, evade the complement-like system of Anopheles gambiae mosquitoes.

    Science.gov (United States)

    Molina-Cruz, Alvaro; DeJong, Randall J; Ortega, Corrie; Haile, Ashley; Abban, Ekua; Rodrigues, Janneth; Jaramillo-Gutierrez, Giovanna; Barillas-Mury, Carolina

    2012-07-10

    Plasmodium falciparum lines differ in their ability to infect mosquitoes. The Anopheles gambiae L3-5 refractory (R) line melanizes most Plasmodium species, including the Brazilian P. falciparum 7G8 line, but it is highly susceptible to some African P. falciparum strains such as 3D7, NF54, and GB4. We investigated whether these lines differ in their ability to evade the mosquito immune system. Silencing key components of the mosquito complement-like system [thioester-containing protein 1 (TEP1), leucine-rich repeat protein 1, and Anopheles Plasmodium-responsive leucine-rich repeat protein 1] prevented melanization of 7G8 parasites, reverting the refractory phenotype. In contrast, it had no effect on the intensity of infection with NF54, suggesting that this line is able to evade TEP1-mediated lysis. When R females were coinfected with a line that is melanized (7G8) and a line that survives (3D7), the coinfection resulted in mixed infections with both live and encapsulated parasites on individual midguts. This finding shows that survival of individual parasites is parasite-specific and not systemic in nature, because parasites can evade TEP1-mediated lysis even when other parasites are melanized in the same midgut. When females from an extensive genetic cross between R and susceptible A. gambiae (G3) mosquitoes were infected with P. berghei, encapsulation was strongly correlated with the TEP1-R1 allele. However, P. falciparum 7G8 parasites were no longer encapsulated by females from this cross, indicating that the TEP1-R1 allele is not sufficient to melanize this line. Evasion of the A. gambiae immune system by P. falciparum may be the result of parasite adaptation to sympatric mosquito vectors and may be an important factor driving malaria transmission. PMID:22623529

  13. Caractérisation moléculaire des moustiques du complexe Anopheles gambiae à Mayotte et à Grande Comore

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    Léong Pock Tsy J.M.

    2003-09-01

    Full Text Available Les moustiques du complexe Anopheles gambiae ont été caractérisés sur le plan spécifique et sub-spécifique dans deux îles de l'archipel des Comores : l'Ile de Mayotte (collectivité départementale française et l'Ile de Grande Comore (Union des Comores. Les résultats sont semblables pour les deux îles et sont présentés groupés. Seule l'espèce An. gambiae s.s. a été observée (détermination sur 149 spécimens par PCR sur un amplicon d'IGS de l'ADNr. Seule la forme moléculaire S, assimilable dans cette zone géographique à la forme chromosomique Savane, a été observée (détermination sur 123 spécimens par PCR sur un autre amplicon de l'IGS de l'ADNr. Enfin, seul le sous-type IB, rencontré en Afrique de l'Est, a été trouvé (détermination sur dix spécimens, par séquençage d'une zone amplifiée de l'ITS de l'ADNr, et observation de la position 871. En conclusion, à Mayotte et à Grande Comore, le complexe An. gambiae comprend uniquement des An. gambiae s.s. de la forme moléculaire S/type IB.

  14. Comparative transcriptome analyses of deltamethrin-resistant and -susceptible Anopheles gambiae mosquitoes from Kenya by RNA-Seq.

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    Mariangela Bonizzoni

    Full Text Available Malaria causes more than 300 million clinical cases and 665,000 deaths each year, and the majority of the mortality and morbidity occurs in sub-Saharan Africa. Due to the lack of effective vaccines and wide-spread resistance to antimalarial drugs, mosquito control is the primary method of malaria prevention and control. Currently, malaria vector control relies on the use of insecticides, primarily pyrethroids. The extensive use of insecticides has imposed strong selection pressures for resistance in the mosquito populations. Consequently, resistance to pyrethroids in Anopheles gambiae, the main malaria vector in sub-Saharan Africa, has become a major obstacle for malaria control. A key element of resistance management is the identification of resistance mechanisms and subsequent development of reliable resistance monitoring tools. Field-derived An. gambiae from Western Kenya were phenotyped as deltamethrin-resistant or -susceptible by the standard WHO tube test, and their expression profile compared by RNA-seq. Based on the current annotation of the An. gambiae genome, a total of 1,093 transcripts were detected as significantly differentially accumulated between deltamethrin-resistant and -susceptible mosquitoes. These transcripts are distributed over the entire genome, with a large number mapping in QTLs previously linked to pyrethorid resistance, and correspond to heat-shock proteins, metabolic and transport functions, signal transduction activities, cytoskeleton and others. The detected differences in transcript accumulation levels between resistant and susceptible mosquitoes reflect transcripts directly or indirectly correlated with pyrethroid resistance. RNA-seq data also were used to perform a de-novo Cufflinks assembly of the An. gambiae genome.

  15. Comparative transcriptome analyses of deltamethrin-resistant and -susceptible Anopheles gambiae mosquitoes from Kenya by RNA-Seq.

    Science.gov (United States)

    Bonizzoni, Mariangela; Afrane, Yaw; Dunn, William Augustine; Atieli, Francis K; Zhou, Goufa; Zhong, Daibin; Li, Jun; Githeko, Andrew; Yan, Guiyun

    2012-01-01

    Malaria causes more than 300 million clinical cases and 665,000 deaths each year, and the majority of the mortality and morbidity occurs in sub-Saharan Africa. Due to the lack of effective vaccines and wide-spread resistance to antimalarial drugs, mosquito control is the primary method of malaria prevention and control. Currently, malaria vector control relies on the use of insecticides, primarily pyrethroids. The extensive use of insecticides has imposed strong selection pressures for resistance in the mosquito populations. Consequently, resistance to pyrethroids in Anopheles gambiae, the main malaria vector in sub-Saharan Africa, has become a major obstacle for malaria control. A key element of resistance management is the identification of resistance mechanisms and subsequent development of reliable resistance monitoring tools. Field-derived An. gambiae from Western Kenya were phenotyped as deltamethrin-resistant or -susceptible by the standard WHO tube test, and their expression profile compared by RNA-seq. Based on the current annotation of the An. gambiae genome, a total of 1,093 transcripts were detected as significantly differentially accumulated between deltamethrin-resistant and -susceptible mosquitoes. These transcripts are distributed over the entire genome, with a large number mapping in QTLs previously linked to pyrethorid resistance, and correspond to heat-shock proteins, metabolic and transport functions, signal transduction activities, cytoskeleton and others. The detected differences in transcript accumulation levels between resistant and susceptible mosquitoes reflect transcripts directly or indirectly correlated with pyrethroid resistance. RNA-seq data also were used to perform a de-novo Cufflinks assembly of the An. gambiae genome. PMID:22970263

  16. Inferring selection in the Anopheles gambiae species complex: an example from immune-related serine protease inhibitors

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    Little Tom J

    2009-06-01

    Full Text Available Abstract Background Mosquitoes of the Anopheles gambiae species complex are the primary vectors of human malaria in sub-Saharan Africa. Many host genes have been shown to affect Plasmodium development in the mosquito, and so are expected to engage in an evolutionary arms race with the pathogen. However, there is little conclusive evidence that any of these mosquito genes evolve rapidly, or show other signatures of adaptive evolution. Methods Three serine protease inhibitors have previously been identified as candidate immune system genes mediating mosquito-Plasmodium interaction, and serine protease inhibitors have been identified as hot-spots of adaptive evolution in other taxa. Population-genetic tests for selection, including a recent multi-gene extension of the McDonald-Kreitman test, were applied to 16 serine protease inhibitors and 16 other genes sampled from the An. gambiae species complex in both East and West Africa. Results Serine protease inhibitors were found to show a marginally significant trend towards higher levels of amino acid diversity than other genes, and display extensive genetic structuring associated with the 2La chromosomal inversion. However, although serpins are candidate targets for strong parasite-mediated selection, no evidence was found for rapid adaptive evolution in these genes. Conclusion It is well known that phylogenetic and population history in the An. gambiae complex can present special problems for the application of standard population-genetic tests for selection, and this may explain the failure of this study to detect selection acting on serine protease inhibitors. The pitfalls of uncritically applying these tests in this species complex are highlighted, and the future prospects for detecting selection acting on the An. gambiae genome are discussed.

  17. 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.

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

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    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

  19. IMP PCR primers detect single nucleotide polymorphisms for Anopheles gambiae species identification, Mopti and Savanna rDNA types, and resistance to dieldrin in Anopheles arabiensis

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    Howell Paul I

    2006-12-01

    Full Text Available Abstract Background Polymerase chain reactions to distinguish single-nucleotide polymorphisms are commonly used for mosquito identification and identifying insecticide resistance alleles. However, the existing methods used for primer design often result in analyses that are not robust or require additional steps. Methods Utilizing oligonucleotides that are unique in having an intentional mismatch to both templates three bases from the SNP at the 3-prime end, three new PCR assays that distinguish SNP targets using standard gel electrophoresis of undigested DNA fragments were developed and tested. These were applied to: (1 an alternative ribosomal DNA PCR assay to distinguish five members of the Anopheles gambiae complex; (2 detection of the Mopti and Savanna rDNA types; and (3 an assay to distinguish resistance to dieldrin (Rdl alleles in Anopheles arabiensis. Results Reproducible specific amplification of the target alleles was observed in all three assays. The results were consistent with existing analyses but proved simpler and the results more distinct in our hands. Conclusion The simplicity and effectiveness of the method should be utilized in these and other PCR analyses to increase their specificity and simplicity. These results have the potential to be extended not only to mosquito analyses but also to parasite and human polymorphisms.

  20. Alstonia boonei De Wild oil extract in the management of mosquito (Anopheles gambiae, a vector of malaria disease

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    Kayode David Ileke

    2015-07-01

    Full Text Available Objective: To evaluate the insecticidal potential of Alstonia boonei (A. boonei oils and derivatives against different life stages of a malaria vector, Anopheles gambiae. Methods: The leaf, stem bark and root bark of A. boonei were collected from an open field and air dried before being blended to fine powder. Oils from this plant were extracted by cold extraction and were prepared at different concentrations. Contact toxicity of A. boonei was tested against the larvae and pupae of the insect while smoke toxicity of the plant materials in form of mosquito coil was tested against the adult insect. Results: Alstodine recorded the highest insect mortality rate and the order of susceptibility of the life stages of the insect to the plant was pupae alstonine > stem bark extract > leaf extract > root bark extract.

  1. Alstonia booneiDe Wildoil extract in the management of mosquito (Anopheles gambiae), a vector of malaria disease

    Institute of Scientific and Technical Information of China (English)

    Kayode David Ileke; Olaniyi Charles Ogungbite

    2015-01-01

    Objective:To evaluate the insecticidal potential ofAlstonia boonei(A. boonei)oils and derivatives against different life stages of a malaria vector,Anopheles gambiae. Methods:The leaf, stem bark and root bark ofA. boonei were collected from an open field and air dried before being blended to fine powder. Oils from this plant were extracted by cold extraction and were prepared at different concentrations. Contact toxicity ofA. boonei was tested against the larvae and pupae of the insect while smoke toxicity of the plant materials in form of mosquito coil was tested against the adult insect. Results: Alstodine recorded the highest insect mortality rate and the order of susceptibility of the life stages of the insect to the plant was pupae alstonine > stem bark extract > leaf extract > root bark extract.

  2. Insecticide susceptibility of natural populations of Anopheles coluzzii and Anopheles gambiae (sensu stricto) from Okyereko irrigation site, Ghana, West Africa

    OpenAIRE

    Chabi, Joseph; Baidoo, Philip K.; Datsomor, Alex K.; Okyere, Dora; Ablorde, Aikins; Iddrisu, Alidu; Wilson, Michael D; Dadzie, Samuel K.; Jamet, Helen P.; Diclaro, Joseph W.

    2016-01-01

    Background The increasing spread of insecticide resistance in malaria vectors has been well documented across sub-Saharan Africa countries. The influence of irrigation on increasing vector resistance is poorly understood, and is critical to successful and ethical implementation of food security policies. This study investigated the insecticide resistance status of An. gambiae (s.l.) mosquitoes collected from the irrigated rice area of Okyereko, a village containing about 42 hectares of irriga...

  3. 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

  4. 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.

  5. 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...

  6. 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

  7. Insecticidal Activities of Bark, Leaf and Seed Extracts of Zanthoxylum heitzii against the African Malaria Vector Anopheles gambiae

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    Hans J. Overgaard

    2014-12-01

    Full Text Available The olon tree, Zanthoxylum heitzii (syn. Fagara heitzii is commonly found in the central-west African forests. In the Republic of Congo (Congo-Brazzaville its bark is anecdotally reported to provide human protection against fleas. Here we assess the insecticidal activities of Z. heitzii stem bark, seed and leaf extracts against Anopheles gambiae s.s, the main malaria vector in Africa. Extracts were obtained by Accelerated Solvent Extraction (ASE using solvents of different polarity and by classical Soxhlet extraction using hexane as solvent. The insecticidal effects of the crude extracts were evaluated using topical applications of insecticides on mosquitoes of a susceptible reference strain (Kisumu [Kis], a strain homozygous for the L1014F kdr mutation (kdrKis, and a strain homozygous for the G119S Ace1R allele (AcerKis. The insecticidal activities were measured using LD50 and LD95 and active extracts were characterized by NMR spectroscopy and HPLC chromatography. Results show that the ASE hexane stem bark extract was the most effective compound against An. gambiae (LD50 = 102 ng/mg female, but was not as effective as common synthetic insecticides. Overall, there was no significant difference between the responses of the three mosquito strains to Z. heitzii extracts, indicating no cross resistance with conventional pesticides.

  8. Insecticidal activities of bark, leaf and seed extracts of Zanthoxylum heitzii against the African malaria vector Anopheles gambiae.

    Science.gov (United States)

    Overgaard, Hans J; Sirisopa, Patcharawan; Mikolo, Bertin; Malterud, Karl E; Wangensteen, Helle; Zou, Yuan-Feng; Paulsen, Berit S; Massamba, Daniel; Duchon, Stephane; Corbel, Vincent; Chandre, Fabrice

    2014-01-01

    The olon tree, Zanthoxylum heitzii (syn. Fagara heitzii) is commonly found in the central-west African forests. In the Republic of Congo (Congo-Brazzaville) its bark is anecdotally reported to provide human protection against fleas. Here we assess the insecticidal activities of Z. heitzii stem bark, seed and leaf extracts against Anopheles gambiae s.s, the main malaria vector in Africa. Extracts were obtained by Accelerated Solvent Extraction (ASE) using solvents of different polarity and by classical Soxhlet extraction using hexane as solvent. The insecticidal effects of the crude extracts were evaluated using topical applications of insecticides on mosquitoes of a susceptible reference strain (Kisumu [Kis]), a strain homozygous for the L1014F kdr mutation (kdrKis), and a strain homozygous for the G119S Ace1R allele (AcerKis). The insecticidal activities were measured using LD50 and LD95 and active extracts were characterized by NMR spectroscopy and HPLC chromatography. Results show that the ASE hexane stem bark extract was the most effective compound against An. gambiae (LD50 = 102 ng/mg female), but was not as effective as common synthetic insecticides. Overall, there was no significant difference between the responses of the three mosquito strains to Z. heitzii extracts, indicating no cross resistance with conventional pesticides. PMID:25525826

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

    Science.gov (United States)

    Engdahl, Cecilia; Knutsson, Sofie; Fredriksson, Sten-Åke; Linusson, Anna; Bucht, Göran; Ekström, Fredrik

    2015-01-01

    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. PMID:26447952

  10. Reactive oxygen species detoxification by catalase is a major determinant of fecundity in the mosquito Anopheles gambiae.

    Science.gov (United States)

    DeJong, Randall J; Miller, Lisa M; Molina-Cruz, Alvaro; Gupta, Lalita; Kumar, Sanjeev; Barillas-Mury, Carolina

    2007-02-13

    The mosquito Anopheles gambiae is a primary vector of Plasmodium parasites in Africa. The effect of aging on reproductive output in A. gambiae females from three strains that differ in their ability to melanize Plasmodium and in their systemic levels of hydrogen peroxide (H2O2), a reactive oxygen species (ROS), was analyzed. The number of eggs oviposited after the first blood meal decreases with age in all strains; however, this decline was much more pronounced in the G3 (unselected) and R (refractory to Plasmodium infection) strains than in the S (highly susceptible to Plasmodium) strain. Reduction of ROS levels in G3 and R females by administration of antioxidants reversed this age-related decline in fecundity. The S and G3 strains were fixed for two functionally different catalase alleles that differ at the second amino acid position (Ser2Trp). Biochemical analysis of recombinant proteins revealed that the Trp isoform has lower specific activity and higher Km than the Ser isoform, indicating that the former is a less efficient enzyme. The Trp-for-Ser substitution appears to destabilize the functional tetrameric form of the enzyme. Both alleles are present in the R strain, and Ser/Ser females had significantly higher fecundity than Trp/Trp females. Finally, a systemic reduction in catalase activity by dsRNA-mediated knockdown significantly reduced the reproductive output of mosquito females, indicating that catalase plays a central role in protecting the oocyte and early embryo from ROS damage. PMID:17284604

  11. The Anopheles gambiae Oxidation Resistance 1 (OXR1) Gene Regulates Expression of Enzymes That Detoxify Reactive Oxygen Species

    Science.gov (United States)

    Jaramillo-Gutierrez, Giovanna; Molina-Cruz, Alvaro; Kumar, Sanjeev; Barillas-Mury, Carolina

    2010-01-01

    Background OXR1 is an ancient gene, present in all eukaryotes examined so far that confers protection from oxidative stress by an unknown mechanism. The most highly conserved region of the gene is the carboxyl-terminal TLDc domain, which has been shown to be sufficient to prevent oxidative damage. Methodology/Principal Findings OXR1 has a complex genomic structure in the mosquito A. gambiae, and we confirm that multiple splice forms are expressed in adult females. Our studies revealed that OXR1 regulates the basal levels of catalase (CAT) and glutathione peroxidase (Gpx) expression, two enzymes involved in detoxification of hydrogen peroxide, giving new insight into the mechanism of action of OXR1. Gene silencing experiments indicate that the Jun Kinase (JNK) gene acts upstream of OXR1 and also regulates expression of CAT and GPx. Both OXR1 and JNK genes are required for adult female mosquitoes to survive chronic oxidative stress. OXR1 silencing decreases P. berghei oocyst formation. Unexpectedly, JNK silencing has the opposite effect and enhances Plasmodium infection in the mosquito, suggesting that JNK may also mediate some, yet to be defined, antiparasitic response. Conclusion The JNK pathway regulates OXR1 expression and OXR1, in turn, regulates expression of enzymes that detoxify reactive oxygen species (ROS) in Anopheles gambiae. OXR1 silencing decreases Plasmodium infection in the mosquito, while JNK silencing has the opposite effect and enhances infection. PMID:20567517

  12. Reactive oxygen species detoxification by catalase is a major determinant of fecundity in the mosquito Anopheles gambiae

    Science.gov (United States)

    DeJong, Randall J.; Miller, Lisa M.; Molina-Cruz, Alvaro; Gupta, Lalita; Kumar, Sanjeev; Barillas-Mury, Carolina

    2007-01-01

    The mosquito Anopheles gambiae is a primary vector of Plasmodium parasites in Africa. The effect of aging on reproductive output in A. gambiae females from three strains that differ in their ability to melanize Plasmodium and in their systemic levels of hydrogen peroxide (H2O2), a reactive oxygen species (ROS), was analyzed. The number of eggs oviposited after the first blood meal decreases with age in all strains; however, this decline was much more pronounced in the G3 (unselected) and R (refractory to Plasmodium infection) strains than in the S (highly susceptible to Plasmodium) strain. Reduction of ROS levels in G3 and R females by administration of antioxidants reversed this age-related decline in fecundity. The S and G3 strains were fixed for two functionally different catalase alleles that differ at the second amino acid position (Ser2Trp). Biochemical analysis of recombinant proteins revealed that the Trp isoform has lower specific activity and higher Km than the Ser isoform, indicating that the former is a less efficient enzyme. The Trp-for-Ser substitution appears to destabilize the functional tetrameric form of the enzyme. Both alleles are present in the R strain, and Ser/Ser females had significantly higher fecundity than Trp/Trp females. Finally, a systemic reduction in catalase activity by dsRNA-mediated knockdown significantly reduced the reproductive output of mosquito females, indicating that catalase plays a central role in protecting the oocyte and early embryo from ROS damage. PMID:17284604

  13. The Anopheles gambiae oxidation resistance 1 (OXR1 gene regulates expression of enzymes that detoxify reactive oxygen species.

    Directory of Open Access Journals (Sweden)

    Giovanna Jaramillo-Gutierrez

    Full Text Available BACKGROUND: OXR1 is an ancient gene, present in all eukaryotes examined so far that confers protection from oxidative stress by an unknown mechanism. The most highly conserved region of the gene is the carboxyl-terminal TLDc domain, which has been shown to be sufficient to prevent oxidative damage. METHODOLOGY/PRINCIPAL FINDINGS: OXR1 has a complex genomic structure in the mosquito A. gambiae, and we confirm that multiple splice forms are expressed in adult females. Our studies revealed that OXR1 regulates the basal levels of catalase (CAT and glutathione peroxidase (Gpx expression, two enzymes involved in detoxification of hydrogen peroxide, giving new insight into the mechanism of action of OXR1. Gene silencing experiments indicate that the Jun Kinase (JNK gene acts upstream of OXR1 and also regulates expression of CAT and GPx. Both OXR1 and JNK genes are required for adult female mosquitoes to survive chronic oxidative stress. OXR1 silencing decreases P. berghei oocyst formation. Unexpectedly, JNK silencing has the opposite effect and enhances Plasmodium infection in the mosquito, suggesting that JNK may also mediate some, yet to be defined, antiparasitic response. CONCLUSION: The JNK pathway regulates OXR1 expression and OXR1, in turn, regulates expression of enzymes that detoxify reactive oxygen species (ROS in Anopheles gambiae. OXR1 silencing decreases Plasmodium infection in the mosquito, while JNK silencing has the opposite effect and enhances infection.

  14. 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.

  15. 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

  16. Variation in susceptibility of African Plasmodium falciparum malaria parasites to TEP1 mediated killing in Anopheles gambiae mosquitoes.

    Science.gov (United States)

    Eldering, Maarten; Morlais, Isabelle; van Gemert, Geert-Jan; van de Vegte-Bolmer, Marga; Graumans, Wouter; Siebelink-Stoter, Rianne; Vos, Martijn; Abate, Luc; Roeffen, Will; Bousema, Teun; Levashina, Elena A; Sauerwein, Robert W

    2016-01-01

    Anopheles gambiae s.s. mosquitoes are efficient vectors for Plasmodium falciparum, although variation exists in their susceptibility to infection. This variation depends partly on the thioester-containing protein 1 (TEP1) and TEP depletion results in significantly elevated numbers of oocysts in susceptible and resistant mosquitoes. Polymorphism in the Plasmodium gene coding for the surface protein Pfs47 modulates resistance of some parasite laboratory strains to TEP1-mediated killing. Here, we examined resistance of P. falciparum isolates of African origin (NF54, NF165 and NF166) to TEP1-mediated killing in a susceptible Ngousso and a refractory L3-5 strain of A. gambiae. All parasite clones successfully developed in susceptible mosquitoes with limited evidence for an impact of TEP1 on transmission efficiency. In contrast, NF166 and NF165 oocyst densities were strongly reduced in refractory mosquitoes and TEP1 silencing significantly increased oocyst densities. Our results reveal differences between African P. falciparum strains in their capacity to evade TEP1-mediated killing in resistant mosquitoes. There was no significant correlation between Pfs47 genotype and resistance of a given P. falciparum isolate for TEP1 killing. These data suggest that polymorphisms in this locus are not the sole mediators of immune evasion of African malaria parasites. PMID:26861587

  17. Studies on the behaviour of peridomestic and endophagic M form Anopheles gambiae from a rice growing area of Ghana.

    Science.gov (United States)

    Charlwood, J D; Tomás, E V E; Salgueiro, P; Egyir-Yawson, A; Pitts, R J; Pinto, J

    2011-10-01

    The 'paddy paradox', the occurrence of large populations of vectors but low amounts of malaria transmission where irrigated rice is grown, was investigated in a village in Ghana where M form Anopheles gambiae are common. Peridomestic and indoor host-seeking mosquitoes were collected in tent traps and light traps over 21 consecutive nights at the start of the rainy season in June 2009 when the population increased exponentially from less than 100 per night to over 1000. Infection rates in the overall mosquito population were 0.3% and in the estimated parous population were 1.9%. Numbers of An. gambiae in the tent trap peaked between midnight and 02:40 am. The majority of insects were taking their first blood meal, as virgins or shortly after mating. More than expected were collected in the light trap during a rainstorm at the start of the rains but overall numbers were not affected. Fewer than expected were collected after a subsequent storm. Recruitment to the adult population decreased over the following days. It is hypothesised that the 'paddy paradox' is due to young pre-gravid insects dispersing more widely than gravid ones, not necessarily to low survival in the mosquito. PMID:21401973

  18. Observation of granulations in the basal body of ovarioles and follicular dilatations for the determination of physiological age ofAnopheles gambiaes.s.

    Institute of Scientific and Technical Information of China (English)

    Rodrigue Anagonou; Virgile Gnanguenon; Fiacre Agossa; Bruno Akinro; Armand Akpo; Martial Gbegbo; Albert Salako; Martin Akogbto

    2015-01-01

    Objective:To explore ovariole basal body granulations and follicular dilatations for determining physiological age inAnopheles gambiaes.s.(An. gambiaes.s.). Methods: Mosquitoes were collected by using window trap catch and identified morphologically. For the first lot ofmosquitoes, they were dissected, and ovary was left in distilled water for reading ovarian tracheoles and the second was cut and transferred to another blade in a physiological liquid for verification of ovariole basal body granulations. The same approach was followed with the second lot of mosquitoes where follicular dilatations were found after classic dilaceration of ovaries were transferred into physiological liquid. The other body parts of mosquitoes were used to identify the species of theAn. gambiaes.s. complex by PCR. Results:Among the 123An. gambiae s.s. of the first lot, the method of Detinova determined the age of 89 mosquitoes versus 114 for the observation of granulations (P > 0.05). Among the 112An. gambiae s.s. of the second lot, the method of Detinova determined the age of 84 mosquitoes versus 93 for the observation of follicular dilatations (P > 0.05). Unlike the method of Detinova, observation of follicular dilatations and basal body granulations of ovarioles were possible beyond the stage II Christophers. Conclusions: Overall, the observation of follicular dilatations and ovariole basal body granulations are reliable for the determination of the physiological age inAn. gambiaes.s. Furthermore, these two methods can be used beyond the stage II.

  19. Rodent malaria-resistant strains of the mosquito, Anopheles gambiae, have slower population growth than -susceptible strains

    Directory of Open Access Journals (Sweden)

    Taylor Pam J

    2009-04-01

    Full Text Available Abstract Background Trade-offs between anti-parasite defence mechanisms and other life history traits limit the evolution of host resistance to parasites and have important implications for understanding diseases such as malaria. Mosquitoes have not evolved complete resistance to malaria parasites and one hypothesis is that anti-malaria defence mechanisms are costly. Results We used matrix population models to compare the population growth rates among lines of Anopheles gambiae that had been selected for resistance or high susceptibility to the rodent malaria parasite, Plasmodium yoelii nigeriensis. The population growth rate of the resistant line was significantly lower than that of the highly susceptible and the unselected control lines, regardless of whether mosquitoes were infected with Plasmodium or not. The lower population growth of malaria-resistant mosquitoes was caused by reduced post blood-feeding survival of females and poor egg hatching. Conclusion With respect to eradicating malaria, the strategy of releasing Plasmodium-resistant Anopheles mosquitoes is unlikely to be successful if the costs of Plasmodium-resistance in the field are as great as the ones measured in this study. High densities of malaria-resistant mosquitoes would have to be maintained by continuous release from captive breeding facilities.

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

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    Braïma James

    2009-05-01

    Full Text Available 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 were performed to assess the susceptibility of malaria vectors to various agricultural insecticides and biochemical analysis were done to characterize molecular status of population of An. gambiae. Results This research showed that: (1 The rapid development of urban agriculture is related to unemployment observed in cities, rural exodus and the search for a balanced diet by urban populations; (2 Urban agriculture increases the farmers' household income and their living standard; (3 At a molecular level, PCR revealed the presence of three sub-species of An. gambiae (An. gambiae s.s., Anopheles melas and Anopheles arabiensis and two molecular forms (M and S. The kdr west mutation recorded in samples from the three sites and more specifically on the M forms seems to be one of the major resistance mechanisms found in An. gambiae from agricultural areas. Insecticide susceptibility tests conducted during this research revealed a clear pattern of resistance to permethrin (76% mortality rate at Parakou; 23.5% at Porto-Novo and 17% at Cotonou. Conclusion This study confirmed an increase activity of the vegetable farming in urban areas of Benin. This has led to the use of insecticide in an improper manner to control vegetable pests, thus exerting a huge selection pressure on mosquito larval population, which resulted to the emergence of insecticide resistance in malaria vectors.

  1. 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

  2. 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...

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

    OpenAIRE

    Yadouleton Anges; Martin Thibaud; Padonou Gil; Chandre Fabrice; Asidi Alex; Djogbenou Luc; Dabiré Roch; Aïkpon Rock; Boko Michel; Glitho Isabelle; Akogbeto Martin

    2011-01-01

    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...

  4. Inferring selection in the Anopheles gambiae species complex: an example from immune-related serine protease inhibitors

    OpenAIRE

    Little Tom J; Welch John J; Obbard Darren J

    2009-01-01

    Abstract Background Mosquitoes of the Anopheles gambiae species complex are the primary vectors of human malaria in sub-Saharan Africa. Many host genes have been shown to affect Plasmodium development in the mosquito, and so are expected to engage in an evolutionary arms race with the pathogen. However, there is little conclusive evidence that any of these mosquito genes evolve rapidly, or show other signatures of adaptive evolution. Methods Three serine protease inhibitors have previously be...

  5. Differential gene expression in abdomens of the malaria vector mosquito, Anopheles gambiae, after sugar feeding, blood feeding and Plasmodium berghei infection

    OpenAIRE

    Romans Patricia A; Kern Marcia K; Hillenmeyer Maureen E; Lobo Neil F; Dana Ali N; Collins Frank H

    2006-01-01

    Abstract Background Large scale sequencing of cDNA libraries can provide profiles of genes expressed in an organism under defined biological and environmental circumstances. We have analyzed sequences of 4541 Expressed Sequence Tags (ESTs) from 3 different cDNA libraries created from abdomens from Plasmodium infection-susceptible adult female Anopheles gambiae. These libraries were made from sugar fed (S), rat blood fed (RB), and P. berghei-infected (IRB) mosquitoes at 30 hours after the bloo...

  6. Polymorphism of intron-1 in the voltage-gated sodium channel gene of Anopheles gambiae s.s. populations from Cameroon with emphasis on insecticide knockdown resistance mutations

    OpenAIRE

    Etang, J; Vicente, J. L.; Nwane, P.; Chouaibou, M.; Morlais, Isabelle; Do Rosario, V. E.; Simard, Frédéric; Awono Ambéné, P.; Toto, J. C.; Pinto, J

    2009-01-01

    Sequence variation at the intron-1 of the voltage-gated sodium channel gene in Anopheles gambiae M- and S-forms from Cameroon was assessed to explore the number of mutational events originating knockdown resistance (kdr) alleles. Mosquitoes were sampled between December 2005 and June 2006 from three geographical areas: (i) Magba in the western region; (ii) Loum, Tiko, Douala, Kribi, and Campo along the Atlantic coast; and (iii) Bertoua, in the eastern continental plateau. Both 1014S and 1014F...

  7. The effect of water turbidity on the near-surface water temperature of larval habitats of the malaria mosquito Anopheles gambiae

    OpenAIRE

    K. P. Paaijmans; Takken, W.; Githeko, A.K.; Jacobs, A. F. G.

    2008-01-01

    Water temperature is an important determinant in many aquatic biological processes, including the growth and development of malaria mosquito (Anopheles arabiensis and A. gambiae) immatures. Water turbidity affects water temperature, as suspended particles in a water column absorb and scatter sunlight and hence determine the extinction of solar radiation. To get a better understanding of the relationship between water turbidity and water temperature, a series of semi-natural larval habitats (d...

  8. Inducible immune factors of the vector mosquito Anopheles gambiae: biochemical purification of a defensin antibacterial peptide and molecular cloning of preprodefensin cDNA.

    Science.gov (United States)

    Richman, A M; Bulet, P; Hetru, C; Barillas-Mury, C; Hoffmann, J A; Kafalos, F C

    1996-08-01

    Larvae of the mosquito vector of human malaria, Anopheles gambiae, were inoculated with bacteria and extracts were biochemically fractionated by reverse-phase HPLC. Multiple induced polypeptides and antibacterial activities were observed following bacterial infection, including a member of the insect defensin family of antibacterial proteins. A cDNA encoding An. gambiae preprodefensin was isolated using PCR primers based on phylogenetically conserved sequences. The mature peptide is highly conserved, but the signal and propeptide segments are not, relative to corresponding defensin sequences of other insects. Defensin expression is induced in response to bacterial infection, in both adult and larval stages. In contrast, pupae express defensin mRNA constitutively. Defensin expression may prove a valuable molecular marker to monitor the An. gambiae host response to infection by parasitic protozoa of medical importance. PMID:8799739

  9. 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...

  10. Apolipophorin-III mediates antiplasmodial epithelial responses in Anopheles gambiae (G3 mosquitoes.

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    Lalita Gupta

    Full Text Available BACKGROUND: Apolipophorin-III (ApoLp-III is known to play an important role in lipid transport and innate immunity in lepidopteran insects. However, there is no evidence of involvement of ApoLp-IIIs in the immune responses of dipteran insects such as Drosophila and mosquitoes. METHODOLOGY/PRINCIPAL FINDINGS: We report the molecular and functional characterization of An. gambiae apolipophorin-III (AgApoLp-III. Mosquito ApoLp-IIIs have diverged extensively from those of lepidopteran insects; however, the predicted tertiary structure of AgApoLp-III is similar to that of Manduca sexta (tobacco hornworm. We found that AgApoLp-III mRNA expression is strongly induced in the midgut of An. gambiae (G3 strain mosquitoes in response to Plasmodium berghei infection. Furthermore, immunofluorescence stainings revealed that high levels of AgApoLp-III protein accumulate in the cytoplasm of Plasmodium-invaded cells and AgApoLp-III silencing increases the intensity of P. berghei infection by five fold. CONCLUSION: There are broad differences in the midgut epithelial responses to Plasmodium invasion between An. gambiae strains. In the G3 strain of An. gambiae AgApoLp-III participates in midgut epithelial defense responses that limit Plasmodium infection.

  11. Apolipophorin-III Mediates Antiplasmodial Epithelial Responses in Anopheles gambiae (G3) Mosquitoes

    Science.gov (United States)

    Jo, Yong Hun; Oh, Seung Han; Kumar, Sanjeev; Noh, Mi Young; Lee, Yong Seok; Cha, Sung-Jae; Seo, Sook Jae; Kim, Iksoo; Han, Yeon Soo; Barillas-Mury, Carolina

    2010-01-01

    Background Apolipophorin-III (ApoLp-III) is known to play an important role in lipid transport and innate immunity in lepidopteran insects. However, there is no evidence of involvement of ApoLp-IIIs in the immune responses of dipteran insects such as Drosophila and mosquitoes. Methodology/Principal Findings We report the molecular and functional characterization of An. gambiae apolipophorin-III (AgApoLp-III). Mosquito ApoLp-IIIs have diverged extensively from those of lepidopteran insects; however, the predicted tertiary structure of AgApoLp-III is similar to that of Manduca sexta (tobacco hornworm). We found that AgApoLp-III mRNA expression is strongly induced in the midgut of An. gambiae (G3 strain) mosquitoes in response to Plasmodium berghei infection. Furthermore, immunofluorescence stainings revealed that high levels of AgApoLp-III protein accumulate in the cytoplasm of Plasmodium-invaded cells and AgApoLp-III silencing increases the intensity of P. berghei infection by five fold. Conclusion There are broad differences in the midgut epithelial responses to Plasmodium invasion between An. gambiae strains. In the G3 strain of An. gambiae AgApoLp-III participates in midgut epithelial defense responses that limit Plasmodium infection. PMID:21072214

  12. 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

  13. 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

  14. Crystal and Solution Studies of the “Plus-C” Odorant-binding Protein 48 from Anopheles gambiae

    Science.gov (United States)

    Tsitsanou, Katerina E.; Drakou, Christina E.; Thireou, Trias; Vitlin Gruber, Anna; Kythreoti, Georgia; Azem, Abdussalam; Fessas, Dimitrios; Eliopoulos, Elias; Iatrou, Kostas; Zographos, Spyros E.

    2013-01-01

    Much physiological and behavioral evidence has been provided suggesting that insect odorant-binding proteins (OBPs) are indispensable for odorant recognition and thus are appealing targets for structure-based discovery and design of novel host-seeking disruptors. Despite the fact that more than 60 putative OBP-encoding genes have been identified in the malaria vector Anopheles gambiae, the crystal structures of only six of them are known. It is therefore clear that OBP structure determination constitutes the bottleneck for structure-based approaches to mosquito repellent/attractant discovery. Here, we describe the three-dimensional structure of an A. gambiae “Plus-C” group OBP (AgamOBP48), which exhibits the second highest expression levels in female antennae. This structure represents the first example of a three-dimensional domain-swapped dimer in dipteran species. A combined binding site is formed at the dimer interface by equal contribution of each monomer. Structural comparisons with the monomeric AgamOBP47 revealed that the major structural difference between the two Plus-C proteins localizes in their N- and C-terminal regions, and their concerted conformational change may account for monomer-swapped dimer conversion and furthermore the formation of novel binding pockets. Using a combination of gel filtration chromatography, differential scanning calorimetry, and analytical ultracentrifugation, we demonstrate the AgamOBP48 dimerization in solution. Eventually, molecular modeling calculations were used to predict the binding mode of the most potent synthetic ligand of AgamOBP48 known so far, discovered by ligand- and structure-based virtual screening. The structure-aided identification of multiple OBP binders represents a powerful tool to be employed in the effort to control transmission of the vector-borne diseases. PMID:24097978

  15. Synergy between repellents and non-pyrethroid insecticides strongly extends the efficacy of treated nets against Anopheles gambiae

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    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.

  16. Losing identity: structural diversity of transposable elements belonging to different classes in the genome of Anopheles gambiae

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    Fernández-Medina Rita D

    2012-06-01

    Full Text Available Abstract Background Transposable elements (TEs, both DNA transposons and retrotransposons, are genetic elements with the main characteristic of being able to mobilize and amplify their own representation within genomes, utilizing different mechanisms of transposition. An almost universal feature of TEs in eukaryotic genomes is their inability to transpose by themselves, mainly as the result of sequence degeneration (by either mutations or deletions. Most of the elements are thus either inactive or non-autonomous. Considering that the bulk of some eukaryotic genomes derive from TEs, they have been conceived as “TE graveyards.” It has been shown that once an element has been inactivated, it progressively accumulates mutations and deletions at neutral rates until completely losing its identity or being lost from the host genome; however, it has also been shown that these “neutral sequences” might serve as raw material for domestication by host genomes. Results We have analyzed the sequence structural variations, nucleotide divergence, and pattern of insertions and deletions of several superfamilies of TEs belonging to both class I (long terminal repeats [LTRs] and non-LTRs [NLTRs] and II in the genome of Anopheles gambiae, aiming at describing the landscape of deterioration of these elements in this particular genome. Our results describe a great diversity in patterns of deterioration, indicating lineage-specific differences including the presence of Solo-LTRs in the LTR lineage, 5′-deleted NLTRs, and several non-autonomous and MITEs in the class II families. Interestingly, we found fragments of NLTRs corresponding to the RT domain, which preserves high identity among them, suggesting a possible remaining genomic role for these domains. Conclusions We show here that the TEs in the An. gambiae genome deteriorate in different ways according to the class to which they belong. This diversity certainly has implications not only at the host

  17. 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.

  18. Risk mapping of Anopheles gambiae s.l. densities using remotely-sensed environmental and meteorological data in an urban area: Dakar, Senegal.

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    Vanessa Machault

    Full Text Available INTRODUCTION: High malaria transmission heterogeneity in an urban environment is basically due to the complex distribution of Anopheles larval habitats, sources of vectors. Understanding 1 the meteorological and ecological factors associated with differential larvae spatio-temporal distribution and 2 the vectors dynamic, both may lead to improving malaria control measures with remote sensing and high resolution data as key components. In this study a robust operational methodology for entomological malaria predictive risk maps in urban settings is developed. METHODS: The Tele-epidemiology approach, i.e., 1 intensive ground measurements (Anopheles larval habitats and Human Biting Rate, or HBR, 2 selection of the most appropriate satellite data (for mapping and extracting environmental and meteorological information, and 3 use of statistical models taking into account the spatio-temporal data variability has been applied in Dakar, Senegal. RESULTS: First step was to detect all water bodies in Dakar. Secondly, environmental and meteorological conditions in the vicinity of water bodies favoring the presence of Anopheles gambiae s.l. larvae were added. Then relationship between the predicted larval production and the field measured HBR was identified, in order to generate An. gambiae s.l. HBR high resolution maps (daily, 10-m pixel in space. DISCUSSION AND CONCLUSION: A robust operational methodology for dynamic entomological malaria predictive risk maps in an urban setting includes spatio-temporal variability of An. gambiae s.l. larval habitats and An. gambiae s.l. HBR. The resulting risk maps are first examples of high resolution products which can be included in an operational warning and targeting system for the implementation of vector control measures.

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

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    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

  20. 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

  1. 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.

  2. Insecticidal activity of petroleum ether extract and essential oil of Chenopodium ambrosioides L.(Chenopodiaceae) against Anopheles gambiae(Diptera: Culicidae)%土荆芥的石油醚提取物及精油对冈比亚按蚊的杀虫活性

    Institute of Scientific and Technical Information of China (English)

    Abiodun A. DENLOYE; Oluwakemi K. AJELARA; Rasaq A. OLOWU; Adeolu O. ESHILOKUN; Winifred A. MAKANJUOLA

    2009-01-01

    . ambrosioides for the control An. gambiae.%48 h致死中浓度(LC50)的测试结果表明,石油醚提取物对1龄幼虫的毒性最强(14.89 mg/L),其次是对4龄幼虫(18.90 mg/L),对3龄幼虫的毒性最低(183.77 mg/L); 精油对4龄幼虫毒性最强(36.62 mg/L),其次是对1龄幼虫(90.75 mg/L).推算的土荆芥精油对冈比亚按蚊的LC50为1.01 μL/L.本研究揭示了土荆芥对冈比亚按蚊的防治潜力.

  3. Annotation and analysis of a large cuticular protein family with the R&R Consensus in Anopheles gambiae

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    He Ningjia

    2008-01-01

    Full Text Available Abstract Background The most abundant family of insect cuticular proteins, the CPR family, is recognized by the R&R Consensus, a domain of about 64 amino acids that binds to chitin and is present throughout arthropods. Several species have now been shown to have more than 100 CPR genes, inviting speculation as to the functional importance of this large number and diversity. Results We have identified 156 genes in Anopheles gambiae that code for putative cuticular proteins in this CPR family, over 1% of the total number of predicted genes in this species. Annotation was verified using several criteria including identification of TATA boxes, INRs, and DPEs plus support from proteomic and gene expression analyses. Two previously recognized CPR classes, RR-1 and RR-2, form separate, well-supported clades with the exception of a small set of genes with long branches whose relationships are poorly resolved. Several of these outliers have clear orthologs in other species. Although both clades are under purifying selection, the RR-1 variant of the R&R Consensus is evolving at twice the rate of the RR-2 variant and is structurally more labile. In contrast, the regions flanking the R&R Consensus have diversified in amino-acid composition to a much greater extent in RR-2 genes compared with RR-1 genes. Many genes are found in compact tandem arrays that may include similar or dissimilar genes but always include just one of the two classes. Tandem arrays of RR-2 genes frequently contain subsets of genes coding for highly similar proteins (sequence clusters. Properties of the proteins indicated that each cluster may serve a distinct function in the cuticle. Conclusion The complete annotation of this large gene family provides insight on the mechanisms of gene family evolution and clues about the need for so many CPR genes. These data also should assist annotation of other Anopheles genes.

  4. The angiotensin-converting enzyme (ACE) gene family of Anopheles gambiae.

    OpenAIRE

    Isaac R Elwyn; Lee Alison J; Smith Judith A; Burnham Susan; Shirras Alan D

    2005-01-01

    Abstract Background Members of the M2 family of peptidases, related to mammalian angiotensin converting enzyme (ACE), play important roles in regulating a number of physiological processes. As more invertebrate genomes are sequenced, there is increasing evidence of a variety of M2 peptidase genes, even within a single species. The function of these ACE-like proteins is largely unknown. Sequencing of the A. gambiae genome has revealed a number of ACE-like genes but probable errors in the Ensem...

  5. Allomonal effect of breath contributes to differential attractiveness of humans to the African malaria vector Anopheles gambiae

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    Takken Willem

    2004-01-01

    Full Text Available Abstract Background Removal of exhaled air from total body emanations or artificially standardising carbon dioxide (CO2 outputs has previously been shown to eliminate differential attractiveness of humans to certain blackfly (Simuliidae and mosquito (Culicidae species. Whether or not breath contributes to between-person differences in relative attractiveness to the highly anthropophilic malaria vector Anopheles gambiae sensu stricto remains unknown and was the focus of the present study. Methods The contribution to and possible interaction of breath (BR and body odours (BO in the attraction of An. gambiae s.s. to humans was investigated by conducting dual choice tests using a recently developed olfactometer. Either one or two human subjects were used as bait. The single person experiments compared the attractiveness of a person's BR versus that person's BO or a control (empty tent with no odour. His BO and total emanations (TE = BR+BO were also compared with a control. The two-person experiments compared the relative attractiveness of their TE, BO or BR, and the TE of each person against the BO of the other. Results Experiments with one human subject (P1 as bait found that his BO and TE collected more mosquitoes than the control (P = 0.005 and P 1 attracted more mosquitoes than that of another person designated P8 (P 8 attracted more mosquitoes than the BR of P1 (P = 0.001. The attractiveness of the BO of P1 versus the BO of P8 did not differ (P = 0.346. The BO from either individual was consistently more attractive than the TE from the other (P Conclusions We demonstrated for the first time that human breath, although known to contain semiochemicals that elicit behavioural and/or electrophysiological responses (CO2, ammonia, fatty acids in An. gambiae also contains one or more constituents with allomonal (~repellent properties, which inhibit attraction and may serve as an important contributor to between-person differences in the relative

  6. 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

  7. 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

  8. A possible mechanism for the suppression of Plasmodium berghei development in the mosquito Anopheles gambiae by the microsporidian Vavraia culicis.

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    Irka Bargielowski

    Full Text Available 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 gambiae with one of 4 isolates of the microsporidian Vavraia culicis and reared one group as an uninfected control. Within each treatment, we fed half the adult females on a mix of P. berghei ookinetes and blood and inoculated the other half with a negatively charged CM-25 Sephadex bead to evaluate the mosquitoes' melanisation response. CONCLUSIONS: The microsporidian-infected mosquitoes were less likely to harbour oocysts (58.5% vs. 81.8%, harboured fewer oocysts (8.9 oocysts vs. 20.7 oocysts if the malaria parasite did develop and melanised the Sephadex bead to a greater degree (73% vs. 35% than the controls. While the isolates differed in the number of oocysts and in the melanisation response, the stimulation of the immune response was not correlated with either measure of malaria development. Nevertheless, the consistent difference between microsporidian-infected and -uninfected mosquitoes--more effective melanisation and less successful infection by malaria--suggests that microsporidians impede the development of malaria by priming the mosquito's immune system.

  9. Spatiotemporal dynamics of gene flow and hybrid fitness between the M and S forms of the malaria mosquito, Anopheles gambiae.

    Science.gov (United States)

    Lee, Yoosook; Marsden, Clare D; Norris, Laura C; Collier, Travis C; Main, Bradley J; Fofana, Abdrahamane; Cornel, Anthony J; Lanzaro, Gregory C

    2013-12-01

    The M and S forms of Anopheles gambiae have been the focus of intense study by malaria researchers and evolutionary biologists interested in ecological speciation. Divergence occurs at three discrete islands in genomes that are otherwise nearly identical. An "islands of speciation" model proposes that diverged regions contain genes that are maintained by selection in the face of gene flow. An alternative "incidental island" model maintains that gene flow between M and S is effectively zero and that divergence islands are unrelated to speciation. A "divergence island SNP" assay was used to explore the spatial and temporal distributions of hybrid genotypes. Results revealed that hybrid individuals occur at frequencies ranging between 5% and 97% in every population examined. A temporal analysis revealed that assortative mating is unstable and periodically breaks down, resulting in extensive hybridization. Results suggest that hybrids suffer a fitness disadvantage, but at least some hybrid genotypes are viable. Stable introgression of the 2L speciation island occurred at one site following a hybridization event. PMID:24248386

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

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    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

  11. Modeling the role of environmental variables on the population dynamics of the malaria vector Anopheles gambiae sensu stricto

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    Parham Paul E

    2012-08-01

    Full Text Available Abstract Background The impact of weather and climate on malaria transmission has attracted considerable attention in recent years, yet uncertainties around future disease trends under climate change remain. Mathematical models provide powerful tools for addressing such questions and understanding the implications for interventions and eradication strategies, but these require realistic modeling of the vector population dynamics and its response to environmental variables. Methods Published and unpublished field and experimental data are used to develop new formulations for modeling the relationships between key aspects of vector ecology and environmental variables. These relationships are integrated within a validated deterministic model of Anopheles gambiae s.s. population dynamics to provide a valuable tool for understanding vector response to biotic and abiotic variables. Results A novel, parsimonious framework for assessing the effects of rainfall, cloudiness, wind speed, desiccation, temperature, relative humidity and density-dependence on vector abundance is developed, allowing ease of construction, analysis, and integration into malaria transmission models. Model validation shows good agreement with longitudinal vector abundance data from Tanzania, suggesting that recent malaria reductions in certain areas of Africa could be due to changing environmental conditions affecting vector populations. Conclusions Mathematical models provide a powerful, explanatory means of understanding the role of environmental variables on mosquito populations and hence for predicting future malaria transmission under global change. The framework developed provides a valuable advance in this respect, but also highlights key research gaps that need to be resolved if we are to better understand future malaria risk in vulnerable communities.

  12. Site-specific integration and expression of an anti-malarial gene in transgenic Anopheles gambiae significantly reduces Plasmodium infections.

    Directory of Open Access Journals (Sweden)

    Janet M Meredith

    Full Text Available Diseases transmitted by mosquitoes have a devastating impact on global health and this is worsening due to difficulties with existing control measures and climate change. Genetically modified mosquitoes that are refractory to disease transmission are seen as having great potential in the delivery of novel control strategies. Historically the genetic modification of insects has relied upon transposable elements which have many limitations despite their successful use. To circumvent these limitations the Streptomyces phage phiC31 integrase system has been successfully adapted for site-specific transgene integration in insects. Here, we present the first site-specific transformation of Anopheles gambiae, the principal vector of human malaria. Mosquitoes were initially engineered to incorporate the phiC31 targeting site at a defined genomic location. A second phase of genetic modification then achieved site-specific integration of Vida3, a synthetic anti-malarial gene. Expression of Vida3, specifically in the midgut of bloodfed females, offered consistent and significant protection against Plasmodium yoelii nigeriensis, reducing average parasite intensity by 85%. Similar protection was observed against Plasmodium falciparum in some experiments, although protection was inconsistent. In the fight against malaria, it is imperative to establish a broad repertoire of both anti-malarial effector genes and tissue-specific promoters for their expression, enabling those offering maximum effect with minimum fitness cost to be identified. In the future, this technology will allow effective comparisons and informed choices to be made, potentially leading to complete transmission blockade.

  13. Anopheles gambiae collagen IV genes: cloning, phylogeny and midgut expression associated with blood feeding and Plasmodium infection.

    Science.gov (United States)

    Gare, D C; Piertney, S B; Billingsley, P F

    2003-07-01

    A prerequisite for understanding the role that mosquito midgut extracellular matrix molecules play in malaria parasite development is proper isolation and characterisation of the genes coding for components of the basal lamina. Here we have identified genes coding for alpha1 and alpha2 chains of collagen IV from the major malaria vector, Anopheles gambiae. Conserved sequences in the terminal NC1 domain were used to obtain partial gene sequences of this functional region, and full sequence was isolated from a pupal cDNA library. In a DNA-derived phylogeny, the alpha1 and alpha2 chains cluster with dipteran orthologs, and the alpha2 is ancestral. The expression of collagen alpha1(IV) peaked during the pupal stage of mosquito development, and was expressed continuously in the adult female following a blood meal with a further rise detected in older mosquitoes. Collagen alpha1(IV) is also upregulated when the early oocyst of Plasmodium yoelii was developing within the mosquito midgut and may contribute to a larger wound healing response. A model describing the expression of basal lamina proteins during oocyst development is presented, and we hypothesise that the development of new basal lamina between the oocyst and midgut epithelium is akin to a wound healing process. PMID:12814648

  14. Anopheles gambiae Ag-STAT, a new insect member of the STAT family, is activated in response to bacterial infection.

    Science.gov (United States)

    Barillas-Mury, C; Han, Y S; Seeley, D; Kafatos, F C

    1999-02-15

    A new insect member of the STAT family of transcription factors (Ag-STAT) has been cloned from the human malaria vector Anopheles gambiae. The domain involved in DNA interaction and the SH2 domain are well conserved. Ag-STAT is most similar to Drosophila D-STAT and to vertebrate STATs 5 and 6, constituting a proposed ancient class A of the STAT family. The mRNA is expressed at all developmental stages, and the protein is present in hemocytes, pericardial cells, midgut, skeletal muscle and fat body cells. There is no evidence of transcriptional activation following bacterial challenge. However, bacterial challenge results in nuclear translocation of Ag-STAT protein in fat body cells and induction of DNA-binding activity that recognizes a STAT target site. In vitro treatment with pervanadate (vanadate and H2O2) translocates Ag-STAT to the nucleus in midgut epithelial cells. This is the first evidence of direct participation of the STAT pathway in immune responses in insects. PMID:10022838

  15. 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...

  16. Visual and olfactory associative learning in the malaria vector Anopheles gambiae sensu stricto

    OpenAIRE

    Chilaka Nora; Perkins Elisabeth; Tripet Frédéric

    2012-01-01

    Abstract Background Memory and learning are critical aspects of the ecology of insect vectors of human pathogens because of their potential effects on contacts between vectors and their hosts. Despite this epidemiological importance, there have been only a limited number of studies investigating associative learning in insect vector species and none on Anopheline mosquitoes. Methods A simple behavioural assays was developed to study visual and olfactory associative learning in Anopheles gambi...

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

    OpenAIRE

    Yan Guiyun; Soares Dinesh C; Jiggins Francis M; Callister Deborah M; Obbard Darren J; Little Tom J

    2008-01-01

    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 b...

  18. Apolipophorin-III Mediates Antiplasmodial Epithelial Responses in Anopheles gambiae (G3) Mosquitoes

    OpenAIRE

    Gupta, Lalita; Noh, Ju Young; Jo, Yong Hun; Oh, Seung Han; Kumar, Sanjeev; Noh, Mi Young; Lee, Yong Seok; Cha, Sung-Jae; Seo, Sook Jae; Kim, Iksoo; Han, Yeon Soo; Barillas-Mury, Carolina

    2010-01-01

    Background Apolipophorin-III (ApoLp-III) is known to play an important role in lipid transport and innate immunity in lepidopteran insects. However, there is no evidence of involvement of ApoLp-IIIs in the immune responses of dipteran insects such as Drosophila and mosquitoes. Methodology/Principal Findings We report the molecular and functional characterization of An. gambiae apolipophorin-III (AgApoLp-III). Mosquito ApoLp-IIIs have diverged extensively from those of lepidopteran insects; ho...

  19. Observation of granulations in the basal body of ovarioles and follicular dilatations for the determination of physiological age of Anopheles gambiae s.s.

    Directory of Open Access Journals (Sweden)

    Rodrigue Anagonou

    2015-07-01

    Full Text Available Objective: To explore ovariole basal body granulations and follicular dilatations for determining physiological age in Anopheles gambiae s.s. (An. gambiae s.s.. Methods: Mosquitoes were collected by using window trap catch and identified morphologically. For the first lot of mosquitoes, they were dissected, and ovary was left in distilled water for reading ovarian tracheoles and the second was cut and transferred to another blade in a physiological liquid for verification of ovariole basal body granulations. The same approach was followed with the second lot of mosquitoes where follicular dilatations were found after classic dilaceration of ovaries were transferred into physiological liquid. The other body parts of mosquitoes were used to identify the species of the An. gambiae s.s. complex by PCR. Results: Among the 123 An. gambiae s.s. of the first lot, the method of Detinova determined the age of 89 mosquitoes versus 114 for the observation of granulations (P > 0.05. Among the 112 An. gambiae s.s. of the second lot, the method of Detinova determined the age of 84 mosquitoes versus 93 for the observation of follicular dilatations (P > 0.05. Unlike the method of Detinova, observation of follicular dilatations and basal body granulations of ovarioles were possible beyond the stage II Christophers. Conclusions: Overall, the observation of follicular dilatations and ovariole basal body granulations are reliable for the determination of the physiological age in An. gambiae s.s. Furthermore, these two methods can be used beyond the stage II.

  20. Influence of Water Type and Commercial Diets on the Production of Anopheles gambiae Giles, under Laboratory Conditions

    OpenAIRE

    Foko Dadji, G. A.; Messi J.; Tamesse J. L.

    2007-01-01

    In the present research we investigated the influence of water resources (tap water, pond water and sprint water…) and nutritional quality on egg hatching and larval development of An. gambiae (Diptera: culicidae). Whatever the nutritive quality, the hatching rate was 84±4 in tap water, 89± 1.4 in pond water and 91.8±2.2 in spring water. The duration of hatching is 72 hours in tap water and 48 h in spring water. The duration of development (from egg to emergence) is 19.3±1.1 days in tap water...

  1. Next-generation site-directed transgenesis in the malaria vector mosquito Anopheles gambiae: self-docking strains expressing germline-specific phiC31 integrase.

    Directory of Open Access Journals (Sweden)

    Janet M Meredith

    Full Text Available Diseases transmitted by mosquitoes have a devastating impact on global health and the situation is complicated due to difficulties with both existing control measures and the impact of climate change. Genetically modified mosquitoes that are refractory to disease transmission are seen as having great potential in the delivery of novel control strategies. The Streptomyces phage phiC31 integrase system has been successfully adapted for site-directed transgene integration in a range of insects, thus overcoming many limitations due to size constraints and random integration associated with transposon-mediated transformation. Using this technology, we previously published the first site-directed transformation of Anopheles gambiae, the principal vector of human malaria. Mosquitoes were initially engineered to incorporate the phiC31 docking site at a defined genomic location. A second phase of genetic modification then achieved site-directed integration of an anti-malarial effector gene. In the current publication we report improved efficiency and utility of the phiC31 integrase system following the generation of Anopheles gambiae self-docking strains. Four independent strains, with docking sites at known locations on three different chromosome arms, were engineered to express integrase under control of the regulatory regions of the nanos gene from Anopheles gambiae. The resulting protein accumulates in the posterior oocyte to provide integrase activity at the site of germline development. Two self-docking strains, exhibiting significantly different levels of integrase expression, were assessed for site-directed transgene integration and found to demonstrate greatly improved survival and efficiency of transformation. In the fight against malaria, it is imperative to establish a broad repertoire of both anti-malarial effector genes and tissue-specific promoters to regulate their expression, enabling those offering maximum effect with minimum fitness

  2. 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...

  3. Structure-Function Analysis of the Anopheles gambiae LRIM1/APL1C Complex and its Interaction with Complement C3-Like Protein TEP1

    OpenAIRE

    Povelones, Michael; Upton, Leanna M.; Sala, Katarzyna A.; Christophides, George K.

    2011-01-01

    Malaria threatens half the world's population and exacts a devastating human toll. The principal malaria vector in Africa, the mosquito Anopheles gambiae, encodes 24 members of a recently identified family of leucine-rich repeat proteins named LRIMs. Two members of this family, LRIM1 and APL1C, are crucial components of the mosquito complement-like pathway that is important for immune defense against Plasmodium parasites. LRIM1 and APL1C circulate in the hemolymph exclusively as a disulfide-b...

  4. Structure-function analysis of the Anopheles gambiae LRIM1/APL1C complex and its interaction with complement C3-like protein TEP1.

    OpenAIRE

    Michael Povelones; Upton, Leanna M.; Sala, Katarzyna A.; Christophides, George K.

    2011-01-01

    Malaria threatens half the world's population and exacts a devastating human toll. The principal malaria vector in Africa, the mosquito Anopheles gambiae, encodes 24 members of a recently identified family of leucine-rich repeat proteins named LRIMs. Two members of this family, LRIM1 and APL1C, are crucial components of the mosquito complement-like pathway that is important for immune defense against Plasmodium parasites. LRIM1 and APL1C circulate in the hemolymph exclusively as a disulfide-b...

  5. Molecular characterisation and chromosomal mapping of transcripts having tissue-specific expression in the malaria mosquito Anopheles gambiae: possible involvement in visual or olfactory processes.

    Science.gov (United States)

    Ricci, Irene; Santolamazza, Federica; Costantini, Carlo; Favia, Guido

    2002-01-01

    We have compared the transcriptional activity of heads, antennae + palps, and carcasses in the mosquito Anopheles gambiae by means of differential display PCR (DD-PCR). Three transcripts specifically or preferentially expressed in the heads and in the antennae + palps have been selected. All are very similar to genes related to visual and olfactory mechanisms of several different organisms. They have been named Ag arrestin, Ag rLDL, and Ag dynamin. The potential of the DD-PCR technique in identifying genes involved in mosquito behaviour and the usefulness of the molecular characterisation of these transcripts are discussed. PMID:11822731

  6. Optimization of sugar and blood feeding regimen in Anopheles gambiae mass production system

    International Nuclear Information System (INIS)

    The sterile insect technique (SIT) is being developed for the control of malaria transmitting mosquitoes. Critical to the success of applying the SIT is the establishment of standardized mass production systems for the target species. As part of efforts to develop standardised mass production systems for malaria vectors, this project sought to optimize adult blood and sugar feeding in a mass production system. Different sugar types (glucose, sucrose and honey) were evaluated at 6% and 10% concentrations in water to determine the best sugar diet and concentration for feeding adult An. gambiae. Different blood feeding methods, restrained Guinea pig, anaesthetised Guinea pig and human arm feeding were evaluated. Adult survival, female insemination and egg production were used as criteria to determine optimum sugar and blood feeding. The effect of anaesthetics on blood feeding response and egg production of female An. gambiae was determined by comparing feeding response and egg production of females fed with anaesthetised Guinea pigs as against physically restrained Guinea pigs (Control). The specific effect of different anaesthetic agents on blood feeding response and egg production of female mosquitoes were was also determined by comparing the feeding response and egg production of females fed with either Ketamine/Xylazine anaesthetised Guinea pigs or Ketamine/Diazepam anaesthetised Guinea pigs. Effects due to sugar types and concentrations on percentage survival of male and female mosquitoes were observed to be significant at (p 0.05). However, human ann feeding (HAP) method and Ketamine/Xylazine (KX) anaesthetics fed for 25 minutes recorded higher percentage feeding (76.0% and 68.0% respectively) and egg production of 19.0% and 20.8% respectively. Anaesthetised Guinea pig feeding (AGF) of adults for 15 minutes followed closely with 60.0% and 15.1% blood feeding and egg production respectively whilst restrained Guinea pig feeding (RGF) method and Ketamine

  7. Pyrethroid resistance in Anopheles gambiae leads to increased susceptibility to the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana

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    Knols Bart GJ

    2010-06-01

    Full Text Available Abstract Background Entomopathogenic fungi are being investigated as a new mosquito control tool because insecticide resistance is preventing successful mosquito control in many countries, and new methods are required that can target insecticide-resistant malaria vectors. Although laboratory studies have previously examined the effects of entomopathogenic fungi against adult mosquitoes, most application methods used cannot be readily deployed in the field. Because the fungi are biological organisms it is important to test potential field application methods that will not adversely affect them. The two objectives of this study were to investigate any differences in fungal susceptibility between an insecticide-resistant and insecticide-susceptible strain of Anopheles gambiae sensu stricto, and to test a potential field application method with respect to the viability and virulence of two fungal species Methods Pieces of white polyester netting were dipped in Metarhizium anisopliae ICIPE-30 or Beauveria bassiana IMI391510 mineral oil suspensions. These were kept at 27 ± 1°C, 80 ± 10% RH and the viability of the fungal conidia was recorded at different time points. Tube bioassays were used to infect insecticide-resistant (VKPER and insecticide-susceptible (SKK strains of An. gambiae s.s., and survival analysis was used to determine effects of mosquito strain, fungus species or time since fungal treatment of the net. Results The resistant VKPER strain was significantly more susceptible to fungal infection than the insecticide-susceptible SKK strain. Furthermore, B. bassiana was significantly more virulent than M. anisopliae for both mosquito strains, although this may be linked to the different viabilities of these fungal species. The viability of both fungal species decreased significantly one day after application onto polyester netting when compared to the viability of conidia remaining in suspension. Conclusions The insecticide

  8. The angiotensin-converting enzyme (ACE gene family of Anopheles gambiae

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    Isaac R Elwyn

    2005-12-01

    Full Text Available Abstract Background Members of the M2 family of peptidases, related to mammalian angiotensin converting enzyme (ACE, play important roles in regulating a number of physiological processes. As more invertebrate genomes are sequenced, there is increasing evidence of a variety of M2 peptidase genes, even within a single species. The function of these ACE-like proteins is largely unknown. Sequencing of the A. gambiae genome has revealed a number of ACE-like genes but probable errors in the Ensembl annotation have left the number of ACE-like genes, and their structure, unclear. Results TBLASTN and sequence analysis of cDNAs revealed that the A. gambiae genome contains nine genes (AnoACE genes which code for proteins with similarity to mammalian ACE. Eight of these genes code for putative single domain enzymes similar to other insect ACEs described so far. AnoACE9, however, has several features in common with mammalian somatic ACE such as a two domain structure and a hydrophobic C terminus. Four of the AnoACE genes (2, 3, 7 and 9 were shown to be expressed at a variety of developmental stages. Expression of AnoACE3, AnoACE7 and AnoACE9 is induced by a blood meal, with AnoACE7 showing the largest (approximately 10-fold induction. Conclusion Genes coding for two-domain ACEs have arisen several times during the course of evolution suggesting a common selective advantage to having an ACE with two active-sites in tandem in a single protein. AnoACE7 belongs to a sub-group of insect ACEs which are likely to be membrane-bound and which have an unusual, conserved gene structure.

  9. The mode of action of spatial repellents and their impact on vectorial capacity of Anopheles gambiae sensu stricto.

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    Sheila B Ogoma

    Full Text Available Malaria vector control relies on toxicity of insecticides used in long lasting insecticide treated nets and indoor residual spraying. This is despite evidence that sub-lethal insecticides reduce human-vector contact and malaria transmission. The impact of sub-lethal insecticides on host seeking and blood feeding of mosquitoes was measured. Taxis boxes distinguished between repellency and attraction inhibition of mosquitoes by measuring response of mosquitoes towards or away from Transfluthrin coils and humans. Protective effective distance of coils and long-term effects on blood feeding were measured in the semi-field tunnel and in a Peet Grady chamber. Laboratory reared pyrethroid susceptible Anopheles gambiae sensu stricto mosquitoes were used. In the taxis boxes, a higher proportion of mosquitoes (67%-82% were activated and flew towards the human in the presence of Transfluthrin coils. Coils did not hinder attraction of mosquitoes to the human. In the semi-field Tunnel, coils placed 0.3 m from the human reduced feeding by 86% (95% CI [0.66; 0.95] when used as a "bubble" compared to 65% (95% CI [0.51; 0.76] when used as a "point source". Mosquitoes exposed to coils inside a Peet Grady chamber were delayed from feeding normally for 12 hours but there was no effect on free flying and caged mosquitoes exposed in the semi-field tunnel. These findings indicate that airborne pyrethroids minimize human-vector contact through reduced and delayed blood feeding. This information is useful for the development of target product profiles of spatial repellent products that can be used to complement mainstream malaria vector control tools.

  10. Asymmetric introgression between the M and S forms of the malaria vector, Anopheles gambiae, maintains divergence despite extensive hybridisation

    Science.gov (United States)

    Marsden, Clare D.; Lee, Yoosook; Nieman, Catelyn C.; Sanford, Michelle R.; Dinis, Joao; Martins, Cesario; Rodrigues, Amabelia; Cornel, Anthony J.; Lanzaro, Gregory C.

    2011-01-01

    The suggestion that genetic divergence can arise and/or be maintained in the face of gene flow, has been contentious since first proposed. This controversy and a rarity of good examples has limited our understanding of this process. Partially reproductively isolated taxa have been highlighted as offering unique opportunities for identifying the mechanisms underlying divergence with gene flow. The African malaria vector, Anopheles gambiae s.s., is widely regarded as consisting of two sympatric forms, thought by many to represent incipient species, the M and S molecular forms. However, there has been much debate about the extent of reproductive isolation between M and S, with one view positing that divergence may have arisen and is being maintained in the presence of gene flow, and the other proposing a more advanced speciation process with little realised gene flow due to low hybrid fitness. These hypotheses have been difficult to address because hybrids are typically rare (<1%). Here, we assess samples from an area of high hybridisation and demonstrate that hybrids are fit and responsible for extensive introgression. Nonetheless, we show that strong divergent selection at a subset of loci combined with highly asymmetric introgression has enabled M and S to remain genetically differentiated despite extensive gene flow. We propose the extent of reproductive isolation between M and S varies across West Africa resulting in a “geographic mosaic of reproductive isolation”; a finding which adds further complexity to our understanding of divergence in this taxon and which has considerable implications for transgenic control strategies. PMID:22059383

  11. An epithelial serine protease, AgESP, is required for Plasmodium invasion in the mosquito Anopheles gambiae.

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    Janneth Rodrigues

    Full Text Available 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 salivary glands that is critical for Plasmodium parasites to cross these two epithelial barriers. AgESP silencing greatly reduces Plasmodium berghei and Plasmodium falciparum midgut invasion and prevents the transcriptional activation of gelsolin, a key regulator of actin remodeling and a reported Plasmodium agonist. AgESP expression is highly induced in midgut cells invaded by Plasmodium, suggesting that this protease also participates in the apoptotic response to invasion. In salivary gland epithelial cells, AgESP is localized on the basal side--the surface with which sporozoites interact. AgESP expression in the salivary gland is also induced in response to P. berghei and P. falciparum sporozoite invasion, and AgESP silencing significantly reduces the number of sporozoites that invade this organ. CONCLUSION: Our findings indicate that AgESP is required for Plasmodium parasites to effectively traverse the midgut and salivary gland epithelial barriers. Plasmodium parasites need to modify the actin cytoskeleton of mosquito epithelial cells to successfully complete their life cycle in the mosquito and AgESP appears to be a major player in the regulation of this process.

  12. An Epithelial Serine Protease, AgESP, Is Required for Plasmodium Invasion in the Mosquito Anopheles gambiae

    Science.gov (United States)

    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 salivary glands that is critical for Plasmodium parasites to cross these two epithelial barriers. AgESP silencing greatly reduces Plasmodium berghei and Plasmodium falciparum midgut invasion and prevents the transcriptional activation of gelsolin, a key regulator of actin remodeling and a reported Plasmodium agonist. AgESP expression is highly induced in midgut cells invaded by Plasmodium, suggesting that this protease also participates in the apoptotic response to invasion. In salivary gland epithelial cells, AgESP is localized on the basal side–the surface with which sporozoites interact. AgESP expression in the salivary gland is also induced in response to P. berghei and P. falciparum sporozoite invasion, and AgESP silencing significantly reduces the number of sporozoites that invade this organ. Conclusion Our findings indicate that AgESP is required for Plasmodium parasites to effectively traverse the midgut and salivary gland epithelial barriers. Plasmodium parasites need to modify the actin cytoskeleton of mosquito epithelial cells to successfully complete their life cycle in the mosquito and AgESP appears to be a major player in the regulation of this process. PMID:22509400

  13. 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

  14. 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

  15. Characterization and expression analysis of gene encoding heme peroxidase HPX15 in major Indian malaria vector Anopheles stephensi (Diptera: Culicidae).

    Science.gov (United States)

    Kajla, Mithilesh; Kakani, Parik; Choudhury, Tania Pal; Gupta, Kuldeep; Gupta, Lalita; Kumar, Sanjeev

    2016-06-01

    The interaction of mosquito immune system with Plasmodium is critical in determining the vector competence. Thus, blocking the crucial mosquito molecules that regulate parasite development might be effective in controlling the disease transmission. In this study, we characterized a full-length AsHPX15 gene from the major Indian malaria vector Anopheles stephensi. This gene is true ortholog of Anopheles gambiae heme peroxidase AgHPX15 (AGAP013327), which modulates midgut immunity and regulates Plasmodium falciparum development. We found that AsHPX15 is highly induced in mosquito developmental stages and blood fed midguts. In addition, this is a lineage-specific gene that has identical features and 65-99% amino acids identity with other HPX15 genes present in eighteen worldwide-distributed anophelines. We discuss that the conserved HPX15 gene might serve as a common target to manipulate mosquito immunity and arresting Plasmodium development inside the vector host. PMID:26943999

  16. Sequencing and analysis of the complete mitochondrial genome in Anopheles culicifacies species B (Diptera: Culicidae).

    Science.gov (United States)

    Hua, Ya-Qiong; Yan, Zhen-Tian; Fu, Wen-Bo; He, Qi-Yi; Zhou, Yong; Chen, Bin

    2016-07-01

    The complete mitochondrial genome sequence of Anopheles culicifacial species B was sequenced in this study. The length of the mitochondrial genome is 15 330 bp, which contains 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and a non-coding control region. The gene order and the gene composition are consistent with those previously reported for other mosquito species. The initiation codon of the PCGs complies with the ATN rule except for COI using TCG and ND5 using GTG as a start codon, and the termination codon is TAA or imcomplete, an only T. The total base composition is 40.4% A, 38.1% T, 12.4% C, and 9.1% G. The phylogenetic tree based on the sequences of 13 protein-coding genes showed that these species were classified into two clades, corresponding to the subgenus Cellia and subgenus Nyssorhynchus. An. culicifacies species B of Myzomyia Series was clustered with An. gambiae of Pyretophorus Series with a high bootstrap value of 100%. The complete mitogenome data can provide a basis for molecular identification and phylogenetic studies of mosquito species. PMID:26114319

  17. 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

  18. Evidence of increasing L1014F kdr mutation frequency in Anopheles gambiae s.l. pyrethroid resistant following a nationwide distribution of LLINs by the Beninese National Malaria Control Programme

    Institute of Scientific and Technical Information of China (English)

    Nazaire Azoun; Rock Akpon; Martin Akogbto

    2014-01-01

    Objective:To determine the susceptibility status to pyrethroid in Anopheles gambiae s.l. (An. gambiae), the distribution of kdr“Leu-Phe”mutation in malaria vectors in Benin and to compare the current frequency of kdr“Leu-Phe”mutation to the previous frequency after long-lasting insecticide treated nets implementation. Methods: Larvae and pupae of An. gambiae s.l. mosquitoes were collected from the breeding sites in Littoral, Zou, Borgou and Alibori provinces. CDC susceptibility tests were conducted on unfed females mosquitoes aged 2-5 d old. An. gambiae mosquitoes were identified to species using PCR techniques. Molecular assays were also carried out to identify kdr mutations in individual mosquitoes. Results: The results showed that An. gambiae Malanville and Suru-lere populations were resistant to deltamethrin. Regarding An. gambiae Parakou and Bohicon populations, they were resistant to permethrin. PCR revealed 100%of mosquitoes tested were An. gambiae s.s. The L1014F kdr mutation was found in An. gambiae s.s. Malanville and Parakou at various allelic frequencies. The increase of kdr allelic frequency was positively correlated with CDC bioassays data. Conclusions: Pyrethroid resistance is widespread in malaria vector in Benin and kdr mutation is the main resistance mechanism involved. More attention may be paid for the future success of malaria control programmes based on LLINs with pyrethroids in the country.

  19. 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.

  20. The Cry4B toxin of Bacillus thuringiensis subsp. israelensis kills Permethrin-resistant Anopheles gambiae, the principal vector of malaria.

    Science.gov (United States)

    Ibrahim, Mohamed A; Griko, Natalya B; Bulla, Lee A

    2013-04-01

    Resurgence of malaria has been attributed, in part, to the development of resistance by Anopheles gambiae, a principal vector of the disease, to various insecticidal compounds such as Permethrin. Permethrin, a neurotoxicant, is widely used to impregnate mosquito nets. An alternative strategy to control mosquitoes is the use of Bacillus thuringiensis subsp. israelensis (Bti) because there is no observable resistance in the field to the bacterium. Bti kills mosquitoes by targeting cadherin molecules residing in the midgut epithelium of larvae of the insect. Cry proteins (Cry4A, Cry4B, Cry10A and Cry11A) produced by the bacterium during the sporulation phase of its life cycle bind to the cadherin molecules, which serve as receptors for the proteins. These Cry proteins have variable specificity to a variety of mosquitoes, including Culex and Aedes as well as Anopheles. Importantly, selective mosquitocidal action is occasioned by binding of the respective Cry toxins to cadherins distinctive to individual mosquito species. Differential fractionation of the four Cry proteins from a novel Bti isolate (M1) and cloning and expression of their genes in Escherichia coli revealed that Cry4B is the only Cry protein that exerts insecticidal action against An. gambiae. Indeed, it does so against a Permethrin-resistant strain of the mosquito. The other three Cry proteins are ineffective. Multiple sequence alignments of the four Cry proteins revealed a divergent sequence motif in the Cry4B toxin, which most likely determines binding of the toxin to its cognate receptor, BT-R3, in An. gambiae and to its specific toxicity. A model showing Cry4B toxin binding to BT-R3 is presented. PMID:23760000

  1. 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

  2. Effect of sugar on male Anopheles gambiae mating performance, as modified by temperature, space, and body size

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    Cannon James W

    2009-04-01

    Full Text Available Abstract Background Anopheles gambiae plant-sugar feeding was thought to be rare and physiologically optional. Unlike adult females, males have no alternative source of energy and soon die with only water, yet they might be competent to inseminate all females within their brief lifespan. This study was designed to detect sugar's effect, if any, on male performance. Methods Males with and without 20% sucrose were evaluated at two body sizes and two temperatures, 23° and 27°C. Survival was recorded twice daily, and sexual behaviour was recorded each night after adult emergence. Insemination at a 2:1 male:female ratio was examined in three cage sizes, including walk-in mesocosms. Results Without sugar, males of both sizes lived longer at 23° than 27°C, and large males lived longer at each temperature. Survival of large males at low temperature averaged 3.7 days, small males at high temperature, 1.9 days. With sugar, males in all four treatments suffered minimal mortality. With sugar, in small cages, large males at 27°C matured most rapidly. A few erected fibrillae and inseminated females on night 1. On night 2, maximal proportions erected fibrillae and swarmed, and over one-third of females became inseminated. Small sugar-fed males at 23°C matured most slowly but had achieved nearly maximal levels of swarming by night 3. By night 5, small males had inseminated more than half the females, and large males had inseminated nearly all of them. Without sugar, large males progressed similarly during the first two nights. On night 3, however, the proportion erecting fibrillae and swarming declined precipitously at 27°C, and to a lesser degree at 23°C. Cumulative insemination never reached high levels. Small males never achieved high levels of fibrillar erection or swarming and inseminated few females, even at 23°C. In larger cages and under more semi-natural conditions, regardless of body size, without sugar male insemination capacity was

  3. Identification and characterization of the fibrinogen-like domain of fibrinogen-related proteins in the mosquito, Anopheles gambiae, and the fruitfly, Drosophila melanogaster, genomes

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    Zhao Qin

    2005-09-01

    Full Text Available Abstract Background The fibrinogen-like (FBG domain, which consists of approximately 200 amino acid residues, has high sequence similarity to the C-terminal halves of fibrinogen β and γ chains. Fibrinogen-related proteins (FREPs, which contain FBG domains in their C-terminal region, are found universally in vertebrates and invertebrates. In invertebrates, FREPs are involved in immune responses and other aspects of physiology. To understand the complexity of this family in insects, we analyzed FREPs in the mosquito genome and made comparisons to FREPs in the fruitfly genome. Results By using the genome data of the mosquito, Anopheles gambiae, 53 FREPs were identified, whereas only 20 members were found in the Drosophila melanogaster genome. Using sequence profile analysis, we found that FBG domains have high sequence similarity and are highly conserved throughout the FBG domain region. By secondary structure analysis and comparison, the FBG domains of FREPs are predicted to function in recognition of carbohydrates and their derivatives on the surface of microorganisms in innate immunity. Conclusion Detailed sequence and structural analysis discloses that the FREP family contains FBG domains that have high sequence similarity in the A. gambiae genome. Expansion of the FREP family in mosquitoes during evolutionary history is mainly accounted for by a major expansion of the FBG domain architecture. The characterization of the FBG domains in the FREP family is likely to aid in the experimental analysis of the ability of mosquitoes to recognize parasites in innate immunity and physiologies associated with blood feeding.

  4. Combining two-dimensional gel electrophoresis and metabolomic data in support of dry-season survival in the two main species of the malarial mosquito Anopheles gambiae

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    Hidalgo K.

    2015-12-01

    Full Text Available In dry savannahs of West-Africa, the malarial mosquitoes of the Anopheles gambiae sensu stricto complex annually survive the harsh desiccating conditions of the dry season. However, the physiological and biochemical mechanisms underlying how these mosquitoes survive such desiccating conditions are still undefined, and controversial. In this context, we provide the first work examining both proteomic and metabolomic changes in the two molecular forms of A. gambiae s.s (M and S forms experimentally exposed to the rainy and dry season conditions as they experience in the field. Protein abundances of the mosquitoes were measured using a two-dimensional fluorescence difference gel electrophoresis (2D DIGE coupled with a matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF and tandem mass spectrometry (MS for protein identification. These assays were conducted by Applied Biomics (http://www.appliedbiomics.com, Applied Biomics, Inc. Hayward, CA, USA, and the mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium (http://proteomecentral.proteomexchange.org via the PRIDE partner repository with the dataset identifier PXD000294. The metabolomic analysis was conducted using both Acquity UPLC® system (for amino acid identification, and a gas-chromatography-mass spectrometry platform (for sugars identification. Metabolomic fingerprintings were assessed in the University of Rennes 1, UMR CNRS 6553 EcoBio (France. A detailed interpretation of the obtained data can be found in Hidalgo et al. (2014 [1] (Journal of Insect Physiology (2014.

  5. Effects of co-habitation between Anopheles gambiae s.s. and Culex quinquefasciatus aquatic stages on life history traits

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    Kweka Eliningaya J

    2012-02-01

    Full Text Available Abstract Background The effective measures for the control of malaria and filariasis vectors can be achieved by targeting immature stages of anopheline and culicine mosquitoes in productive habitat. To design this strategy, the mechanisms (like biotic interactions with conspecifc and heterospecific larvae regulating mosquito aquatic stages survivorship, development time and the size of emerging adults should be understood. This study explored the effect of co-habitation between An. gambiae s.s. and Cx. quinquefasciatus on different life history traits of both species under different densities and constant food supply in the habitats of the same size under semi-natural conditions. Methods Experiments were set up with three combinations; Cx. quinquefasciatus alone (single species treatment, An. gambiae s.s. alone (single species treatment; and An. gambiae s.s. with Cx. quiquefasciatus (co-habitation treatment in different densities in semi field situation. Results The effect of co-habitation of An. gambiae s.s. and Cx. quinquefasciatus was found to principally affect three parameters. The wing-lengths (a proxy measure of body size of An. gambiae s.s. in co-habitation treatments were significantly shorter in both females and males than in An. gambiae s.s single species treatments. In Cx. quinquefasciatus, no significant differences in wing-length were observed between the single species and co-habitation treatments. Daily survival rates were not significantly different between co-habitation and single species treatments for both An. gambiae s.s. and Cx. quinquefasciatus. Developmental time was found to be significantly different with single species treatments developing better than co-habitation treatments. Sex ratio was found to be significantly different from the proportion of 0.5 among single and co-habitation treatments species at different densities. Single species treatments had more males than females emerging while in co

  6. Transcriptional mediators Kto and Skd are involved in the regulation of the IMD pathway and anti-Plasmodium defense in Anopheles gambiae.

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    Yang Chen

    Full Text Available The malarial parasite Plasmodium must complete a complex lifecycle in its Anopheles mosquito host, the main vector for Plasmodium. The mosquito resists infection with the human malarial parasite P. falciparum by engaging the NF-κB immune signaling pathway, IMD. Here we show that the conserved transcriptional mediators Kto and Skd are involved in the regulation of the mosquito IMD pathway. RNAi-mediated depletion of Kto and Skd in the Anopheles gambiae cell line L5-3 resulted in a decrease in the transcript abundance of Cec1, which is controlled by the IMD pathway. Silencing the two genes also resulted in an increased susceptibility of the mosquito to bacterial and Plasmodium falciparum infection, but not to infection with the rodent malaria parasite P. berghei. We also showed that Kto and Skd are not transcriptional co-activators of Rel2 or other key factors of the IMD pathway; however, they participate in the regulation of the IMD pathway, which is crucial for the mosquito's defense against P. falciparum.

  7. Target-site resistance mutations (kdr and RDL), but not metabolic resistance, negatively impact male mating competiveness in the malaria vector Anopheles gambiae.

    Science.gov (United States)

    Platt, N; Kwiatkowska, R M; Irving, H; Diabaté, A; Dabire, R; Wondji, C S

    2015-09-01

    The implementation of successful insecticide resistance management strategies for malaria control is currently hampered by poor understanding of the fitness cost of resistance on mosquito populations, including their mating competiveness. To fill this knowledge gap, coupled and uncoupled Anopheles gambiae s.l. males (all M form (Anopheles coluzzii)) were collected from mating swarms in Burkina Faso. This multiple insecticide resistant population exhibited high 1014F kdr(R) allele frequencies (>60%) and RDL(R) (>80%) in contrast to the Ace-1(R) allele (RDL(R)/RDL(S) were also more likely to mate than homozygote-resistant males (OR=2.58; P=0.007). Furthermore, an additive mating disadvantage was detected in male homozygotes for both kdr/RDL-resistant alleles. In contrast, no fitness difference was observed for the Ace-1 mutation. Comparative microarray-based genome-wide transcription analysis revealed that metabolic resistance did not significantly alter the mating competitiveness of male An. coluzzii mosquitoes. Indeed, no significant difference of expression levels was observed for the main metabolic resistance genes, suggesting that metabolic resistance has a limited impact on male mating competiveness. In addition, specific gene classes/GO terms associated with mating process were detected including sensory perception and peroxidase activity. The detrimental impact of insecticide resistance on mating competiveness observed here suggests that resistance management strategies such as insecticide rotation could help reverse the resistance, if implemented early. PMID:25899013

  8. Successful field trial of attractive toxic sugar bait (ATSB plant-spraying methods against malaria vectors in the Anopheles gambiae complex in Mali, West Africa

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    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

  9. Humoral response to the Anopheles gambiae salivary protein gSG6: a serological indicator of exposure to Afrotropical malaria vectors.

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    Cinzia Rizzo

    Full Text Available Salivary proteins injected by blood feeding arthropods into their hosts evoke a saliva-specific humoral response which can be useful to evaluate exposure to bites of disease vectors. However, saliva of hematophagous arthropods is a complex cocktail of bioactive factors and its use in immunoassays can be misleading because of potential cross-reactivity to other antigens. Toward the development of a serological marker of exposure to Afrotropical malaria vectors we expressed the Anopheles gambiae gSG6, a small anopheline-specific salivary protein, and we measured the anti-gSG6 IgG response in individuals from a malaria hyperendemic area of Burkina Faso, West Africa. The gSG6 protein was immunogenic and anti-gSG6 IgG levels and/or prevalence increased in exposed individuals during the malaria transmission/rainy season. Moreover, this response dropped during the intervening low transmission/dry season, suggesting it is sensitive enough to detect variation in vector density. Members of the Fulani ethnic group showed higher anti-gSG6 IgG response as compared to Mossi, a result consistent with the stronger immune reactivity reported in this group. Remarkably, anti-gSG6 IgG levels among responders were high in children and gradually declined with age. This unusual pattern, opposite to the one observed with Plasmodium antigens, is compatible with a progressive desensitization to mosquito saliva and may be linked to the continued exposure to bites of anopheline mosquitoes. Overall, the humoral anti-gSG6 IgG response appears a reliable serological indicator of exposure to bites of the main African malaria vectors (An. gambiae, Anopheles arabiensis and, possibly, Anopheles funestus and it may be exploited for malaria epidemiological studies, development of risk maps and evaluation of anti-vector measures. In addition, the gSG6 protein may represent a powerful model system to get a deeper understanding of molecular and cellular mechanisms underlying the

  10. 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

  11. Comparative egg morphology of six species of the Albimanus section of Anopheles (Nyssorhynchus) (Diptera:Culicidae).

    Science.gov (United States)

    Lounibos, L P; Duzak, D; Linley, J R

    1997-03-01

    Scanning electron micrographs were used to describe and compare structures of eggs obtained from wild-caught females of 6 species of the Albimanus section of Anopheles (Nyssorhynchus) from South America, which includes important regional vectors of human malaria. Among species from the Oswaldoi Complex, eggs of Anopheles oswaldoi (Peryassu) were not differentiated from those of its sibling Anopheles konderi Galvão & Damasceno, and eggs of the former species from Brazil, Ecuador, and Suriname showed no regionally distinguishing characteristics. Eggs of Anopheles dunhami Causey were recognized by the reticulate beadwork of outer chorion on the dorsal plastron, 1 of several egg characters separating this species from the related Anopheles trinkae Faran and Anophels nuneztovari Gabaldón. In both species examined from the Strodei Complex, Anopheles strodei Root and Anopheles benarrochi Gabaldón, Cova Garcia & Lopez, the anterior frill forms a distinctive ventral crown separated from the floats. Anopheles triannulatus (Neiva & Pinto), collected from 4 geographic sites, differed in the occurrence of perforated mounds on the dorsal plastron, but these chorionic structures and the extent of overlap of floats varied among eggs from single females. Changes among related species in the structure of the anterior frill and dorsal plastron are described for phylogenetic and developmental inferences. PMID:9103756

  12. Mapping the Anopheles gambiae odorant binding protein 1 (AgamOBP1) using modeling techniques, site directed mutagenesis, circular dichroism and ligand binding assays.

    Science.gov (United States)

    Rusconi, B; Maranhao, A C; Fuhrer, J P; Krotee, P; Choi, S H; Grun, F; Thireou, T; Dimitratos, S D; Woods, D F; Marinotti, O; Walter, M F; Eliopoulos, E

    2012-08-01

    The major malaria vector in Sub-Saharan Africa is the Anopheles gambiae mosquito. This species is a key target of malaria control measures. Mosquitoes find humans primarily through olfaction, yet the molecular mechanisms associated with host-seeking behavior remain largely unknown. To further understand the functionality of A. gambiae odorant binding protein 1 (AgamOBP1), we combined in silico protein structure modeling and site-directed mutagenesis to generate 16 AgamOBP1 protein analogues containing single point mutations of interest. Circular dichroism (CD) and ligand-binding assays provided data necessary to probe the effects of the point mutations on ligand binding and the overall structure of AgamOBP1. Far-UV CD spectra of mutated AgamOBP1 variants displayed both substantial decreases to ordered α-helix structure (up to22%) and increases to disordered α-helix structure(up to 15%) with only minimal changes in random coil (unordered) structure. In mutations Y54A, Y122A and W114Q, aromatic side chain removal from the binding site significantly reduced N-phenyl-1-naphthylamine binding. Several non-aromatic mutations (L15T, L19T, L58T, L58Y, M84Q, M84K, H111A, Y122A and L124T) elicited changes to protein conformation with subsequent effects on ligand binding. This study provides empirical evidence for the in silico predicted functions of specific amino acids in AgamOBP1 folding and ligand binding characteristics. PMID:22564768

  13. Crystal and solution studies of the "Plus-C" odorant-binding protein 48 from Anopheles gambiae: control of binding specificity through three-dimensional domain swapping.

    Science.gov (United States)

    Tsitsanou, Katerina E; Drakou, Christina E; Thireou, Trias; Vitlin Gruber, Anna; Kythreoti, Georgia; Azem, Abdussalam; Fessas, Dimitrios; Eliopoulos, Elias; Iatrou, Kostas; Zographos, Spyros E

    2013-11-15

    Much physiological and behavioral evidence has been provided suggesting that insect odorant-binding proteins (OBPs) are indispensable for odorant recognition and thus are appealing targets for structure-based discovery and design of novel host-seeking disruptors. Despite the fact that more than 60 putative OBP-encoding genes have been identified in the malaria vector Anopheles gambiae, the crystal structures of only six of them are known. It is therefore clear that OBP structure determination constitutes the bottleneck for structure-based approaches to mosquito repellent/attractant discovery. Here, we describe the three-dimensional structure of an A. gambiae "Plus-C" group OBP (AgamOBP48), which exhibits the second highest expression levels in female antennae. This structure represents the first example of a three-dimensional domain-swapped dimer in dipteran species. A combined binding site is formed at the dimer interface by equal contribution of each monomer. Structural comparisons with the monomeric AgamOBP47 revealed that the major structural difference between the two Plus-C proteins localizes in their N- and C-terminal regions, and their concerted conformational change may account for monomer-swapped dimer conversion and furthermore the formation of novel binding pockets. Using a combination of gel filtration chromatography, differential scanning calorimetry, and analytical ultracentrifugation, we demonstrate the AgamOBP48 dimerization in solution. Eventually, molecular modeling calculations were used to predict the binding mode of the most potent synthetic ligand of AgamOBP48 known so far, discovered by ligand- and structure-based virtual screening. The structure-aided identification of multiple OBP binders represents a powerful tool to be employed in the effort to control transmission of the vector-borne diseases. PMID:24097978

  14. Effects of co-habitation between Anopheles gambiae s.s. and Culex quinquefasciatus aquatic stages on life history traits

    OpenAIRE

    Kweka Eliningaya J; Zhou Goufa; Beilhe Leila B; Dixit Amruta; Afrane Yaw; Gilbreath Thomas M; Munga Stephen; Nyindo Mramba; Githeko Andrew K; Yan Guiyun

    2012-01-01

    Abstract Background The effective measures for the control of malaria and filariasis vectors can be achieved by targeting immature stages of anopheline and culicine mosquitoes in productive habitat. To design this strategy, the mechanisms (like biotic interactions with conspecifc and heterospecific larvae) regulating mosquito aquatic stages survivorship, development time and the size of emerging adults should be understood. This study explored the effect of co-habitation between An. gambiae s...

  15. The Anopheles gambiae Oxidation Resistance 1 (OXR1) Gene Regulates Expression of Enzymes That Detoxify Reactive Oxygen Species

    OpenAIRE

    Jaramillo-Gutierrez, Giovanna; Molina-Cruz, Alvaro; Kumar, Sanjeev; Barillas-Mury, Carolina

    2010-01-01

    Background OXR1 is an ancient gene, present in all eukaryotes examined so far that confers protection from oxidative stress by an unknown mechanism. The most highly conserved region of the gene is the carboxyl-terminal TLDc domain, which has been shown to be sufficient to prevent oxidative damage. Methodology/Principal Findings OXR1 has a complex genomic structure in the mosquito A. gambiae, and we confirm that multiple splice forms are expressed in adult females. Our studies revealed that OX...

  16. Clarification of anomalies in the application of a 2La molecular karyotyping method for the malaria vector Anopheles gambiae

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    Knols Bart GJ

    2008-12-01

    Full Text Available Abstract Background Chromosomal inversions have been considered to be potentially important barriers to gene flow in many groups of animals through their effect on recombination suppression in heterokaryotypic individuals. Inversions can also enhance local adaptation in different groups of organisms and may often represent species-specific differences among closely related taxa. We conducted a study to characterize the 2La inversion karyotypes of An. gambiae sensu stricto mosquitoes sampled from the Kilombero Valley (Tanzania using a newly designed PCR assay. Results We frequently encountered a (687 bp fragment which was only present in the Kilombero Valley populations. Laboratory crossing between An. gambiae s.s. from Njage (Tanzania and Kisumu (Western Kenya populations resulted in F1 offspring carrying the observed fragment. Karyotype analysis did not indicate differences in 2La region chromosome morphology between individuals carrying the PCR fragments, the 207 bp fragment, or the 687 bp fragement. Conclusion The observed insertion/deletion polymorphism within the region amplified by the 2La PCR diagnostic test may confound the interpretation of this assay and should be well considered in order to maintain an acceptable level of reliability in studies using this assay to describe the distribution and frequency of the 2La inversion among natural populations of An. gambiae s.s.

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

    Science.gov (United States)

    Ruiz, Freddy; Linton, Yvonne-Marie; Ponsonby, David J; Conn, Jan E; Herrera, Manuela; Quiñones, Martha L; Vélez, Iván D; Wilkerson, Richard C

    2010-11-01

    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. PMID:21120360

  18. 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.

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

    OpenAIRE

    Freddy Ruiz; Yvonne-Marie Linton; Ponsonby, David J; Conn, Jan E.; Manuela Herrera; Martha L Quiñones; Iván D. Vélez; Wilkerson, Richard C

    2010-01-01

    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...

  20. Dissecting the mechanisms responsible for the multiple insecticide resistance phenotype in Anopheles gambiae s.s., M form, from Vallée du Kou, Burkina Faso.

    Science.gov (United States)

    Kwiatkowska, Rachel M; Platt, Naomi; Poupardin, Rodolphe; Irving, Helen; Dabire, Roch K; Mitchell, Sara; Jones, Christopher M; Diabaté, Abdoulaye; Ranson, Hilary; Wondji, Charles S

    2013-04-25

    With the exception of target site mutations, insecticide resistance mechanisms in the principle malaria vector Anopheles gambiae, remains largely uncharacterized in Burkina Faso. Here we detected high prevalence of resistance in Vallée du Kou (VK) to pyrethroids, DDT and dieldrin, moderate level for carbamates and full susceptibility to organophosphates. High frequencies of L1014F kdr (75%) and Rdl (87%) mutations were observed showing strong correlation with pyrethroids/DDT and dieldrin resistance. The frequency of ace1R mutation was low even in carbamate resistant mosquitoes. Microarray analysis identified genes significantly over-transcribed in VK. These include the cytochrome P450 genes, CYP6P3 and CYP6Z2, previously associated with pyrethroid resistance. Gene Ontology (GO) enrichment analysis suggested that elevated neurotransmitter activity is associated with resistance, with the over-transcription of target site resistance genes such as acetylcholinesterase and the GABA receptor. A rhodopsin receptor gene previously associated with pyrethroid resistance in Culex pipiens pallens was also over-transcribed in VK. This study highlights the complex network of mechanisms conferring multiple resistance in malaria vectors and such information should be taken into account when designing and implementing resistance control strategies. PMID:23380570

  1. 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...

  2. Spatio-temporal variations of Anopheles coluzzii and An. gambiae and their Plasmodium infectivity rates in Lobito, Angola

    OpenAIRE

    Carnevale, Pierre; Toto, J. C.; Dos Santos, M.A.; Fortes, F; Allan, R; Manguin, Sylvie

    2015-01-01

    From 2003 to 2007, entomological surveys were conducted in Lobito town (Benguela Province, Angola) to determine which Anopheles species were present and to identify the vectors responsible for malaria transmission in areas where workers of the Sonamet Company live. Two types of surveys were conducted: (1) time and space surveys in the low and upper parts of Lobito during the rainy and dry periods; (2) a two-year longitudinal study in Sonamet workers' houses provided with long-lasting insectic...

  3. Larval Habitat Characteristics of the Genus Anopheles (Diptera: Culicidae and a Checklist of Mosquitoes in Guilan Province, Northern Iran

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    S Azari-Hamidian

    2011-06-01

    Full Text Available Background: Ecological data are important in the vector control management of mosquitoes. There is scattered pub­lished information about the larval habitat characteristics and ecology of the genus Anopheles (Diptera: Culicidae in Iran and most of available data is in relation to malaria vectors in southern Iran.Methods: This cross sectional investigation was carried out to study the mosquito fauna and ecology in Guilan Province, northern Iran, during April–December 2000. Larvae were collected using the standard dipping technique. Larval habitat characteristics were recorded according to water situation (clear or turbid, vegetation, substrate type, sunlight situation, habitat situation (transient or permanent, running or stagnant, habitat type (natural or artificial, and water temperature. Results: In total, 1547 third- and fourth-instar larvae of Anopheles from 90 habitats were collected and morphologi­cally identified. Five species; Anopheles claviger, An.’hyrcanus’, An. maculipennis s.l., An. plumbeus, and An. su­perpictus were identified and respectively comprised 6.3%, 22.4%, 54.4%, 13.0%, and 3.9% of the samples. The mean and range temperatures of the larval habitat water were 19.6oC (n=14 (16–25oC, 22.6oC (n=53 (12–33oC, 23.8oC (n=52 (10–33oC, 11.5oC (n=12 (9–21oC, and 20.4oC (n=7 (12–26oC, respectively. There was a signifi­cant difference in the mean water temperatures (11.5–23.5oC of the larval habitats of different species (P=0.000. Most of the genus larvae were collected from natural habitats (86.9% such as river bed pools (46.4% and rain pools (33.1% with transient (98.3%, stagnant (99.5% and clear (95.3% water, with vegetation (69.9%, mud (42.0% or gravel (39.7% substrate in full sunlight (69.6% or shaded (22.7% area. A checklist of the province mosquitoes including 30 species and seven genera has been provided.Conclusion: The main larval habitats of the most abundant species, An.’hyrcanus’ and An

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

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    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.

  5. Interaction affinity of Delta and Epsilon class glutathione-s-transferases (GSTs to bind with DDT for detoxification and conferring resistance in Anopheles gambiae, a malaria vector

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    V. Aravindan

    2014-01-01

    Full Text Available Background & objectives: The enzyme glutathione-s-transferases (GSTs are associated with detoxification of DDT, as experimentally proved in Anopheles gambiae. Insect GSTs are classified into six classes and among them Delta and Epsilon class GSTs have been implicated in detoxification of organochlorine insecticides. Both Delta and Epsilon GSTs produce, in total, 24 transcripts that result in the production of corresponding enzyme proteins. However, the conventional assay estimates the level of total GSTs and relates to development of resistance to DDT. Hence, it would be more reliable to estimate the level of the specific class GSTs that shows higher affinity with DDT. This would also lead to design a specific molecular tool for resistance diagnosis. Methods: Of the 24 GSTs, computational models for 23 GSTs, which are available in Swiss-Prot database, were retrieved and for the remaining one, D7-2, for which no model is available in the data bank, a structural model was developed using the sequence of An. dirus B with a PDB ID of 1R5A as the template. All the models were docked with DDT in the presence of reduced glutathione. Results: The energy output showed that Delta, D6 has the highest interaction affinity with DDT. Hence, this particular GST (D6 is likely to get elevated on exposure of mosquitoes to DDT. Interpretation & conclusion: It would be, therefore, possible to design a specific molecular assay to determine the expression level of such high affinity transcript(s and to use for resistance diagnosis reliably in the vector surveillance programme.

  6. Structure-function analysis of the Anopheles gambiae LRIM1/APL1C complex and its interaction with complement C3-like protein TEP1.

    Science.gov (United States)

    Povelones, Michael; Upton, Leanna M; Sala, Katarzyna A; Christophides, George K

    2011-04-01

    Malaria threatens half the world's population and exacts a devastating human toll. The principal malaria vector in Africa, the mosquito Anopheles gambiae, encodes 24 members of a recently identified family of leucine-rich repeat proteins named LRIMs. Two members of this family, LRIM1 and APL1C, are crucial components of the mosquito complement-like pathway that is important for immune defense against Plasmodium parasites. LRIM1 and APL1C circulate in the hemolymph exclusively as a disulfide-bonded complex that specifically interacts with the mature form of the complement C3-like protein, TEP1. We have investigated the specificity of LRIM1/APL1C complex formation and which regions of these proteins are required for interactions with TEP1. To address these questions, we have generated a set of LRIM1 and APL1C alleles altering key conserved structural elements and assayed them in cell culture for complex formation and interaction with TEP1. Our data indicate that heterocomplex formation is an intrinsic ability of LRIM1 and APL1C and identify key homologous cysteine residues forming the intermolecular disulfide bond. We also demonstrate that the coiled-coil domain is the binding site for TEP1 but also contributes to the specificity of LRIM1/APL1C complex formation. In addition, we show that the LRIM1/APL1C complex interacts with the mature forms of three other TEP proteins, one of which, TEP3, we have characterized as a Plasmodium antagonist. We conclude that LRIM1 and APL1C contain three distinct modules: a C-terminal coiled-coil domain that can carry different TEP protein cargoes, potentially with distinct functions, a central cysteine-rich region that controls complex formation and an N-terminal leucine-rich repeat with a putative role in pathogen recognition. PMID:21533217

  7. Structure-function analysis of the Anopheles gambiae LRIM1/APL1C complex and its interaction with complement C3-like protein TEP1.

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    Michael Povelones

    2011-04-01

    Full Text Available Malaria threatens half the world's population and exacts a devastating human toll. The principal malaria vector in Africa, the mosquito Anopheles gambiae, encodes 24 members of a recently identified family of leucine-rich repeat proteins named LRIMs. Two members of this family, LRIM1 and APL1C, are crucial components of the mosquito complement-like pathway that is important for immune defense against Plasmodium parasites. LRIM1 and APL1C circulate in the hemolymph exclusively as a disulfide-bonded complex that specifically interacts with the mature form of the complement C3-like protein, TEP1. We have investigated the specificity of LRIM1/APL1C complex formation and which regions of these proteins are required for interactions with TEP1. To address these questions, we have generated a set of LRIM1 and APL1C alleles altering key conserved structural elements and assayed them in cell culture for complex formation and interaction with TEP1. Our data indicate that heterocomplex formation is an intrinsic ability of LRIM1 and APL1C and identify key homologous cysteine residues forming the intermolecular disulfide bond. We also demonstrate that the coiled-coil domain is the binding site for TEP1 but also contributes to the specificity of LRIM1/APL1C complex formation. In addition, we show that the LRIM1/APL1C complex interacts with the mature forms of three other TEP proteins, one of which, TEP3, we have characterized as a Plasmodium antagonist. We conclude that LRIM1 and APL1C contain three distinct modules: a C-terminal coiled-coil domain that can carry different TEP protein cargoes, potentially with distinct functions, a central cysteine-rich region that controls complex formation and an N-terminal leucine-rich repeat with a putative role in pathogen recognition.

  8. Anopheles gambiae odorant binding protein crystal complex with the synthetic repellent DEET: implications for structure-based design of novel mosquito repellents.

    Science.gov (United States)

    Tsitsanou, K E; Thireou, T; Drakou, C E; Koussis, K; Keramioti, M V; Leonidas, D D; Eliopoulos, E; Iatrou, K; Zographos, S E

    2012-01-01

    Insect odorant binding proteins (OBPs) are the first components of the olfactory system to encounter and bind attractant and repellent odors emanating from various sources for presentation to olfactory receptors, which trigger relevant signal transduction cascades culminating in specific physiological and behavioral responses. For disease vectors, particularly hematophagous mosquitoes, repellents represent important defenses against parasitic diseases because they effect a reduction in the rate of contact between the vectors and humans. OBPs are targets for structure-based rational approaches for the discovery of new repellent or other olfaction inhibitory compounds with desirable features. Thus, a study was conducted to characterize the high resolution crystal structure of an OBP of Anopheles gambiae, the African malaria mosquito vector, in complex with N,N-diethyl-m-toluamide (DEET), one of the most effective repellents that has been in worldwide use for six decades. We found that DEET binds at the edge of a long hydrophobic tunnel by exploiting numerous non-polar interactions and one hydrogen bond, which is perceived to be critical for DEET's recognition. Based on the experimentally determined affinity of AgamOBP1 for DEET (K (d) of 31.3 μΜ) and our structural data, we modeled the interactions for this protein with 29 promising leads reported in the literature to have significant repellent activities, and carried out fluorescence binding studies with four highly ranked ligands. Our experimental results confirmed the modeling predictions indicating that structure-based modeling could facilitate the design of novel repellents with enhanced binding affinity and selectivity. PMID:21671117

  9. Anopheles gambiae distribution and insecticide resistance in the cities of Douala and Yaoundé (Cameroon: influence of urban agriculture and pollution

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    Awono-Ambene Parfait

    2011-06-01

    Full Text Available Abstract Background Urban malaria is becoming a major health priority across Africa. A study was undertaken to assess the importance of urban pollution and agriculture practice on the distribution and susceptibility to insecticide of malaria vectors in the two main cities in Cameroon. Methods Anopheline larval breeding sites were surveyed and water samples analysed monthly from October 2009 to December 2010. Parameters analysed included turbidity, pH, temperature, conductivity, sulfates, phosphates, nitrates, nitrites, ammonia, aluminium, alkalinity, iron, potassium, manganese, magnesium, magnesium hardness and total hardness. Characteristics of water bodies in urban areas were compared to rural areas and between urban sites. The level of susceptibility of Anopheles gambiae to 4% DDT, 0.75% permethrin, 0.05% deltamethrin, 0.1% bendiocarb and 5% malathion were compared between mosquitoes collected from polluted, non polluted and cultivated areas. Results A total of 1,546 breeding sites, 690 in Yaoundé and 856 in Douala, were sampled in the course of the study. Almost all measured parameters had a concentration of 2- to 100-fold higher in urban compare to rural breeding sites. No resistance to malathion was detected, but bendiocarb resistance was present in Yaounde. Very low mortality rates were observed following DDT or permethrin exposure, associated with high kdr frequencies. Mosquitoes collected in cultivated areas, exhibited the highest resistant levels. There was little difference in insecticide resistance or kdr allele frequency in mosquitoes collected from polluted versus non-polluted sites. Conclusion The data confirm high selection pressure on mosquitoes originating from urban areas and suggest urban agriculture rather than pollution as the major factor driving resistance to insecticide.

  10. Genome-wide identification and characterization of odorant-binding protein (OBP) genes in the malaria vector Anopheles sinensis (Diptera: Culicidae).

    Science.gov (United States)

    He, Xiu; He, Zheng-Bo; Zhang, Yu-Juan; Zhou, Yong; Xian, Peng-Jie; Qiao, Liang; Chen, Bin

    2016-06-01

    Anopheles sinensis is a major malaria vector. Insect odorant-binding proteins (OBPs) may function in the reception of odorants in the olfactory system. The classification and characterization of the An. sinensis OBP genes have not been systematically studied. In this study, 64 putative OBP genes were identified at the whole-genome level of An. sinensis based on the comparison between OBP conserved motifs, PBP_GOBP, and phylogenetic analysis with An. gambiae OBPs. The characterization of An. sinensis OBPs, including the motif's conservation, gene structure, genomic organization and classification, were investigated. A new gene, AsOBP73, belonging to the Plus-C subfamily, was identified with the support of transcript and conservative motifs. These An. sinensis OBP genes were classified into three subfamilies with 37, 15 and 12 genes in the subfamily Classic, Atypical and Plus-C, respectively. The genomic organization of An. sinensis OBPs suggests a clustered distribution across nine different scaffolds. Eight genes (OBP23-28, OBP63-64) might originate from a single gene through a series of historic duplication events at least before divergence of Anopheles, Culex and Aedes. The microsynteny analyses indicate a very high synteny between An. sinensis and An. gambiae OBPs. OBP70 and OBP71 earlier classified under Plus-C in An. gambiae are recognized as belonging to the group Obp59a of the Classic subfamily, and OBP69 earlier classified under Plus-C has been moved to the Atypical subfamily in this study. The study established a basic information frame for further study of the OBP genes in insects as well as in An. sinensis. PMID:26970073

  11. 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. ...

  12. Detection of knockdown resistance (kdr mutations in Anopheles gambiae: a comparison of two new high-throughput assays with existing methods

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    Ball Amanda

    2007-08-01

    Full Text Available Abstract Background Knockdown resistance (kdr is a well-characterized mechanism of resistance to pyrethroid insecticides in many insect species and is caused by point mutations of the pyrethroid target site the para-type sodium channel. The presence of kdr mutations in Anopheles gambiae, the most important malaria vector in Africa, has been monitored using a variety of molecular techniques. However, there are few reports comparing the performance of these different assays. In this study, two new high-throughput assays were developed and compared with four established techniques. Methods Fluorescence-based assays based on 1 TaqMan probes and 2 high resolution melt (HRM analysis were developed to detect kdr alleles in An. gambiae. Four previously reported techniques for kdr detection, Allele Specific Polymerase Chain Reaction (AS-PCR, Heated Oligonucleotide Ligation Assay (HOLA, Sequence Specific Oligonucleotide Probe – Enzyme-Linked ImmunoSorbent Assay (SSOP-ELISA and PCR-Dot Blot were also optimized. The sensitivity and specificity of all six assays was then compared in a blind genotyping trial of 96 single insect samples that included a variety of kdr genotypes and African Anopheline species. The relative merits of each assay was assessed based on the performance in the genotyping trial, the length/difficulty of each protocol, cost (both capital outlay and consumable cost, and safety (requirement for hazardous chemicals. Results The real-time TaqMan assay was both the most sensitive (with the lowest number of failed reactions and the most specific (with the lowest number of incorrect scores. Adapting the TaqMan assay to use a PCR machine and endpoint measurement with a fluorimeter showed a slight reduction in sensitivity and specificity. HRM initially gave promising results but was more sensitive to both DNA quality and quantity and consequently showed a higher rate of failure and incorrect scores. The sensitivity and specificity of AS

  13. Physiological correlates of ecological divergence along an urbanization gradient: differential tolerance to ammonia among molecular forms of the malaria mosquito Anopheles gambiae

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    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

  14. 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

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    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

  15. 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.

  16. [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

  17. 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.

  18. 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.

  19. Detection of Plasmodium sp.-infested Anopheles hyrcanus (Pallas 1771) (Diptera: Culicidae) in Austria, 2012.

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    Seidel, Bernhard; Silbermayr, Katja; Kolodziejek, Jolanta; Indra, Alexander; Nowotny, Norbert; Allerberger, Franz

    2013-03-01

    On July 15, 2012, adult Anopheles hyrcanus (Pallas 1771) mosquitoes were caught next to a farm barn near Rust, Burgenland, close to Lake Neusiedl National Park in eastern Austria. Six weeks later, adults of this invasive species were also found in a sheep shelter outside the village of Oggau and another 2 weeks later, in a horse barn in Mörbisch. The morphological typing was confirmed genetically by amplification and sequencing of a 1,404-bp-long fragment within the 5.8S ribosomal RNA gene, the internal transcribed spacer 2, and the 28S ribosomal RNA gene. Out of two A. hyrcanus pools analyzed, one was found positive for Plasmodium sp. A 460-bp-long sequence within the mitochondrial cytochrome b region revealed 100 % identity to a sequence of a Plasmodium parasite identified in a New Zealand bellbird (Anthornis melanura). The Austrian finding sites are close to the Hungarian border. In Hungary, the occurrence of A. hyrcanus was already reported in 1963. A. hyrcanus is considered the most important potential vector of malaria in southern France today. In Austria, sporadic autochthonous malaria cases could emerge, caused by immigration from malaria-endemic countries and heavy tourism. However, the broad population coverage of the Austrian health care system makes the reestablishment of endemic areas for malaria unlikely. PMID:23440524

  20. [Anopheles mosquitoes (Diptera, Culicidae) of the Tien Shan: morphological, cytogenetic, and molecular genetic analysis].

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    Gordeev, M I; Zvantsov, A B; Goriacheva, I I; Shaĭkevich, E V; Ezhov, M N; Usenbaev, N T; Shapieva, Zh Zh; Zhakhongirov, Sh M

    2008-01-01

    Morphological, cytogenetic, and molecular genetic studies of the Anopheles fauna in the valley and foothills of the Tien Shan identified 5 species of malaria mosquitoes: An. artemievi Gordeev et al., An. messeae Fall, An. claviger Meigen, An. hyrcanus Pallas, An. pulcherrimus Theobald, and superpictus Grassi. An. claviger, An. hyrcanus, and An. messeae were prevalent in the Northern Tien-Shan. An. artemievi, An. claviger, An. hyrcanus, An. messeae, and An. superpictus were detected in the Western Tien Shan. An. artemievi was first recorded in Kazakhstan. An. artemievi, An. claviger, and An. superpictus were noted in the Inferior Tien Shan. An. messeae was first observed in the Issyk Kul hollow. An. artemievi, An. claviger, and An. superpictus were habitants of the foothills of the South-Western Tien Shan. An. artemievi, An. hyrcanus, An. superpictus, and An. pulcherrimus were in the plain. An. pulcherrimus and An. superpicts mosquitoes are regarded as important vectors in the new malaria foci of the Fergana regions. The role of An. artemievi in the transmission of malaria is to be specified. PMID:18822504

  1. 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.

  2. Larvicidal activity of indigenous plant extracts on the rural malarial vector, Anopheles culicifacies Giles. (Diptera: Culicidae

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    K. Kovendan

    2014-12-01

    Full Text Available Vector control is one of the most important components in combating vector-borne diseases throughout the world. Application of insecticides is a widely known and popular vector control strategy. The objective of the present study was to evaluate the larvicidal activity of the hexane, diethyl ether, ethyl acetate and acetone extracts of Abutilon indicum, Hyptis suaveolens and Leucas aspera against third-stage larvae of Anopheles culicifiacies. The results clearly suggest that all three selected plant extracts exhibited moderate larvicidal activity after 24, 48 and 72 h at 250, 500, 750 and 1000 ppm; the lethal concentrations (LC at 50% and 90% of A. indicum, H. suaveolens against third instar larvae at 24, 48 and 72 h (hexane, diethyl ether, ethyl acetate and acetone were as follows: A. indicum, LC50=1031.65, 949.18, 833.58 and 673.68 ppm; LC90=2215.87, 2234.39, 2152.97 and 2455.10 ppm; H. suaveolens, LC50=423.00, 347.50, 236.58 and 217.24 ppm; LC90=1431.91, 1292.15, 1138.49 and 1049.27 ppm and L. aspera, LC50=559.77, 401.56, 299.71 and 263.01 ppm; LC90=1400.80, 1549.31, 1157.96 and 1108.72 ppm at 24 h, respectively. Overall, the highest larvicidal activity was observed with H. suaveolens extract followed by L. aspera and A. indicum at various concentrations at 48 and 72 h, respectively. The objective of this investigation was an attempt to search for a user- and eco-friendly vector control agent. The study proved that the selected plant leaf extracts could serve as potent larvicidal agents against A. culicifacies in vector control programs.

  3. Genetic differentiation and diagnostic loci of Anopheles nuneztovari, An. trinkae, and An. rangeli (Diptera: Culicidae).

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    Fritz, G N; Bermudez, H; Seawright, J A

    1995-09-01

    Samples of Anopheles rangeli Gabaldon, Cova Garcia & Lopez, An. trinkae Causey, and An. nuneztovari Gabaldon from Venezuela, Ecuador, Brazil, and Bolivia were analyzed for genetic variability at 24 enzyme loci. Estimates of genetic variability for An. rangeli and An. trinkae from Ecuador and for An. nuneztovari in Venezuela had the following ranges: 46-58% polymorphic loci, 1.7-2.0 (SEM = 0.1-0.3) mean number of alleles per locus, and 0.069-0.113 (SEM = 0.03-0.04) expected mean heterozygosity. Genetic variability estimates of An. rangeli from Bolivia were 20.8-29.2% polymorphic loci, 1.2-1.6 (SEM = 0.1-0.2) mean number of alleles per locus, and 0.037-0.054 (SEM = 0.02-0.03) expected mean heterozygosity. The estimated genetic distance between An. rangeli and An. trinkae ranged from 0.149 to 0.197. The genetic distance between these 2 species and An. nuneztovari ranged from 0.319 to 0.440. Although there were allele frequency differences at some loci between samples of An. nuneztovari sampled from either side of the Andes Mountains in Venezuela, there were no diagnostic loci and the estimated genetic distance was only 0.023. Seven enzyme loci were diagnostic between An. nuneztovari and one or both of its sister species: Acon-2, Ao, Hk-1, Idh-2, Me, Pgi, and Pgm. The diagnostic loci Hk-1 and Acon-2 were not polymorphic in any species. An. rangeli and An. trinkae can be distinguished by the diagnostic loci Ao, Idh-2, and Me-1, and with a 97% probability by Pgm. Distance Wagner and unweighted pair-group method with arithmetic averaging analyses support a close phylogenetic relationship between An. trinkae and An. rangeli. PMID:7473622

  4. Chemical Constituents and Combined Larvicidal Effects of Selected Essential Oils against Anopheles cracens (Diptera: Culicidae

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    Jitrawadee Intirach

    2012-01-01

    Full Text Available A preliminary study on larvicidal activity against laboratory-colonized Anopheles cracens mosquitos revealed that five of ten plant oils at concentration of 100 ppm showed 95–100% larval mortality. The essential oils of five plants, including Piper sarmentosum, Foeniculum vulgare, Curcuma longa, Myristica fragrans, and Zanthoxylum piperitum, were then selected for chemical analysis, dose-response larvicidal experiments, and combination-based bioassays. Chemical compositions analyzed by gas chromatography coupled to mass spectrometry demonstrated that the main component in the oil derived from P. sarmentosum, F. vulgare, C. longa, M. fragrans, and Z. piperitum was croweacin (71.01%, anethole (63.00%, ar-turmerone (30.19%, safrole (46.60%, and 1,8-cineole (21.27%, respectively. For larvicidal bioassay, all five essential oils exerted promising efficacy in a dose-dependent manner and different performances on A. cracens after 24 hours of exposure. The strongest larvicidal potential was established from P. sarmentosum, followed by F. vulgare, C. longa, M. fragrans, and Z. piperitum, with LC50 values of 16.03, 32.77, 33.61, 40.00, and 63.17 ppm, respectively. Binary mixtures between P. sarmentosum, the most effective oil, and the others at the highest ratio were proved to be highly efficacious with a cotoxicity coefficient value greater than 100, indicating synergistic activity. Results of mixed formulations of different essential oils generating synergistic effects may prove helpful in developing effective, economical, and ecofriendly larvicides, as favorable alternatives for mosquito management.

  5. 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

  6. Comparative Studies on the Stenogamous and Eurygamous Behavior of Eight Anopheles Species of the Hyrcanus Group (Diptera: Culicidae in Thailand

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    Adulsak Wijit

    2016-03-01

    Full Text Available Establishment of laboratory colony is essential for mosquito-borne-disease research. Mating behavior of stenogamous Anopheles peditaeniatus and seven eurygamous species (Anopheles argyropus, Anopheles crawfordi, Anopheles nigerrimus, Anopheles nitidus, Anopheles paraliae (=An. lesteri, Anopheles pursati and Anopheles sinensis, were investigated and compared in this study. The self-mating success of adult mosquitoes in different size cages at two density resting surface (DRS values, 3.6 and 7.2, was statistically significant between stenogamous and eurygamous species. The results obtained from comparative measurements of specific characters in adult females (maxillary palpomere and antennal sensilla characters and males (wing and genitalia indicate those characters might influence the mating success of An. peditaeniatus in a small cage. The gonostylus of An. peditaeniatus was shorter than the eurygamous species. Additionally, the lower frequency of clasper movement and shorter mating time could be important mechanisms that control the stenogamous behavior of An. peditaeniatus. Interestingly, for the first time, a cluster of large sensilla coeloconica was recorded on the antenna of An. argyropus and An. peditaeniatus females. There was no statistically significant difference in the mean number per female of those large antennal sensilla coeloconica among six of the eurygamous species.

  7. Field experiments of Anopheles gambiae attraction to local fruits/seedpods and flowering plants in Mali to optimize strategies for malaria vector control in Africa using attractive toxic sugar bait methods

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    Bah Sekou

    2010-09-01

    Full Text Available Abstract Background Based on recent studies in Israel demonstrating that attractive toxic sugar bait (ATSB methods can be used to decimate local anopheline and culicine mosquito populations, an important consideration is whether the same methods can be adapted and improved to attract and kill malaria vectors in Africa. The ATSB approach uses fruit or flower scent as an attractant, sugar solution as a feeding stimulant, and an oral toxin. The ATSB solutions are either sprayed on vegetation or suspended in simple bait stations, and the mosquitoes ingesting the toxic solutions are killed. As such, this approach targets sugar-feeding female and male mosquitoes. This study examines the attractiveness of African malaria vectors to local fruits/seedpods and flowering plants, key biological elements of the ATSB approach for mosquito control. Methods Three field experiments were conducted at sites in Mali. The attraction of Anopheles gambiae s.l. to 26 different local fruits and seedpods was determined at a site in the semi-arid Bandiagara District of Mali. Wire mesh glue traps with fruits/seedpods suspended on skewers inside were set along a seasonal lagoon. Seven replicates of each fruit/seedpod species were tested, with a water-soaked sponge and a sugar-soaked sponge as controls. The attraction of An. gambiae s.l. to 26 different types of flowering plants was determined at a site near Mopti in Mali. The flowering plants held in a water-filled buried container were tested using the same glue traps, with controls including water only and sugar solution. Six replicates of each selected plant type were tested on transects between rice paddies. Additional studies using CDC light traps were done to determine the relative densities and periodicity of An. gambiae s.l. attraction to branches of the most highly attractive flowering plant, branches without flowers, human odor, and candescent light. Results Of the 26 fruits and seedpods tested, 6 were attractive

  8. 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.

  9. Control of pyrethroid and DDT-resistant Anopheles gambiae by application of indoor residual spraying or mosquito nets treated with a long-lasting organophosphate insecticide, chlorpyrifos-methyl

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    Chabi Joseph

    2010-02-01

    Full Text Available Abstract Background Scaling up of long-lasting insecticidal nets (LLINs and indoor residual spraying (IRS with support from the Global Fund and President's Malaria Initiative is providing increased opportunities for malaria control in Africa. The most cost-effective and longest-lasting residual insecticide DDT is also the most environmentally persistent. Alternative residual insecticides exist, but are too short-lived or too expensive to sustain. Dow Agrosciences have developed a microencapsulated formulation (CS of the organophosphate chlorpyrifos methyl as a cost-effective, long-lasting alternative to DDT. Methods Chlorpyrifos methyl CS was tested as an IRS or ITN treatment in experimental huts in an area of Benin where Anopheles gambiae and Culex quinquefasiactus are resistant to pyrethroids, but susceptible to organophosphates. Efficacy and residual activity was compared to that of DDT and the pyrethroid lambdacyalothrin. Results IRS with chlorpyrifos methyl killed 95% of An. gambiae that entered the hut as compared to 31% with lambdacyhalothrin and 50% with DDT. Control of Cx. quinquefasciatus showed a similar trend; although the level of mortality with chlorpyrifos methyl was lower (66% it was still much higher than for DDT (14% or pyrethroid (15% treatments. Nets impregnated with lambdacyhalothrin were compromized by resistance, killing only 30% of An. gambiae and 8% of Cx. quinquefasciatus. Nets impregnated with chlorpyrifos methyl killed more (45% of An gambiae and 15% of Cx. quinquefasciatus, but its activity on netting was of short duration. Contact bioassays on the sprayed cement-sand walls over the nine months of monitoring showed no loss of activity of chlorpyrifos methyl, whereas lambdacyhalothrin and DDT lost activity within a few months of spraying. Conclusion As an IRS treatment against pyrethroid resistant mosquitoes chlorpyrifos methyl CS outperformed DDT and lambdacyhalothrin. In IRS campaigns, chlorpyrifos methyl CS should

  10. Update on resistance status of Anopheles gambiae s.s. to conventional insecticides at a previous WHOPES field site, "Yaokoffikro", 6 years after the political crisis in Côte d'Ivoire

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    Koffi Alphonsine A

    2012-04-01

    Full Text Available Abstract Background At Yaokoffikro field site near Bouaké, in central Côte d'Ivoire, a group of experimental huts built in 1996 served over many years for the evaluation of insecticides against highly resistant mosquitoes. Breeding sites of mosquitoes and selection pressure in the area were maintained by local farming practices until a war broke out in September 2002. Six years after the crisis, we conducted bioassays and biochemical analysis to update the resistance status of Anopheles gambiae s.s. populations and detect other potential mechanisms of resistance that might have evolved. Methods An. gambiae s.s. larvae from Yaokoffikro were collected in breeding sites and reared to adults. Resistance status of this population to insecticides was assessed using WHO bioassay test kits for adult mosquitoes with seven insecticides: two pyrethroids, a pseudo-pyrethroid, an organochloride, two carbamates and an organophosphate. Molecular and biochemical assays were carried out to identify the L1014F kdr and ace-1R alleles in individual mosquitoes and to detect potential increase in mixed function oxidases (MFO, non-specific esterases (NSE and glutathione S-transferases (GST activity. Results High pyrethroids, DDT and carbamate resistance was confirmed in An. gambiae s.s. populations from Yaokoffikro. Mortality rates were less than 70% with pyrethroids and etofenprox, 12% with DDT, and less than 22% with the carbamates. Tolerance to fenitrothion was observed, with 95% mortality after 24 h. PCR analysis of samples from the site showed high allelic frequency of the L1014F kdr (0.94 and the ace-1R (0.50 as before the crisis. In addition, increased activity of NSE, GST and to a lesser extent MFO was found relative to the reference strain Kisumu. This was the first report detecting enhanced activity of these enzymes in An. gambiae s.s from Yaokoffikro, which could have serious implications in detoxification of insecticides. Their specific roles in

  11. Morphological analysis of three populations of Anopheles (Nyssorhynchus) nuneztovari Gabaldón (Diptera: Culicidae) from Colombia.

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    Fajardo Ramos, Mayury; González Obando, Ranulfo; Fidel Suárez, Marco; López, David; Wilkerson, Richard; Sallum, Maria Anice Mureb

    2008-02-01

    Based on the results of comparative analyses of 1,039 specimens of several progenies of Anopheles nuneztovarifrom three localities in Colombia, eight costal wing spot patterns were observed. Patterns I and III were the most frequent: 77.96% and 11.36%, respectively. Using the diagnostic characters ratio of the length of the basal dark area of hind tarsomere II/length of hind tarsomere II, ratio of the length of the humeral pale spot/length of the pre-humeral dark spot, and the ratio of the length of the subcostal pale spot/length of the distal sector dark spot (DS-III2/Ta-III2, HP/PHD, SCP/DSD) approximately 5% of the adult females were misidentified as a species of Nyssorhynchus, different from An. nuneztovari. Approximately 5% of the specimens showed DS-III2/Ta-III2 ratio less than 0.25 (range 0.21 - 0.24), and among them 3.34% shared a HP/PHD ratio less than 1.50. Consequently, 1.52% of An. nuneztovari individuals can be misidentified as Anopheles oswaldoi. In those specimens with the DS-III2/Ta-III2 ratios higher than 0.25, 34.45% displayed SCP/DSD values greater than 0.50 and of these, 3.65% displayed HP/PHD values greater than 1.8. This combination of characters could lead one to misidentify samples of An. nuneztovari as Anopheles rangeli. Similarly, 2.43% of the females could be identified erroneously as either Anopheles aquasalis or Anopheles benarrochi. Individuals with a HP/PHD ratio greater than 2.0, could be misidentified as Anopheles trinkae, Anopheles strodei or Anopheles evansae. A distinct combination of diagnostic characters for An. nuneztovari from Colombia is proposed. PMID:18368239

  12. Morphological analysis of three populations of Anopheles (Nyssorhynchus nuneztovari Gabaldón (Diptera: Culicidae from Colombia

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    Mayury Fajardo Ramos

    2008-02-01

    Full Text Available Based on the results of comparative analyses of 1,039 specimens of several progenies of Anopheles nuneztovarifrom three localities in Colombia, eight costal wing spot patterns were observed. Patterns I and III were the most frequent: 77.96% and 11.36%, respectively. Using the diagnostic characters ratio of the length of the basal dark area of hind tarsomere II/length of hind tarsomere II, ratio of the length of the humeral pale spot/length of the pre-humeral dark spot, and the ratio of the length of the subcostal pale spot/length of the distal sector dark spot (DS-III2/Ta-III2, HP/PHD, SCP/DSD approximately 5% of the adult females were misidentified as a species of Nyssorhynchus, different from An. nuneztovari. Approximately 5% of the specimens showed DS-III2/Ta-III2 ratio less than 0.25 (range 0.21 - 0.24, and among them 3.34% shared a HP/PHD ratio less than 1.50. Consequently, 1.52% of An. nuneztovari individuals can be misidentified as Anopheles oswaldoi. In those specimens with the DS-III2/Ta-III2 ratios higher than 0.25, 34.45% displayed SCP/DSD values greater than 0.50 and of these, 3.65% displayed HP/PHD values greater than 1.8. This combination of characters could lead one to misidentify samples of An. nuneztovari as Anopheles rangeli. Similarly, 2.43% of the females could be identified erroneously as either Anopheles aquasalis or Anopheles benarrochi. Individuals with a HP/PHD ratio greater than 2.0, could be misidentified as Anopheles trinkae, Anopheles strodei or Anopheles evansae. A distinct combination of diagnostic characters for An. nuneztovari from Colombia is proposed.

  13. 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.

  14. 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

  15. Experimental hut evaluation of bednets treated with an organophosphate (chlorpyrifos-methyl or a pyrethroid (lambdacyhalothrin alone and in combination against insecticide-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes

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    Corbel Vincent

    2005-05-01

    Full Text Available Abstract Background Pyrethroid resistant mosquitoes are becoming increasingly common in parts of Africa. It is important to identify alternative insecticides which, if necessary, could be used to replace or supplement the pyrethroids for use on treated nets. Certain compounds of an earlier generation of insecticides, the organophosphates may have potential as net treatments. Methods Comparative studies of chlorpyrifos-methyl (CM, an organophosphate with low mammalian toxicity, and lambdacyhalothrin (L, a pyrethroid, were conducted in experimental huts in Côte d'Ivoire, West Africa. Anopheles gambiae and Culex quinquefasciatus mosquitoes from the area are resistant to pyrethroids and organophosphates (kdr and insensitive acetylcholinesterase Ace.1R. Several treatments and application rates on intact or holed nets were evaluated, including single treatments, mixtures, and differential wall/ceiling treatments. Results and Conclusion All of the treatments were effective in reducing blood feeding from sleepers under the nets and in killing both species of mosquito, despite the presence of the kdr and Ace.1R genes at high frequency. In most cases, the effects of the various treatments did not differ significantly. Five washes of the nets in soap solution did not reduce the impact of the insecticides on A. gambiae mortality, but did lead to an increase in blood feeding. The three combinations performed no differently from the single insecticide treatments, but the low dose mixture performed encouragingly well indicating that such combinations might be used for controlling insecticide resistant mosquitoes. Mortality of mosquitoes that carried both Ace.1R and Ace.1S genes did not differ significantly from mosquitoes that carried only Ace.1S genes on any of the treated nets, indicating that the Ace.1R allele does not confer effective resistance to chlorpyrifos-methyl under the realistic conditions of an experimental hut.

  16. IgG1 and IgG4 antibody responses to the Anopheles gambiae salivary protein gSG6 in the sympatric ethnic groups Mossi and Fulani in a malaria hyperhendemic area of Burkina Faso.

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    Cinzia Rizzo

    Full Text Available Human antibody response to the Anopheles gambiae salivary protein gSG6 has recently emerged as a potentially useful tool for malaria epidemiological studies and for the evaluation of vector control interventions. However, the current understanding of the host immune response to mosquito salivary proteins and of the possible crosstalk with early response to Plasmodium parasites is still very limited. We report here the analysis of IgG1 and IgG4 subclasses among anti-gSG6 IgG responders belonging to Mossi and Fulani from Burkina Faso, two ethnic groups which are known for their differential humoral response to parasite antigens and for their different susceptibility to malaria. The IgG1 antibody response against the gSG6 protein was comparable in the two groups. On the contrary, IgG4 titers were significantly higher in the Fulani where, in addition, anti-gSG6 IgG4 antibodies appeared in younger children and the ratio IgG4/IgG1 stayed relatively stable throughout adulthood. Both gSG6-specific IgG1 and IgG4 antibodies showed a tendency to decrease with age whereas, as expected, the IgG response to the Plasmodium circumsporozoite protein (CSP exhibited an opposite trend in the same individuals. These observations are in line with the idea that the An. gambiae gSG6 salivary protein induces immune tolerance, especially after intense and prolonged exposure as is the case for the area under study, suggesting that gSG6 may trigger in exposed individuals a Th2-oriented immune response.

  17. Evaluation of PermaNet 3.0 a deltamethrin-PBO combination net against Anopheles gambiae and pyrethroid resistant Culex quinquefasciatus mosquitoes: an experimental hut trial in Tanzania

    Directory of Open Access Journals (Sweden)

    Malima Robert

    2010-01-01

    Full Text Available Abstract Background Combination mosquito nets incorporating two unrelated insecticides or insecticide plus synergist are designed to control insecticide resistant mosquitoes. PermaNet 3.0 is a long-lasting combination net incorporating deltamethrin on the side panels and a mixture of deltamethrin and synergist piperonyl butoxide (PBO on the top panel. PBO is an inhibitor of mixed function oxidases implicated in pyrethroid resistance. Method An experimental hut trial comparing PermaNet 3.0, PermaNet 2.0 and a conventional deltamethrin-treated net was conducted in NE Tanzania using standard WHOPES procedures. The PermaNet arms included unwashed nets and nets washed 20 times. PermaNet 2.0 is a long-lasting insecticidal net incorporating deltamethrin as a single active. Results Against pyrethroid susceptible Anopheles gambiae the unwashed PermaNet 3.0 showed no difference to unwashed PermaNet 2.0 in terms of mortality (95% killed, but showed differences in blood-feeding rate (3% blood-fed with PermaNet 3.0 versus 10% with PermaNet 2.0. After 20 washes the two products showed no difference in feeding rate (10% with 3.0 and 9% with 2.0 but showed small differences in mortality (95% with 3.0 and 87% with 2.0. Against pyrethroid resistant Culex quinquefasciatus, mediated by elevated oxidase and kdr mechanisms, the unwashed PermaNet 3.0 killed 48% and PermaNet 2.0 killed 32% but after 20 washes there was no significant difference in mortality between the two products (32% killed by 3.0 and 30% by 2.0. For protecting against Culex PermaNet 3.0 showed no difference to PermaNet 2.0 when either unwashed or after 20 washes; both products were highly protective against biting. Laboratory tunnel bioassays confirmed the loss of biological activity of the PBO/deltamethrin-treated panel after washing. Conclusion Both PermaNet products were highly effective against susceptible Anopheles gambiae. As a long-lasting net to control or protect against pyrethroid

  18. The Anopheles gambiae cE5, a tight- and fast-binding thrombin inhibitor with post-transcriptionally regulated salivary-restricted expression

    Czech Academy of Sciences Publication Activity Database

    Ronca, R.; Kotsyfakis, Michalis; Lombardo, F.; Rizzo, C.; Currà, C.; Ponzi, M.; Fiorentino, G.; Ribeiro, J.M.C.; Arcà, B.

    2012-01-01

    Roč. 42, č. 9 (2012), s. 610-620. ISSN 0965-1748 R&D Projects: GA ČR GAP502/12/2409 Institutional research plan: CEZ:AV0Z60220518 Keywords : Anopheles * Salivary protein * Anti-thrombin * Anophelin * Hematophagy * Post-transcriptional regulation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.234, year: 2012

  19. Distribution and Frequency of kdr Mutations within Anopheles gambiae s.l. Populations and First Report of the Ace.1G119S Mutation in Anopheles arabiensis from Burkina Faso (West Africa)

    OpenAIRE

    Dabiré, Roch K.; Namountougou, Moussa; Diabaté, Abdoulaye; Soma, Dieudonné D.; Bado, Joseph; Toé, Hyacinthe K; Bass, Chris; Combary, Patrice

    2014-01-01

    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 o...

  20. Development of an allele-specific, loop-mediated, isothermal amplification method (AS-LAMP to detect the L1014F kdr-w mutation in Anopheles gambiae s. l.

    Directory of Open Access Journals (Sweden)

    Badolo Athanase

    2012-07-01

    Full Text Available Abstract Background Malaria control relies heavily on treated bed nets and indoor residual spraying with pyrethroid insecticides. Unfortunately, the resistance to pyrethroid insecticides, mainly due to the kdr mutation, is spreading in the main malaria vector Anopheles gambiae s.l., decreasing the insecticides’ efficacy. To manage the insecticide resistance rapidly and flexibly, simple and effective tools for the early detection of resistant mosquitoes are needed. This study aimed to develop an allele-specific, loop-mediated, isothermal amplification (AS-LAMP method to detect the West African-type kdr mutation (kdr-w; L1014F in field-collected mosquitoes. Methods DNA fragments of the wild-type and the mutated kdr gene were used to select the primers and develop the method. The primers were designed with the mutation at the 5’ end of the backward inner primer (BIP. The AS-LAMP method was compared to the AS-PCR method using the genomic DNA of 120 field-collected mosquitoes. Results The AS-LAMP method could discriminate between the wild-type homozygote, the heterozygote, and the kdr-w homozygote within 75 min. The AS-LAMP method has the advantage of being faster and at least as sensitive and specific as the AS-PCR method. Conclusions The AS-LAMP method can be used to detect the kdr mutation for quick decision-making, even in less well-equipped laboratories.

  1. Effect of Bacillus sphaericus Neide on Anopheles (Diptera: Culicidae and associated insect fauna in fish ponds in the Amazon

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    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.

  2. 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...

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

    Directory of Open Access Journals (Sweden)

    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.

  4. The application of radioactive tracers to a study of the behaviour and physiology of two twin species of the complex Anopheles gambiae in a sympatric region of Madagascar

    International Nuclear Information System (INIS)

    The author studied the behaviour of species A and B of the complex Anopheles gambiæ in Madagascar. The adult mosquitoes of these two species are morphologically indistinguishable. Reared females labelled with 32P for one species and 35S for the other were released and then recaptured. The author was thereby able to bring to light considerable differences in the biting habits of each species. (author)

  5. Mosquito larvicidal and ovicidal properties of Pemphis acidula Frost. (Lythraceae) against Culex tritaeniorhynchus Giles and Anopheles subpictus Grassi (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    K. Samidurai

    2012-01-01

    Objective: This study was undertaken to assess the larvicidal and ovicidal potential of the crude methanol, benzene and acetone solvent extracts from the medicinal plant Pemphis acidula (Pe. acidula) against the medically important mosquito vectors, Culex tritaeniorhynchus (Cx. tritaeniorhynchus) and Anopheles subpictus (An. subpictus) were exposed to various concentrations and (Diptera: Culicidae). Methods: Twenty five late third instar of Cx. tritaeniorhynchus and An. subpictus were exposed to various concentrations and were assayed in the laboratory by using the protocol of WHO 2005. The larval mortality was observed 24 h of treatment. Hundred eggs of Cx. tritaeniorhynchus and An. subpictus were exposed to various concentrations and were assayed in the laboratory by using the protocol of Su and Mulla 1998. The ovicidal activity was observed 48 h of treatment. Results: The LC50 and LC90 values being 10.81and 20.64 and 22.10 and 43.71 ppm and hundred percent of egg mortality was observed at 350 and 400 ppm methanol extract of Pe. acidula against Cx. tritaeniorhynchus and An. subpictus, respectively. Conclusion: These results suggest that the leaf extracts have the potential to be used as an ideal ecofriendly approach for the control of mosquitoes.

  6. 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.

  7. Differential effect of human ivermectin treatment on blood feeding Anopheles gambiae and Culex quinquefasciatus

    DEFF Research Database (Denmark)

    Derua, Yahya A.; Kisinza, William N.; Simonsen, Paul Erik

    2015-01-01

    BACKGROUND: Widespread and large scale use of ivermectin in humans and domestic animals can have unexpected effects on non-target organisms. As a search for a possible explanation for an observed longitudinal decline in density of anopheline vector mosquitoes, but not in Culex quinquefasciatus, in...... to receive either ivermectin or placebo. Twenty four hours after treatment, one volunteer from each group was concurrently exposed to 50 laboratory reared An. gambiae on one arm and 50 laboratory reared Cx. quinquefasciatus on the other arm for 15-30 minutes. Engorged mosquitoes were maintained on 10...

  8. 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

    Directory of Open Access Journals (Sweden)

    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

  9. 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...

  10. 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...

  11. IgG responses to Anopheles gambiae salivary antigen gSG6 detect variation in exposure to malaria vectors and disease risk

    DEFF Research Database (Denmark)

    Stone, Will; Bousema, Teun; Jones, Sophie;

    2012-01-01

    .04). Additionally, IgG responses to gSG6 in individual children showed a strong positive association with household level mosquito exposure. IgG levels for all antigens except AMA-1 were associated with the frequency of malaria episodes following sampling. gSG6 seropositivity was strongly positively associated with...... subsequent malaria incidence (test for trend p¿=¿0.004), comparable to malaria antigens MSP-1 and GLURP R2. Our results show that the gSG6 assay is sensitive to micro-epidemiological variations in exposure to Anopheles mosquitoes, and provides a correlate of malaria risk that is unrelated to immune...

  12. 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

  13. PCR identification of five species from the Anopheles maculipennis complex (Diptera: Culicidae) in North-Eastern Romania.

    Science.gov (United States)

    Ivanescu, Maria-Larisa; Acatrinei, Dumitru; Pavel, Ionuţ; Sulesco, Tatiana; Miron, Liviu

    2015-06-01

    The members of the Anopheles maculipennis complex have been incriminated for the transmission of the malaria in Europe, which was endemic until the middle of the century. The global warming and the intensification of the intercontinental travel constitute a risk of the re-emergence of the malaria in Europe, given the presence of the Anopheles vectors. The study has attempted the identification by using the PCR (Polymerase Chain Reaction) of the members of the Anopheles maculipennis complex from the North-eastern area of Romania from the city of Iaşi. In total there have been identified by using the PCR amplifying the ITS2 sequence of the ribosomal DNA, 217 specimens belonging to the complex of A. maculipennis among which: 58 A. atroparvus, 18 A. melanoon, 2 A. labranchiae, 52 A. maculipennis and 87 A. messeae. The ITS2 sequences of the ribosomal DNA have been compared to those of the species belonging to the A. maculipennis available in GenBank. The Species A. labranchiae is reported for the first time in Romania, being identified in the larval stage IV. The adaptation of a new species to the climatic conditions present in the North-eastern Romania, confirms the phenomenon of global warming and also the intensification of the travelling. As a result of the analysis of the A. labranchiae sequence, this one corresponds to the extent of 96% to the species from Italy, registered in GenBank, given the fact that a high number of the inhabitants of the municipality of Iaşi are working in this country. PMID:26203997

  14. Morphological analysis of three populations of Anopheles (Nyssorhynchus) nuneztovari Gabaldón (Diptera: Culicidae) from Colombia

    OpenAIRE

    Mayury Fajardo Ramos; Ranulfo González Obando; Marco Fidel Suárez; David López; Richard Wilkerson; Maria Anice Mureb Sallum

    2008-01-01

    Based on the results of comparative analyses of 1,039 specimens of several progenies of Anopheles nuneztovarifrom three localities in Colombia, eight costal wing spot patterns were observed. Patterns I and III were the most frequent: 77.96% and 11.36%, respectively. Using the diagnostic characters ratio of the length of the basal dark area of hind tarsomere II/length of hind tarsomere II, ratio of the length of the humeral pale spot/length of the pre-humeral dark spot, and the ratio of the le...

  15. A heterodimeric complex of the LRR proteins LRIM1 and APL1C regulates complement-like immunity in Anopheles gambiae

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Richard H.G.; Steinert, Stefanie; Chelliah, Yogarany; Volohonsky, Gloria; Levashina, Elena A.; Deisenhofer, Johann (CNRS-UMR); (UTSMC)

    2012-01-20

    The leucine-rich repeat (LRR) proteins LRIM1 and APL1C control the function of the complement-like protein TEP1 in Anopheles mosquitoes. The molecular structure of LRIM1 and APL1C and the basis of their interaction with TEP1 represent a new type of innate immune complex. The LRIM1/APL1C complex specifically binds and solubilizes a cleaved form of TEP1 without an intact thioester bond. The LRIM1 and APL1C LRR domains have a large radius of curvature, glycosylated concave face, and a novel C-terminal capping motif. The LRIM1/APL1C complex is a heterodimer with a single intermolecular disulfide bond. The structure of the LRIM1/APL1C heterodimer reveals an interface between the two LRR domains and an extensive C-terminal coiled-coil domain. We propose that a cleaved form of TEP1 may act as a convertase for activation of other TEP1 molecules and that the LRIM1/APL1C heterodimer regulates formation of this TEP1 convertase.

  16. Mosquito adulticidal and repellent activities of botanical extracts against malarial vector,Anopheles stephensi Liston (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Marimuthu Govindarajan; Rajamohan Sivakumar

    2011-01-01

    Objective:To determine the adulticidal and repellent activities of different solvent leaf extracts ofEclipta alba (E. alba) andAndrographis paniculata (A. paniculata)against malarial vector, Anopheles stephensi (An. stephensi).Methods:Adulticidal efficacy of the crude leaf extracts ofE. alba andA. paniculata with five different solvents like benzene, hexane, ethyl acetate, methanol and chloroform was tested against the five to six day old adult female mosquitoes of An. stephensi. The adult mortality was observed after24 h under the laboratory conditions. The repellent efficacy was determined againstAn. stephensimosquito species at three concentrations viz.,1.0, 2.5 and 5.0 mg/cm2 under laboratory conditions.Results: Among the tested solvents the maximum efficacy was observed in the methanol extract. TheLC50 andLC90 values ofE. alba andA. paniculata against adults ofAn. stephensiwere150.36, 130.19 ppm and285.22, 244.16ppm, respectively. No mortality was observed in controls. Thechi-square values were significant at P<0.05 level. Methanol extract of E. alba andA. paniculata was produce maximum repellency againstAn. stephensi.Conclusions:From the results it can be concluded the crude extract ofE. alba andA. paniculatawas an excellent potential for controllingAn. stephensimosquitoes.

  17. Deforestation and Malaria on the Amazon Frontier: Larval Clustering of Anopheles darlingi (Diptera: Culicidae) Determines Focal Distribution of Malaria.

    Science.gov (United States)

    Barros, Fábio S M; Honório, Nildimar A

    2015-11-01

    We performed bimonthly mosquito larval collections during 1 year, in an agricultural settlement in the Brazilian Amazon, as well as an analysis of malaria incidence in neighboring houses. Water collections located at forest fringes were more commonly positive for Anopheles darlingi larvae and Kulldorff spatial analysis pinpointed significant larval clusters at sites directly beneath forest fringes, which were called larval "hotspots." Remote sensing identified 43 "potential" hotspots. Sampling of these areas revealed an 85.7% positivity rate for A. darlingi larvae. Malaria was correlated with shorter distances to potential hotpots and settlers living within 400 m of potential hotspots had a 2.60 higher risk of malaria. Recently arrived settlers, usually located closer to the tip of the triangularly shaped deforestation imprints of side roads, may be more exposed to malaria due to their proximity to the forest fringe. As deforestation progresses, transmission decreases. However, forest remnants inside deforested areas conferred an increased risk of malaria. We propose a model for explaining frontier malaria in the Amazon: because of adaptation of A. darlingi to the forest fringe ecotone, humans are exposed to an increased transmission risk when in proximity to these areas, especially when small dams are created on naturally running water collections. PMID:26416110

  18. A molecular phylogeny of Anopheles annulipes (Diptera: Culicidae) sensu lato: the most species-rich anopheline complex.

    Science.gov (United States)

    Foley, D H; Wilkerson, R C; Cooper, R D; Volovsek, M E; Bryan, J H

    2007-04-01

    The Australasian Annulipes Complex is the most species-rich among Anopheles mosquitoes, with at least 15 sibling species suspected. Members of this complex are the most likely vectors of malaria in the past in southern Australia and are involved in the spread of myxomatosis among rabbits. In this, the first comprehensive molecular study of the Annulipes Complex, 23 ITS2 rDNA variants were detected from collections throughout Australia and Papua New Guinea, including diagnostic variants for the previously identified An. annulipes species A-G. Specimens of each ITS2 variant were sequenced for portions of the mitochondrial COI, COII and nuclear EF-1alpha genes. Partitioned Bayesian and Maximum Parsimony analyses confirmed the monophyly of the Annulipes Complex and revealed at least 17 clades that we designate species A-Q. These species belong to two major clades, one in the north and one mainly in the south, suggesting that climate was a driver of species radiation. We found that 65% (11) of the 17 sibling species recorded here had unique COI sequences, suggesting that DNA barcoding will be useful for diagnosing species within the Annulipes Complex. A comparison of the taxa revealed morphological characters that may be diagnostic for some species. Our results substantially increase the size of the subgenus Cellia in Australasia, and will assist species-level studies of the Annulipes Complex. PMID:17126567

  19. Green chemistry focus on optimization of silver nanoparticles using response surface methodology (RSM) and mosquitocidal activity: Anopheles stephensi (Diptera: Culicidae).

    Science.gov (United States)

    Ondari Nyakundi, Erick; Padmanabhan, M Nalini

    2015-10-01

    There is an exigent necessity for development of environmental friendly bio-control agent(s) for elimination of mosquito due to increased resistance resurgence against synthetic control agents. Mosquito control strategy will lay a strong foundation to malaria exclusion or it can be curbed to certain level especially in the developing nations. In this study, silver nanoparticles were synthesized by green chemistry approach using Tridax procumbens leaf extract as a reducing agent. The reaction medium involved in the synthesis process was optimized by statistical experimental design using response surface methodology to obtain better yield, uniform size, shape and stability. Further, these synthesized nanoparticles were confirmed through UV-Visible, FT-IR spectroscopy, PSA and SEM Subsequently, the bioefficacy of these particles were investigated on Anopheles stephensi for larvicidal and pupicidal activity. Interestingly, time period of 90 min, temperature of 76±2 °C, pH 7.2±2, 2 mM silver nitrate (AgNO3), 3mM PEG and 2mM PVP showed excellent parameters for bioprocess design for large scale production of stabilized nanoparticles. A concentration of 5 ppm of PVP stabilized nanoparticles exhibited 100% mortality. Thus, the obtained results clearly suggest that silver nanoparticles stabilized by PEG and PVP may have important function as stabilizers, dispersants as well as larvicides for mosquito control. PMID:26010566

  20. Monoclonal antibodies AC-43 and AC-29 disrupt Plasmodium vivax development in the Indian malaria vector Anopheles culicifacies (Diptera: culicidae)

    Indian Academy of Sciences (India)

    Manoj Chugh; B R Gulati; S K Gakhar

    2010-03-01

    A repertoire of monoclonal antibodies (mAbs) was generated against the midgut proteins of Anopheles culicifacies mosquitoes. The mAbs AC-43 and AC-29 significantly inhibited Plasmodium vivax development inside the mosquito midgut. The number of oocysts that developed was reduced by 78.6% when mosquitoes ingested a combination of these two mAbs along with the blood meal. AC-43 mAb binds to the epitope common in 97, 80 and 43 kDa polypeptides from the midgut protein extract, as indicated by western blot analysis. Similarly, the mAb AC-29 recognized 52, 44, 40 and 29 kDa polypeptides. These female midgut-specific polypeptides are shared between An. culicifacies and An. stephensi, two major vectors of malaria in India. Deglycosylation assays revealed that -linked carbohydrates are the major components in epitopes corresponding to AC-43 and AC-29. Gold particle labelling revealed that both these mAbs preferentially bind to glycoproteins at the apical microvilli and the microvillus-associated network present inside transverse sections of the gut epithelium. These regions are particularly known to have receptors for ookinetes, which enable them to cross this epithelial barrier and provide them with certain necessary chemicals or components for further development into oocysts. Therefore, these glycoproteins appear to be potential candidates for a vectordirected transmission-blocking vaccine (TBV).

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

    Directory of Open Access Journals (Sweden)

    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

  2. Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus,Aedes aegypti and Anopheles stephensi(Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Govindarajan; M; Mathivanan; T; Elumalai; K; Krishnappa; K; Anandan; A

    2011-01-01

    Objective:To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria(E.coronaria) and Caeslpinia pulckerrima(C.pulcherrima) against Culex quinquefasciatus(Cx.quinquefasciatus),Aedes aegypti(Ae.aegypti) and Anopheles stephensi(An. stephensi).Methods:The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions.The hatch rates were assessed 48 h after treatment.The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0,2.5 and 5.0 mg/cm under the laboratory conditions. Results:The crude extract of E.coronaria exerted zero hatchability(100%mortality) at 250.200 and 150 ppm for Cx.quinqitefasciatus,Ae.aegypti and An.stephensi,respectively.The crude extract of C.pulchenima exerted zero hatchability(100%mortality) at 375.300 and 225 ppm for Cx.quinquefasciatus,Ae.aegypti and An.Stephensi,respectively.The methanol extract of E. coronaria found to be more repellenct than C.pukherrima extract.A higher concentration of 5.0 mg/cm~2 provided 100%protection up to 150.180 and 210 min against Cx.quinquefasciatus,Ae. aegypti and An.stephensi,respectively.The results clearly showed that repellent activity was dose dependent.Conclusions:From the results it can be concluded the crude extracts of E.coronaria and C.pukherrima are an excellent potential for controlling Cx.quinquefasciatus,Ae.aegypti and An.stephensi mosquitoes.

  3. Larvicidal and repellent properties of Adansonia digitata against medically important human malarial vector mosquito Anopheles stephensi (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    K. Krishnappa , K. Elumalai , S. Dhanasekaran & J. Gokulakrishnan

    2012-06-01

    Full Text Available 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 concentrations (30–180 mg/l in thelaboratory by using the standard protocol described by WHO (2005. The larvae were exposed for 24 h andmortalities were subjected to log-probit analysis. Repellent activity of crude leaf extract at the dosages of 2, 4and 6 mg/cm2 was evaluated in a net cage (45 × 30 × 45 cm containing 100 blood starved female mosquitoes ofAn. stephensi using the protocol of WHO (1996.Results: Preliminary phytochemical analysis of A. digitata showed the presence of triterpenoids and saponins.The LC50 and LC90 values of hexane, benzene, chloroform, and methanol extracts of A. digitata against An.stephensi larvae in 24 h were 111.32, 97.13, 88.55, 78.18 and 178.63, 176.19, 168.14, 155.42 mg/l, respectively.The repellent activity of methanol extract was found to be most effective and at higher concentration of 6mg/cm2 benzene, chloroform hexane and methanol extracts provided 100% protection up to 150, 180, 120 and210 min against An. stephensi, respectively.Conclusion: The preliminary study indicated that A. digitata showed larvicidal and repellent activities againstAn. stephensi and could be used for controlling mosquitoes. Further studies are indicated to purify the activecompounds from these plants for developing larvicide and repellents.

  4. 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

  5. DETERMINATION OF SUSCEPTIBILITY OF ANOPHELES SACHAROVI COLLECTED FROM DASHT ARGEN IN FARS PROVINCE TO DDT, MALATHION FENITROTHION (DIPTERA, CULICIDAE

    Directory of Open Access Journals (Sweden)

    S. Ghavami

    1999-12-01

    Full Text Available To determine the degree of susceptibility of An. Sacharovi to malathion 5%, fenitrothion 1% and DDT 4% extended studies were carried out on sucked blood engorged mosquitoes collected from Dasht Argen (Fars province in 1997. Testing method was according to standard WHO method in lots of 25 adults' mosquitoes in 4 replicates. An. Sacharovi were touched by malathion 5% and DDT 4% insecticides in 15, 30 and 60 minutes exposure time. Based on the results, mortality level was found to be 53.1%, 84.3% and 100% for malathion and 48.5%, 85.4% and 100% for D.D.T. LD50 and LD90 for DDT was found to be 15.70 and 32.55 min, respectively. According to the results, An. Sacharovi was susceptible to malathion and D.D.T. However, this Anophel had strong resistance background to D.D.T. in other areas in Iran. Another insecticide tested was fenitrothion with 1% in 60, 75, 90 and 120 min exposure time mortality was 35.4%, 60.6%, 64.3% and 84.5%, with LD50 and LD90 of about 69.83 and 138.9 min, respectively. Due to absence of fenitrothion application in malaria vectors control program in southern Iran and also susceptibility to malathion, it seems that the fenitrothion dosage of 1% in 120 min time might not be effective, therefore, it is recommended to change that concentration of insecticide or the amount of exposure time.

  6. 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.

  7. 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

  8. Population structure of the malaria vector Anopheles sinensis (Diptera: Culicidae in China: two gene pools inferred by microsatellites.

    Directory of Open Access Journals (Sweden)

    Yajun Ma

    Full Text Available BACKGROUND: Anopheles sinensis is a competent malaria vector in China. An understanding of vector population structure is important to the vector-based malaria control programs. However, there is no adequate data of A. sinensis population genetics available yet. METHODOLOGY/PRINCIPAL FINDINGS: This study used 5 microsatellite loci to estimate population genetic diversity, genetic differentiation and demographic history of A. sinensis from 14 representative localities in China. All 5 microsatellite loci were highly polymorphic across populations, with high allelic richness and heterozygosity. Hardy-Weinberg disequilibrium was found in 12 populations associated with heterozygote deficits, which was likely caused by the presence of null allele and the Wahlund effect. Bayesian clustering analysis revealed two gene pools, grouping samples into two population clusters; one includes six and the other includes eight populations. Out of 14 samples, six samples were mixed with individuals from both gene pools, indicating the coexistence of two genetic units in the areas sampled. The overall differentiation between two genetic pools was moderate (F(ST = 0.156. Pairwise differentiation between populations were lower within clusters (F(ST = 0.008-0.028 in cluster I and F(ST = 0.004-0.048 in cluster II than between clusters (F(ST = 0.120-0.201. A reduced gene flow (Nm = 1-1.7 was detected between clusters. No evidence of isolation by distance was detected among populations neither within nor between the two clusters. There are differences in effective population size (Ne = 14.3-infinite across sampled populations. CONCLUSIONS/SIGNIFICANCE: Two genetic pools with moderate genetic differentiation were identified in the A. sinensis populations in China. The population divergence was not correlated with geographic distance or barrier in the range. Variable effective population size and other demographic effects of historical population

  9. Larvicidal potential of some plants from West Africa against Culex quinquefasciatus (Say) and Anopheles gambiae Giles (Diptera: Culicidae)

    OpenAIRE

    Alain Azokou; Mamidou W. Koné; Koudou, Benjamin G; Honora F. Tra Bi

    2013-01-01

    Background & objectives: Mosquitoes increased resistance to insecticides, and environmental concerns about the use of insecticides, pose a major challenge in the search for new molecules to deplete and incapacitate mosquito populations. Plants are the valuable source as practices consisting in exploiting plant materials as repellents, and are still in wide use throughout developing countries. The aim of the present study was to screen plants from Cτte d'Ivoire for larvicidal activity aga...

  10. 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...

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

    Directory of Open Access Journals (Sweden)

    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

  12. Isolation of Tahyna virus (California Encephalitis Group) from Anopheles hyrcanus (Diptera, Culicidae), a mosquito species new to, and expanding in, Central Europe

    Czech Academy of Sciences Publication Activity Database

    Hubálek, Zdeněk; Šebesta, Oldřich; Peško, Juraj; Betášová, Lenka; Blažejová, Hana; Venclíková, Kristýna; Rudolf, Ivo

    2014-01-01

    Roč. 51, č. 6 (2014), s. 1264-1267. ISSN 0022-2585 EU Projects: European Commission(XE) 261504 - EDENEXT Institutional support: RVO:68081766 Keywords : Tahyna virus * Orthobunyavirus * mosquito * Anopheles hyrcanus Subject RIV: EE - Microbiology, Virology Impact factor: 1.953, year: 2014

  13. Evaluation of Methods for Sampling the Malaria Vector Anopheles darlingi (Diptera, Culicidae) in Suriname and the Relation With Its Biting Behavior

    NARCIS (Netherlands)

    Hiwat-van Laar, H.; Rijk, de M.; Andriessen, R.; Koenraadt, C.J.M.; Takken, W.

    2011-01-01

    The effectiveness of CO2-baited and human-baited mosquito traps for the sampling of Anopheles darlingi Root was evaluated and compared with human landing collections in Suriname. Biting preferences of this mosquito on a human host were studied and related to trapping data. Traps used were the Center

  14. Studies on larvicidal and pupicidal activity of Leucas aspera Willd. (Lamiaceae) and bacterial insecticide, Bacillus sphaericus, against malarial vector, Anopheles stephensi Liston (Diptera: Culicidae)

    Science.gov (United States)

    The efficacy of whole plant ethanolic extracts of Leucas aspera and of Bacillus sphaericus was determined for larvae and pupae of Anopheles stephensi. When larvae were exposed to one of five concentrations of plant extract (6%, 8%, 10%, 12%, and 14%) for 24 h, mortality in 4th instars ranged from 1...

  15. Molecular species identification, host preference and detection of myxoma virus in the Anopheles maculipennis complex (Diptera: Culicidae) in southern England, UK.

    OpenAIRE

    Brugman, VA; Hernández-Triana, LM; Prosser, SW; Weland, C; Westcott, DG; Fooks, AR; Johnson, N

    2015-01-01

    Background Determining the host feeding patterns of mosquitoes by identifying the origin of their blood-meals is an important part of understanding the role of vector species in current and future disease transmission cycles. Collecting large numbers of blood-fed mosquitoes from the field is difficult, therefore it is important to maximise the information obtained from each specimen. This study aimed to use mosquito genome sequence to identify the species within Anopheles maculipennis sensu l...

  16. Estimation of vectorial capacity of Anopheles minimus Theobald & An. fluviatilis James (Diptera: Culicidae) in a malaria endemic area of Odisha State, India

    OpenAIRE

    K Gunasekaran; S S Sahu; Jambulingam, P.

    2014-01-01

    Background & objectives: Anopheles minimus and An. fluviatilis were incriminated as the major malaria vectors in Keonjhar district of Odisha State recently. This study was carried out to elucidate the potential role of these two vector species in transmission of malaria during different seasons, and vectorial capacity of these species was also estimated. Methods: Three hilly and forested villages of Keonjhar district were randomly selected. Vectorial capacity (C) was calculated using the...

  17. Anopheles (Kerteszia) lepidotus (Diptera: Culicidae), not the malaria vector we thought it was: Revised male and female morphology; larva, pupa, and male genitalia characters; and molecular verification

    OpenAIRE

    Bruce A. Harrison; RUIZ-LOPEZ, FREDDY; FALERO, GUILLERMO CALDERON; SAVAGE, HARRY M.; James E Pecor; Wilkerson, Richard C.

    2012-01-01

    The name Anopheles (Kerteszia) lepidotus Zavortink, commonly used for an important malaria vector in the eastern cordillera of the Andes, is here corrected to An. pholidotus Zavortink. We discovered that An. (Ker.) specimens from Peru, and reared-associated specimens from Ecuador, had unambiguous habitus characters that matched those on the male holotype of An. lepidotus. However, the specimens do not exhibit characters of the female allotype and female paratypes of An. lepidotus, which are a...

  18. "Repellent Effect of Extracts and Essential Oils of Citrus limon (Rutaceae) and Melissa officinalis (Labiatae) Against Main Malaria Vector, Anopheles stephensi (Diptera: Culicidae)"

    OpenAIRE

    MA Oshaghi; R Ghalandari; Vatandoost, H; M Shayeghi; M Kamali-nejad; H Tourabi-Khaledi; Abolhassani, M.; M Hashemzadeh"

    2003-01-01

    Repellet effect of extracts and essential oils of Citrus limon (L.) Burm.F., (lemon) and Melissa officinalis, (balm) were evaluated against Anopheles stephensi in laboratory on animal and human and compared with synthetic repellent, N,Ndiethyl- 3-methylbenzamide (Deet) as a standard. Results of statistical analysis revealed significant differences between oils and extracts (P< 0.05) against the tested species, thus oils were more effective than extracts. There was no significant difference...

  19. 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...

  20. Estudio ambiental de criaderos de anopheles (n) albimanus (diptera: culicidae) en la provincia holguín. año 2009

    OpenAIRE

    Niurka Lien Torres-Rodríguez; Mariluz Escalona-Rodríguez; Liliana Leyva-Ruiz

    2012-01-01

    Se presenta el estudio de la incidencia y comportamiento del anopheles albimanus, (transmisor del paludismo o malaria) en los 282 criaderos potenciales y habituales de culícidos de la provincia holguín durante el año 2009.a partir de la información semanal enviada a la unidad provincial de vigilancia y lucha antivectorial (upvla), se caracterizó el comportamiento de esta especie la que se encuentra ampliamente distribuida en la provincia. Se observó mayor incidencia en los municipios FranK Pa...

  1. Partial mitochondrial DNA sequences suggest the existence of a cryptic species within the Leucosphyrus group of the genus Anopheles (Diptera: Culicidae, forest malaria vectors, in northern Vietnam

    Directory of Open Access Journals (Sweden)

    Yasunami Michio

    2010-04-01

    Full Text Available Abstract Background During the last decade, Southeast Asian countries have been very successful in reducing the burden of malaria. However, malaria remains endemic in these countries, especially in remote and forested areas. The Leucosphyrus group of the genus Anopheles harbors the most important malaria vectors in forested areas of Southeast Asia. In Vietnam, previous molecular studies have resulted in the identification of only Anopheles dirus sensu stricto (previously known as An. dirus species A among the Leucosphyrus group members. However, Vietnamese entomologists have recognized that mosquitoes belonging to the Leucosphyrus group in northern Vietnam exhibit morphological characteristics similar to those of Anopheles takasagoensis, which has been reported only from Taiwan. Here, we aimed to confirm the genetic and morphological identities of the members of the Leucosphyrus group in Vietnam. Results In the molecular phylogenetic trees reconstructed using partial COI and ND6 mitochondrial gene sequences, samples collected from southern and central Vietnam clustered together with GenBank sequences of An. dirus that were obtained from Thailand. However, samples from northern Vietnam formed a distinct clade separated from both An. dirus and An. takasagoensis by other valid species. Conclusions The results suggest the existence of a cryptic species in northern Vietnam that is morphologically similar to, but phylogenetically distant from both An. dirus and An. takasagoensis. We have tentatively designated this possible cryptic species as Anopheles aff. takasagoensis for convenience, until a valid name is assigned. However, it is difficult to distinguish the species solely on the basis of morphological characteristics. Further studies on such as karyotypes and polytene chromosome banding patterns are necessary to confirm whether An. aff. takasagoensis is a valid species. Moreover, studies on (1 the geographic distribution, which is potentially

  2. "Repellent Effect of Extracts and Essential Oils of Citrus limon (Rutaceae and Melissa officinalis (Labiatae Against Main Malaria Vector, Anopheles stephensi (Diptera: Culicidae"

    Directory of Open Access Journals (Sweden)

    "MA Oshaghi

    2003-10-01

    Full Text Available Repellet effect of extracts and essential oils of Citrus limon (L. Burm.F., (lemon and Melissa officinalis, (balm were evaluated against Anopheles stephensi in laboratory on animal and human and compared with synthetic repellent, N,Ndiethyl- 3-methylbenzamide (Deet as a standard. Results of statistical analysis revealed significant differences between oils and extracts (P< 0.05 against the tested species, thus oils were more effective than extracts. There was no significant difference between Deet and lemon oil, whereas the difference between lemon and melissa oils was significant. Relative efficacy of lemon oil to Deet was 0.88 whereas it was 0.71 for melissa oil. The results were found marginally superior in repellency for animals than human. Due to advantages of botanic compounds to synthetic compounds we recommend lemon essential oil as an effective alternative to Deet with potential as a means of personal protection against mosquito vectors of disease.

  3. Comparison of two commercial formulations of Bacillus thuringiensis var. israelensis for the control of Anopheles aquasalis (Diptera: Culicidae at three salt concentrations

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    Frances R Osborn

    2007-02-01

    Full Text Available Anopheles aquasalis larvae are salt water tolerant, preferring concentrations between 10 and 20 parts per thousand (ppt. The larvicidal efficacy of two formulations of Bacillus thuringiensis var. israelensis (Vectobac-12AS® and Bactivec®, was investigated against An. aquasalis at salinities of 0, 10, and 20 ppt. A probit analysis was used to calculate the lethal concentrations (LC50 and LC95 for each product at each salinity. The LC50 and LC95 were higher for Bactivec® than Vectobac-12AS®, and for Bactivec®, the LC50 and LC95 increased with salinity. Vectobac-12AS® should thus be preferred to Bactivec® for An. aquasalis control, especially in saline breeding habitats.

  4. Effect of anti-mosquito hemolymph antibodies on fecundity and on the infectivity of malarial parasite Plasmodium vivax to Anopheles stephensi (Diptera:Insecta).

    Science.gov (United States)

    Gulia, Monika; Suneja, Amita; Gakhar, Surendra K

    2002-06-01

    Rabbit antibodies to hemolymph antigens (102.5, 101, 100, 96, 88, 80, 64, 55, 43, 29, and 23 kDa) of Anopheles stephensi reduced fecundity as well as viability in An. stephensi. However, ingestion of these antibodies was not associated with a marked effect on the engorgement of mosquitoes but egg laying was significantly delayed. Antisera raised against hemolymph proteins were also used to identify cross reactive antigens/epitopes present in other tissues by Western blotting, as well as by in vivo ELISA. In addition, a significant reduction in oocyst development was also observed in An. stephensi mosquitoes that ingested anti-hemolymph antibodies along with Plasmodium vivax. The results confirmed the feasibility of targeting mosquito antigens as a novel anti-mosquito strategy, as well as confirmed the usefulness of such antigens for the development of a transmission-blocking vaccine. PMID:12195047

  5. Dynamics of immature stages of Anopheles arabiensis and other mosquito species (Diptera: Culicidae) in relation to rice cropping in a rice agro-ecosystem in Kenya.

    Science.gov (United States)

    Mwangangi, Joseph; Shililu, Josephat; Muturi, Ephantus; Gu, Weidong; Mbogo, Charles; Kabiru, Ephantus; Jacob, Benjamin; Githure, John; Novak, Robert

    2006-12-01

    We determined changes in species composition and densities of immature stages of Anopheles arabiensis mosquitoes in relation to rice growth cycle in order to generate data for developing larval control strategies in rice ecosystems. Experimental rice paddies (6.3m x 3.15m) exposed to natural colonization of mosquitoes were sampled weekly for two rice growing cycles between February 2004 and March 2005. Overall, 21,325 Anopheles larvae were collected, of which 91.9% were 1st and 2nd instars and 8.1% were 3rd and 4th instars. An. arabiensis was the predominant species (84.1%) with other species, An. pharoensis (13.5%), An. funestus (2.1%), An. coustani (0.3%), and An. maculipalpis (0.1%) accounting for only a small proportion of the anophelines collected. Culex quinquefasciatus (65.7%) was the predominant species among the non-anopheline species. Others species collected included: C. annulioris (9.9%), C. poicilipes (7.3%), C. tigripes (7.2%), C. duttoni (0.6%), Aedes aegypti (5.3%), Ae. cumminsii (3.5%), and Ae. vittatus (0.7%). The densities of the major anopheline species were closely related to rice stage and condition of the rice field. An. arabiensis, the predominant species, was most abundant over a three-week period after transplanting. Low densities of larvae were collected during the late vegetative, reproductive, and ripening phases of rice. An increase in larval density ten days post-transplanting was found to correlate with the application of fertilizer (sulphate of ammonia). Culicine and aedine species densities were significantly higher during the post-harvesting period. Our results suggest that the transplanting stage is favorable for the growth of immature stages of An. arabiensis and provides a narrow window for targeted larval intervention in rice. PMID:17249341

  6. Field investigation on the repellent activity of some aromatic plants by traditional means against Anopheles arabiensis and An. pharoensis (Diptera: Culicidae) around Koka, central Ethiopia.

    Science.gov (United States)

    Dugassa, Sisay; Medhin, Girmay; Balkew, Meshesha; Seyoum, Aklilu; Gebre-Michael, Teshome

    2009-10-01

    A study was undertaken to evaluate the impact of traditional application methods of mosquito repellent plants in the reduction of the human-vector contact of malaria vectors in central Ethiopia. The plants (Corymbia citriodora, Eucalyptus camaldulensis, Ocimum suave and Ocimum basilicum) were tested by thermal expulsion and direct burning on traditional stoves in the field against two important malaria vectors in Ethiopia (Anopheles arabiensis and An. pharoensis). A Latin-square design was applied for randomly assigning the treatment plants and control to experimental houses over different nights. The percentage repellency of each candidate plant by both application methods was estimated from the catches of mosquitoes in the treatment and control houses. On direct burning of the plants, O. basilicum showed the highest percentage repellency (73.11%, Pcitriodora on the other hand gave the highest repellency (72.87%, Pcitriodora exhibited the highest repellency (78.69%, Pcitriodora gave the highest repellency (72.9%, P65%) against the house-entry and biting of two important malaria vectors in Ethiopia, and thus have a potential to be used at least as supplements to other control methods. However, feasibility and actual impact on disease transmission need to be known on these and other potentially useful plants. PMID:19539591

  7. The Influence of Insecticide Resistance, Age, Sex, and Blood Feeding Frequency on Thermal Tolerance of Wild and Laboratory Phenotypes of Anopheles funestus (Diptera: Culicidae).

    Science.gov (United States)

    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

  8. Production of a Transgenic Mosquito Expressing Circumsporozoite Protein, a Malarial Protein, in the Salivary Gland of Anopheles stephensi (Diptera:Culicidae

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    Matsuoka,Hiroyuki

    2010-08-01

    Full Text Available We are producing a transgenic mosquito, a flying syringe, to deliver a vaccine protein to human beings via the saliva the mosquito deposits in the skin while biting. The mosquito produces a vaccine protein in the salivary gland (SG and deposits the protein into the host's skin when it takes the host's blood. We chose circumsporozoite protein (CSP, currently the most promising malaria vaccine candidate, to be expressed in the SG of Anopheles stephensi. To transform the mosquitoes, plasmid containing the CSP gene under the promoter of female SG-specific gene, as well as the green fluorescent protein (GFP gene under the promoter of 3xP3 as a selection marker in the eyes, was injected into more than 400 eggs. As a result, five strains of GFP-expressing mosquitoes were established, and successful CSP expression in the SG was confirmed in one strain. The estimated amount of CSP in the SG of the strain was 40ng per mosquito. We allowed the CSP-expressing mosquitoes to feed on mice to induce the production of anti-CSP antibody. However, the mice did not develop anti-CSP antibody even after transgenic mosquitoes had bitten them several times. We consider that CSP in the SG was not secreted properly into the saliva. Further techniques and trials are required in order to realize vaccine-delivering mosquitoes.

  9. Mosquitocidal activity of indigenenous plants of Western Ghats, Achras sapota Linn. (Sapotaceae) and Cassia auriculata L. (Fabaceae) against a common malarial vector, Anopheles stephensi Liston (Culicidae:Diptera)

    Institute of Scientific and Technical Information of China (English)

    Kaliyamoorthy Krishnappa; Kuppusamy Elumalai

    2014-01-01

    Objective: To evaluate the mosquito larvicidal, ovicidal, pupicidal and repellent activities of hexane, diethyl ether, dichloromethane, acetone and methanol extracts of Indian medicinal plants, Achras sapota (A. sapota) and Cassia auriculata (C. auriculata) at different concentrations against Anopheles stephensi (An. stephensi), a malarial vector. Methods: Twenty five early third instar larvae of An. stephensi were exposed to various concentrations (30-210 mg/L) of plants extracts and were assayed in the laboratory by using the protocol of WHO 2005;then after 24 h LC50 values of the A. sapota and C. auriculata leaf extract was determined by probit analysis. The ovicidal activity was tested with the extracts ranging from 50-350 mg/L. The pupicidal activity was recorded after 24 h of exposure to the extract. The repellent efficacy was determined against mosquito species at two different concentrations 1.5 and 3.0 mg/cm2 under laboratory conditions. Results:Among the five different extracts tested against the An. stephensi, methanol extract of A. sapota proved to be an more effective solvent extract in almost all the parameters studied than C. auriculata. Conclusions:It is inferred that the leaf extract of A. sapota and C. auriculata could be used in vector control programme.

  10. Estudio ambiental de criaderos de anopheles (n albimanus (diptera: culicidae en la provincia holguín. año 2009

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    Niurka Lien Torres-Rodríguez

    2012-01-01

    Full Text Available Se presenta el estudio de la incidencia y comportamiento del anopheles albimanus, (transmisor del paludismo o malaria en los 282 criaderos potenciales y habituales de culícidos de la provincia holguín durante el año 2009.a partir de la información semanal enviada a la unidad provincial de vigilancia y lucha antivectorial (upvla, se caracterizó el comportamiento de esta especie la que se encuentra ampliamente distribuida en la provincia. Se observó mayor incidencia en los municipios FranK País, Rafael Freyre y Mayarí, con predominio en zanjas, lagunas y arroyos. Se aprecia una mayor asociación con el culex quinquefasciatus y el mayor número de muestras larvarias fueron colectadas en octubre. Teniendo en cuenta los resultados obtenidos y el riesgo de introducción de esta enfermedad en el país se recomienda continuar los estudios de esta especie en la provincia.

  11. First Record of Anopheles darlingi Root (Diptera, Culicidae in the Volta Grande Environmental Reserve, Conceição das Alagoas Municipality, Minas Gerais, Brazil

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    Rafael Martins

    2015-04-01

    Resumo. Três espécimes de Anopheles darlingi Root foram encontrados na reserva ambiental Volta Grande, na área de influência da barragem do Rio Grande construída pela usina hidrelétrica de Volta Grande, em Conceição das Alagoas, Minas Gerais, Brasil. O mosquito An. darlingi é um dos principais vetores da malária humana no Brasil, devido à sua preferência alimentar por sangue humano, um fator que é acentuado pelo comportamento endofílico da espécie. O presente relato poderá ser útil à vigilância entomológica local para monitoramento dos impactos gerados pela formação do reservatório hidrelétrico, uma vez que a presença deste vetor neste tipo de ambiente indica um risco potencial de transmissão da malária.

  12. Larvicidal,ovicidal and repellent activities of marine sponge Cliona celata(Grant) extracts against Anopheles stephensi Liston(Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Appadurai; Daniel; Reegan; Arokia; Valan; Kinsalin; Michael; Gabriel; Paulraj; Savarimuthu; Ignacimuthu

    2015-01-01

    Obective:To evaluate the larvieidal.ovieidal and repellent properties of solvent extracts of marine sponge Cliona celala(C.celata)(Grant) against the malarial vector Anopheles stephensi(An.stephensi) Listen.Methods:Marine sponge C.celala was thoroughly washed with distilled water and shade dried for 48 h.Then the sponges were homogenized and extracted sequentially with hexane,ethyl acetate and methanol,Lanvicidal and ovicidal activities were tested at four different concentrations viz.,62.5.125.0.250.0 and 500.0 ppm.for repellent study extracts were taken in three different concentrations viz..5.0.2.5.1.0 mg/cm at.Results:Among the three solvent extracts of C.celata,methanol extract showed thc highest lanvieidal activity at 500 ppm against the fourth inslar larvae of An.stephensi.The LC50and LC90 values of C.celata methanol extract were recorded as 80.61 and 220.81 ppm against An.stephensi larvae respectively.High ovieidal activity of 91.2%was recorded al 500 ppm concentration of methanol extract.The haxane extract was found to be the most effective protectant against the adult female mosquitoes of An.stephensi.The mean protection time recorded in hexane extract was up to 245 min at 5 mg/cm2 dosage against An.Stephensi adults.Conclusions:The screening results suggest that the hexane and methanol extracts of C.celata arc promising in mosquito control.Considering these bioaclivitics.C.celata could the probed further to obtain some novel pesticidal molecules.

  13. Efficacy of larvicidal and pupicidal activity of Catharanthus roseus aqueous and solvent extracts against Anopheles stephensi Liston and Culex quinquefasciatus Say (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Selladurai Subarani; Selvi Sabhanayakam; Chinnaperumal Kamaraj; Gandhi Elango; Mohamed Abdul Kadir

    2013-01-01

    Objective:To investigate the larvicidal and pupicidal activities of aqueous, ethyl acetate and methanol extracts of Catharanthus roseus (C. roseus) against malaria and filariasis vectors. Methods:The larvicidal and pupicidal activities of C. roseus leaf extracts were tested against the fourth instar larvae and pupae of Anopheles stephensi (An. stephensi) and Culex quinquefasciatus (Cx. quinquefasciatus). The mortality was observed after 24 and 48 h post the treatment. The data were subjected to probit analysis to determine the lethal concentrations (LC50 and LC90) at which 50%and 90%of the treated larvae or pupae of the tested species were killed. Results:The larval and pupal mortality were observed after 24 and 48 h of exposure of aqueous, ethyl acetate and methanol extracts of C. roseus; no mortality was observed in the control group. The LC50 values against the fourth-instar larvae of An. stephensi were 68.62 and 72.04 mg/mL for the aqueous extract, 82.47 mg/mL for the ethyl acetate extract, and 78.80 and 86.64 mg/mL for the methanol extract, while the aqueous, ethyl acetate and methanol extracts had LC50 values of 85.21, 76.84 and 94.20 mg/mL against the fourth-instar larvae of Cx. quinquefasciatus. The aqueous, ethyl acetate and methanol extracts had LC50 values of 118.08, 182.47 and 143.80 mg/mL against the pupae of An. stephensi and 146.20, 226.84 and 156.62 mg/mL against the pupae of Cx. quinquefasciatus, respectively. Conclusions: The aqueous and methanol extracts of C. roseus leaves had an excellent potential to control the malarial vector An. stephensi and filariasis vector Cx. quinquefasciatus.

  14. Estimation of vectorial capacity of Anopheles minimus Theobald & An. fluviatilis James (Diptera: Culicidae in a malaria endemic area of Odisha State, India

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    K Gunasekaran

    2014-01-01

    Full Text Available Background & objectives: Anopheles minimus and An. fluviatilis were incriminated as the major malaria vectors in Keonjhar district of Odisha State recently. This study was carried out to elucidate the potential role of these two vector species in transmission of malaria during different seasons, and vectorial capacity of these species was also estimated. Methods: Three hilly and forested villages of Keonjhar district were randomly selected. Vectorial capacity (C was calculated using the Macdonald′s formula as modified by Garret-Jones. The human landing density of the vector species was obtained from all night human landing collections (bait protected by bed-net. Man feeding habit was estimated by multiplying the human blood index with feeding frequency, which was obtained on daily basis from the duration of gonotrophic cycle. The probability of survival through the extrinsic incubation cycle was calculated from the probability of survival through one day and duration of sporogonic cycle. Results: The estimated vectorial capacity of An. minimus varied between 0.014 and 1.09 for Plasmodium falciparum (Pf and between 0.1 and 1.46 for P. vivax (Pv. The C of An. minimus for both Pf and Pv was higher during rainy season than the other two seasons. The estimated C of An. fluviatilis varied between 0.04 and 1.28 for Pf and between 0.20 and 1.54 for Pv. Interpretation & conclusions: Based on the estimated values of vectorial capacity of the two vector species, the area could be stratified and such stratification would reflect the difference in the intensity of transmission between different strata and accordingly the appropriate control strategy could be adopted for each stratum.

  15. The abundance and host-seeking behavior of culicine species (Diptera: Culicidae) and Anopheles sinensis in Yongcheng city, people's Republic of China

    Science.gov (United States)

    2011-01-01

    Background The knowledge of mosquito species diversity and the level of anthropophily exhibited by each species in a region are of great importance to the integrated vector control. Culicine species are the primary vectors of Japanese encephalitis (JE) virus and filariasis in China. Anopheles sinensis plays a major role in the maintenance of Plasmodium vivax malaria transmission in China. The goal of this study was to compare the abundance and host-seeking behavior of culicine species and An. sinensis in Yongcheng city, a representative region of P. vivax malaria. Specifically, we wished to determine the relative attractiveness of different animal baits versus human bait to culicine species and An. sinensis. Results Culex tritaeniorhynchus was the most prevalent mosquito species and An. sinensis was the sole potential vector of P. vivax malaria in Yongcheng city. There were significant differences (P < 0.01) in the abundance of both An. sinensis and Cx. tritaeniorhynchus collected in distinct baited traps. The relative attractiveness of animal versus human bait was similar towards both An. sinensis and Cx. tritaeniorhynchus. The ranking derived from the mean number of mosquitoes per bait indicated that pigs, goats and calves frequently attracted more mosquitoes than the other hosts tested (dogs, humans, and chickens). These trends were similar across all capture nights at three distinct villages. The human blood index (HBI) of female An. sinensis was 2.94% when computed with mixed meals while 3.70% computed with only the single meal. 19:00~21:00 was the primary peak of host-seeking female An. sinensis while 4:00~5:00 was the smaller peak at night. There was significant correlation between the density of female An. sinensis and the average relative humidity (P < 0.05) in Wangshanzhuang village. Conclusions Pigs, goats and calves were more attractive to An. sinensis and Cx. tritaeniorhynchus than dogs, humans, and chickens. Female An. sinensis host-seeking activity

  16. The abundance and host-seeking behavior of culicine species (Diptera: Culicidae and Anopheles sinensis in Yongcheng city, people's Republic of China

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    Liu Xiao-Bo

    2011-11-01

    Full Text Available Abstract Background The knowledge of mosquito species diversity and the level of anthropophily exhibited by each species in a region are of great importance to the integrated vector control. Culicine species are the primary vectors of Japanese encephalitis (JE virus and filariasis in China. Anopheles sinensis plays a major role in the maintenance of Plasmodium vivax malaria transmission in China. The goal of this study was to compare the abundance and host-seeking behavior of culicine species and An. sinensis in Yongcheng city, a representative region of P. vivax malaria. Specifically, we wished to determine the relative attractiveness of different animal baits versus human bait to culicine species and An. sinensis. Results Culex tritaeniorhynchus was the most prevalent mosquito species and An. sinensis was the sole potential vector of P. vivax malaria in Yongcheng city. There were significant differences (P An. sinensis and Cx. tritaeniorhynchus collected in distinct baited traps. The relative attractiveness of animal versus human bait was similar towards both An. sinensis and Cx. tritaeniorhynchus. The ranking derived from the mean number of mosquitoes per bait indicated that pigs, goats and calves frequently attracted more mosquitoes than the other hosts tested (dogs, humans, and chickens. These trends were similar across all capture nights at three distinct villages. The human blood index (HBI of female An. sinensis was 2.94% when computed with mixed meals while 3.70% computed with only the single meal. 19:00~21:00 was the primary peak of host-seeking female An. sinensis while 4:00~5:00 was the smaller peak at night. There was significant correlation between the density of female An. sinensis and the average relative humidity (P Conclusions Pigs, goats and calves were more attractive to An. sinensis and Cx. tritaeniorhynchus than dogs, humans, and chickens. Female An. sinensis host-seeking activity mainly occurred from 19:00 to 21:00. Thus

  17. Low-cost and eco-friendly green synthesis of silver nanoparticles using Feronia elephantum (Rutaceae) against Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Veerakumar, Kaliyan; Govindarajan, Marimuthu; Rajeswary, Mohan; Muthukumaran, Udaiyan

    2014-05-01

    Mosquitoes transmit serious human diseases, causing millions of deaths every year. The use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. Insecticides of synthesized natural products for vector control have been a priority in this area. In the present study, the larvicidal activity of silver nanoparticles (AgNPs) synthesized using Feronia elephantum plant leaf extract against late third-instar larvae of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus was determined. The range of concentrations of synthesized AgNPs (5, 10, 15, 20, and 25 μg mL(-1)) and aqueous leaf extract (25, 50, 75, 100, and 125 μg mL(-1)) were tested against the larvae of A. stephensi, A. aegypti, and C. quinquefasciatus. Larvae were exposed to varying concentrations of aqueous crude extract and synthesized AgNPs for 24 h. Considerable mortality was evident after the treatment of F. elephantum for all three important vector mosquitoes. The synthesized AgNPs from F. elephantum were highly toxic than crude leaf aqueous extract to three important vector mosquito species. The results were recorded from UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy analysis (EDX). Synthesized AgNPs against the vector mosquitoes A. stephensi, A. aegypti, and C. quinquefasciatus had the following LC50 and LC90 values: A. stephensi had LC50 and LC90 values of 11.56 and 20.56 μg mL(-1); A. aegypti had LC50 and LC90 values of 13.13 and 23.12 μg mL(-1); and C. quinquefasciatus had LC50 and LC90 values of 14.19 and 24.30 μg mL(-1). No mortality was observed in the control. These results suggest that the green synthesis of silver nanoparticles using F. elephantum has the potential to be used as an ideal eco-friendly approach for the control of A. stephensi, A. aegypti, and C

  18. Mosquito larvicidal potential of silver nanoparticles synthesized using Chomelia asiatica (Rubiaceae) against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Muthukumaran, Udaiyan; Govindarajan, Marimuthu; Rajeswary, Mohan

    2015-03-01

    Mosquitoes transmit serious human diseases, causing millions of deaths every year. Mosquito control is to enhance the health and quality of life of county residents and visitors through the reduction of mosquito populations. Mosquito control is a serious concern in developing countries like India due to the lack of general awareness, development of resistance, and socioeconomic reasons. Today, nanotechnology is a promising research domain which has a wide ranging application in vector control programs. These are nontoxic, easily available at affordable prices, biodegradable, and show broad-spectrum target-specific activities against different species of vector mosquitoes. In the present study, larvicidal activity of aqueous leaf extract and silver nanoparticles (AgNPs) synthesized using C. asiatica plant leaves against late third instar larvae of Anopheles stephensi, Aedes aegypti, and Cx. quinquefasciatus. The range of varying concentrations of synthesized AgNPs (8, 16, 24, 32, and 40 μg/mL) and aqueous leaf extract (40, 80, 120, 160, and 200 μg/mL) were tested against the larvae of An. stephensi, Ae. aegypti, and Cx. quinquefasciatus. The synthesized AgNPs from C. asiatica were highly toxic than crude leaf aqueous extract in three important vector mosquito species. The results were recorded from UV-Vis spectrum, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis (EDX). Considerable mortality was evident after the treatment of C. asiatica for all three important vector mosquitoes. The LC50 and LC90 values of C. asiatica aqueous leaf extract appeared to be effective against An. stephensi (LC50, 90.17 μg/mL; LC90, 165.18 μg/mL) followed by Ae. aegypti (LC50, 96.59 μg/mL; LC90, 173.83 μg/mL) and Cx. quinquefasciatus (LC50, 103.08 μg/mL; LC90, 183.16 μg/mL). Synthesized AgNPs against the vector mosquitoes of An. stephensi, Ae. aegypti, and Cx. quinquefasciatus had the following LC50 and LC90

  19. Distribuição das espécies do gênero Anopheles (Diptera, Culicidae no Estado do Maranhão, Brasil Distribution of species from genus Anopheles (Diptera, Culicidae in the State of Maranhão, Brazil

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    José M. Macário Rebêlo

    2007-12-01

    Full Text Available Estudou-se a distribuição e diversidade de espécies de Anopheles em 123 municípios do Estado do Maranhão, Brasil. O método básico foi a captura de fêmeas dentro e nos arredores das habitações humanas, em intervalos compreendidos entre 18h e 6h, no período de janeiro de 1992 a dezembro de 2001. Foram capturados 84.467 exemplares distribuídos em 24 espécies, com o predomínio de A. triannulatus sensu lato (20.788, A. darlingi (19.083, A. nuneztovari (16.884, A. albitarsis s.l. (14.352, A. aquasalis (8.202 e A. evansae (2.885. As outras 18 espécies juntas representaram apenas 2,7%. As espécies encontradas no maior número de municípios foram: A. albitarsis s.l. (109 municípios, A. triannulatus s.l. (106, A. nuneztovari (93, A. darlingi (87 e A. evansae (64. A riqueza e a ampla distribuição das espécies de anofelinos no Maranhão concordam com a posição geográfica do estado, entre as macrorregiões que caracterizam o Brasil, resultando em uma fauna mista, com elementos representativos dessas regiões.We studied the distribution and diversity of Anopheles species in 123 counties (municipalities in the State of Maranhão, Brazil. The basic method consisted of capturing female specimens inside and around human dwellings between 6 PM and 6 AM from January 1992 to December 2001. A total of 84,467 specimens belonging to 24 species were captured, with a predominance of A. triannulatus sensu lato (20,788, A. darlingi (19,083, A. nuneztovari (16,884, A. albitarsis s.l. (14,352, A. aquasalis (8.202, and A. evansae (2,885. The other 18 species together accounted for only 2.7% of the total. The species found in the most counties were A. albitarsis s.l. (109 counties, A. triannulatus s.l. (106, A. nuneztovari (93, A. darlingi (87, and A. evansae (64. The richness and wide distribution of anopheline species in Maranhão agree with the State's geographic position among Brazil's macro-regions, resulting in a mixed fauna with representative

  20. Determinação das fontes alimentares de Anopheles aquasalis (Diptera: Culicidae no Estado do Rio de Janeiro, Brasil, pelo teste de precipitina Blood-meal sources of Anopheles aquasalis (Diptera: Culicidae in a South-eastern State of Brazil

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    Carmen Flores-Mendoza

    1996-04-01

    Full Text Available Anopheles aquasalis é um mosquito ora encarado como antropofílico, ora como zoofílico ou eclético. Realizou-se estudo em Guapimirim, Estado do Rio de Janeiro, de maio a novembro de 1992, com o intuito de se verificar a fonte alimentar preferida desse anofelino através de teste imunológico de precipitina. De 1.366 fêmeas capturadas em abrigos naturais, 725 estavam ingurgitadas. O conteúdo digestivo de apenas 473 delas reagiu no teste de precipitina, sendo que em 75,3% dos casos foi identificada apenas uma fonte alimentar. Mais da metade dessas fêmeas havia se alimentado em boi (52,2%, enquanto poucas tinham sugado homem (1,1%. Por outro lado, 24,7% dos espécimes haviam se alimentado em mais de uma fonte sangüínea, principalmente boi e cavalo. Conclui-se que An. aquasalis é zoófilo nessa região do País, utilizando grande variedade de hospedeiros, porém preferindo se alimentar em animais de grande porte, especialmente o boi e cavalo.Anopheles aquasalis has shown local variations in blood-host preference in Brazil: it seems to be anthropophilic in the northeast and zoophilic or opportunistic in the Amazon and other regions. A study was carried out in Guapimirim county, State of Rio de Janeiro, from May to November 1992, for the purpose of identifying the blood meal source of this anopheline by capillary tube precipitin test. A total of 1,366 females were captured at natural resting-places, 725 of which were blood-fed. The gut content of 473 blood fed females reacted to the antisera used (human, cow, horse, pig, dog and chicken. The majority of the females ¾ 356 (75.3% ¾ had blood from only one source. A substantial bovine preference was observed ¾ 52.2% had fed on cows, 29.8% on horses, 10.7% on pigs, 4.5% on chickens and 1.7% on dogs, but only few had fed on man (1.1% and none on rats. On the other hand, 24.7% of the females had fed on more than one host, mainly on cows and horses. It was assumed that An. aquasalis is zoophilic

  1. 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

  2. Radiation-induced sterility for pupal and adult stages of the malaria mosquito Anopheles arabiensis

    OpenAIRE

    Knols Bart GJ; Parker Andrew G; Helinski Michelle EH

    2006-01-01

    Abstract 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

  3. Biologia de Anopheles (Kerteszia neivai H., D. & K., 1913 (Diptera: Culicidae en la Costa Pacífica de Colombia: III. Medidas de luminosidad y el comportamiento de picadura Biologia do Anopheles (Kerteszia neivai H., D. & K., 1913 (Diptera: Culicidae na costa do Pacífico Colombiano: III - Medições da luminosidade e estudo do comportamento durante o repasto Biology of Anopheles (Kerteszia neivai H., D. & K., 1913 (Diptera: Culicidae on the Pacific Coast of Colombia: III. Light intensity measurements and biting behavior

    Directory of Open Access Journals (Sweden)

    César Murillo B.

    1988-04-01

    Full Text Available El estudio del comportamiento de picadura de mosquitos capturados picando humanos en un área despejada del poblado de Charambirá, Chocó, en la costa Pacífica de Colombia, indico que cambios en la intensidad de la luz, influenciaban el início y el fin de la actividad de vuelo de Anopheles (Kerteszia neivai, especie con marcados hábitos crepusculares. Esta especie está considerada como vectora de esa enfermedad, malaria, en la costa pacífica colombiana.O estudo do comportamento de mosquitos capturados picando humanos numa zona desmatada do povoado de Charambirá, Chocó, na costa do Pacífico Colombiano, indicaram que mudanças na intensidade da luz influenciam o início e o fim da atividade de vôo do Anopheles (Kerteszia neivai, verificando-se que o repasto ocorre durante as horas crepusculares. Esta espécie é considerada como vetora da malária na costa do país.The study of mosquitoes captured while biting man in a forest cleared zone of Charambirá, Chocó, on the Pacific Coast of Colombia, indicated that changes in light intensity stimulated the beginning and end of the flight activity of Anopheles (Kerteszia neivai, a species with crepuscular biting behavior incriminated as malaria vector in this region of the county.

  4. Hemocyte differentiation mediates innate immune memory in Anopheles gambiae mosquitoes.

    Science.gov (United States)

    Rodrigues, Janneth; Brayner, Fábio André; Alves, Luiz Carlos; Dixit, Rajnikant; Barillas-Mury, Carolina

    2010-09-10

    Mosquito midgut invasion by ookinetes of the malaria parasite Plasmodium disrupts the barriers that normally prevent the gut microbiota from coming in direct contact with epithelial cells. This triggers a long-lived response characterized by increased abundance of granulocytes, a subpopulation of hemocytes that circulates in the insect's hemocoel, and enhanced immunity to bacteria that indirectly reduces survival of Plasmodium parasites upon reinfection. In mosquitoes, differentiation of hemocytes was necessary and sufficient to confer innate immune memory. PMID:20829487

  5. Hemocyte Differentiation Mediates Innate Immune Memory in Anopheles gambiae Mosquitoes

    OpenAIRE

    Rodrigues, Janneth; Brayner, Fábio André; Alves, Luiz Carlos; Dixit, Rajnikant; Barillas-Mury, Carolina

    2010-01-01

    Mosquito midgut invasion by ookinetes of the malaria parasite Plasmodium disrupts the barriers that normally prevent the gut microbiota from coming in direct contact with epithelial cells. This triggers a long-lived response characterized by increased abundance of granulocytes, a subpopulation of hemocytes, circulating in the insect’s hemocoel, and enhanced immunity to bacteria that indirectly reduces survival of Plasmodium parasites upon reinfection. In mosquitoes, differentiation of hemocyt...

  6. Hemocyte Differentiation Mediates Innate Immune Memory in Anopheles gambiae Mosquitoes

    Science.gov (United States)

    Rodrigues, Janneth; Brayner, Fábio André; Alves, Luiz Carlos; Dixit, Rajnikant; Barillas-Mury, Carolina

    2012-01-01

    Mosquito midgut invasion by ookinetes of the malaria parasite Plasmodium disrupts the barriers that normally prevent the gut microbiota from coming in direct contact with epithelial cells. This triggers a long-lived response characterized by increased abundance of granulocytes, a subpopulation of hemocytes, circulating in the insect’s hemocoel, and enhanced immunity to bacteria that indirectly reduces survival of Plasmodium parasites upon reinfection. In mosquitoes, differentiation of hemocytes was necessary and sufficient to confer innate immune memory. PMID:20829487

  7. Biologia de Anopheles (Kerteszia) neivai H., D. & K., 1913 (Diptera: Culicidae) en la Costa Pacífica de Colombia: III. Medidas de luminosidad y el comportamiento de picadura Biologia do Anopheles (Kerteszia) neivai H., D. & K., 1913 (Diptera: Culicidae) na costa do Pacífico Colombiano: III - Medições da luminosidade e estudo do comportamento durante o repasto Biology of Anopheles (Kerteszia) neivai H., D. & K., 1913 (Diptera: Culicidae) on the Pacific Coast of Colombia: III. Light intensity measurements and biting behavior

    OpenAIRE

    César Murillo B.; Rodrigo Astaiza V.; Paulina Fajardo O.

    1988-01-01

    El estudio del comportamiento de picadura de mosquitos capturados picando humanos en un área despejada del poblado de Charambirá, Chocó, en la costa Pacífica de Colombia, indico que cambios en la intensidad de la luz, influenciaban el início y el fin de la actividad de vuelo de Anopheles (Kerteszia) neivai, especie con marcados hábitos crepusculares. Esta especie está considerada como vectora de esa enfermedad, malaria, en la costa pacífica colombiana.O estudo do comportamento de mosquitos ca...

  8. Complex genome evolution in Anopheles coluzzii associated with increased insecticide usage in Mali.

    Science.gov (United States)

    Main, Bradley J; Lee, Yoosook; Collier, Travis C; Norris, Laura C; Brisco, Katherine; Fofana, Abdrahamane; Cornel, Anthony J; Lanzaro, Gregory C

    2015-10-01

    In certain cases, a species may have access to important genetic variation present in a related species via adaptive introgression. These novel alleles may interact with their new genetic background, resulting in unexpected phenotypes. In this study, we describe a selective sweep on standing variation on the X chromosome in the mosquito Anopheles coluzzii, a principal malaria vector in West Africa. This event may have been influenced by the recent adaptive introgression of the insecticide resistance gene known as kdr from the sister species Anopheles gambiae. Individuals carrying both kdr and a nearly fixed X-linked haplotype, encompassing at least four genes including the P450 gene CYP9K1 and the cuticular protein CPR125, have rapidly increased in relative frequency. In parallel, a reproductively isolated insecticide-susceptible A. gambiae population (Bamako form) has been driven to local extinction, likely due to strong selection from increased insecticide-treated bed net usage. PMID:26359110

  9. 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

  10. 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...

  11. Biología de Anopheles (Kerteszia neivai H., D. & K., 1913 (Diptera: Culicidae en la Costa Pacifica de Colombia: IV - Estructura etárea y transmisión de malaria Biologia do Anopheles (Kerteszia neivai H., D. & K., 1913 (Diptera: Culicidae na Costa do Pacífico Colombiano: IV - Estrutura etária e transmissão da malária Biology of Anopheles (Kerteszia neivai H., D. & K., 1913 (Diptera: Culicidae on the Pacific Coast of Colombia: IV - Age structure and malaria transmission

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    César Murillo B.

    1989-10-01

    Full Text Available Con el fin de determinar la dinamica de transmisión de malaria en el poblado de Charambirá (Chocó, Colombia, se estudió la estructura etárea de Anopheles neivai (reconocido vector en la Costa Pacífica con base en su estado gonadotrófico. Se recolectaron mosquitos intradomiciliarmente durante el crepúsculo vespertino con cebos humanos y aspiradores bucales. Los mosquitos recolectados se mantuvieron en cajas cilíndricas de cartón con papel humedecido y dispensadores alimenticios hasta su disección al día siguiente. De los 200 mosquitos disecados entre septiembre y octubre de 1986,68 (34% presentaban huellas de menos de tres oviposturas y los restantes (66% habían efectuado al menos tres oviposturas. La diferencia entre el primer grupo considerado como mosquitos "no infectivos" y el segundo considerado como los "potencialmente infectivos" fue altamente significativa (X² = 10,68; P = 0,001. El 1,5% de A. neivai estudiados presentaban huellas correspondientes a 10 oviposturas mostrando una marcada longevidad y múltiples alimentaciones sanguíneas. Los resultados sugieren que existe un alto riesgo de contraer malaria en Charambirá durante el crepúsculo vespertino.Com o intuito de determinar a dinâmica de transmissão da malária no povoado de Charambirá (Chocó, Colômbia, foi estudada a estrutura etária do mosquito Anopheles neivai (reconhecido vetor da Costa Pacífica com base em seu estado gonadotrófico. As coletas foram realizadas intradomiciliarmente no crepúsculo vespertino com isca humana e auxílio de tubos de sucção manual. Os mosquitos coletados foram mantidos em caixas cilíndricas de papelão, contendo papel umidecido e alimento. Dos 200 mosquitos dissecados entre setembro e outubro de 1986, 68 (34% apresentaram vestígios de menos de três oviposturas (oviposições e os demais (66% apresentavam, pelo menos, três ovipoturas. A diferença entre o primeiro grupo considerado como mosquitos "não infectantes" e o

  12. 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...

  13. 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

    Directory of Open Access Journals (Sweden)

    César Murillo B.

    1988-04-01

    Full Text Available En Charambirá, localidad del município de Istmina (Chocó en la costa Pacífica de Colombia, donde existe un problema de malaria endémica, se estudió la fluctuación de la población larval y las características de los criaderos de Anopheles (Kerteszia neivai, especie considerada como posible vectora de malaria en esa región del país. La vegetación circundante fue dividida en tres estratos de acuerdo al grado de cobertura foliar. Se demarcaron cuadrantes de 100 m² en cada estrato para el muestreo de plantas epífitas de la família Bromeliaceae, en las cuales se acumula agua que sirve como criadero para esta especie de anofelino. Se tomaron datos de temperatura, pH y volumen del agua contenida en cada bromelia. El mayor número de larvas se detectó en el estrato 1 (manglar a una altitud inferior a 4 m, pero no se encontró evidencia significativa de estratificación vertical de la población larval de A. neivai hasta los 8 m. Se evidenció una correlación lineal positiva entre el número de larvas y el volumen de agua contenida en cada bromelia; por otra parte se observó también una correlación directa entre la precipitación mensual acumulada y la fluctuación poblacional de esta especie. Los índices larvales mas altos se observaron entre los meses de marzo a abril y de julio a agosto. La mortalidad larval fue alta en el primer estadío (43,5% y solo un 23,7% sobrevivió hasta el cuarto.Em Charambirá, localidade do Município de Istmina (Chocó, na costa do Pacífico Colombiano, localidade endêmica de malária, estudou-se a flutuação da população larval e as características dos locais de criação do Anopheles (Kerteszia neivai, espécie considerada como possível vector da malária naquela região do país. A vegetação circundante foi dividida em três estratos segundo seu grau de cobertura foliar. Demarcaram-se quadrantes de 100 m² para a amostragem de plantas epífitas da família Bromeliaceae, nas quais se

  14. 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

    Full Text Available En la localidad de Charambirá, situada en el município de Istmina (Chocó en la costa Pacífica de Colombia, se presenta un problema de malaria endémica asociada con grandes poblaciones de mosquitos Anopheles del subgénero Kerteszia (A. neivai. Estos se crían en las colecciones de agua formadas por plantas epífitas de la família Bromeliaceae, que son muy abundantes en los árboles de mangle. En esa localidad se estudiaron: fluctuación poblacional y algunos aspectos ecológicos y etológicos de los adultos de esa especie de mosquito, con el objetivo de determinar su papel en la transmisión de malaria. Todos los mosquitos fueron colectados por cebos humanos. Los picos máximos de actividad ocurrieron en las horas crepusculares de la mañana y de la tarde (5:30 a 6:30 y 18:00 a 19:00 horas. En el período nocturno la actividad intradomiciliar fue baja y no hubo ninguna durante el día. El estado gonadotrófico de las hembras colectadas durante nos picos de actividad, mostró la existencia de dos poblaciones de mosquitos: una, en su mayoría individuos jóvenes que buscan su alimento en las horas de la tarde y la otra compuesta por individuos mas longevos, que buscan su alimento en la mañana. El estudio de la variación estacional mostró que las poblaciones son bajas en los meses de poca precipitación, pero a medida que aumenta el índice pluviométrico, aumenta el número de mosquitos. Se discute la relación que existe entre la presencia de los mosquitos y la prevalencia de malaria humana; se sugiere que A. neivai puede ser el responsable de la transmisión de malaria en la zona estudiada.Na localidade de Charambirá, situada no Municipio de Istmina (Chocó, na costa do Pacífico Colombiano, ocorre um tipo de malária endêmica associada com grandes populações de Anopheles do subgênero Kerteszia (A. neivai. Estes criam-se em coleções de água formadas por plantas epífitas pertencentes à família Bromeliaceae, as quais são muito

  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. 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

  17. 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

  18. "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"

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    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.

  19. 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.

  20. Vectorial status and insecticide resistance of Anopheles funestus from a sugar estate in southern Mozambique

    Directory of Open Access Journals (Sweden)

    Nhamahanga Eduardo

    2011-02-01

    Full Text Available Abstract Background The dual problems of rising insecticide resistance in the malaria vectors and increasing human malaria cases since 2001 in southern Mozambique are cause for serious concern. The selection of insecticides for use in indoor residual spraying (IRS programmes is highly dependent on the extent to which local mosquitoes are susceptible to the approved classes of insecticides. The insecticide resistance status and role in malaria transmission of Anopheles funestus was evaluated at the Maragra Sugar Estate in southern Mozambique where an IRS vector control programme has been in operation for seven years using the carbamate insecticide bendiocarb. Results No Anopheles species were captured inside the sugar estate control area. Anopheles funestus group captured outside of the estate represented 90% (n = 475 of the total collections. Of the specimens identified to species by PCR (n = 167, 95% were An. funestus s.s. One An. rivulorum was identified and seven specimens did not amplify. The Anopheles gambiae complex was less abundant (n = 53 and of those identified (n = 33 76% were An. arabiensis and 24% An. merus. Insecticide susceptibility tests showed that wild-caught and F-1 family An. funestus were resistant to deltamethrin (32.5% mortality and lambda-cyhalothrin (14.6% mortality, less so to bendiocarb (71.5% mortality and fully susceptible to both malathion and DDT (100%. Bendiocarb and pyrethroid resistance was nullified using 4% piperonyl butoxide (Pbo, strongly suggesting that both are mediated by P450 monooxygenase detoxification. ELISA tests of An. funestus for Plasmodium falciparum, gave a sporozoite rate of 6.02% (n = 166. One unidentified member of the An. gambiae complex tested positive for P. falciparum sporozoites. Conclusion Anopheles funestus was found to be the most abundant and principle vector of malaria in this area, with members of the An. gambiae complex being secondary vectors. Despite the continual use of

  1. α-Humulene and β-elemene from Syzygium zeylanicum (Myrtaceae) essential oil: highly effective and eco-friendly larvicides against Anopheles subpictus, Aedes albopictus, and Culex tritaeniorhynchus (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, Marimuthu; Benelli, Giovanni

    2016-07-01

    Mosquitoes transmit serious pathogens and parasites to humans and animals, including malaria, dengue, Japanese encephalitis and filariasis. The extensive use of chemical pesticides leads to the development of resistance in mosquito vector populations and serious non-target effects on human health and the environment. Myrtaceae plants can be a useful reservoir of natural products effective against Culicidae young instars. In this research, we evaluated the mosquitocidal potential of the essential oil (EO) from Syzygium zeylanicum leaves against larvae of three mosquitoes of medical and veterinary importance, the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus, and the Japanese encephalitis vector Culex tritaeniorhynchus. The chemical composition of the EO was analyzed by gas chromatography-mass spectroscopy. GC-MS revealed that the S. zeylanicum EO contained at least 18 compounds. The major chemical components were α-humulene (37.8.5 %) and β-elemene (10.7 %). The EO had a significant toxic effect against early third-stage larvae of An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus, with LC50 values of 83.11, 90.45, and 97.96 μg/ml, respectively. The two major constituents extracted from the S. zeylanicum EO were tested individually for acute toxicity against larvae of the three mosquito vectors. α-Humulene and β-elemene appeared highly effective against An. subpictus (LC50 = 6.19 and 10.26 μg/ml, respectively), followed by Ae. albopictus (LC50 = 6.86 and 11.15 μg/ml) and Cx. tritaeniorhynchus (LC50 = 7.39 and 12.05 μg/ml). Furthermore, the EO and its major components was safe towards the non-target fish Gambusia affinis; LC50 values were 20374.26, 1024.95, and 2073.18 μg/ml, respectively for EO, α-humulene and β-elemene. Overall, this study highlighted that the acute toxicity of S. zeylanicum EO towards mosquito larvae was mainly due to the presence of α-humulene and β-elemene. Furthermore, we pointed

  2. 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...

  3. 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

  4. GENETIC ISOLATION WITHIN THE MALARIA MOSQUITO ANOPHELES MELAS

    Science.gov (United States)

    Deitz, Kevin C; Athrey, Giri; Reddy, Michael R; Overgaard, Hans J; Matias, Abrahan; Jawara, Musa; della Torre, Alessandra; Petrarca, Vincenzo; Pinto, Joao; Kiszewski, Anthony; Kengne, Pierre; Costantini, Carlo; Caccone, Adalgisa; Slotman, Michel A

    2014-01-01

    Anopheles melas is a brackish water-breeding member of the An. gambiae complex that is distributed along the coast of West Africa and is a major malaria vector within its range. Because little is known about the population structure of this species, we analyzed 15 microsatellite markers and 1,161 bp of mtDNA in 11 An. melas populations collected throughout its range. Compared to its sibling species An. gambiae, An. melas populations have a high level of genetic differentiation between them, representing its patchy distribution due to its fragmented larval habitat which is associated with mangroves and salt marsh grass. Populations clustered into three distinct groups representing Western Africa, Southern Africa, and Bioko Island populations that appear to be mostly isolated. Fixed differences in the mtDNA are present between all three clusters, and a Bayesian clustering analysis of the microsatellite data found no evidence for migration from mainland to Bioko Island populations, and little migration was evident between the Southern to the Western cluster. Surprisingly, mtDNA divergence between the three An. melas clusters is on par with levels of divergence between other species of the An. gambiae complex, and no support for monophyly was observed in a maximum likelihood phylogenetic analysis. Finally, an Approximate Bayesian Analysis of microsatellite data indicates that Bioko Island An. melas populations were connected to the mainland populations in the past, but became isolated, presumably when sea levels rose after the last glaciation period (≥10,000-11,000 years ago). This study has exposed species level genetic divergence within An. melas, and also has implications for control of this malaria vector. PMID:22882458

  5. Sampling of An.gambiae s.s mosquitoes using Limburger cheese, heat and moisture as baits in a homemade trap

    Science.gov (United States)

    2011-01-01

    Background Ample evidence has shown that odour baited traps are likely to provide an objective monitoring tool for the host-seeking fraction of mosquito vectors of diseases like malaria and bancroftian filariasis. Such traps could eventually become part of primary healthcare systems used to study the vector biology and epidemiology of mosquito-borne diseases. I hereby, report a study that sampled Anopheles gambiae sensu stricto mosquitoes in a screen house using a homemade trap baited with a combination of Limburger cheese and moisture, Limburger cheese and heat, or Limburger cheese, moisture and heat. Findings Tests on the efficacy of the developed trap to sample An. gambiae s.s, mosquitoes using Limburger cheese, moisture and heat as baits were carried out in a screen house measuring 11.4 × 7.1 × 2.8 m. The studies were done in three phases. In the first phase the efficacy of the trap to sample An. gambiae s.s. using odour and moisture was tested. The second phase was to test the efficacy of the trap to sample An. gambiae s.s. using Limburger cheese and heat. In the third phase a combination of Limburger cheese, moisture and heat was tested. Tests were carried out for 27 consecutive nights. The designed trap collected a total of 59 An. gambiae s.s. in three trials. The trap baited with Limburger cheese and moisture collected 7 An. gambiae s.s in 7 days. The mean catch per day was 1. The trap baited with Limburger cheese and heat collected zero An. gambiae s.s in 11 days. The mean catch per day was therefore 0. The trap baited with Limburger cheese, moisture and heat collected 52 mosquitoes in 27 days and the mean catch was 1.93. Conclusions This study indicates that a non-electric fan driven trap baited with a combination of Limburger cheese, heat and moisture has a potential as an effective sampling tool for the malaria vector, Anopheles gambiae s.s. However, further optimization studies would be necessary. PMID:21835032

  6. PEANUT SHELL FUEL FOR THE GAMBIA

    Science.gov (United States)

    The project will develop a household-scale human-powered briquette maker that will convert peanut shells into an efficient cooking fuel. The briquette maker will be designed such that it can be manufactured and used in The Gambia.

  7. Checklist and pictorial key to fourth-instar larvae of mosquitoes (Diptera: Culicidae) of Saudi Arabia.

    Science.gov (United States)

    Al Ahmad, Azzam M; Sallam, Mohamed F; Khuriji, Mohamed A; Kheir, Salah M; Azari-Hamidian, Shahyad

    2011-07-01

    The Kingdom of Saudi Arabia includes fauna from three zoogeographic regions: the Afrotropical, Oriental, and Palaearctic regions. To study the mosquito (Diptera: Culicidae) fauna of these regions in Saudi Arabia, larval collections were made at 15 sites during 2005-2006. Thirty-three species representing nine genera were found. Six species, Anopheles culicifacies Giles s.l., Anopheles subpictus Grassi s.l., Culex arbieeni Salem, Culex simpsoni Theobald, Culex univittatus Theobald, and Ochlerotatus detritus Haliday are reported for the first time for Saudi Arabia. An annotated checklist and an illustrated key to the fourth-instar larvae of the 33 species are presented, along with some remarks about problematic species. Eleven species of genus Anopheles Meigen, five species of tribe Aedini, 13 species of genus Culex L., two species of genus Culiseta Felt, one species of genus Lutzia Theobald, and one species of genus Uranotaenia Lynch Arribátlzaga were recorded during the study. PMID:21845930

  8. Plasmodium falciparum infection rates for some Anopheles spp. from Guinea-Bissau, West Africa.

    Science.gov (United States)

    Sanford, Michelle R; Cornel, Anthony J; Nieman, Catelyn C; Dinis, Joao; Marsden, Clare D; Weakley, Allison M; Han, Sarah; Rodrigues, Amabelia; Lanzaro, Gregory C; Lee, Yoosook

    2014-01-01

    Presence of Plasmodium falciparum circumsporozoite protein (CSP) was detected by enzyme linked immunosorbent assay (ELISA) in a sample of Anopheles gambiae s.s., A. melas and A. pharoensis collected in Guinea-Bissau during October and November 2009. The percentage of P. falciparum infected samples (10.2% overall; confidence interval (CI): 7.45-13.6%) was comparable to earlier studies from other sites in Guinea-Bissau (9.6-12.4%). The majority of the specimens collected were identified as A. gambiae which had an individual infection rate of 12.6 % (CI: 8.88-17.6) across collection sites. A small number of specimens of A. coluzzii, A. coluzzii x A. gambiae hybrids, A. melas and A. pharoensis were collected and had infection rates of 4.3% (CI:0.98-12.4), 4.1% (CI:0.35-14.5), 11.1% (CI:1.86-34.1) and 33.3% (CI:9.25-70.4) respectively. Despite being present in low numbers in indoor collections, the exophilic feeding behaviors of A. melas (N=18) and A. pharoensis (N=6) and high infection rates observed in this survey suggest falciparum-malaria transmission potential outside of the protection of bed nets. PMID:25383188

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

    Directory of Open Access Journals (Sweden)

    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.

  10. Ultrastructure of a microsporidium Brachiola gambiae n.sp. parasitising a mosquito Anopheles gambiae, a malaria vector

    Czech Academy of Sciences Publication Activity Database

    Weiser, Jaroslav; Žižka, Zdeněk

    2003-01-01

    Roč. 1, - (2003), s. 1-39. ISSN 1214-021X. [Cells /5./. 08.09.2003-10.09.2003, České Budějovice] Institutional research plan: CEZ:AV0Z5020903; CEZ:AV0Z5007907 Keywords : Nosema stegomyiae Subject RIV: EE - Microbiology, Virology

  11. The susceptibility of five African Anopheles species to Anabaena PCC 7120 expressing Bacillus thuringiensis subsp. israelensis mosquitocidal cry genes

    Directory of Open Access Journals (Sweden)

    Ketseoglou Irene

    2012-10-01

    Full Text Available Abstract Background Malaria, one of the leading causes of death in Africa, is transmitted by the bite of an infected female Anopheles mosquito. Problems associated with the development of resistance to chemical insecticides and concerns about the non-target effects and persistence of chemical insecticides have prompted the development of environmentally friendly mosquito control agents. The aim of this study was to evaluate the larvicidal activity of a genetically engineered cyanobacterium, Anabaena PCC 7120#11, against five African Anopheles species in laboratory bioassays. Findings There were significant differences in the susceptibility of the anopheline species to PCC 7120#11. The ranking of the larvicidal activity of PCC 7120#11 against species in the An. gambiae complex was: An. merus An. arabiensis An. gambiae An. quadriannulatus, where 50. The LC50 of PCC 7120#11 against the important malaria vectors An. gambiae and An. arabiensis was 12.3 × 105 cells/ml and 8.10 × 105 cells/ml, respectively. PCC 7120#11 was not effective against An. funestus, with less than 50% mortality obtained at concentrations as high as 3.20 × 107 cells/ml. Conclusions PCC 7120#11 exhibited good larvicidal activity against larvae of the An. gambiae complex, but relatively weak larvicidal activity against An. funestus. The study has highlighted the importance of evaluating a novel mosquitocidal agent against a range of malaria vectors so as to obtain a clear understanding of the agent’s spectrum of activity and potential as a vector control agent.

  12. Risk factors for house-entry by malaria vectors in a rural town and satellite villages in The Gambia

    Directory of Open Access Journals (Sweden)

    Jasseh Momadou

    2008-01-01

    Full Text Available Abstract Background In the pre-intervention year of a randomized controlled trial investigating the protective effects of house screening against malaria-transmitting vectors, a multi-factorial risk factor analysis study was used to identify factors that influence mosquito house entry. Methods Mosquitoes were sampled using CDC light traps in 976 houses, each on one night, in Farafenni town and surrounding villages during the malaria-transmission season in The Gambia. Catches from individual houses were both (a left unadjusted and (b adjusted relative to the number of mosquitoes caught in four sentinel houses that were operated nightly throughout the period, to allow for night-to-night variation. Houses were characterized by location, architecture, human occupancy and their mosquito control activities, and the number and type of domestic animals within the compound. Results 106,536 mosquitoes were caught, of which 55% were Anopheles gambiae sensu lato, the major malaria vectors in the region. There were seven fold higher numbers of An. gambiae s.l. in the villages (geometric mean per trap night = 43.7, 95% confidence intervals, CIs = 39.5–48.4 than in Farafenni town (6.3, 5.7–7.2 and significant variation between residential blocks (p Conclusion This study demonstrates that the risk of malaria transmission is greatest in rural areas, where large numbers of people sleep in houses made of mud blocks, where the eaves are open, horses are not tethered nearby and where churai is not burnt at night. These factors need to be considered in the design and analysis of intervention studies designed to reduce malaria transmission in The Gambia and other parts of sub-Saharan Africa.

  13. Molasses as a source of carbon dioxide for attracting the malaria mosquitoes Anopheles gambiae and Anopheles funestus

    OpenAIRE

    Mweresa, C. K.; Omusula, P.; Otieno, B.; Loon, van, R.R.; Takken, W.; Mukabana, W.R.

    2014-01-01

    Background. Most odour baits for haematophagous arthropods contain carbon dioxide (CO2). The CO2 is sourced artificially from the fermentation of refined sugar (sucrose), dry ice, pressurized gas cylinders or propane. These sources of CO2 are neither cost-effective nor sustainable for use in remote areas of sub-Saharan Africa. In this study, molasses was evaluated as a potential substrate for producing CO2 used as bait for malaria mosquitoes. Methods. The attraction of laboratory-reared and w...

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

    Directory of Open Access Journals (Sweden)

    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

  15. The effect of water physical quality and water level changes on the occurrence and density of larvae of Anopheles mosquitoes around the shoreline of the Koka reservoir, Central Ethiopia

    Directory of Open Access Journals (Sweden)

    S. Kibret

    2010-08-01

    Full Text Available Entomological studies to determine the effect of the physical characteristics of larval breeding water bodies and reservoir water level changes on the occurrence of Anopheles mosquito larvae and on the spatial and temporal formation of larval breeding habitats were conducted in two villages at Koka reservoir between August and December 2007. Of the two study villages, Ejersa is in close proximity to the reservoir, and Kuma is 5 km away from it. Data on the type, number and physical characteristics of Anopheles larval breeding habitat, species composition and densities of anopheles mosquitoes in and around the study villages were investigated and recorded. Meteorological and reservoir water level data were compared with availability of Anopheles larval breeding sites and densities. Entomological data from the weekly larval collections showed that Anopheles pharoensis Theobald, Anopheles gambiae s.l. Giles, Anopheles coustani Laveran and Anopheles squamosus Theobald were breeding in the study area. The mean larval density of A. gambiae s.l. in this study was higher in slightly turbid and shallow aquatic habitats than in turbid and relatively deep aquatic habitats (F=16.97, pF=6.03, pA. pharoensis in habitat with floating vegetation and with relatively shady conditions was significantly higher than that of less shaded aquatic habitat and greater emergent vegetation (F=15.75, pF=10.56, pAnopheles larvae with water temperature of the breeding habitat and daily minimum atmospheric temperature (r=0.541, pr=0.604, pr=0.605, pAnopheles larval count, and the density of Anopheles mosquitoes in the vicinity. The proliferation of suitable breeding habitats around the reservoir villages is strongly associated with reservoir water level changes. This is particularly important for A. pharoensis and A. arabiensis which are important vectors of malaria in the area. Further investigation on the species diversity, physical and chemical habitat characteristics and

  16. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Elimination of lymphatic filariasis in the Gambia.

    Directory of Open Access Journals (Sweden)

    Maria P Rebollo

    2015-03-01

    Full Text Available The prevalence of Wuchereria bancrofti, which causes lymphatic filariasis (LF in The Gambia was among the highest in Africa in the 1950s. However, surveys conducted in 1975 and 1976 revealed a dramatic decline in LF endemicity in the absence of mass drug administration (MDA. The decline in prevalence was partly attributed to a significant reduction in mosquito density through the widespread use of insecticidal nets. Based on findings elsewhere that vector control alone can interrupt LF, we asked the question in 2013 whether the rapid scale up in the use of insecticidal nets in The Gambia had interrupted LF transmission.We present here the results of three independently designed filariasis surveys conducted over a period of 17 years (1997-2013, and involving over 6000 subjects in 21 districts across all administrative divisions in The Gambia. An immunochromatographic (ICT test was used to detect W. bancrofti antigen during all three surveys. In 2001, tests performed on stored samples collected between 1997 and 2000, in three divisions, failed to show positive individuals from two divisions that were previously highly endemic for LF, suggesting a decline towards extinction in some areas. Results of the second survey conducted in 2003 showed that LF was no longer endemic in 16 of 21 districts surveyed. The 2013 survey used a WHO recommended LF transmission verification tool involving 3180 6-7 year-olds attending 60 schools across the country. We demonstrated that transmission of W. bancrofti has been interrupted in all 21 districts.We conclude that LF transmission may have been interrupted in The Gambia through the extensive use of insecticidal nets for malaria control for decades. The growing evidence for the impact of malaria vector control activities on parasite transmission has been endorsed by WHO through a position statement in 2011 on integrated vector management to control malaria and LF.

  19. Elimination of lymphatic filariasis in the Gambia.

    OpenAIRE

    Rebollo, Maria P.; Sana Malang Sambou; Brent Thomas; Nana-Kwadwo Biritwum; Momodou C Jaye; Louise Kelly-Hope; Alba Gonzalez Escalada; Molyneux, David H; Bockarie, Moses J.

    2015-01-01

    Background The prevalence of Wuchereria bancrofti, which causes lymphatic filariasis (LF) in The Gambia was among the highest in Africa in the 1950s. However, surveys conducted in 1975 and 1976 revealed a dramatic decline in LF endemicity in the absence of mass drug administration (MDA). The decline in prevalence was partly attributed to a significant reduction in mosquito density through the widespread use of insecticidal nets. Based on findings elsewhere that vector control alone can interr...

  20. The Gambia : Country Procurement Issues Paper

    OpenAIRE

    World Bank

    2005-01-01

    This Country Procurement Issues Paper (CPIP), is an interim assessment of the public procurement system of The Gambia based on the self-evaluation conducted by the Government in early 2005. The CPIP follows-up the Country Procurement Assessment Review (CPAR) undertaken in 1998, which led to the preparation and implementation of the public procurement reform program. Since the 1998's review, progress has been made especially in the legal, regulatory, and institutional framework. In 2001, Parli...

  1. Agriculture and growth nexus in Gambia

    OpenAIRE

    Bukhari Sillah

    2013-01-01

    Agriculture is a major engine for the economic well-being of the Gambia. The successive governments from the colonial periods to the present have all recognized this importance of the agricultural sector but failed to do something that bear any fruit since government encouraged slash and burn technology and putting increasingly more people onto the land instead of increasing the yields per acre. More people than before do remain still on the land, but they are now poorer than their forefather...

  2. Agriculture and growth nexus in Gambia

    OpenAIRE

    Bukhari Sillah; Odior Simeon Ernest

    2014-01-01

    Agriculture is a major engine for the economic well-being of the Gambia. The successive governments from the colonial periods to the present have all recognized this importance of the agricultural sector but failed to do something that bear any fruit since government encouraged slash and burn technology and putting increasingly more people onto the land instead of increasing the yields per acre. More people than before do remain still on the land, but they are now poorer than their forefather...

  3. Molecular functional characterization of appetence maturation and its nutrient-dependent control in the African malaria mosquito “Anopheles gambiae”

    OpenAIRE

    Arsic, Dany; Guerin, Patrick

    2008-01-01

    Le moustique Anopheles gambiae (anophèle) est le principal vecteur du paludisme (malaria) en Afrique sub-saharienne. Les repas sanguins fréquents pris par les femelles adultes sur des êtres humains multiplient les occasions de transmission des parasites sanguins du genre Plasmodium responsables du paludisme. Une meilleure compréhension de la régulation des comportements de recherche d’hôte entrepris par les moustiques femelles, ainsi que de leurs comportements alimentaires et de leur reproduc...

  4. 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...

  5. The accumulation of specific mRNAs following multiple blood meals in Anopheles gambiae

    OpenAIRE

    Xavier, Nirmala; Marinotti, Osvaldo; James, Anthony A

    2005-01-01

    One approach to genetic control of transmission of the parasites that cause human malaria is based on expressing effector genes in mosquitoes that disable the pathogens. Endogenous mosquito promoter and other cis-acting DNA sequences are needed to direct the optimal tissue-, stage- and sex-specific expression of the effector molecules. The mRNA accumulation profiles of eight different genes expressed specifically in the midgut, salivary glands or fat body tissues of the malaria vector, Anophe...

  6. Genetic structure of Anopheles gambiae populations on islands in northwestern Lake Victoria, Uganda

    Directory of Open Access Journals (Sweden)

    Coulibaly Mamadou B

    2005-12-01

    Full Text Available Abstract Background Alternative means of malaria control are urgently needed. Evaluating the effectiveness of measures that involve genetic manipulation of vector populations will be facilitated by identifying small, genetically isolated vector populations. The study was designed to use variation in microsatellite markers to look at genetic structure across four Lake Victoria islands and two surrounding mainland populations and for evidence of any restriction to free gene flow. Methods Four Islands (from 20–50 km apart and two surrounding mainland populations (96 km apart were studied. Samples of indoor resting adult mosquitoes, collected over two consecutive years, were genotyped at microsatellite loci distributed broadly throughout the genome and analysed for genetic structure, effective migration (Nem and effective population size (Ne. Results Ne estimates showed island populations to consist of smaller demes compared to the mainland ones. Most populations were significantly differentiated geographically, and from one year to the other. Average geographic pair-wise FST ranged from 0.014–0.105 and several pairs of populations had Ne m Conclusion These island populations are significantly genetically differentiated. Differences reoccurred over the study period, between the two mainland populations and between each other. This appears to be the product of their separation by water, dynamics of small populations and local adaptation. With further characterisation these islands could become possible sites for applying measures evaluating effectiveness of control by genetic manipulation.

  7. Plasmodium falciparum infection increases Anopheles gambiae attraction to nectar sources and sugar uptake

    Science.gov (United States)

    Plasmodium parasites are known to manipulate the behaviour of their vectors so as to enhance their transmission. However, it is unknown if this vector manipulation also affects mosquito-plant interaction and sugar uptake. Dual-choice olfactometer and probing assays were used to study plant seeking b...

  8. Plasmodium sexual development and the role of Plasmepsin X in Plasmodium falciparum transmission to anopheles gambiae

    OpenAIRE

    Bounkeua, Viengngeun

    2010-01-01

    This work explored sexual development of the lethal human malaria parasite, Plasmodium falciparum. A method to cultivate Plasmodium falciparum sexual stage parasites in vitro was optimized and increased ookinete yield > 20-fold over previous reports. This method was adapted for Plasmodium vivax, a neglected human malaria parasite, and found to generate Plasmodium vivax ookinetes. The method was essential for investigation of the role of a novel aspartic protease, Plasmepsin X, in sexual stage...

  9. Natural microbe-mediated refractoriness to Plasmodium infection in Anopheles gambiae

    OpenAIRE

    Cirimotich, Chris M; Dong, Yuemei; Clayton, April M.; Sandiford, Simone L.; Jayme A Souza-Neto; Mulenga, Musapa; Dimopoulos, George

    2011-01-01

    Malaria parasite transmission depends on the successful transition of Plasmodium through discrete developmental stages in the lumen of the mosquito midgut. Like the human intestinal tract, the mosquito midgut contains a diverse microbial flora, which may compromise the ability of Plasmodium to establish infection. We have identified an Enterobacter bacterium isolated from wild mosquito populations in Zambia that renders the mosquito 99% resistant to infection with the human malaria parasite P...

  10. Molecular Evolution of Immune Genes in the Malaria Mosquito Anopheles gambiae

    OpenAIRE

    Lehmann, Tovi; Hume, Jen C. C.; Licht, Monica; Burns, Christopher S.; Wollenberg, Kurt; Simard, Fred; Ribeiro, Jose M. C.

    2009-01-01

    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...

  11. Hemocyte differentiation mediates the mosquito late-phase immune response against Plasmodium in Anopheles gambiae.

    Science.gov (United States)

    Smith, Ryan C; Barillas-Mury, Carolina; Jacobs-Lorena, Marcelo

    2015-06-30

    Plasmodium parasites must complete development in the mosquito vector for transmission to occur. The mosquito innate immune response is remarkably efficient in limiting parasite numbers. Previous work has identified a LPS-induced TNFα transcription factor (LITAF)-like transcription factor, LITAF-like 3 (LL3), which significantly influences parasite numbers. Here, we demonstrate that LL3 does not influence invasion of the mosquito midgut epithelium or ookinete-to-oocyst differentiation but mediates a late-phase immune response that decreases oocyst survival. LL3 expression in the midgut and hemocytes is activated by ookinete midgut invasion and is independent of the mosquito microbiota, suggesting that LL3 may be a component of a wound-healing response. LL3 silencing abrogates the ability of mosquito hemocytes to differentiate and respond to parasite infection, implicating hemocytes as critical modulators of the late-phase immune response. PMID:26080400

  12. Hemocyte differentiation mediates the mosquito late-phase immune response against Plasmodium in Anopheles gambiae

    OpenAIRE

    Smith, Ryan C.; Barillas-Mury, Carolina; Jacobs-Lorena, Marcelo

    2015-01-01

    The innate immune response is a major determinant of malaria parasite success in its mosquito host. Previous experiments have implicated LPS-induced TNFα transcription factor (LITAF)-like 3 (LL3) as an integral component of the mosquito immune response to the malaria parasite. This study reports that LL3 influences oocyst survival and demonstrates its role in mosquito blood cell (hemocyte) differentiation in response to parasite infection. Integrating previous data, we provide evidence that h...

  13. Hemocyte differentiation mediates the mosquito late-phase immune response against Plasmodium in Anopheles gambiae

    Science.gov (United States)

    Smith, Ryan C.; Barillas-Mury, Carolina; Jacobs-Lorena, Marcelo

    2015-01-01

    Plasmodium parasites must complete development in the mosquito vector for transmission to occur. The mosquito innate immune response is remarkably efficient in limiting parasite numbers. Previous work has identified a LPS-induced TNFα transcription factor (LITAF)-like transcription factor, LITAF-like 3 (LL3), which significantly influences parasite numbers. Here, we demonstrate that LL3 does not influence invasion of the mosquito midgut epithelium or ookinete-to-oocyst differentiation but mediates a late-phase immune response that decreases oocyst survival. LL3 expression in the midgut and hemocytes is activated by ookinete midgut invasion and is independent of the mosquito microbiota, suggesting that LL3 may be a component of a wound-healing response. LL3 silencing abrogates the ability of mosquito hemocytes to differentiate and respond to parasite infection, implicating hemocytes as critical modulators of the late-phase immune response. PMID:26080400

  14. The bionomics of the malaria mosquito Anopheles gambiae sensu lato in Southeast Tanzania.

    NARCIS (Netherlands)

    Lyimo, E.O.K.

    1993-01-01

    Size of adult mosquitoes is known to affect both population dynamics as well as disease transmission. Studies devoted to this topic have given different results for different species. For example in some mosquito species, large size was found to be associated with high fecundity and longer survival

  15. The bionomics of the malaria mosquito Anopheles gambiae sensu lato in Southeast Tanzania.

    OpenAIRE

    Lyimo, E.O.K.

    1993-01-01

    Size of adult mosquitoes is known to affect both population dynamics as well as disease transmission. Studies devoted to this topic have given different results for different species. For example in some mosquito species, large size was found to be associated with high fecundity and longer survival (Steinwascher, 1982; Nasci, 1986a; 1986b; 1987) but in others large size did not result in longer survival (Walker et al ., 1987; Landry et al ., 1988; Pumpuni & Walker, 1989). Similar data were fo...

  16. A New Role of the Mosquito Complement-like Cascade in Male Fertility in Anopheles gambiae

    OpenAIRE

    Pompon, Julien; Levashina, Elena A.

    2015-01-01

    Thioester-containing protein 1 (TEP1) is a key immune factor that determines mosquito resistance to a wide range of pathogens, including malaria parasites. Here we report a new allele-specific function of TEP1 in male fertility. We demonstrate that during spermatogenesis TEP1 binds to and removes damaged cells through the same complement-like cascade that kills malaria parasites in the mosquito midgut. Further, higher fertility rates are mediated by an allele that renders the mosquito suscept...

  17. Single Sensillum Recordings in the Insects Drosophila melanogaster and Anopheles gambiae

    OpenAIRE

    Pellegrino, Maurizio; Nakagawa, Takao; Vosshall, Leslie B.

    2010-01-01

    The sense of smell is essential for insects to find foods, mates, predators, and oviposition sites3. Insect olfactory sensory neurons (OSNs) are enclosed in sensory hairs called sensilla, which cover the surface of olfactory organs. The surface of each sensillum is covered with tiny pores, through which odorants pass and dissolve in a fluid called sensillum lymph, which bathes the sensory dendrites of the OSNs housed in a given sensillum. The OSN dendrites express odorant receptor (OR) protei...

  18. Agriculture and growth nexus in Gambia

    Directory of Open Access Journals (Sweden)

    Bukhari Sillah

    2013-12-01

    Full Text Available Agriculture is a major engine for the economic well-being of the Gambia. The successive governments from the colonial periods to the present have all recognized this importance of the agricultural sector but failed to do something that bear any fruit since government encouraged slash and burn technology and putting increasingly more people onto the land instead of increasing the yields per acre. More people than before do remain still on the land, but they are now poorer than their forefathers. Using autoregressive and vector error correction techniques to examine the growth-agriculture relation in the Gambia for the period from 1966 to 2009, it is found that the capital per worker is a significant and relevant factor input for the economic growth. The agricultural labor per acre is found to be irrelevant in both the short run and the long run analyses. The agricultural productivity measured as crop yields per acre is the most important variable for the economic growth in the Gambia. It boosts both the economic growth and the capital formation in the country. The agricultural policies should be focused on increasing the crop yields per acre not having more people back to the land. The processing, services and small manufacturing sectors should be developed and built into the agricultural policies in order to create redeployments for the agricultural labor surpluses.

  19. Life-table analysis of Anopheles malaria vectors: generational mortality as tool in mosquito vector abundance and control studies

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    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.

  20. 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.

  1. 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.

  2. La escolarización en Gambia

    OpenAIRE

    Anna Farjas Bonet

    2002-01-01

    Actualmente en Gambia el número total de alumnos matriculados en escuelas de modelo británico es mucho más alto que en escuelas coránicas formales o madrasas. De todas formas, la popularidad de los centros coránicos formales va creciendo, aunque lentamente, en todo el país. Las escuelas de modelo británico aún son vistas por la población rural como un elemento extranjero. De hecho, la educación occidental ha sido vista como un elemento extranjero desde su introducción. Las escuelas, sobre...

  3. Comparative analyses reveal discrepancies among results of commonly used methods for Anopheles gambiaemolecular form identification

    Directory of Open Access Journals (Sweden)

    Pinto João

    2011-08-01

    Full Text Available Abstract Background Anopheles gambiae M and S molecular forms, the major malaria vectors in the Afro-tropical region, are ongoing a process of ecological diversification and adaptive lineage splitting, which is affecting malaria transmission and vector control strategies in West Africa. These two incipient species are defined on the basis of single nucleotide differences in the IGS and ITS regions of multicopy rDNA located on the X-chromosome. A number of PCR and PCR-RFLP approaches based on form-specific SNPs in the IGS region are used for M and S identification. Moreover, a PCR-method to detect the M-specific insertion of a short interspersed transposable element (SINE200 has recently been introduced as an alternative identification approach. However, a large-scale comparative analysis of four widely used PCR or PCR-RFLP genotyping methods for M and S identification was never carried out to evaluate whether they could be used interchangeably, as commonly assumed. Results The genotyping of more than 400 A. gambiae specimens from nine African countries, and the sequencing of the IGS-amplicon of 115 of them, highlighted discrepancies among results obtained by the different approaches due to different kinds of biases, which may result in an overestimation of MS putative hybrids, as follows: i incorrect match of M and S specific primers used in the allele specific-PCR approach; ii presence of polymorphisms in the recognition sequence of restriction enzymes used in the PCR-RFLP approaches; iii incomplete cleavage during the restriction reactions; iv presence of different copy numbers of M and S-specific IGS-arrays in single individuals in areas of secondary contact between the two forms. Conclusions The results reveal that the PCR and PCR-RFLP approaches most commonly utilized to identify A. gambiae M and S forms are not fully interchangeable as usually assumed, and highlight limits of the actual definition of the two molecular forms, which might

  4. Diptera. Chapter 10

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    Marcela Skuhravá

    2010-07-01

    Full Text Available Of the 19,400 native species and 125 families forming the European diptera fauna, 98 species (less than 0.5% in 22 families are alien to Europe. These aliens constitute 66 species (18 families of the suborder Brachycera and 32 species (4 families of the suborder Nematocera. By family in this category, there are 23 Cecidomyiidae species, 18 Drosophilidae, nine Phoridae, eight Tachinidae and seven Culicidae. Another 32 fly species belonging to five families are considered to be alien in Europe. These invasives native to other European countries are composed of 14 species of Cecidomyiidae, seven Syrphidae, five Culicidae and three species each of Anthomyiidae and Tephritidae. The date of the first record in Europe is known for 84 alien species. Arrivals of alien species of Diptera have accelerated rapidly since the second half of the 20th century. North America appears to be the dominant contributor of the alien flies. The majority of alien Diptera were introduced into or within Europe unintentionally, with only three predators released intentionally for biological control. Alien Diptera are predominantly phytophagous (35.6%, while a lesser portion are zoophagous (28.6% or detrivorous/mycetophagous (29.6%. Ecological impacts on native fauna and flora have not been documented for any of the alien species established in Europe. However, 14 alien species have economic impacts on crops.

  5. Fauna europaea: Diptera - brachycera.

    Science.gov (United States)

    Pape, Thomas; Beuk, Paul; Pont, Adrian Charles; Shatalkin, Anatole I; Ozerov, Andrey L; Woźnica, Andrzej J; Merz, Bernhard; Bystrowski, Cezary; Raper, Chris; Bergström, Christer; Kehlmaier, Christian; Clements, David K; Greathead, David; Kameneva, Elena Petrovna; Nartshuk, Emilia; Petersen, Frederik T; Weber, Gisela; Bächli, Gerhard; Geller-Grimm, Fritz; Van de Weyer, Guy; Tschorsnig, Hans-Peter; de Jong, Herman; van Zuijlen, Jan-Willem; Vaňhara, Jaromír; Roháček, Jindřich; Ziegler, Joachim; Majer, József; Hůrka, Karel; Holston, Kevin; Rognes, Knut; Greve-Jensen, Lita; Munari, Lorenzo; de Meyer, Marc; Pollet, Marc; Speight, Martin C D; Ebejer, Martin John; Martinez, Michel; Carles-Tolrá, Miguel; Földvári, Mihály; Chvála, Milan; Barták, Miroslav; Evenhuis, Neal L; Chandler, Peter J; Cerretti, Pierfilippo; Meier, Rudolf; Rozkosny, Rudolf; Prescher, Sabine; Gaimari, Stephen D; Zatwarnicki, Tadeusz; Zeegers, Theo; Dikow, Torsten; Korneyev, Valery A; Richter, Vera Andreevna; Michelsen, Verner; Tanasijtshuk, Vitali N; Mathis, Wayne N; Hubenov, Zdravko; de Jong, Yde

    2015-01-01

    Fauna Europaea provides a public web-service with an index of scientific names (including important synonyms) of all extant multicellular European terrestrial and freshwater animals and their geographical distribution at the level of countries and major islands (east of the Urals and excluding the Caucasus region). The Fauna Europaea project comprises about 230,000 taxonomic names, including 130,000 accepted species and 14,000 accepted subspecies, which is much more than the originally projected number of 100,000 species. Fauna Europaea represents a huge effort by more than 400 contributing taxonomic specialists throughout Europe and is a unique (standard) reference suitable for many user communities in science, government, industry, nature conservation and education. The Diptera-Brachycera is one of the 58 Fauna Europaea major taxonomic groups, and data have been compiled by a network of 55 specialists. Within the two-winged insects (Diptera), the Brachycera constitute a monophyletic group, which is generally given rank of suborder. The Brachycera may be classified into the probably paraphyletic 'lower brachyceran grade' and the monophyletic Eremoneura. The latter contains the Empidoidea, the Apystomyioidea with a single Nearctic species, and the Cyclorrhapha, which in turn is divided into the paraphyletic 'aschizan grade' and the monophyletic Schizophora. The latter is traditionally divided into the paraphyletic 'acalyptrate grade' and the monophyletic Calyptratae. Our knowledge of the European fauna of Diptera-Brachycera varies tremendously among families, from the reasonably well known hoverflies (Syrphidae) to the extremely poorly known scuttle flies (Phoridae). There has been a steady growth in our knowledge of European Diptera for the last two centuries, with no apparent slow down, but there is a shift towards a larger fraction of the new species being found among the families of the nematoceran grade (lower Diptera), which due to a larger number of small

  6. Plasmodium falciparum infection rates for some Anopheles spp. from Guinea-Bissau, West Africa [v1; ref status: indexed, http://f1000r.es/4in

    Directory of Open Access Journals (Sweden)

    Michelle R. Sanford

    2014-10-01

    Full Text Available Presence of Plasmodium falciparum circumsporozoite protein (CSP was detected by enzyme linked immunosorbent assay (ELISA in a sample of Anopheles gambiae s.s., A. melas and A. pharoensis collected in Guinea-Bissau during October and November 2009. The percentage of P. falciparum infected samples (10.2% overall was comparable to earlier studies from other sites in Guinea-Bissau (9.6-12.4%. The majority of the specimens collected were identified as A. gambiae which had an individual infection rate of 12.6 % across collection sites. A small number of specimens of A. coluzzii, A. coluzzii x A. gambiae hybrids, A. melas and A. pharoensis were collected and had infection rates of 4.3%, 4.1%, 11.1% and 33.3% respectively. Despite being present in low numbers in indoor collections, the exophilic feeding behaviors of A. melas (N=18 and A. pharoensis (N=6 and high infection rates observed in this survey suggest falciparum-malaria transmission potential outside of the protection of bed nets.

  7. A Belgian traveler who acquired yellow fever in The Gambia

    OpenAIRE

    Colebunders, R; Mariage, J. L.; Coche, J. C.; Pirenne, B; Kempinaire, S.; Hantson, P.; Gompel, A; Niedrig, M; Van Esbroeck, M.; Bailey, R; Drosten, C.; Schmitz, H

    2002-01-01

    A 47-year-old Belgian woman acquired yellow fever during a 1-week vacation in The Gambia; she had never been vaccinated against yellow fever. She died of massive gastrointestinal bleeding 7 days after the onset of the first symptoms. This dramatic case demonstrates that it is important for persons to be vaccinated against yellow fever before they travel to countries where yellow fever is endemic, even if the country, like The Gambia, does not require travelers to be vaccinated.

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

    Directory of Open Access Journals (Sweden)

    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

  9. 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

  10. Cloning, characterization, and expression of microRNAs from the Asian malaria mosquito, Anopheles stephensi

    Directory of Open Access Journals (Sweden)

    Tu Zhijian

    2008-05-01

    Full Text Available Abstract Background microRNAs (miRNAs are non-coding RNAs that are now recognized as a major class of gene-regulating molecules widely distributed in metozoans and plants. miRNAs have been found to play important roles in apoptosis, cancer, development, differentiation, inflammation, longevity, and viral infection. There are a few reports describing miRNAs in the African malaria mosquito, Anopheles gambiae, on the basis of similarity to known miRNAs from other species. An. stephensi is the most important malaria vector in Asia and it is becoming a model Anopheline species for physiological and genetics studies. Results We report the cloning and characterization of 27 distinct miRNAs from 17-day old An. stephensi female mosquitoes. Seventeen of the 27 miRNAs matched previously predicted An. gambiae miRNAs, offering the first experimental verification of miRNAs from mosquito species. Ten of the 27 are miRNAs previously unknown to mosquitoes, four of which did not match any known miRNAs in any organism. Twenty-five of the 27 Anopheles miRNAs had conserved sequences in the genome of a divergent relative, the yellow fever mosquito Aedes aegypti. Two clusters of miRNAs were found within introns of orthologous genes in An. gambiae, Ae. aegypti, and Drosophila melanogaster. Mature miRNAs were detected in An. stephensi for all of the nine selected miRNAs, including the four novel miRNAs (miR-x1- miR-x4, either by northern blot or by Ribonuclease Protection Assay. Expression profile analysis of eight of these miRNAs revealed distinct expression patterns from early embryo to adult stages in An. stephensi. In both An. stephensi and Ae. aegypti, the expression of miR-x2 was restricted to adult females and predominantly in the ovaries. A significant reduction of miR-x2 level was observed 72 hrs after a blood meal. Thus miR-x2 is likely involved in female reproduction and its function may be conserved among divergent mosquitoes. A mosquito homolog of miR-14, a

  11. The monitoring of mosquitoes (Diptera, Culicidae) in the area affected by the Gabcikovo hydroelectric power structures

    International Nuclear Information System (INIS)

    Monitoring of the impact of the Gabcikovo hydroelectric power structures on mosquitoes (Diptera, Culicidae) in 8 areas and 16 stationary stands during 1990-1994 is presented. The following 9 species of mosquitoes were ascertained: Anopheles maculipennis, s.1, Culiseta annulata, Aedes vexans, Aedes sticticus, Aedes dorsalis, Aedes cinereus, Culex pipiens, Culex territans a Culex modestus. Important changes in the quantity as well as the quality of mosquitoes, were observed in connection with the changes in the ground water level. In 1994 we recorded only 4 species of mosquitoes: Anopheles maculipennis s.1, Aedes vexans, Aedes sticticus, Culex territans. The quantity of mosquitoes decreased significantly at all monitored stands near the river Danube upstream of the confluence with the tail race canal. Cunovo reservoir acted positively on the adjacent monitoring localities Kopac Island and Cunovo-Ostrovne lucky. The recorded communities of mosquitoes Anopheles maculipennis s.1 a Culex territans, are, according to our observations, typical for stabilised water levels. (author). 1 tab., 2 refs

  12. Combining Technical Competence and Stakeholder Impact in Environmental Education: The Gambia All Schools Nursery Competition

    Science.gov (United States)

    Paulete, Francisca E.; Orr, Blair

    2010-01-01

    Under the guidance of the Department of Forestry, the Regional Education Directorate, and Peace Corps/The Gambia, the Gambia All Schools Tree Nursery Competition, an environmental education program, was developed to introduce practical environmental education in The Gambia. Data for this report were collected using a rapid appraisal approach.…

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

    Directory of Open Access Journals (Sweden)

    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

  14. Overexpression and altered nucleocytoplasmic distribution of Anopheles ovalbumin-like SRPN10 serpins in Plasmodium-infected midgut cells.

    Science.gov (United States)

    Danielli, Alberto; Barillas-Mury, Carolina; Kumar, Sanjeev; Kafatos, Fotis C; Loukeris, Thanasis G

    2005-02-01

    The design of effective, vector-based malaria transmission blocking strategies relies on a thorough understanding of the molecular and cellular interactions that occur during the parasite sporogonic cycle in the mosquito. During Plasmodium berghei invasion, transcription from the SRPN10 locus, encoding four serine protease inhibitors of the ovalbumin family, is strongly induced in the mosquito midgut. Herein we demonstrate that intense induction as well as redistribution of SRPN10 occurs specifically in the parasite-invaded midgut epithelial cells. Quantitative analysis establishes that in response to epithelial invasion, SRPN10 translocates from the nucleus to the cytoplasm and this is followed by strong SRPN10 overexpression. The invaded cells exhibit signs of apoptosis, suggesting a link between this type of intracellular serpin and epithelial damage. The SRPN10 gene products constitute a novel, robust and cell-autonomous marker of midgut invasion by ookinetes. The SRPN10 dynamics at the subcellular level confirm and further elaborate the 'time bomb' model of P. berghei invasion in both Anopheles stephensi and Anopheles gambiae. In contrast, this syndrome of responses is not elicited by mutant P. berghei ookinetes lacking the major ookinete surface proteins, P28 and P25. Molecular markers with defined expression patterns, in combination with mutant parasite strains, will facilitate dissection of the molecular mechanisms underlying vector competence and development of effective transmission blocking strategies. PMID:15659062

  15. Inducible peroxidases mediate nitration of anopheles midgut cells undergoing apoptosis in response to Plasmodium invasion.

    Science.gov (United States)

    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

  16. Adaptation through chromosomal inversions in Anopheles

    Directory of Open Access Journals (Sweden)

    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.

  17. Distinct population structure for co-occurring Anopheles goeldii and Anopheles triannulatus in Amazonian Brazil

    OpenAIRE

    Sascha Naomi McKeon; Marta Moreno; Maria Anise Sallum; Marinete Marins Povoa; Jan Evelyn Conn

    2013-01-01

    To evaluate whether environmental heterogeneity contributes to the genetic heterogeneity in Anopheles triannulatus, larval habitat characteristics across the Brazilian states of Roraima and Pará and genetic sequences were examined. A comparison with Anopheles goeldii was utilised to determine whether high genetic diversity was unique to An. triannulatus. Student t test and analysis of variance found no differences in habitat characteristics between the species. Analysis of population structur...

  18. 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

  19. 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.

  20. Coxiella burnetii Seroprevalence in Small Ruminants in The Gambia

    NARCIS (Netherlands)

    Klaassen, M.; Roest, Hendrik-Jan; Hoek, van der W.; Goossens, B.; Secka, A.; Stegeman, A.

    2014-01-01

    Q fever is a zoonosis caused by Coxiella burnetii, a Gram negative bacterium present worldwide. Small ruminants are considered the main reservoirs for infection of humans. This study aimed to estimate the extent of C. burnetii infection among sheep and goats in part of The Gambia.