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Sample records for african malaria vector

  1. SIT for African malaria vectors: Epilogue

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    Townson Harold

    2009-11-01

    Full Text Available Abstract As a result of increased support and the diligent application of new and conventional anti-malaria tools, significant reductions in malaria transmission are being accomplished. Historical and current evolutionary responses of vectors and parasites to malaria interventions demonstrate that it is unwise to assume that a limited suite of tools will remain effective indefinitely, thus efforts to develop new interventions should continue. This collection of manuscripts surveys the prospects and technical challenges for applying a novel tool, the sterile insect technique (SIT, against mosquitoes that transmit malaria. The method has been very successful against many agricultural pest insects in area-wide programs, but demonstrations against malaria vectors have not been sufficient to determine its potential relative to current alternatives, much of which will hinge ultimately upon cost. These manuscripts provide an overview of current efforts to develop SIT and identify key research issues that remain.

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

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    Kevin C. Deitz

    2016-09-01

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

  3. Contained semi-field environments for ecological studies on transgenic African malaria vectors: benefits and constraints

    NARCIS (Netherlands)

    Knols, B.G.J.; Njiru, B.N.; Mukabana, W.R.; Mathenge, E.M.; Killeen, G.F.

    2002-01-01

    New interventions are needed to reduce the burden of vector-borne diseases like malaria and dengué, which are among the most serious and prevalent infectious diseases worldwide. The release of genetically modified (GM) mosquitoes may offer an alternative strategy to do so while circumventing the pit

  4. 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

  5. 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.

  6. Larval density dependence in Anopheles gambiae s.s., the major African vector of malaria

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    Muriu, Simon M.; Coulson, Tim; Mbogo, Charles M.; Godfray, H. Charles J.

    2017-01-01

    Summary Anopheles gambiae sensu stricto is the most important vector of malaria in Africa although relatively little is known about the density-dependent processes determining its population size.Mosquito larval density was manipulated under semi-natural conditions using artificial larval breeding sites placed in the field in coastal Kenya; two experiments were conducted: one manipulating the density of a single cohort of larvae across a range of densities and the other employing fewer densities but with the treatments crossed with four treatments manipulating predator access.In the first experiment, larval survival, development rate and the size of the adult mosquito all decreased with larval density (controlling for block effects between 23% and 31% of the variance in the data could be explained by density).In the second experiment, the effects of predator manipulation were not significant, but again we observed strong density dependence in larval survival (explaining 30% of the variance).The results are compared with laboratory studies of A. gambiae larval competition and the few other studies conducted in the field, and the consequences for malaria control are discussed PMID:23163565

  7. Advantages of larval control for African malaria vectors: Low mobility and behavioural responsiveness of immature mosquito stages allow high effective coverage

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    Knols Bart GJ

    2002-06-01

    Full Text Available Abstract Background Based on sensitivity analysis of the MacDonald-Ross model, it has long been argued that the best way to reduce malaria transmission is to target adult female mosquitoes with insecticides that can reduce the longevity and human-feeding frequency of vectors. However, these analyses have ignored a fundamental biological difference between mosquito adults and the immature stages that precede them: adults are highly mobile flying insects that can readily detect and avoid many intervention measures whereas mosquito eggs, larvae and pupae are confined within relatively small aquatic habitats and cannot readily escape control measures. Presentation of the hypothesis We hypothesize that the control of adult but not immature mosquitoes is compromised by their ability to avoid interventions such as excito-repellant insecticides. Testing the hypothesis We apply a simple model of intervention avoidance by mosquitoes and demonstrate that this can substantially reduce effective coverage, in terms of the proportion of the vector population that is covered, and overall impact on malaria transmission. We review historical evidence that larval control of African malaria vectors can be effective and conclude that the only limitations to the effective coverage of larval control are practical rather than fundamental. Implications of the hypothesis Larval control strategies against the vectors of malaria in sub-Saharan Africa could be highly effective, complementary to adult control interventions, and should be prioritized for further development, evaluation and implementation as an integral part of Rolling Back Malaria.

  8. 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.

  9. 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

    2014-12-17

    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.

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

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    Lyons Candice L

    2012-07-01

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

  12. 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

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

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

    2016-01-01

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

  14. [Research progress on malaria vector control].

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    Zhu, Guo-Ding; Cao, Jun; Zhou, Hua-Yun; Gao, Qi

    2013-06-01

    Vector control plays a crucial role in the stages of malaria control and elimination. Currently, it mainly relies on the chemical control methods for adult mosquitoes in malaria endemic areas, however, it is undergoing the serious threat by insecticide resistance. In recent years, the transgenic technologies of malaria vectors have made a great progress in the laboratory. This paper reviews the challenges of the traditional methods and the rapid developed genetic modified technology in the application of vector control.

  15. Insecticidal activity of the essential oil from fruits and seeds of Schinus terebinthifolia Raddi against African malaria vectors

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    Mosha Franklin

    2011-07-01

    Full Text Available Abstract Background Alternative insecticides for the control of malaria and filarial vectors are of paramount need as resistance is increasing among classes of insecticides currently in use in the public health sector. In this study, mosquitocidal activity of Schinus terebinthifolia essential oil against Anopheles gambiae s.s., An. arabiensis and Culex quinquefasciatus was assessed in laboratory, semi- field and full- field conditions Method Twenty third instar larvae of both Anopheles gambiae s.s. and Cx. quinquefasciatus were exposed to different dosages of plant extract in both laboratory and semi- field environments. Observation of the mortality response was assessed at intervals of 12, 24, 48 and 72 hours. Adult semi- gravid female mosquitoes were exposed to papers treated with S. terebinthifolia and compared with WHO standard paper treated with alphacypermethrin (0.05%. Results Gas chromatography, coupled to mass spectrometry, identified 15 compounds from S. terebinthifolia extracts, the most abundant identified compound was δ-3-carene (55.36% and the least was γ-elemene (0.41%. The density of the oil was found to be 0.8086 g/ml. The effective dosages in the insectary ranged from 202.15 to 2625.20 ppm and were further evaluated in the semi- field situation. In the laboratory, the mortality of Cx. quinquefasciatus ranged from 0.5 to 96.75% while for An. gambiae s.s it was from 13.75 to 97.91%. In the semi- field experiments, the mortality rates observed varied for both species with time and concentrations. The LC50 and LC95 value in the laboratory was similar for both species while in the semi- field they were different for each. In wild, adult mosquitoes, the KT50 for S. terebinthifolia was 11.29 minutes while for alphacypermethrin was 19.34 minutes. The 24 hour mortality was found to be 100.0% for S. terebinthifolia and 75.0% for alphacypermethrin which was statistically significant (P Conclusion The efficacy shown by essential oils of

  16. [Study on malaria vectors in malaria endemic areas of Tibet autonomous region].

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    Wu, Song; Huang, Fang; Zhou, Shui-Sen; Tang, Lin-Hua

    2012-12-01

    The malaria situation in Tibet has been in an active status and the malaria incidence reached the second in China in 2010. Malaria vector prevention and control is one of the important methods for malaria control, while the malaria vectors are still unknown in Tibet. The author summarized the past researches on malaria vectors in Tibet, so as to provide the evidence for improving malaria control investigation in malaria endemic areas of Tibet, with hopes to provide useful vector message for other researcher.

  17. PMI Activity TZ-1,2: IRS and LLIN: Integration of Methods and Insecticide Mode of Actions for Control of African Malaria Vector Mosquitoes

    OpenAIRE

    Fredros O Okumu; Moore, Sarah J.

    2012-01-01

    Long lasting Insecticidal nets (LLINs) and indoor residual spraying (IRS) are the preferred techniques for malaria vector control in Africa, where their application has a proven contribution to the recent significant reductions in the burden of the disease. Even though both methods are commonly used together in the same households, evidence of improved malaria control due to the use of combinations as opposed to use of either method alone has been minimal and inconclusive.To measure the mode ...

  18. Establishment of a large semi-field system for experimental study of African malaria vector ecology and control in Tanzania

    NARCIS (Netherlands)

    Ferguson, H.M.; Ng'habi, K.R.; Walder, T.; Kadungula, D.; Moore, S.J.; Lyimo, I.; Russell, T.L.; Urassa, H.; Mshinda, H.; Killeen, G.F.; Knols, B.G.J.

    2008-01-01

    Background - Medical entomologists increasingly recognize that the ability to make inferences between laboratory experiments of vector biology and epidemiological trends observed in the field is hindered by a conceptual and methodological gap occurring between these approaches which prevents hypothe

  19. Shifting suitability for malaria vectors across Africa with warming climates

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    Peterson A Townsend

    2009-05-01

    Full Text Available Abstract Background Climates are changing rapidly, producing warm climate conditions globally not previously observed in modern history. Malaria is of great concern as a cause of human mortality and morbidity, particularly across Africa, thanks in large part to the presence there of a particularly competent suite of mosquito vector species. Methods I derive spatially explicit estimates of human populations living in regions newly suitable climatically for populations of two key Anopheles gambiae vector complex species in Africa over the coming 50 years, based on ecological niche model projections over two global climate models, two scenarios of climate change, and detailed spatial summaries of human population distributions. Results For both species, under all scenarios, given the changing spatial distribution of appropriate conditions and the current population distribution, the models predict a reduction of 11.3–30.2% in the percentage of the overall population living in areas climatically suitable for these vector species in coming decades, but reductions and increases are focused in different regions: malaria vector suitability is likely to decrease in West Africa, but increase in eastern and southern Africa. Conclusion Climate change effects on African malaria vectors shift their distributional potential from west to east and south, which has implications for overall numbers of people exposed to these vector species. Although the total is reduced, malaria is likely to pose novel public health problems in areas where it has not previously been common.

  20. Malaria vector control: current and future strategies

    NARCIS (Netherlands)

    Takken, W.; Knols, B.G.J.

    2009-01-01

    The recently announced call for malaria eradication represents a new page in the history of this disease. This has been triggered by remarkable reductions in malaria resulting from combined application of effective drugs and vector control. However, this strategy is threatened by development of inse

  1. Advantages of larval control for African malaria vectors: Low mobility and behavioural responsiveness of immature mosquito stages allow high effective coverage

    OpenAIRE

    Knols Bart GJ; Fillinger Ulrike; Killeen Gerry F

    2002-01-01

    Abstract Background Based on sensitivity analysis of the MacDonald-Ross model, it has long been argued that the best way to reduce malaria transmission is to target adult female mosquitoes with insecticides that can reduce the longevity and human-feeding frequency of vectors. However, these analyses have ignored a fundamental biological difference between mosquito adults and the immature stages that precede them: adults are highly mobile flying insects that can readily detect and avoid many i...

  2. The Genome of Anopheles darlingi, the main neotropical malaria vector

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    Marinotti, Osvaldo; Cerqueira, Gustavo C.; de Almeida, Luiz Gonzaga Paula; Ferro, Maria Inês Tiraboschi; Loreto, Elgion Lucio da Silva; Zaha, Arnaldo; Teixeira, Santuza M. R.; Wespiser, Adam R.; Almeida e Silva, Alexandre; Schlindwein, Aline Daiane; Pacheco, Ana Carolina Landim; da Silva, Artur Luiz da Costa; Graveley, Brenton R.; Walenz, Brian P.; Lima, Bruna de Araujo; Ribeiro, Carlos Alexandre Gomes; Nunes-Silva, Carlos Gustavo; de Carvalho, Carlos Roberto; Soares, Célia Maria de Almeida; de Menezes, Claudia Beatriz Afonso; Matiolli, Cleverson; Caffrey, Daniel; Araújo, Demetrius Antonio M.; de Oliveira, Diana Magalhães; Golenbock, Douglas; Grisard, Edmundo Carlos; Fantinatti-Garboggini, Fabiana; de Carvalho, Fabíola Marques; Barcellos, Fernando Gomes; Prosdocimi, Francisco; May, Gemma; de Azevedo Junior, Gilson Martins; Guimarães, Giselle Moura; Goldman, Gustavo Henrique; Padilha, Itácio Q. M.; Batista, Jacqueline da Silva; Ferro, Jesus Aparecido; Ribeiro, José M. C.; Fietto, Juliana Lopes Rangel; Dabbas, Karina Maia; Cerdeira, Louise; Agnez-Lima, Lucymara Fassarella; Brocchi, Marcelo; de Carvalho, Marcos Oliveira; Teixeira, Marcus de Melo; Diniz Maia, Maria de Mascena; Goldman, Maria Helena S.; Cruz Schneider, Maria Paula; Felipe, Maria Sueli Soares; Hungria, Mariangela; Nicolás, Marisa Fabiana; Pereira, Maristela; Montes, Martín Alejandro; Cantão, Maurício E.; Vincentz, Michel; Rafael, Miriam Silva; Silverman, Neal; Stoco, Patrícia Hermes; Souza, Rangel Celso; Vicentini, Renato; Gazzinelli, Ricardo Tostes; Neves, Rogério de Oliveira; Silva, Rosane; Astolfi-Filho, Spartaco; Maciel, Talles Eduardo Ferreira; Ürményi, Turán P.; Tadei, Wanderli Pedro; Camargo, Erney Plessmann; de Vasconcelos, Ana Tereza Ribeiro

    2013-01-01

    Anopheles darlingi is the principal neotropical malaria vector, responsible for more than a million cases of malaria per year on the American continent. Anopheles darlingi diverged from the African and Asian malaria vectors ∼100 million years ago (mya) and successfully adapted to the New World environment. Here we present an annotated reference A. darlingi genome, sequenced from a wild population of males and females collected in the Brazilian Amazon. A total of 10 481 predicted protein-coding genes were annotated, 72% of which have their closest counterpart in Anopheles gambiae and 21% have highest similarity with other mosquito species. In spite of a long period of divergent evolution, conserved gene synteny was observed between A. darlingi and A. gambiae. More than 10 million single nucleotide polymorphisms and short indels with potential use as genetic markers were identified. Transposable elements correspond to 2.3% of the A. darlingi genome. Genes associated with hematophagy, immunity and insecticide resistance, directly involved in vector–human and vector–parasite interactions, were identified and discussed. This study represents the first effort to sequence the genome of a neotropical malaria vector, and opens a new window through which we can contemplate the evolutionary history of anopheline mosquitoes. It also provides valuable information that may lead to novel strategies to reduce malaria transmission on the South American continent. The A. darlingi genome is accessible at www.labinfo.lncc.br/index.php/anopheles-darlingi. PMID:23761445

  3. Ecology and Epidemiology of Integrated Malaria Vector Management in Dar es Salaam, Tanzania

    OpenAIRE

    Geissbühler, Yvonne

    2008-01-01

    Malaria remains one of the major contributors to the global burden of disease with approximately 70% of the clinical malaria attacks occurring in sub-Saharan Africa. Sub- Saharan Africa has the highest risk as ideal climatic conditions for transmission coincide with occurrence of some of the most efficient malaria vectors, namely Anopheles gambiae s.s., Anopheles arabiensis and Anopheles funestus.. Even though it is estimated that by the year 2030 more than 50% of the African p...

  4. Integrated vector management for malaria control

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    Impoinvil Daniel E

    2008-12-01

    Full Text Available Abstract Integrated vector management (IVM is defined as "a rational decision-making process for the optimal use of resources for vector control" and includes five key elements: 1 evidence-based decision-making, 2 integrated approaches 3, collaboration within the health sector and with other sectors, 4 advocacy, social mobilization, and legislation, and 5 capacity-building. In 2004, the WHO adopted IVM globally for the control of all vector-borne diseases. Important recent progress has been made in developing and promoting IVM for national malaria control programmes in Africa at a time when successful malaria control programmes are scaling-up with insecticide-treated nets (ITN and/or indoor residual spraying (IRS coverage. While interventions using only ITNs and/or IRS successfully reduce transmission intensity and the burden of malaria in many situations, it is not clear if these interventions alone will achieve those critical low levels that result in malaria elimination. Despite the successful employment of comprehensive integrated malaria control programmes, further strengthening of vector control components through IVM is relevant, especially during the "end-game" where control is successful and further efforts are required to go from low transmission situations to sustained local and country-wide malaria elimination. To meet this need and to ensure sustainability of control efforts, malaria control programmes should strengthen their capacity to use data for decision-making with respect to evaluation of current vector control programmes, employment of additional vector control tools in conjunction with ITN/IRS tactics, case-detection and treatment strategies, and determine how much and what types of vector control and interdisciplinary input are required to achieve malaria elimination. Similarly, on a global scale, there is a need for continued research to identify and evaluate new tools for vector control that can be integrated with

  5. 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

  6. The Biological Control of the Malaria Vector

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    Layla Kamareddine

    2012-09-01

    Full Text Available The call for malaria control, over the last century, marked a new epoch in the history of this disease. Many control strategies targeting either the Plasmodium parasite or the Anopheles vector were shown to be effective. Yet, the emergence of drug resistant parasites and insecticide resistant mosquito strains, along with numerous health, environmental, and ecological side effects of many chemical agents, highlighted the need to develop alternative tools that either complement or substitute conventional malaria control approaches. The use of biological means is considered a fundamental part of the recently launched malaria eradication program and has so far shown promising results, although this approach is still in its infancy. This review presents an overview of the most promising biological control tools for malaria eradication, namely fungi, bacteria, larvivorous fish, parasites, viruses and nematodes.

  7. Predicting and mapping malaria under climate change scenarios: the potential redistribution of malaria vectors in Africa

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    Kangalawe Richard YM

    2010-04-01

    Full Text Available Abstract Background Malaria is rampant in Africa and causes untold mortality and morbidity. Vector-borne diseases are climate sensitive and this has raised considerable concern over the implications of climate change on future disease risk. The problem of malaria vectors (Anopheles mosquitoes shifting from their traditional locations to invade new zones is an important concern. The vision of this study was to exploit the sets of information previously generated by entomologists, e.g. on geographical range of vectors and malaria distribution, to build models that will enable prediction and mapping the potential redistribution of Anopheles mosquitoes in Africa. Methods The development of the modelling tool was carried out through calibration of CLIMEX parameters. The model helped estimate the potential geographical distribution and seasonal abundance of the species in relation to climatic factors. These included temperature, rainfall and relative humidity, which characterized the living environment for Anopheles mosquitoes. The same parameters were used in determining the ecoclimatic index (EI. The EI values were exported to a GIS package for special analysis and proper mapping of the potential future distribution of Anopheles gambiae and Anophles arabiensis within the African continent under three climate change scenarios. Results These results have shown that shifts in these species boundaries southward and eastward of Africa may occur rather than jumps into quite different climatic environments. In the absence of adequate control, these predictions are crucial in understanding the possible future geographical range of the vectors and the disease, which could facilitate planning for various adaptation options. Conclusion Thus, the outputs from this study will be helpful at various levels of decision making, for example, in setting up of an early warning and sustainable strategies for climate change and climate change adaptation for malaria

  8. High resolution niche models of malaria vectors in northern Tanzania: a new capacity to predict malaria risk?

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    Manisha A Kulkarni

    Full Text Available BACKGROUND: Malaria transmission rates in Africa can vary dramatically over the space of a few kilometres. This spatial heterogeneity reflects variation in vector mosquito habitat and presents an important obstacle to the efficient allocation of malaria control resources. Malaria control is further complicated by combinations of vector species that respond differently to control interventions. Recent modelling innovations make it possible to predict vector distributions and extrapolate malaria risk continentally, but these risk mapping efforts have not yet bridged the spatial gap to guide on-the-ground control efforts. METHODOLOGY/PRINCIPAL FINDINGS: We used Maximum Entropy with purpose-built, high resolution land cover data and other environmental factors to model the spatial distributions of the three dominant malaria vector species in a 94,000 km(2 region of east Africa. Remotely sensed land cover was necessary in each vector's niche model. Seasonality of precipitation and maximum annual temperature also contributed to niche models for Anopheles arabiensis and An. funestus s.l. (AUC 0.989 and 0.991, respectively, but cold season precipitation and elevation were important for An. gambiae s.s. (AUC 0.997. Although these niche models appear highly accurate, the critical test is whether they improve predictions of malaria prevalence in human populations. Vector habitat within 1.5 km of community-based malaria prevalence measurements interacts with elevation to substantially improve predictions of Plasmodium falciparum prevalence in children. The inclusion of the mechanistic link between malaria prevalence and vector habitat greatly improves the precision and accuracy of prevalence predictions (r(2 = 0.83 including vector habitat, or r(2 = 0.50 without vector habitat. Predictions including vector habitat are unbiased (observations vs. model predictions of prevalence: slope = 1.02. Using this model, we generate a high resolution map of predicted

  9. VECTORS OF MALARIA AND FILARIASIS IN INDONESIA

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    Hoedojo Hoedojo

    2012-09-01

    Full Text Available Malaria at present is still one of the important mosquito-borne diseases in Indonesia. The disease is widespread all over the country and involves nearly all islands. Sixteen Anopheles species have been reconfirmed as malaria vectors. They were distributed geographi­cally as follows: Coastal areas and lagoons ------------------------------------- An sundaicus and An.subpictus Cultivated ricefields and swampy areas -------------------- An.aconitus, An.barbirostris, An.nigerrimus and An.sinensis Forest inland areas in shaded temporary pools, muddy animal wallows and hoof-prints -------------------------------------------------------- An.balabacensis, An.bancrofti, An.farauti, An.koliensis and An.punctulatus Swamp forest edge in ditches with vegeta- ---------------- An.letifer and An.ludlowae don Hilly areas in seepages, streams and clear moving water ---------------------------------------------- Anflavirostris, An.maculatus and Anminimus.   The species (of most general importance is An.sundaicus, which is restricted by its preference for brackish water and is prevalent in coastal areas of Java. Their types in behaviour of An.sundaicus appear as follows : 1. An.sundaicus in South Coast of Java in general. This species is essentially anthropophilic, exophagic and rests outdoor. It shows susceptible to DDT. 2. An.sundaicus in Cilacap, Central Java. This mosquito is a pure anthropophilic form. It bites man in houses and outdoors, rests indoors and is known resistant to DDT. 3. An.sundaicus in Yogyakarta and Purworejo, Central Java. This mosquito is a strong zoophilic species. It rests and prefers to bite outdoors and shows tolerance to DDT. Human filariasis in Indonesia is the result of infection by three endemic species, namely, Wuchereria bancrofti, Brugia malayi, and Brugia timori.W.bancrofti infection is found in both urban and rural areas. Twenty species of mosquitoes are confirmed as filariasis vectors. The urban type bancroftian filariasis

  10. Molecular characterization and evolution of a gene family encoding male-specific reproductive proteins in the African malaria vector Anopheles gambiae

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    Sharakhov Igor V

    2011-10-01

    Full Text Available Abstract Background During copulation, the major Afro-tropical malaria vector Anopheles gambiae s.s. transfers male accessory gland (MAG proteins to females as a solid mass (i.e. the "mating plug". These proteins are postulated to function as important modulators of female post-mating responses. To understand the role of selective forces underlying the evolution of these proteins in the A. gambiae complex, we carried out an evolutionary analysis of gene sequence and expression divergence on a pair of paralog genes called AgAcp34A-1 and AgAcp34A-2. These encode MAG-specific proteins which, based on homology with Drosophila, have been hypothesized to play a role in sperm viability and function. Results Genetic analysis of 6 species of the A. gambiae complex revealed the existence of a third paralog (68-78% of identity, that we named AgAcp34A-3. FISH assays showed that this gene maps in the same division (34A of chromosome-3R as the other two paralogs. In particular, immuno-fluorescence assays targeting the C-terminals of AgAcp34A-2 and AgAcp34A-3 revealed that these two proteins are localized in the posterior part of the MAG and concentrated at the apical portion of the mating plug. When transferred to females, this part of the plug lies in proximity to the duct connecting the spermatheca to the uterus, suggesting a potential role for these proteins in regulating sperm motility. AgAcp34A-3 is more polymorphic than the other two paralogs, possibly because of relaxation of purifying selection. Since both unequal crossing-over and gene conversion likely homogenized the members of this gene family, the interpretation of the evolutionary patterns is not straightforward. Although several haplotypes of the three paralogs are shared by most A. gambiae s.l. species, some fixed species-specific replacements (mainly placed in the N- and C-terminal portions of the secreted peptides were also observed, suggesting some lineage-specific adaptation. Conclusions

  11. Malaria vectors of Timor-Leste

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    Frances Stephen P

    2010-02-01

    Full Text Available Abstract Background The island of Timor lies at the south-eastern edge of Indonesia on the boundary of the Oriental and Australian faunal regions. The country of Timor-Leste, which occupies the eastern part of the island, is malarious but anopheline faunal surveys and malaria vector incrimination date back to the 1960 s. Over the last decade the malaria vectors of south-east Asia and the south-west Pacific have been intensely studied using molecular techniques that can confirm identification within complexes of isomorphic species. The aim of this study is to accurately identify the Anopheles fauna of Timor-Leste using these techniques. Methods The survey was carried out over the period February to June 2001. Standard entomological techniques - human landing collections, larval collections and CO2 baited light traps - were used to collect anophelines from the main geographical regions: coastal plains, inland plains, and highlands. Specimens were processed for identification by morphology and genotyped for the ribosomal DNA ITS2 by restriction analysis and/or DNA sequencing. Phylogenetic relationship of Anopheles sundaicus and Anopheles subpictus individuals was also assessed using DNA sequences from the ITS2 and mitochondrial cytochrome-b. All specimens, other than those from larval surveys, were processed to detect the presence of the Plasmodium parasite circumsporozoite protein by ELISA for vector incrimination. Results Of 2,030 specimens collected, seven species were identified by morphology: Anopheles barbirostris, Anopheles aconitus, Anopheles annularis, Anopheles maculatus, Anopheles peditaeniatus, An. sundaicus and Anopheles vagus. These were confirmed by molecular analysis with the addition of Anopheles flavirostris and an unidentified species designated here as An. vagus genotype B. This latter species was morphologically similar to An. vagus and An. subpictus and is likely to be the An. subpictus described by other workers for Timor

  12. Toxicity of six plant extracts and two pyridine alkaloids from Ricinus communis against the malaria vector Anopheles gambiae

    Science.gov (United States)

    The African malaria vector, Anopheles gambiae s.s., is known to feed selectively on certain plants for sugar sources. However, the adaptive significance of this behavior especially on how the extracts of such plants impact on the fitness of this vector has not been explored. This study determined th...

  13. High Resolution Niche Models of Malaria Vectors in Northern Tanzania: A New Capacity to Predict Malaria Risk?

    OpenAIRE

    Kulkarni, Manisha A; Desrochers, Rachelle E; Kerr, Jeremy T.

    2010-01-01

    Background Malaria transmission rates in Africa can vary dramatically over the space of a few kilometres. This spatial heterogeneity reflects variation in vector mosquito habitat and presents an important obstacle to the efficient allocation of malaria control resources. Malaria control is further complicated by combinations of vector species that respond differently to control interventions. Recent modelling innovations make it possible to predict vector distributions and extrapolate malaria...

  14. Predicting malaria vector distribution under climate change scenarios in China: Challenges for malaria elimination

    Science.gov (United States)

    Ren, Zhoupeng; Wang, Duoquan; Ma, Aimin; Hwang, Jimee; Bennett, Adam; Sturrock, Hugh J. W.; Fan, Junfu; Zhang, Wenjie; Yang, Dian; Feng, Xinyu; Xia, Zhigui; Zhou, Xiao-Nong; Wang, Jinfeng

    2016-02-01

    Projecting the distribution of malaria vectors under climate change is essential for planning integrated vector control activities for sustaining elimination and preventing reintroduction of malaria. In China, however, little knowledge exists on the possible effects of climate change on malaria vectors. Here we assess the potential impact of climate change on four dominant malaria vectors (An. dirus, An. minimus, An. lesteri and An. sinensis) using species distribution models for two future decades: the 2030 s and the 2050 s. Simulation-based estimates suggest that the environmentally suitable area (ESA) for An. dirus and An. minimus would increase by an average of 49% and 16%, respectively, under all three scenarios for the 2030 s, but decrease by 11% and 16%, respectively in the 2050 s. By contrast, an increase of 36% and 11%, respectively, in ESA of An. lesteri and An. sinensis, was estimated under medium stabilizing (RCP4.5) and very heavy (RCP8.5) emission scenarios. in the 2050 s. In total, we predict a substantial net increase in the population exposed to the four dominant malaria vectors in the decades of the 2030 s and 2050 s, considering land use changes and urbanization simultaneously. Strategies to achieve and sustain malaria elimination in China will need to account for these potential changes in vector distributions and receptivity.

  15. Autodissemination of the entomopathogenic fungus Metarhizium anisopliae amongst adults of the malaria vector anopheles gambiae s.s.

    NARCIS (Netherlands)

    Scholte, E.J.; Knols, B.G.J.; Takken, W.

    2004-01-01

    Background - The entomopathogenic fungus Metarhizium anisopliae is being considered as a biocontrol agent for adult African malaria vectors. In the laboratory, work was carried out to assess whether horizontal transmission of the pathogen can take place during copulation, as this would enhance the i

  16. Increasing the potential for malaria elimination by targeting zoophilic vectors

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    Waite, Jessica L.; Swain, Sunita; Lynch, Penelope A.; Sharma, S. K.; Haque, Mohammed Asrarul; Montgomery, Jacqui; Thomas, Matthew B.

    2017-01-01

    Countries in the Asia Pacific region aim to eliminate malaria by 2030. A cornerstone of malaria elimination is the effective management of Anopheles mosquito vectors. Current control tools such as insecticide treated nets or indoor residual sprays target mosquitoes in human dwellings. We find in a high transmission region in India, malaria vector populations show a high propensity to feed on livestock (cattle) and rest in outdoor structures such as cattle shelters. We also find evidence for a shift in vector species complex towards increased zoophilic behavior in recent years. Using a malaria transmission model we demonstrate that in such regions dominated by zoophilic vectors, existing vector control tactics will be insufficient to achieve elimination, even if maximized. However, by increasing mortality in the zoophilic cycle, the elimination threshold can be reached. Current national vector control policy in India restricts use of residual insecticide sprays to domestic dwellings. Our study suggests substantial benefits of extending the approach to treatment of cattle sheds, or deploying other tactics that target zoophilic behavior. Optimizing use of existing tools will be essential to achieving the ambitious 2030 elimination target. PMID:28091570

  17. The Plasmodium bottleneck: malaria parasite losses in the mosquito vector

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    Ryan C Smith

    2014-08-01

    Full Text Available Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission.

  18. Lethal and pre-lethal effects of a fungal biopesticide contribute to substantial and rapid control of malaria vectors.

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    Simon Blanford

    Full Text Available Rapidly emerging insecticide resistance is creating an urgent need for new active ingredients to control the adult mosquitoes that vector malaria. Biopesticides based on the spores of entomopathogenic fungi have shown considerable promise by causing very substantial mortality within 7-14 days of exposure. This mortality will generate excellent malaria control if there is a high likelihood that mosquitoes contact fungi early in their adult lives. However, where contact rates are lower, as might result from poor pesticide coverage, some mosquitoes will contact fungi one or more feeding cycles after they acquire malaria, and so risk transmitting malaria before the fungus kills them. Critics have argued that 'slow acting' fungal biopesticides are, therefore, incapable of delivering malaria control in real-world contexts. Here, utilizing standard WHO laboratory protocols, we demonstrate effective action of a biopesticide much faster than previously reported. Specifically, we show that transient exposure to clay tiles sprayed with a candidate biopesticide comprising spores of a natural isolate of Beauveria bassiana, could reduce malaria transmission potential to zero within a feeding cycle. The effect resulted from a combination of high mortality and rapid fungal-induced reduction in feeding and flight capacity. Additionally, multiple insecticide-resistant lines from three key African malaria vector species were completely susceptible to fungus. Thus, fungal biopesticides can block transmission on a par with chemical insecticides, and can achieve this where chemical insecticides have little impact. These results support broadening the current vector control paradigm beyond fast-acting chemical toxins.

  19. Mosquito Vectors and the Globalization of Plasmodium falciparum Malaria.

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    Molina-Cruz, Alvaro; Zilversmit, Martine M; Neafsey, Daniel E; Hartl, Daniel L; Barillas-Mury, Carolina

    2016-11-23

    Plasmodium falciparum malaria remains a devastating public health problem. Recent discoveries have shed light on the origin and evolution of Plasmodium parasites and their interactions with their vertebrate and mosquito hosts. P. falciparum malaria originated in Africa from a single horizontal transfer between an infected gorilla and a human, and became global as the result of human migration. Today, P. falciparum malaria is transmitted worldwide by more than 70 different anopheline mosquito species. Recent studies indicate that the mosquito immune system can be a barrier to malaria transmission and that the P. falciparum Pfs47 gene allows the parasite to evade mosquito immune detection. Here, we review the origin and globalization of P. falciparum and integrate this history with analysis of the biology, evolution, and dispersal of the main mosquito vectors. This new perspective broadens our understanding of P. falciparum population structure and the dispersal of important parasite genetic traits.

  20. Spatial association between malaria vector species richness and malaria in Colombia.

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    Fuller, Douglas O; Alimi, Temitope; Herrera, Socrates; Beier, John C; Quiñones, Martha L

    2016-06-01

    Malaria transmission in Colombia is highly variable in space and time. Using a species distribution model, we mapped potential distribution of five vector species including Anopheles albimanus, Anopheles calderoni, Anopheles darlingi, Anopheles neivai, and Anopheles nuneztovari in five Departments of Colombia where malaria transmission remains problematic. We overlaid the range maps of the five species to reveal areas of sympatry and related per-pixel species richness to mean annual parasite index (API) for 2011-2014 mapped by municipality (n = 287). The relationship between mean number of vector species per municipality and API was evaluated using a Poisson regression, which revealed a highly significant relationship between species richness and API (p = 0 for Wald Chi-Square statistic). The results suggest that areas of relatively high transmission in Colombia typically contain higher number of vector species than areas with unstable transmission and that future elimination strategies should account for vector species richness.

  1. Insecticide resistance in malaria vector mosquitoes at four localities in Ghana, West Africa

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    Kaiser Maria L

    2011-06-01

    Full Text Available Abstract Background Malaria vector control programmes that rely on insecticide-based interventions such as indoor house spraying with residual insecticides or insecticide treated bed nets, need to base their decision-making process on sound baseline data. More and more commercial entities in Africa, such as mining companies, are realising the value to staff productivity of controlling malaria transmission in their areas of operation. This paper presents baseline entomological data obtained during surveys conducted for four mining operations in Ghana, West Africa. Results The vast majority of the samples were identified as Anopheles gambiae S form with only a few M form specimens being identified from Tarkwa. Plasmodium falciparum infection rates ranged from 4.5 to 8.6% in An. gambiae and 1.81 to 8.06% in An. funestus. High survival rates on standard WHO bioassay tests were recorded for all insecticide classes except the organophosphates that showed reasonable mortality at all locations (i.e. > 90%. The West African kdr mutation was detected and showed high frequencies in all populations. Conclusions The data highlight the complexity of the situation prevailing in southern Ghana and the challenges facing the malaria vector control programmes in this region. Vector control programmes in Ghana need to carefully consider the resistance profiles of the local mosquito populations in order to base their resistance management strategies on sound scientific data.

  2. Targeting male mosquito swarms to control malaria vector density

    Science.gov (United States)

    Sawadogo, Simon Peguedwinde; Niang, Abdoulaye; Bilgo, Etienne; Millogo, Azize; Maïga, Hamidou; Dabire, Roch K.; Tripet, Frederic; Diabaté, Abdoulaye

    2017-01-01

    Malaria control programs are being jeopardized by the spread of insecticide resistance in mosquito vector populations. It has been estimated that the spread of resistance could lead to an additional 120000 deaths per year, and interfere with the prospects for sustained control or the feasibility of achieving malaria elimination. Another complication for the development of resistance management strategies is that, in addition to insecticide resistance, mosquito behavior evolves in a manner that diminishes the impact of LLINs and IRS. Mosquitoes may circumvent LLIN and IRS control through preferential feeding and resting outside human houses and/or being active earlier in the evening before people go to sleep. Recent developments in our understanding of mosquito swarming suggest that new tools targeting mosquito swarms can be designed to cut down the high reproductive rate of malaria vectors. Targeting swarms of major malaria vectors may provide an effective control method to counteract behavioral resistance developed by mosquitoes. Here, we evaluated the impact of systematic spraying of swarms of Anopheles gambiae s.l. using a mixed carbamate and pyrethroid aerosol. The impact of this intervention on vector density, female insemination rates and the age structure of males was measured. We showed that the resulting mass killing of swarming males and some mate-seeking females resulted in a dramatic 80% decrease in population size compared to a control population. A significant decrease in female insemination rate and a significant shift in the age structure of the male population towards younger males incapable of mating were observed. This paradigm-shift study therefore demonstrates that targeting primarily males rather than females, can have a drastic impact on mosquito population. PMID:28278212

  3. Phytoextract-induced developmental deformities in malaria vector.

    Science.gov (United States)

    Sharma, Preeti; Mohan, Lalit; Srivastava, C N

    2006-09-01

    Larvicidal potential of petroleum ether (Pee), carbon tetrachloride (Cte) and methanol extract (Mee) of Artemisia annua, Chenopodium album and Sonchus oleraceus was observed against malaria vector, Anopheles stephensi Liston. The Pee of A. annua with LC50 16.85 ppm after 24 h and 11.45 ppm after 48 h of treatment was found most effective, followed by Cte of A. annua and Ch. album, Pee of Ch. album and Mee of A. annua. However, no significant larvicidal activity was observed in Mee of Ch. album and all the three extracts of S. oleraceous. The Pee of A. annua was further investigated for its effect on the metamorphosis and the development of the malaria vector. It influenced the early life cycle of An. stephensi by reducing the percentage of hatching, larval, pupal and adult emergence and also lengthening the larval and pupal periods. The growth index was also reduced significantly. As the extract has remarkable effect on the metamorphosis and high larvicidal potential, it could, therefore, be used as an effective biocontrol agent against the highly nuisant malaria vector.

  4. Multiple insecticide resistance: an impediment to insecticide-based malaria vector control program.

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    Delenasaw Yewhalaw

    Full Text Available BACKGROUND: Indoor Residual Spraying (IRS, insecticide-treated nets (ITNs and long-lasting insecticidal nets (LLINs are key components in malaria prevention and control strategy. However, the development of resistance by mosquitoes to insecticides recommended for IRS and/or ITNs/LLINs would affect insecticide-based malaria vector control. We assessed the susceptibility levels of Anopheles arabiensis to insecticides used in malaria control, characterized basic mechanisms underlying resistance, and evaluated the role of public health use of insecticides in resistance selection. METHODOLOGY/PRINCIPAL FINDINGS: Susceptibility status of An. arabiensis was assessed using WHO bioassay tests to DDT, permethrin, deltamethrin, malathion and propoxur in Ethiopia from August to September 2009. Mosquito specimens were screened for knockdown resistance (kdr and insensitive acetylcholinesterase (ace-1(R mutations using AS-PCR and PCR-RFLP, respectively. DDT residues level in soil from human dwellings and the surrounding environment were determined by Gas Chromatography with Electron Capture Detector. An. arabiensis was resistant to DDT, permethrin, deltamethrin and malathion, but susceptible to propoxur. The West African kdr allele was found in 280 specimens out of 284 with a frequency ranged from 95% to 100%. Ace-1(R mutation was not detected in all specimens scored for the allele. Moreover, DDT residues were found in soil samples from human dwellings but not in the surrounding environment. CONCLUSION: The observed multiple-resistance coupled with the occurrence of high kdr frequency in populations of An. arabiensis could profoundly affect the malaria vector control programme in Ethiopia. This needs an urgent call for implementing rational resistance management strategies and integrated vector control intervention.

  5. Malaria in east African highlands during the past 30 years: impact of environmental changes

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    Yousif El - Safi Himeidan

    2012-08-01

    Full Text Available East African highlands are one of the most populated regions in Africa. The population densities in the highlands ranged between 158 persons/km2 in Ethiopia to 410 persons/km2 in Rwanda. According to the United Nations Population Fund, the region has the world's highest population growth rate. These factors are likely behind the high rates of poverty among the populations. As there were no employment opportunities other than agricultural, this demographic pressure of poor populations have included in an extensive unprecedented land use and land cover changes such as modification of bushland, woodland, and grassland on hillsides to farmland and transformation of papyrus swamps in valley bottoms to dairy pastures and cropland and changing of fallows on hillsides from short or seasonal to longer or perennial. Areas harvested for food crops were therefore increased by more than 100% in most of the highlands. The lost of forest areas, mainly due to subsistence agriculture, between 1990 - 2010 ranged between 8000 ha in Rwanda to 2838000 ha in Ethiopia. These unmitigated environmental changes in the highlands led to rise temperature and optimizing the spread and survival of malaria vectors and development of malaria parasites. Malaria in highlands was initially governed by low ambient temperature, trend of malaria transmission was therefore increased and several epidemics were observed in late 1980s and early 2000s. Although, malaria is decreasing through intensified interventions since mid 2000s onwards, these environmental changes might expose population in the highlands of east Africa to an increase risk of malaria and its epidemic particularly if the current interventions are not sustained.

  6. Malaria control in the African Region: perceptions and viewspoints on proceedings of the Africa Leaders Malaria Alliance (ALMA

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    Sambo Luis

    2011-06-01

    Full Text Available Abstract Background In 2009 a total of 153,408 malaria deaths were reported in Africa. Eleven countries showed a reduction of more than 50% in either confirmed malaria cases or malaria admissions and deaths in recent years. However, many African countries are not on track to achieve the malaria component of the Millennium Development Goal (MDG 6. The African Leaders Malaria Alliance (ALMA working session at the 15th African Union Summit discussed the bottlenecks to achieving MDG 6 (specifically halting and beginning to reverse the incidence of malaria by 2015, success factors, and what countries needed to do to accelerate achievement of the MDG. The purpose of this article is to reflect on the proceedings of the ALMA working session. Methods Working methods of the session included speeches and statements by invited speakers and high-level panel discussions. Discussion The main bottlenecks identified related to the capacity of the health systems to deliver quality care and accessibility issues; need for strong, decentralized malaria-control programmes with linkages with other health and development sectors, the civil society and private sector entities; benefits of co-implementation of malaria control programmes with child survival or other public health interventions; systematic application of integrated promotive, preventive, diagnostic and case management interventions with full community participation; adapting approaches to local political, socio-cultural and administrative environments. The following prerequisites for success were identified: a clear vision and effective leadership of national malaria control programmes; high level political commitment to ensure adequate capacity in expertise, skill mix and number of managers, technicians and service providers; national ownership, intersectoral collaboration and accountability, as well as strong civil society and private sector involvement; functional epidemiological surveillance systems

  7. Population genetic structure of malaria vector Anopheles stephensi Liston (Diptera: Culicidae).

    Science.gov (United States)

    Gakhar, S K; Sharma, Richa; Sharma, Arvind

    2013-04-01

    Malaria is a complex disease that afflicts human today. Malaria epidemiology is associated with drug resistance in parasite and differential distribution and insecticide resistance in vector. Efforts are being made to eradicate malaria but burden of malaria is still increasing. Vector control is essential for malaria prevention strategies. Knowledge of population genetic structure is pre-requisite for determining prevention strategies particularly using transgenic mosquitoes. Population genetic study can predict level of gene flow between different populations. Anopheles stephensi Liston is urban vector of malaria in Indo-Pakistan subcontinent. About 12% of malaria cases of malaria in India are contributed by A. stephensi. Studies conducted on population genetics of A. stephensi using various markers in different parts of the world are discussed in this communication.

  8. A new malaria vector mosquito in South Africa

    Science.gov (United States)

    Burke, Ashley; Dandalo, Leonard; Munhenga, Givemore; Dahan-Moss, Yael; Mbokazi, Frans; Ngxongo, Sifiso; Coetzee, Maureen; Koekemoer, Lizette; Brooke, Basil

    2017-01-01

    South Africa aims to eliminate malaria within its borders by 2018. Despite well-coordinated provincial vector control programmes that are based on indoor residual insecticide spraying, low-level residual malaria transmission continues in the low-altitude border regions of the north-eastern sector of the country. In order to identify the underlying causes of residual transmission, an enhanced vector surveillance system has been implemented at selected sites in the Mpumalanga and KwaZulu-Natal (KZN) provinces. The collection periods for the data presented are March 2015 to April 2016 for Mpumalanga and January 2014 to December 2015 for KZN. The mosquito collection methods used included indoor and outdoor traps based on the use of traditional ceramic pots, modified plastic buckets and exit window traps (KZN only). All Anopheles funestus species group mosquitoes collected were identified to species and all females were screened for the presence of Plasmodium falciparum sporozoites. Two An. vaneedeni females, one from each surveillance site, tested positive for P. falciparum sporozoites. These are the first records of natural populations of An. vaneedeni being infective with P. falciparum. As both specimens were collected from outdoor-placed ceramic pots, these data show that An. vaneedeni likely contributes to residual malaria transmission in South Africa. PMID:28262811

  9. Distribution of the main malaria vectors in Kenya

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    Hay Simon I

    2010-03-01

    Full Text Available Abstract Background A detailed knowledge of the distribution of the main Anopheles malaria vectors in Kenya should guide national vector control strategies. However, contemporary spatial distributions of the locally dominant Anopheles vectors including Anopheles gambiae, Anopheles arabiensis, Anopheles merus, Anopheles funestus, Anopheles pharoensis and Anopheles nili are lacking. The methods and approaches used to assemble contemporary available data on the present distribution of the dominant malaria vectors in Kenya are presented here. Method Primary empirical data from published and unpublished sources were identified for the period 1990 to 2009. Details recorded for each source included the first author, year of publication, report type, survey location name, month and year of survey, the main Anopheles species reported as present and the sampling and identification methods used. Survey locations were geo-positioned using national digital place name archives and on-line geo-referencing resources. The geo-located species-presence data were displayed and described administratively, using first-level administrative units (province, and biologically, based on the predicted spatial margins of Plasmodium falciparum transmission intensity in Kenya for the year 2009. Each geo-located survey site was assigned an urban or rural classification and attributed an altitude value. Results A total of 498 spatially unique descriptions of Anopheles vector species across Kenya sampled between 1990 and 2009 were identified, 53% were obtained from published sources and further communications with authors. More than half (54% of the sites surveyed were investigated since 2005. A total of 174 sites reported the presence of An. gambiae complex without identification of sibling species. Anopheles arabiensis and An. funestus were the most widely reported at 244 and 265 spatially unique sites respectively with the former showing the most ubiquitous distribution

  10. Blood feeding induces hemocyte proliferation and activation in the African malaria mosquito, Anopheles gambiae Giles

    OpenAIRE

    Bryant, William B.; Michel, Kristin

    2014-01-01

    Malaria is a global public health problem, especially in sub-Saharan Africa, where the mosquito Anopheles gambiae Giles serves as the major vector for the protozoan Plasmodium falciparum Welch. One determinant of malaria vector competence is the mosquito's immune system. Hemocytes are a critical component as they produce soluble immune factors that either support or prevent malaria parasite development. However, despite their importance in vector competence, understanding of their basic biolo...

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

    Science.gov (United States)

    Reid, J A

    1980-01-01

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

  12. Impact of highland topography changes on exposure to malaria vectors and immunity in western Kenya

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    Eliningaya Kweka

    2016-10-01

    Full Text Available Background: It is almost an axiom that in the African highlands (above 1500m transmission of P. falciparum is limited primarily by low ambient temperature and that small changes in temperature could result in temporary favourable conditions for unstable transmission within populations that have acquired little functional immunity. The pattern of malaria transmission in the highland plateau ecosystems is less distinct due to the flat topography and diffuse hydrology resulting from numerous streams. The non-homogeneous distribution of larval breeding habitats in east African highlands obviously affects Anopheles spatial distribution which, consequently, leads to heterogeneous human exposure to malaria. Another delicate parameter in the fragile transmission risk of malaria in the highlands is the rapid loss of primary forest due to subsistence agriculture. The implication of this change in land cover on malaria transmission is that deforestation can lead to changes in microclimate of both adult and larval habitats hence increase larvae survival, population density, and gametocytes development in adult mosquitoes. Deforestation has been documented to enhancing vectorial capacity of Anopheles gambiae by nearly 100% compared to forested areas. Method: The study was conducted in five different ecosystems in the western Kenya highlands, two U-shaped valleys (Iguhu, Emutete, two V-shaped valleys (Marani, Fort-Ternan and one plateau (Shikondi for 16 months among 6-15 years old children. Exposure to malaria was tested using circum-sporozoite protein (CSP and merozoite surface protein (MSP immunochromatographic antibody tests. Malaria parasite was examined using different tools which include microscopy based on blood smears, Rapid diagnostic test based on HRP 2 proteins and serology based on human immune response to parasite and vector antigens have been also examined in the highlands in comparison with different topographical systems of western Kenya

  13. Health research ethics in malaria vector trials in Africa.

    Science.gov (United States)

    Kilama, Wen L

    2010-12-13

    Malaria mosquito research in Africa as elsewhere is just over a century old. Early trials for development of mosquito control tools were driven by colonial enterprises and war efforts; they were, therefore, tested in military or colonial settings. The failure of those tools and environmental concerns, coupled with the desperate need for integrated malaria control strategies, has necessitated the development of new malaria mosquito control tools, which are to be tested on humans, their environment and mosquito habitats. Ethical concerns start with phase 2 trials, which pose limited ethical dilemmas. Phase 3 trials, which are undertaken on vulnerable civilian populations, pose ethical dilemmas ranging from individual to community concerns. It is argued that such trials must abide by established ethical principles especially safety, which is mainly enshrined in the principle of non-maleficence. As there is total lack of experience with many of the promising candidate tools (eg genetically modified mosquitoes, entomopathogenic fungi, and biocontrol agents), great caution must be exercised before they are introduced in the field. Since malaria vector trials, especially phase 3 are intrusive and in large populations, individual and community respect is mandatory, and must give great priority to community engagement. It is concluded that new tools must be safe, beneficial, efficacious, effective, and acceptable to large populations in the short and long-term, and that research benefits should be equitably distributed to all who bear the brunt of the research burdens. It is further concluded that individual and institutional capacity strengthening should be provided, in order to undertake essential research, carry out scientific and ethical review, and establish competent regulatory frameworks.

  14. Ecologists can enable communities to implement malaria vector control in Africa

    Directory of Open Access Journals (Sweden)

    Knols Bart GJ

    2006-02-01

    Full Text Available Abstract Background Integrated vector management (IVM for malaria control requires ecological skills that are very scarce and rarely applied in Africa today. Partnerships between communities and academic ecologists can address this capacity deficit, modernize the evidence base for such approaches and enable future scale up. Methods Community-based IVM programmes were initiated in two contrasting settings. On Rusinga Island, Western Kenya, community outreach to a marginalized rural community was achieved by University of Nairobi through a community-based organization. In Dar es Salaam, Tanzania, Ilala Municipality established an IVM programme at grassroots level, which was subsequently upgraded and expanded into a pilot scale Urban Malaria Control Programme with support from national academic institutes. Results Both programmes now access relevant expertise, funding and policy makers while the academic partners benefit from direct experience of community-based implementation and operational research opportunities. The communities now access up-to-date malaria-related knowledge and skills for translation into local action. Similarly, the academic partners have acquired better understanding of community needs and how to address them. Conclusion Until sufficient evidence is provided, community-based IVM remains an operational research activity. Researchers can never directly support every community in Africa so community-based IVM strategies and tactics will need to be incorporated into undergraduate teaching programmes to generate sufficient numbers of practitioners for national scale programmes. Academic ecologists at African institutions are uniquely positioned to enable the application of practical environmental and entomological skills for malaria control by communities at grassroots level and should be supported to fulfil this neglected role.

  15. Vector control in a malaria epidemic occurring within a complex emergency situation in Burundi: a case study

    Directory of Open Access Journals (Sweden)

    D'Alessandro Umberto

    2007-07-01

    Full Text Available Abstract Background African highlands often suffer of devastating malaria epidemics, sometimes in conjunction with complex emergencies, making their control even more difficult. In 2000, Burundian highlands experienced a large malaria outbreak at a time of civil unrest, constant insecurity and nutritional emergency. Because of suspected high resistance to the first and second line treatments, the provincial health authority and Médecins Sans Frontières (Belgium decided to implement vector control activities in an attempt to curtail the epidemic. There are few reported interventions of this type to control malaria epidemics in complex emergency contexts. Here, decisions and actions taken to control this epidemic, their impact and the lessons learned from this experience are reported. Case description Twenty nine hills (administrative areas were selected in collaboration with the provincial health authorities for the vector control interventions combining indoor residual spraying with deltamethrin and insecticide-treated nets. Impact was evaluated by entomological and parasitological surveys. Almost all houses (99% were sprayed and nets use varied between 48% and 63%. Anopheles indoor resting density was significantly lower in treated as compared to untreated hills, the latter taken as controls. Despite this impact on the vector, malaria prevalence was not significantly lower in treated hills except for people sleeping under a net. Discussion Indoor spraying was feasible and resulted in high coverage despite being a logistically complex intervention in the Burundian context (scattered houses and emergency situation. However, it had little impact on the prevalence of malaria infection, possibly because it was implemented after the epidemic's peak. Nevertheless, after this outbreak the Ministry of Health improved the surveillance system, changed its policy with introduction of effective drugs and implementation of vector control to prevent new

  16. Iron deficiency and malaria as determinants of anaemia in African children

    NARCIS (Netherlands)

    Verhoef, H.

    2001-01-01

    Approximately three quarters of east African children <5 y of age suffer from anaemia, which is due, at least in part, to malaria and iron deficiency. In children in areas of seasonal malaria, the benefits of iron supplementation may not outweigh possible inherent risks of adverse effects caused

  17. [INSECTICIDE RESISTANCE IN MAJOR MALARIA VECTORS IN UZBEKISTAN].

    Science.gov (United States)

    Zhakhongirov, Sh M; Saifiev, Sh T; Abidov, Z I

    2016-01-01

    The resistance of Anopheles artemievi to DDT (26.7%) and propoxur (80.0%) was established in the kishlak of Chubat, Bulungursky District, Samarkand Viloyati and that in the kishlak of Rastguzar, Uichinsky District, Namangan Viloyati, was 45.0 and 22.5%, respectively. In the kishlak of Navruz, Kanlikulsky District, Republic of Karakalpakstan, there was reduced propoxur susceptibil- ity (90.0% An. superpictus death); in other human settle- ments, An. artemievi was susceptible--100% death in the use of the test insecticides. An. superpictus proved to be susceptive to 7 test insecticides (other than propoxur). In Uzbekistan, the resistance of An. artemievi was noted only in a small area. Among the major malaria vectors, An. superpictus remained susceptible to pyrethroid insec- ticides.

  18. How effective is integrated vector management against malaria and lymphatic filariasis where the diseases are transmitted by the same vector?

    Directory of Open Access Journals (Sweden)

    Christopher M Stone

    2014-12-01

    Full Text Available The opportunity to integrate vector management across multiple vector-borne diseases is particularly plausible for malaria and lymphatic filariasis (LF control where both diseases are transmitted by the same vector. To date most examples of integrated control targeting these diseases have been unanticipated consequences of malaria vector control, rather than planned strategies that aim to maximize the efficacy and take the complex ecological and biological interactions between the two diseases into account.We developed a general model of malaria and LF transmission and derived expressions for the basic reproductive number (R0 for each disease. Transmission of both diseases was most sensitive to vector mortality and biting rate. Simulating different levels of coverage of long lasting-insecticidal nets (LLINs and larval control confirms the effectiveness of these interventions for the control of both diseases. When LF was maintained near the critical density of mosquitoes, minor levels of vector control (8% coverage of LLINs or treatment of 20% of larval sites were sufficient to eliminate the disease. Malaria had a far greater R0 and required a 90% population coverage of LLINs in order to eliminate it. When the mosquito density was doubled, 36% and 58% coverage of LLINs and larval control, respectively, were required for LF elimination; and malaria elimination was possible with a combined coverage of 78% of LLINs and larval control.Despite the low level of vector control required to eliminate LF, simulations suggest that prevalence of LF will decrease at a slower rate than malaria, even at high levels of coverage. If representative of field situations, integrated management should take into account not only how malaria control can facilitate filariasis elimination, but strike a balance between the high levels of coverage of (multiple interventions required for malaria with the long duration predicted to be required for filariasis elimination.

  19. The role of research in molecular entomology in the fight against malaria vectors.

    Science.gov (United States)

    della Torre, A; Arca, B; Favia, G; Petrarca, V; Coluzzi, M

    2008-06-01

    The text summarizes the principal current fields of investigation and the recent achievements of the research groups presently contributing to the Molecular Entomology Cluster of the Italian Malaria Network. Particular emphasis is given to the researches with a more direct impact on the fight against malaria vectors.

  20. Modeling larval malaria vector habitat locations using landscape features and cumulative precipitation measures

    NARCIS (Netherlands)

    Mc Cann, R.S.; Messina, J.P.; MacFarlane, D.W.; Bayoh, M.N.; Vulule, J.M.; Gimnig, J.E.; Walker, E.D.

    2014-01-01

    BACKGROUND: Predictive models of malaria vector larval habitat locations may provide a basis for understanding the spatial determinants of malaria transmission. METHODS: We used four landscape variables (topographic wetness index [TWI], soil type, land use-land cover, and distance to stream) and acc

  1. Mapping of Malaria Vectors at District Level in India: Changing Scenario and Identified Gaps.

    Science.gov (United States)

    Singh, Poonam; Lingala, Mercy Aparna L; Sarkar, Soma; Dhiman, Ramesh C

    2017-02-01

    Malaria is one of the six major vector-borne diseases in India, the endemicity of which changes with changes in ecological, climatic, and sociodevelopmental conditions. The anopheline vectors are greatly affected by ecological conditions such as deforestation, urbanization, climate and lifestyle. Despite the advent of tools such as Geographic Information System (GIS), the updated information on the distribution of anopheline vectors of malaria is not available. In India, the plan for vector control is organized at subcentral level but information about vectors is unavailable even at the district level. Therefore, a systematic presentation of vector distribution has been made to provide maps in respect of major vector species. A search of the literature for major vector species, that is, Anopheles culicifacies, Anopheles fluviatilis, Anopheles stephensi, Anopheles minimus, and Anopheles dirus sensu lato, since 1927 till 2015 was carried out. Data have been presented as present, absent, and no information about vector species during pre-eradication (1927-1958), posteradication (1959-1999), and current scenario (2000-2015). Vectors' distribution and malaria endemicity were mapped using Arc GIS. Of 630 districts of India, major vectors An. culicifacies, An. fluviatilis, and An. stephensi were present in 420, 241, and 243 districts, respectively. In 183 districts, there is no information on any major malaria vector species although 27 of them from the states of Arunachal Pradesh, Jharkhand, Manipur, and Mizoram are highly endemic for malaria, having incidences of 2-40 cases/1000/year. The identified gaps in vector distribution, particularly in malaria endemic areas, necessitate further surveys so as to generate the missing information.

  2. Avoidance behavior to essential oils by Anopheles minimus, a malaria vector in Thailand

    Science.gov (United States)

    Excito-repellency tests were used to characterize behavioral responses of laboratory colonized Anopheles minimus, a malaria vector in Thailand, using four essential oils, citronella (Cymbopogom nadus), hairy basil (Ocimum americanum), sweet basil (Ocimum basilicum), vetiver (Vetiveria zizanioides), ...

  3. Development of Fungal Applications on Netting Substrates for Malaria Vector Control

    NARCIS (Netherlands)

    Farenhorst, M.; Hilhorst, A.; Thomas, M.B.; Knols, B.G.J.

    2011-01-01

    Mosquito resistance to chemical insecticides is considered a serious threat for the sustainable use of contemporary malaria vector control methods. Fungal entomopathogens show potential as alternative biological control agents against (insecticide-resistant) anophelines. This study was designed to t

  4. Using a geographical-information-system-based decision support to enhance malaria vector control in zambia.

    Science.gov (United States)

    Chanda, Emmanuel; Mukonka, Victor Munyongwe; Mthembu, David; Kamuliwo, Mulakwa; Coetzer, Sarel; Shinondo, Cecilia Jill

    2012-01-01

    Geographic information systems (GISs) with emerging technologies are being harnessed for studying spatial patterns in vector-borne diseases to reduce transmission. To implement effective vector control, increased knowledge on interactions of epidemiological and entomological malaria transmission determinants in the assessment of impact of interventions is critical. This requires availability of relevant spatial and attribute data to support malaria surveillance, monitoring, and evaluation. Monitoring the impact of vector control through a GIS-based decision support (DSS) has revealed spatial relative change in prevalence of infection and vector susceptibility to insecticides and has enabled measurement of spatial heterogeneity of trend or impact. The revealed trends and interrelationships have allowed the identification of areas with reduced parasitaemia and increased insecticide resistance thus demonstrating the impact of resistance on vector control. The GIS-based DSS provides opportunity for rational policy formulation and cost-effective utilization of limited resources for enhanced malaria vector control.

  5. Malaria vector control practices in an irrigated rice agro-ecosystem in central Kenya and implications for malaria control

    Directory of Open Access Journals (Sweden)

    Ng'ang'a Peter N

    2008-07-01

    Full Text Available Abstract Background Malaria transmission in most agricultural ecosystems is complex and hence the need for developing a holistic malaria control strategy with adequate consideration of socio-economic factors driving transmission at community level. A cross-sectional household survey was conducted in an irrigated ecosystem with the aim of investigating vector control practices applied and factors affecting their application both at household and community level. Methods Four villages representing the socio-economic, demographic and geographical diversity within the study area were purposefully selected. A total of 400 households were randomly sampled from the four study villages. Both semi-structured questionnaires and focus group discussions were used to gather both qualitative and quantitative data. Results The results showed that malaria was perceived to be a major public health problem in the area and the role of the vector Anopheles mosquitoes in malaria transmission was generally recognized. More than 80% of respondents were aware of the major breeding sites of the vector. Reported personal protection methods applied to prevent mosquito bites included; use of treated bed nets (57%, untreated bed nets (35%, insecticide coils (21%, traditional methods such as burning of cow dung (8%, insecticide sprays (6%, and use of skin repellents (2%. However, 39% of respondents could not apply some of the known vector control methods due to unaffordability (50.5%, side effects (19.9%, perceived lack of effectiveness (16%, and lack of time to apply (2.6%. Lack of time was the main reason (56.3% reported for non-application of environmental management practices, such as draining of stagnant water (77% and clearing of vegetations along water canals (67%. Conclusion The study provides relevant information necessary for the management, prevention and control of malaria in irrigated agro-ecosystems, where vectors of malaria are abundant and disease

  6. Molecular evolution and population genetics of a Gram-negative binding protein gene in the malaria vector Anopheles gambiae (sensu lato)

    OpenAIRE

    Salgueiro, Patrícia; Lopes, Ana Sofia; Mendes, Cristina; Charlwood, Jacques Derek; Arez, Ana Paula; Pinto, João; Silveira, Henrique

    2016-01-01

    Background Clarifying the role of the innate immune system of the malaria vector Anopheles gambiae is a potential way to block the development of the Plasmodium parasites. Pathogen recognition is the first step of innate immune response, where pattern recognition proteins like GNBPs play a central role. Results We analysed 70 sequences of the protein coding gene GNBPB2 from two species, Anopheles gambiae (s.s.) and An. coluzzii, collected in six African countries. We detected 135 segregating ...

  7. A predator from East Africa that chooses malaria vectors as preferred prey.

    Directory of Open Access Journals (Sweden)

    Ximena J Nelson

    Full Text Available BACKGROUND: All vectors of human malaria, a disease responsible for more than one million deaths per year, are female mosquitoes from the genus Anopheles. Evarcha culicivora is an East African jumping spider (Salticidae that feeds indirectly on vertebrate blood by selecting blood-carrying female mosquitoes as preferred prey. METHODOLOGY/PRINCIPAL FINDINGS: By testing with motionless lures made from mounting dead insects in lifelike posture on cork discs, we show that E. culicivora selects Anopheles mosquitoes in preference to other mosquitoes and that this predator can identify Anopheles by static appearance alone. Tests using active (grooming virtual mosquitoes rendered in 3-D animation show that Anopheles' characteristic resting posture is an important prey-choice cue for E. culicivora. Expression of the spider's preference for Anopheles varies with the spider's size, varies with its prior feeding condition and is independent of the spider gaining a blood meal. CONCLUSIONS/SIGNIFICANCE: This is the first experimental study to show that a predator of any type actively chooses Anopheles as preferred prey, suggesting that specialized predators having a role in the biological control of disease vectors is a realistic possibility.

  8. Spatio-temporal distribution of malaria vectors (Diptera:Culicidae) across different climatic zones of Iran

    Institute of Scientific and Technical Information of China (English)

    Ahmad Ali Hanafi-Bojd; Shahyad Azari-Hamidian; Hassan Vatandoost; Zabihollah Charrahy

    2011-01-01

    Malaria is a main vector-borne public health problem in Iran. The last studies on Iranian mosquitoes show 31 Anopheles species including different sibling species and genotypes, eight of them are reported to play role in malaria transmission. The objective of this study is to provide a reference for malaria vectors of Iran and to map their spatial and temporal distribution in different climatic zones. Shape files of administrative boundaries and climates of Iran were provided by National Cartographic Center. Data on distribution and seasonal activity of malaria vectors were obtained from different sources and a databank in district level was created in Excel 2003, inserted to the shape files and analyzed by ArcGIS 9.2 to provide the maps. Anopheles culicifacies Giles s.l., Anopheles dthali Patton, Anopheles fluviatilis James s.l., Anopheles maculipennis Meigen s.l., Anopheles sacharovi Favre, Anopheles stephensi Liston, and Anopheles superpictus Grassi have been introduced as primary and secondary malaria vectors and Anopheles pulcherrimus Theobald as a suspected vector in Iran. Temporal distribution of anopheline mosquitoes is restricted to April-December in northern Iran, however mosquitoes can be found during the year in southern region. Spatial distribution of malaria vectors is different based on species, thus six of them (except for Anopheles maculipennis s.l. and Anopheles sacharovi) are reported from endemic malarious area in southern and southeastern areas of Iran. The climate of this part is usually warm and humid, which makes it favorable for mosquito rearing and malaria transmission. Correlation between climate conditions and vector distribution can help to predict the potential range of activity for each species and preparedness for malaria epidemics.

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

    Directory of Open Access Journals (Sweden)

    Prapa Sorosjinda-Nunthawarasilp

    2014-01-01

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

  10. First results of phase 3 trial of RTS,S/AS01 malaria vaccine in African children

    DEFF Research Database (Denmark)

    Agnandji, Selidji Todagbe; Lell, Bertrand; Soulanoudjingar, Solange Solmeheim

    2011-01-01

    An ongoing phase 3 study of the efficacy, safety, and immunogenicity of candidate malaria vaccine RTS,S/AS01 is being conducted in seven African countries.......An ongoing phase 3 study of the efficacy, safety, and immunogenicity of candidate malaria vaccine RTS,S/AS01 is being conducted in seven African countries....

  11. Tumor Necrosis Factor and Lymphotoxin-α Polymorphisms and Severe Malaria in African Populations

    OpenAIRE

    Taane G Clark; Diakite, Mahamadou; Auburn, Sarah; Campino, Susana; Fry, Andrew E.; Green, Angela; Richardson, Anna; Small, Kerrin; Teo, Yik Y; Wilson, Jonathan; Jallow, Muminatou; Sisay-Joof, Fatou; Pinder, Margaret; Griffiths, Michael J.; Peshu, Norbert

    2009-01-01

    The tumor necrosis factor gene (TNF) and lymphotoxin-α gene (LTA) have long attracted attention as candidate genes for susceptibility traits for malaria, and several of their polymorphisms have been found to be associated with severe malaria (SM) phenotypes. In a large study involving > 10,000 individuals and encompassing 3 African populations, we found evidence to support the reported associations between the TNF −238 polymorphism and SM in The Gambia. However, no TNF/LTA polymorphisms were ...

  12. Participation of African social scientists in malaria control: identifying enabling and constraining factors

    Directory of Open Access Journals (Sweden)

    Nyamongo Isaac

    2004-12-01

    Full Text Available Abstract Objective To examine the enabling and constraining factors that influence African social scientists involvement in malaria control. Methods Convenience and snowball sampling was used to identify participants. Data collection was conducted in two phases: a mailed survey was followed by in-depth phone interviews with selected individuals chosen from the survey. Findings Most participants did not necessarily seek malaria as a career path. Having a mentor who provided research and training opportunities, and developing strong technical skills in malaria control and grant or proposal writing facilitated career opportunities in malaria. A paucity of jobs and funding and inadequate technical skills in malaria limited the type and number of opportunities available to social scientists in malaria control. Conclusion Understanding the factors that influence job satisfaction, recruitment and retention in malaria control is necessary for better integration of social scientists into malaria control. However, given the wide array of skills that social scientists have and the variety of deadly diseases competing for attention in Sub Saharan Africa, it might be more cost effective to employ social scientists to work broadly on issues common to communicable diseases in general rather than solely on malaria.

  13. Participatory Risk Mapping of Malaria Vector Exposure in Northern South America using Environmental and Population Data.

    Science.gov (United States)

    Fuller, D O; Troyo, A; Alimi, T O; Beier, J C

    2014-03-01

    Malaria elimination remains a major public health challenge in many tropical regions, including large areas of northern South America. In this study, we present a new high spatial resolution (90 × 90 m) risk map for Colombia and surrounding areas based on environmental and human population data. The map was created through a participatory multi-criteria decision analysis in which expert opinion was solicited to determine key environmental and population risk factors, different fuzzy functions to standardize risk factor inputs, and variable factor weights to combine risk factors in a geographic information system. The new risk map was compared to a map of malaria cases in which cases were aggregated to the municipio (municipality) level. The relationship between mean municipio risk scores and total cases by muncípio showed a weak correlation. However, the relationship between pixel-level risk scores and vector occurrence points for two dominant vector species, Anopheles albimanus and An. darlingi, was significantly different (p < 0.05) from a random point distribution, as was a pooled point distribution for these two vector species and An. nuneztovari. Thus, we conclude that the new risk map derived based on expert opinion provides an accurate spatial representation of risk of potential vector exposure rather than malaria transmission as shown by the pattern of malaria cases, and therefore it may be used to inform public health authorities as to where vector control measures should be prioritized to limit human-vector contact in future malaria outbreaks.

  14. Direct and indirect immunosuppression by a malaria parasite in its mosquito vector

    NARCIS (Netherlands)

    Boëte, C.H.J.J.; Paul, R.E.L.; Koëlla, J.C.

    2004-01-01

    Malaria parasites develop as oocysts within the haemocoel of their mosquito vector during a period that is longer than the average lifespan of many of their vectors. How can they escape from the mosquito's immune responses during their long development? Whereas older oocysts might camouflage themsel

  15. The distribution and bionomics of anopheles malaria vector mosquitoes in Indonesia.

    Science.gov (United States)

    Elyazar, Iqbal R F; Sinka, Marianne E; Gething, Peter W; Tarmidzi, Siti N; Surya, Asik; Kusriastuti, Rita; Winarno; Baird, J Kevin; Hay, Simon I; Bangs, Michael J

    2013-01-01

    Malaria remains one of the greatest human health burdens in Indonesia. Although Indonesia has a long and renowned history in the early research and discoveries of malaria and subsequently in the successful use of environmental control methods to combat the vector, much remains unknown about many of these mosquito species. There are also significant gaps in the existing knowledge on the transmission epidemiology of malaria, most notably in the highly malarious eastern half of the archipelago. These compound the difficulty of developing targeted and effective control measures. The sheer complexity and number of malaria vectors in the country are daunting. The difficult task of summarizing the available information for each species and/or species complex is compounded by the patchiness of the data: while relatively plentiful in one area or region, it can also be completely lacking in others. Compared to many other countries in the Oriental and Australasian biogeographical regions, only scant information on vector bionomics and response to chemical measures is available in Indonesia. That information is often either decades old, geographically patchy or completely lacking. Additionally, a large number of information sources are published in Dutch or Indonesian language and therefore less accessible. This review aims to present an updated overview of the known distribution and bionomics of the 20 confirmed malaria vector species or species complexes regarded as either primary or secondary (incidental) malaria vectors within Indonesia. This chapter is not an exhaustive review of each of these species. No attempt is made to specifically discuss or resolve the taxonomic record of listed species in this document, while recognizing the ever evolving revisions in the systematics of species groups and complexes. A review of past and current status of insecticide susceptibility of eight vector species of malaria is also provided.

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

    DEFF Research Database (Denmark)

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

    2006-01-01

    Anopheles darlingi is the primary malaria vector in Latin America, and is especially important in Amazonian is the primary malaria vector in Latin America, and is especially important in Amazonian Brazil. Historically, control efforts have been focused on indoor house spraying using a variety...... malaria epidemic. In contrast, although An. darlingi was eradicated from some districts of the city of Belem (the capital of Para State) in 1968 to reduce malaria, populations around the water protection area in the eastern district were treated only briefly. To investigate the population structure of An...

  17. Molecular biological approaches to the study of vectors in relation to malaria control

    Directory of Open Access Journals (Sweden)

    J. M. Crampton

    1992-01-01

    Full Text Available To a large extent, control of malaria vectors relies on the elimination of breeding sites and the application of chemical agents. There are increasing problems associated with the use of synthetic insecticides for vector control, including the evolution of resistance, the high cost of developing and registering new insecticides and an awareness of pollution from insecticide residues. These factors have stimulated interest in the application of molecular biology to the study of mosquito vectors of malaria; focussing primarily on two aspects. First, the improvement of existing control measures through the development of simplified DNA probe systems suitable for identification of vectors of malaria. The development of synthetic, non-radioactive DNA probes suitable for identification of species in the Anopheles gambiae complex is described with the aim of defining a simplified methodology wich is suitable for entomologist in the field. The second aspect to be considered is the development of completely novel strategies through the development of completely novel strategies through the genetic manipulation of insect vectors of malaria in order to alter their ability to transmit the disease. The major requirements for producing transgenic mosquitoes are outlined together with the progress wich has been made to date and discussed in relation to the prospects which this type of approach has for the future control of malaria.

  18. Malaria, anaemia and antimalarial drug resistance in African children

    NARCIS (Netherlands)

    Obonyo, C.O.

    2006-01-01

    Malaria-associated anaemia is a potentially preventable cause of severe morbidity and mortality in children < 5years of age, in areas of high malaria transmission in sub-Saharan Africa. In a cross-sectional study of 3586 children, 80% were anaemic (haemoglobin [Hb]<11g/dL) and 3% had severe anaemia

  19. Vector incrimination and effects of antimalarial drugs on malaria transmission and control in the Amazon Basin of Brazil

    Directory of Open Access Journals (Sweden)

    T. A. Klein

    1992-01-01

    Full Text Available World ecosystems differ significantly and a multidisciplinary malaria control approach must be adjusted to meet these requirements. These include a comprehensive understanding of the malaria vectors, their behavior, seasonal distribution and abundance, susceptibility to insecticides (physiological and behavioral, methods to reduce the numbers of human gametocyte carriers through effective health care systems and antimalarial drug treatment, urban malaria transmission versus rural or forest malaria transmission, and the impact of vaccine development. Many malaria vectors are members of species complexes and individual relationship to malaria transmission, seasonal distribution, bitting behavior, etc. is poorly understood. Additionaly, malaria patients are not examined for circulating gametocytes and both falciparum and vivax malaria patients may be highly infective to mosquitoes after treatment with currently used antimalarial drugs. Studies on the physiological and behavioral effects of DDT and other insecticides are inconclusive and need to be evalusted.

  20. Asymptomatic malaria in refugees living in a non-endemic South African city.

    Directory of Open Access Journals (Sweden)

    Joyce M Tsoka-Gwegweni

    Full Text Available BACKGROUND: Asymptomatic malaria infection in refugees is both a threat to the lives of the individuals and the public in the host country. Although South Africa has been experiencing an unprecedented influx of refugees since 1994, data on malaria infection among refugees is lacking. Such information is critical since South Africa is among the countries that have planned to eliminate malaria. The objective of this study was to determine prevalence of asymptomatic malaria infection among a refugee population living in a city of KwaZulu-Natal province, South Africa. METHODS AND FINDINGS: A survey was conducted on adult refugee participants who attended a faith-based facility offering social services in a city of KwaZulu-Natal province, South Africa. The participants were screened for the presence of malaria using rapid diagnostic tests and microscopy. Demographic data for the participants were obtained using a closed ended questionnaire. Data was obtained for 303 participants consisting of 51.5% females and 47.5% males, ranging from 19 to 64 years old. More than 95% of them originated from sub-Saharan African countries. Two hundred and ninety participants provided a blood sample for screening of malaria. Of these, 3.8% tested positive for rapid diagnostic test and 5.9% for microscopy. The majority of malaria infections were due to Plasmodium falciparum. CONCLUSIONS: The study confirms the presence of asymptomatic malaria infections among a refugee population residing in a city of KwaZulu-Natal province that is not endemic for malaria. The results have important implications for both public health and malaria control in South Africa, particularly since the country has decided to eliminate malaria by 2018. To achieve this goal, South Africa needs to expand research, surveillance and elimination activities to include non-endemic areas, particularly with high refugee populations. We further recommend use of powerful diagnostic tests such as PCR for

  1. First report of the infection of insecticide-resistant malaria vector mosquitoes with an entomopathogenic fungus under field conditions

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    Akogbéto Martin

    2011-02-01

    Full Text Available Abstract Background Insecticide-resistant mosquitoes are compromising the ability of current mosquito control tools to control malaria vectors. A proposed new approach for mosquito control is to use entomopathogenic fungi. These fungi have been shown to be lethal to both insecticide-susceptible and insecticide-resistant mosquitoes under laboratory conditions. The goal of this study was to see whether entomopathogenic fungi could be used to infect insecticide-resistant malaria vectors under field conditions, and to see whether the virulence and viability of the fungal conidia decreased after exposure to ambient African field conditions. Methods This study used the fungus Beauveria bassiana to infect the insecticide-resistant malaria vector Anopheles gambiae s.s (Diptera: Culicidae VKPER laboratory colony strain. Fungal conidia were applied to polyester netting and kept under West African field conditions for varying periods of time. The virulence of the fungal-treated netting was tested 1, 3 and 5 days after net application by exposing An. gambiae s.s. VKPER mosquitoes in WHO cone bioassays carried out under field conditions. In addition, the viability of B. bassiana conidia was measured after up to 20 days exposure to field conditions. Results The results show that B. bassiana infection caused significantly increased mortality with the daily risk of dying being increased by 2.5× for the fungus-exposed mosquitoes compared to the control mosquitoes. However, the virulence of the B. bassiana conidia decreased with increasing time spent exposed to the field conditions, the older the treatment on the net, the lower the fungus-induced mortality rate. This is likely to be due to the climate because laboratory trials found no such decline within the same trial time period. Conidial viability also decreased with increasing exposure to the net and natural abiotic environmental conditions. After 20 days field exposure the conidial viability was 30%, but

  2. First report of the infection of insecticide-resistant malaria vector mosquitoes with an entomopathogenic fungus under field conditions

    Science.gov (United States)

    2011-01-01

    Background Insecticide-resistant mosquitoes are compromising the ability of current mosquito control tools to control malaria vectors. A proposed new approach for mosquito control is to use entomopathogenic fungi. These fungi have been shown to be lethal to both insecticide-susceptible and insecticide-resistant mosquitoes under laboratory conditions. The goal of this study was to see whether entomopathogenic fungi could be used to infect insecticide-resistant malaria vectors under field conditions, and to see whether the virulence and viability of the fungal conidia decreased after exposure to ambient African field conditions. Methods This study used the fungus Beauveria bassiana to infect the insecticide-resistant malaria vector Anopheles gambiae s.s (Diptera: Culicidae) VKPER laboratory colony strain. Fungal conidia were applied to polyester netting and kept under West African field conditions for varying periods of time. The virulence of the fungal-treated netting was tested 1, 3 and 5 days after net application by exposing An. gambiae s.s. VKPER mosquitoes in WHO cone bioassays carried out under field conditions. In addition, the viability of B. bassiana conidia was measured after up to 20 days exposure to field conditions. Results The results show that B. bassiana infection caused significantly increased mortality with the daily risk of dying being increased by 2.5× for the fungus-exposed mosquitoes compared to the control mosquitoes. However, the virulence of the B. bassiana conidia decreased with increasing time spent exposed to the field conditions, the older the treatment on the net, the lower the fungus-induced mortality rate. This is likely to be due to the climate because laboratory trials found no such decline within the same trial time period. Conidial viability also decreased with increasing exposure to the net and natural abiotic environmental conditions. After 20 days field exposure the conidial viability was 30%, but the viability of control

  3. Productivity of malaria vectors from different habitat types in the western Kenya highlands.

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    Bryson A Ndenga

    Full Text Available BACKGROUND: Mosquito Larval Source Management (LSM could be a valuable additional tool for integrated malaria vector control especially in areas with focal transmission like the highlands of western Kenya if it were not for the need to target all potential habitats at frequent intervals. The ability to determine the productivity of malaria vectors from identified habitats might be used to target LSM only at productive ones. METHODS: Each aquatic habitat within three highland sites in western Kenya was classified as natural swamp, cultivated swamp, river fringe, puddle, open drain or burrow pit. Three habitats of each type were selected in each site in order to study the weekly productivity of adult malaria vectors from February to May 2009 using a sweep-net and their habitat characteristics recorded. RESULTS: All surveyed habitat types produced adult malaria vectors. Mean adult productivity of Anopheles gambiae sensu lato in puddles (1.8/m(2 was 11-900 times higher than in the other habitat types. However, puddles were the most unstable habitats having water at 43% of all sampling occasions and accounted for 5% of all habitats mapped in the study areas whereas open drains accounted for 72%. Densities of anopheline late instars larvae significantly increased with the presence of a biofilm but decreased with increasing surface area or when water was flowing. Taking stability and frequency of the habitat into account, puddles were still the most productive habitat types for malaria vectors but closely followed by open drains. CONCLUSION: Even though productivity of An. gambiae s.l. was greatest in small and unstable habitats, estimation of their overall productivity in an area needs to consider the more stable habitats over time and their surface extension. Therefore, targeting only the highly productive habitats is unlikely to provide sufficient reduction in malaria vector densities.

  4. Strengthening malaria prevention and control: integrating West African militaries' malaria control efforts. The inaugural meeting of the West African Malaria Task Force, April 24-26, 2013, Accra, Ghana.

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    McCollum, Jeffrey T; Hanna, Refaat; Halbach, Alaina C; Cummings, James F

    2015-01-01

    From April 24 to 26, 2013, the Armed Forces Health Surveillance Center and the U.S. Africa Command cosponsored the inaugural meeting of the West Africa Malaria Task Force in Accra, Ghana. The meeting's purpose was to identify common challenges, explore regional and transcontinental collaborations, and to share knowledge about best practices in the fight against malaria in West Africa. Military representatives from Benin, Burkina Faso, Ghana, Liberia, Niger, Nigeria, Senegal, and Togo participated in the Task Force; various U.S. Government agencies were also represented, including the Department of Defense, the Centers for Disease Control and Prevention, and the Agency for International Development. African nation participants presented brief overviews of their military's malaria prevention and control measures, surveillance programs, diagnostic capabilities, and treatment regimens emphasizing gaps within existing programs. Representatives from U.S. agencies discussed activities and capabilities relevant for the region, challenges and lessons learned regarding malaria, and highlighted opportunities for enhanced partnerships to counter malaria in West Africa. This article summarizes the major conclusions of the Task Force meeting, identifies relevant focus areas for future Task Force activities, and outlines opportunities for further inclusion of West African militaries to improve regional malaria surveillance and control efforts.

  5. Fungal infection counters insecticide resistance in African malaria mosquitoes

    NARCIS (Netherlands)

    Farenhorst, M.; Mouatcho, J.C.; Kikankie, C.K.; Brooke, B.D.; Hunt, R.H.; Thomas, M.B.; Koekemoer, L.L.; Knols, B.G.J.; Coetzee, M.

    2009-01-01

    The evolution of insecticide resistance in mosquitoes is threatening the effectiveness and sustainability of malaria control programs in various parts of the world. Through their unique mode of action, entomopathogenic fungi provide promising alternatives to chemical control. However, potential inte

  6. Treatment of African children with severe malaria - towards evidence-informed clinical practice using GRADE

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    English Mike

    2011-07-01

    Full Text Available Abstract Background Severe malaria is a major contributor of deaths in African children up to five years of age. One valuable tool to support health workers in the management of diseases is clinical practice guidelines (CPGs developed using robust methods. A critical assessment of the World Health Organization (WHO and Kenyan paediatric malaria treatment guidelines with quinine was undertaken, with a focus on the quality of the evidence and transparency of the shift from evidence to recommendations. Methods Systematic reviews of the literature were conducted using the Grading of Recommendations Assessment, Development and Evaluation (GRADE tool to appraise included studies. The findings were used to evaluate the WHO and Kenyan recommendations for the management of severe childhood malaria. Results The WHO 2010 malaria guidance on severe malaria in children, which informed the Kenyan guidelines, only evaluated the evidence on one topic on paediatric care using the GRADE tool. Using the GRADE tool, this work explicitly demonstrated that despite the established use of quinine in the management of paediatric cases of severe malaria for decades, low or very low quality evidence of important outcomes, but not critical outcomes such as mortality, have informed national and international guidance on the paediatric quinine dosing, route of administration and adverse effects. Conclusions Despite the foreseeable shift to artesunate as the primary drug for treatment of severe childhood malaria, the findings reported here reflect that the particulars of quinine therapeutics for the management of severe malaria in African children have historically been a neglected research priority. This work supports the application of the GRADE tool to make transparent recommendations and to inform advocacy efforts for a greater research focus in priority areas in paediatric care in Africa and other low-income settings.

  7. The decline of malaria in Finland – the impact of the vector and social variables

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    Hulden Larry

    2009-05-01

    Full Text Available Abstract Background Malaria was prevalent in Finland in the 18th century. It declined slowly without deliberate counter-measures and the last indigenous case was reported in 1954. In the present analysis of indigenous malaria in Finland, an effort was made to construct a data set on annual malaria cases of maximum temporal length to be able to evaluate the significance of different factors assumed to affect malaria trends. Methods To analyse the long-term trend malaria statistics were collected from 1750–2008. During that time, malaria frequency decreased from about 20,000 – 50,000 per 1,000,000 people to less than 1 per 1,000,000 people. To assess the cause of the decline, a correlation analysis was performed between malaria frequency per million people and temperature data, animal husbandry, consolidation of land by redistribution and household size. Results Anopheles messeae and Anopheles beklemishevi exist only as larvae in June and most of July. The females seek an overwintering place in August. Those that overwinter together with humans may act as vectors. They have to stay in their overwintering place from September to May because of the cold climate. The temperatures between June and July determine the number of malaria cases during the following transmission season. This did not, however, have an impact on the long-term trend of malaria. The change in animal husbandry and reclamation of wetlands may also be excluded as a possible cause for the decline of malaria. The long-term social changes, such as land consolidation and decreasing household size, showed a strong correlation with the decline of Plasmodium. Conclusion The indigenous malaria in Finland faded out evenly in the whole country during 200 years with limited or no counter-measures or medication. It appears that malaria in Finland was basically a social disease and that malaria trends were strongly linked to changes in human behaviour. Decreasing household size caused

  8. Bio-ecology of malaria vectors in an endemic area, Southeast of Iran

    Institute of Scientific and Technical Information of China (English)

    Masoud Yeryan; Hamid Rreza Basseri; Ahamd Ali Hanafi-Bojd; Ahmad Raeisi; Hamideh Edalat; Reza Safari

    2016-01-01

    Objective: To determine some bio-ecological aspects of malaria vectors in Jask County, where is targeted for malaria elimination in the national program. Methods: Mosquitoes were collected monthly during 2013-2014 using different collection methods. Subsequently, ELISA test was used to detect the human blood index of mosquitoes. The susceptibility status of Anopheles stephensi was evaluated against the diagnostic dosages of seven WHO recommended insecticides. Results: A total of 3 650 female and 4 736 Anopheles larvae were collected including Anopheles stephensi, Anopheles culicifacies s.l., Anopheles dthali, Anopheles fluviatilis s.l., Anopheles moghulensis and Anopheles turkhodi species. Anopheles stephensi was the dominant collected species on human baits and indoors with high rate of unfed and gravid specimens in internal and external window traps. Human blood index was calculated as 14.3% for this species. It was also found to be resistant to DDT and Dieldrin. Conclusions: The collected species had a wide range of habitats, and resting behaviors. With regarding to the presence of most important malaria vectors in Jask, control of the disease may be so complicated; as based on the weather condition it can be transmitted during the whole year, except for cold months. With this strong potential of transmission, existing population movements in the area may lead to imported cases of malaria and local outbreak(s). So, more specific studies on malaria vectors in high risk areas of Jask County are recommended.

  9. Allelic Variation of Cytochrome P450s Drives Resistance to Bednet Insecticides in a Major Malaria Vector.

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    Sulaiman S Ibrahim

    2015-10-01

    Full Text Available Scale up of Long Lasting Insecticide Nets (LLINs has massively contributed to reduce malaria mortality across Africa. However, resistance to pyrethroid insecticides in malaria vectors threatens its continued effectiveness. Deciphering the detailed molecular basis of such resistance and designing diagnostic tools is critical to implement suitable resistance management strategies. Here, we demonstrated that allelic variation in two cytochrome P450 genes is the most important driver of pyrethroid resistance in the major African malaria vector Anopheles funestus and detected key mutations controlling this resistance. An Africa-wide polymorphism analysis of the duplicated genes CYP6P9a and CYP6P9b revealed that both genes are directionally selected with alleles segregating according to resistance phenotypes. Modelling and docking simulations predicted that resistant alleles were better metabolizers of pyrethroids than susceptible alleles. Metabolism assays performed with recombinant enzymes of various alleles confirmed that alleles from resistant mosquitoes had significantly higher activities toward pyrethroids. Additionally, transgenic expression in Drosophila showed that flies expressing resistant alleles of both genes were significantly more resistant to pyrethroids compared with those expressing the susceptible alleles, indicating that allelic variation is the key resistance mechanism. Furthermore, site-directed mutagenesis and functional analyses demonstrated that three amino acid changes (Val109Ile, Asp335Glu and Asn384Ser from the resistant allele of CYP6P9b were key pyrethroid resistance mutations inducing high metabolic efficiency. The detection of these first DNA markers of metabolic resistance to pyrethroids allows the design of DNA-based diagnostic tools to detect and track resistance associated with bednets scale up, which will improve the design of evidence-based resistance management strategies.

  10. Anopheles barbirostris Confirmation as Malaria Vector in Waikabubak through the Detection of Circumsporozoit Protein

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    Yuneu Yuliasih

    2012-06-01

    Full Text Available Anopheline species confirmed as malaria vector if the salivary gland contained sporozoites. One of the method to confirmed it was through an Enzyme-Linked Immunosorbent Assay (ELISA. The aim of this study was to investigate the presence of circum sporozoite protein (CSP in the mosquito of Anopheles barbirostris with ELISA method. The study was conducted in malaria endemic area named Modu Waimaringu Village, Waikabubak District, Sumba Barat Regency in March 2011. The study design was cross-sectional study, mosquito for the ELISA test were collected only from animal bait. ELISA method examination used on An. barbirostris body parts (i.e. the head-thorax where sporozoites of P. falciparum or P. Vivax possibly be found. The results showed that 40 samples of An. barbirostris mosquitoes which acquired from the mosquite bait in Modu Waimaringu Village was negative (100%. It means that there was no CSP found and An. barbirostris was not a malaria vector in the area

  11. Culex nigripalpus: a natural vector of wild turkey malaria (Plasmodium hermani) in Florida.

    Science.gov (United States)

    Forrester, D J; Nayar, J K; Foster, G W

    1980-07-01

    Durking 1977 and 1978, more than 21,000 female mosquitoes of 15 species were live-trapped in south Florida where high numbers of wild turkeys (Meleagris gallopavo) are known to harbor malarial infections. By inoculation of mosquito extracts into uninfected domestic poults, the presence of sporozoites of Plasmodium hermani was demonstrated in Culex nigrapalpus. This mosquito, previously shown to be a competent experimental vector, is believed to be the primary natural vector of wild turkey malaria in Florida.

  12. Malaria vector control at a crossroads: public health entomology and the drive to elimination.

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    Mnzava, Abraham P; Macdonald, Michael B; Knox, Tessa B; Temu, Emmanuel A; Shiff, Clive J

    2014-09-01

    Vector control has been at the core of successful malaria control. However, a dearth of field-oriented vector biologists threatens to undermine global reductions in malaria burden. Skilled cadres are needed to manage insecticide resistance, to maintain coverage with current interventions, to develop new paradigms for tackling 'residual' transmission and to target interventions as transmission becomes increasingly heterogeneous. Recognising this human resource crisis, in September 2013, WHO Global Malaria Programme issued guidance for capacity building in entomology and vector control, including recommendations for countries and implementing partners. Ministries were urged to develop long-range strategic plans for building human resources for public health entomology and vector control (including skills in epidemiology, geographic information systems, operational research and programme management) and to set in place the requisite professional posts and career opportunities. Capacity building and national ownership in all partner projects and a clear exit strategy to sustain human and technical resources after project completion were emphasised. Implementing partners were urged to support global and regional efforts to enhance public health entomology capacity. While the challenges inherent in such capacity building are great, so too are the opportunities to establish the next generation of public health entomologists that will enable programmes to continue on the path to malaria elimination.

  13. 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 ...

  14. Egg hatching, larval movement and larval survival of the malaria vector Anopheles gambiae in desiccating habitats

    NARCIS (Netherlands)

    Koenraadt, C.J.M.; Paaijmans, K.P.; Githeko, A.K.; Knols, B.G.J.; Takken, W.

    2003-01-01

    Background - Although the effects of rainfall on the population dynamics of the malaria vector Anopheles gambiae have been studied in great detail, the effects of dry periods on its survival remain less clear. Methods - The effects of drying conditions were simulated by creating desiccated habitats,

  15. Feeding and survival of the malaria vector Anopheles gambiae on plants growing in Kenia

    NARCIS (Netherlands)

    Impoinvil, D.E.; Kongere, J.O.; Foster, W.A.; Njiru, B.N.; Killeen, G.F.; Githure, J.I.; Beier, J.C.; Hassanali, A.; Knols, B.G.J.

    2004-01-01

    The propensity of the malaria vector mosquito Anopheles gambiae Giles (Diptera: Culicidae) to ingest sugars from various plants, and subsequent survival rates, were assessed with laboratory-reared males and females offered eight species of plants commonly cultivated and/or growing wild in western Ke

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

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    Romi Roberto

    2011-01-01

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

  17. Seasonal Abundance and Host-Feeding Patterns of Anopheline Vectors in Malaria Endemic Area of Iran

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    Hamidreza Basseri

    2010-01-01

    Full Text Available Seasonal abundance and tendency to feed on humans are important parameters to measure for effective control of malaria vectors. The objective of this study was to describe relation between feeding pattern, abundance, and resting behavior of four malaria vectors in southern Iran. This study was conducted in ten indicator villages (based on malaria incidence and entomological indices in mountainous/hilly and plain regions situated south and southeastern Iran. Mosquito vectors were collected from indoor as well as outdoor shelters and the blood meals were examined by ELISA test. Over all 7654 female Anopheles spp. were captured, the most common species were Anopheles stephensi, An. culicifacies, An. fluviatilis, and An. d'thali. The overall human blood index was 37.50%, 19.83%, 16.4%, and 30.1% for An. fluviatilis, An. stephensi, An. culicifacies, and An. d'thali, respectively. In addition, An. fluviatilis fed on human blood during the entire year but the feeding behavior of An. stephensi and An. culicifacies varied according to seasons. Overall, the abundance of the female mosquito positive to human blood was 4.25% per human shelter versus 17.5% per animal shelter. This result indicates that the vectors had tendency to rest in animal shelters after feeding on human. Therefore, vector control measure should be planned based on such as feeding pattern, abundance, and resting behavior of these vectors in the area.

  18. Ethnobotanical knowledge on botanical repellents employed in the African region against mosquito vectors - A review.

    Science.gov (United States)

    Pavela, Roman; Benelli, Giovanni

    2016-08-01

    Mosquitoes (Diptera: Culicidae) represent a huge threat for millions of humans and animals worldwide, since they act as vectors for important parasites and pathogens, including malaria, filariasis and important arboviruses, such as dengue, West Nile and Zika virus. No vaccines or other specific treatments are available against the arboviruses transmitted by mosquitoes, and avoidance of mosquito bites remains the best strategy. African regions are usually hit most whose inhabitants are poor, and the use of repellent plants is the only efficient protection against vectors they have. Ethnobotanical knowledge of such plants and their use is usually passed on orally from one generation to another. However, it is also important to preserve this information in a written form, as well. Ethnobotanical research projects carried out in the regions of today's Ethiopia, South Africa, Nigeria, Kenya, and Tanzania indicate that the native inhabitants of the African study regions traditionally use 64 plant species, belonging to 30 families. Aromatic plants (i.e., Citrus spp., Eucalyptus spp., Lantana camara, Ocimum spp. and Lippia javanica) the most commonly used in all the study regions. Native people know three major methods of using repellent plants: (i) production of repellent smoke from burning plants, (ii) hanging plants inside the house or sprinkling leaves on the floor, (iii) the use of plant oils, juices from crushed fresh parts of the plants, or various prepared extracts applied on uncovered body parts. Overall, this review covers studies conducted only in a limited part of the African continent, highlighting the importance to undertake further research efforts to preserve the unique knowledge and traditions of the native tribes.

  19. The systemic pathology of cerebral malaria in African children

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    Danny Arnold Milner

    2014-08-01

    Full Text Available Pediatric cerebral malaria carries a high mortality rate in sub-Saharan Africa. We present our systematic analysis of the descriptive and quantitative histopathology of all organs sampled from a series of 103 autopsies performed between 1996 and 2010 in Blantyre, Malawi on pediatric cerebral malaria patients and control patients (without coma, or without malaria infection who were clinically well characterized prior to death. We found brain swelling in all cerebral malaria patients and the majority of controls. The histopathology in patients with sequestration of parasites in the brain demonstrated two patterns: a the classic appearance (i.e., ring hemorrhages, dense sequestration, and extra-erythrocytic pigment which was associated with evidence of systemic activation of coagulation and b the sequestration only appearance associated with shorter duration of illness and higher total burden of parasites in all organs including the spleen. Sequestration of parasites was most intense in the gastrointestinal tract in all parasitemic patients (those with cerebral malarial and those without.

  20. 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.

  1. Scientists and public involvement: a consultation on the relation between malaria, vector control and transgenic mosquitoes.

    Science.gov (United States)

    Boëte, Christophe

    2011-12-01

    Among the hopes for vector-based malaria control, the use of transgenic mosquitoes able to kill malaria parasites is seen as a potential way to interrupt malaria transmission. While this potential solution is gaining some support, the ethical and social aspects related to this high-tech method remain largely unexplored and underestimated. Related to those latter points, the aim of the present survey is to determine how scientists working on malaria and its vector mosquitoes perceive public opinion and how they evaluate public consultations on their research. This study has been performed through a questionnaire addressing questions related to the type of research, the location, the nationality and the perception of the public involvement by scientists. The results suggest that even if malaria researchers agree to interact with a non-scientific audience, they (especially the ones from the global North) remain quite reluctant to have their research project submitted in a jargon-free version to the evaluation and the prior-agreement by a group of non-specialists. The study, by interrogating the links between the scientific community and the public from the perspective of the scientists, reveals the importance of fostering structures and processes that could lead to a better involvement of a non specialist public in the actual debates linking scientific, technological and public health issues in Africa.

  2. Integrated vector management for malaria control in Uganda: knowledge, perceptions and policy development

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    Mutero Clifford M

    2012-01-01

    Full Text Available Abstract Background Integrated vector management (IVM is increasingly being recommended as an option for sustainable malaria control. However, many malaria-endemic countries lack a policy framework to guide and promote the approach. The objective of the study was to assess knowledge and perceptions in relation to current malaria vector control policy and IVM in Uganda, and to make recommendations for consideration during future development of a specific IVM policy. Methods The study used a structured questionnaire to interview 34 individuals working at technical or policy-making levels in health, environment, agriculture and fisheries sectors. Specific questions on IVM focused on the following key elements of the approach: integration of chemical and non-chemical interventions of vector control; evidence-based decision making; inter-sectoral collaboration; capacity building; legislation; advocacy and community mobilization. Results All participants were familiar with the term IVM and knew various conventional malaria vector control (MVC methods. Only 75% thought that Uganda had a MVC policy. Eighty percent (80% felt there was inter-sectoral collaboration towards IVM, but that it was poor due to financial constraints, difficulties in involving all possible sectors and political differences. The health, environment and agricultural sectors were cited as key areas requiring cooperation in order for IVM to succeed. Sixty-seven percent (67% of participants responded that communities were actively being involved in MVC, while 48% felt that the use of research results for evidence-based decision making was inadequate or poor. A majority of the participants felt that malaria research in Uganda was rarely used to facilitate policy changes. Suggestions by participants for formulation of specific and effective IVM policy included: revising the MVC policy and IVM-related policies in other sectors into a single, unified IVM policy and, using legislation to

  3. Self-Adjuvanting Bacterial Vectors Expressing Pre-Erythrocytic Antigens Induce Sterile Protection against Malaria

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    Elke eBergmann-Leitner

    2013-07-01

    Full Text Available Genetically inactivated, Gram-negative bacteria that express malaria vaccine candidates represent a promising novel self-adjuvanting vaccine approach. Antigens expressed on particulate bacterial carriers not only target directly to antigen-presenting cells but also provide a strong danger signal thus circumventing the requirement for potent extraneous adjuvants. E. coli expressing malarial antigens resulted in the induction of either Th1 or Th2 biased responses that were dependent on both antigen and sub-cellular localization. Some of these constructs induced higher quality humoral responses compared to recombinant protein and most importantly they were able to induce sterile protection against sporozoite challenge in a murine model of malaria. In light of these encouraging results, two major Plasmodium falciparum pre-erythrocytic malaria vaccine targets, the Cell-Traversal protein for Ookinetes and Sporozoites (CelTOS fused to the Maltose-binding protein in the periplasmic space and the Circumsporozoite Protein (CSP fused to the Outer membrane protein A in the outer membrane were expressed in a clinically relevant, attenuated Shigella strain (Shigella flexneri 2a. This type of live attenuated vector has previously undergone clinical investigations as a vaccine against shigellosis. Using this novel delivery platform for malaria, we find that vaccination with the whole organism represents an effective vaccination alternative that induces protective efficacy against sporozoite challenge. Shigella GeMI-Vax expressing malaria targets warrant further evaluation to determine their full potential as a dual disease, multivalent, self-adjuvanting vaccine system, against both shigellosis and malaria.

  4. Anthropophily of Malaria Vectors in Kahnouj District, South of Kerman, Iran

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    HR Basseri

    2005-07-01

    Full Text Available This study was conducted to investigate hematophagic tendencies of the malaria vector based on a seasonal basis as well as by geographical region in a malaria endemic area in Kahnouj, southern Iran. This study was carried out for 14 months from Apr/ 2002 up to the end of May 2003. Female anophelines were collected from different shelters in hilly and plain regions of Kahnouj district and their blood meal was tested using ELISA test methods. The five vectors that were active in the study area consisted of An. fluviatilis, An. stephensi, An. dthali, An. culicifacies, and An. superpictus. The dominant Anopheline in hilly areas was An. fluviatilis sibling species T. This species was active during whole year and reached a peak in December. In contrast the dominant species in flat regions was An. stephensi which showed strongly endophilic behavior with two seasonal activity peaks. The anthropophilic index for An. fluviatilis and An. stephensi was estimated at 2.68% and 0.5%, respectively. The population of other species was too low and they did not show a propensity for human blood. The most malaria cases occurred in the hilly area where An. fluviatilis is the active dominant species. It seems that An. fluviatilis is responsible for transmission of malaria in hilly districts of Kahnouj. Thus malaria transmission in this study area is much influenced by resident’s rest habits while a wild vector, An. fluviatilis shows exophilic behavior and uses microclimate shelters with high incidence of human blood feeding. Thus, adapting people to use personal protection such as a bed net instead of residual spraying may be considered as an effective measure in malaria control in hilly regions.

  5. An overview of malaria transmission from the perspective of Amazon Anopheles vectors

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    Paulo FP Pimenta

    2015-02-01

    Full Text Available In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.

  6. Newly incriminated anopheline vectors of human malaria parasites in Junin Department, Peru.

    Science.gov (United States)

    Hayes, J; Calderon, G; Falcon, R; Zambrano, V

    1987-09-01

    Sporozoite data from salivary gland dissections are presented that clearly incriminate Anopheles trinkae, An. pseudopunctipennis, An. sp. near fluminensis, An. oswaldoi, An. nuneztovari and An. rangeli as vectors of malaria parasites in the Rio Ene Valley, a hyperendemic malarious area in Junin Department, eastern Peru. Anopheles trinkae is considered the most important vector based on dissections, abundance and man-vector contact. Other notes are presented on the relative abundance, bionomics and previous records of these species in Peru and in the study sites.

  7. Towards a risk map of malaria for Sri Lanka: the importance of house location relative to vector breeding sites

    DEFF Research Database (Denmark)

    Van Der Hoek, Wim; Konradsen, Flemming; Amerasinghe, Priyanie H

    2003-01-01

    BACKGROUND: In Sri Lanka, the major malaria vector Anopheles culicifacies breeds in pools formed in streams and river beds and it is likely that people living close to such breeding sites are at higher risk of malaria than people living further away. This study was done to quantify the importance...... of house location relative to vector breeding sites for the occurrence of malaria in order to assess the usefulness of this parameter in future malaria risk maps. Such risk maps could be important tools for planning efficient malaria control measures. METHODS: In a group of seven villages in north central...... Sri Lanka, malaria cases were compared with community controls for distance from house to breeding sites and a number of other variables, including type of housing construction and use of anti-mosquito measures. The presence of An. culicifacies in bedrooms was determined by indoor insecticide spray...

  8. Malaria in Africa: vector species' niche models and relative risk maps.

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    Alexander Moffett

    Full Text Available A central theoretical goal of epidemiology is the construction of spatial models of disease prevalence and risk, including maps for the potential spread of infectious disease. We provide three continent-wide maps representing the relative risk of malaria in Africa based on ecological niche models of vector species and risk analysis at a spatial resolution of 1 arc-minute (9 185 275 cells of approximately 4 sq km. Using a maximum entropy method we construct niche models for 10 malaria vector species based on species occurrence records since 1980, 19 climatic variables, altitude, and land cover data (in 14 classes. For seven vectors (Anopheles coustani, A. funestus, A. melas, A. merus, A. moucheti, A. nili, and A. paludis these are the first published niche models. We predict that Central Africa has poor habitat for both A. arabiensis and A. gambiae, and that A. quadriannulatus and A. arabiensis have restricted habitats in Southern Africa as claimed by field experts in criticism of previous models. The results of the niche models are incorporated into three relative risk models which assume different ecological interactions between vector species. The "additive" model assumes no interaction; the "minimax" model assumes maximum relative risk due to any vector in a cell; and the "competitive exclusion" model assumes the relative risk that arises from the most suitable vector for a cell. All models include variable anthrophilicity of vectors and spatial variation in human population density. Relative risk maps are produced from these models. All models predict that human population density is the critical factor determining malaria risk. Our method of constructing relative risk maps is equally general. We discuss the limits of the relative risk maps reported here, and the additional data that are required for their improvement. The protocol developed here can be used for any other vector-borne disease.

  9. Malaria vectors in a traditional dry zone village in Sri Lanka

    DEFF Research Database (Denmark)

    Amerasinghe, P H; Amerasinghe, F P; Konradsen, F;

    1999-01-01

    Malaria transmission by anopheline mosquitoes was studied in a traditional tank-irrigation-based rice-producing village in the malaria-endemic low country dry zone of northcentral Sri Lanka during the period August 1994-February 1997. Adult mosquitoes were collected from human and bovid bait...... catches, bovid-baited trap huts, indoor catches, and pit traps. Mosquito head-thoraces were tested for the presence of Plasmodium falciparum and P. vivax, and blood-engorged abdomens for the presence of human blood by ELISAs. House surveys were done at two-day intervals to record cases of blood film...... in An. culicifacies and An. peditaeniatus. Malaria parasite infections were seen in seven mosquito species, with 75% of the positive mosquitoes containing P. falciparum and 25% P. vivax. Polymorph PV247 was recorded from a vector (i.e., An. varuna) for the first time in Sri Lanka. Computations of mean...

  10. Polyamidoamine nanoparticles as nanocarriers for the drug delivery to malaria parasite stages in the mosquito vector.

    Science.gov (United States)

    Urbán, Patricia; Ranucci, Elisabetta; Fernàndez-Busquets, Xavier

    2015-11-01

    Malaria is arguably one of the main medical concerns worldwide because of the numbers of people affected, the severity of the disease and the complexity of the life cycle of its causative agent, the protist Plasmodium spp. With the advent of nanoscience, renewed hopes have appeared of finally obtaining the long sought-after magic bullet against malaria in the form of a nanovector for the targeted delivery of antimalarial compounds exclusively to Plasmodium-infected cells, thus increasing drug efficacy and minimizing the induction of resistance to newly developed therapeutic agents. Polyamidoamine-derived nanovectors combine into a single chemical structure drug encapsulating capacity, antimalarial activity, low unspecific toxicity, specific targeting to Plasmodium, optimal in vivo activity and affordable synthesis cost. After having shown their efficacy in targeting drugs to intraerythrocytic parasites, now polyamidoamines face the challenge of spearheading a new generation of nanocarriers aiming at the malaria parasite stages in the mosquito vector.

  11. On the use of classic epidemiological formulae for estimating the intensity of endemic malaria transmission by vectors in the Amazon.

    Science.gov (United States)

    Barros, F S M; Tadei, W P; Arruda, M E; Honório, Nildimar A

    2012-10-01

    Although various reports have described entomological inoculation rates of malaria vector species, most were limited to providing descriptive field data. Here, we report biting rates and survival data for two important malaria vectors in the Amazon, Anopheles darlingi (Root) and Anopheles albitarsis E (Lynch-Arribalzaga) (Diptera: Culicidae), in the state of Roraima, Brazil. We calculated theoretical sporozoite infection rates and critical vector biting rates for these species during 1 year, comprising six bimestrial collections. Anopheles darlingi had higher sporozoite rates and lower critical biting rates, indicating that it would be the more efficient vector at the beginning of epidemic malaria transmission. Our data, together with compiled information from the literature in the Amazon, suggest that epidemic malaria transmission may be initiated by the primary vector, such as A. darlingi, while secondary vectors, such as A. albitarsis E, may only become epidemiologically important when there is an increase in the prevalence of human malaria. We propose that mathematical modeling may be able to quantify the relative importance of secondary vector species in malaria epidemiology.

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

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    Sochantha Tho

    2009-04-01

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

  13. Malaria

    Science.gov (United States)

    ... and can even be fatal. SymptomsWhat are the symptoms of malaria?The symptoms of malaria include:High fever (can often be 104° F ... give someone else malaria?If I do get malaria, should I travel while I have symptoms? Other organizationsInternational Society of Travel MedicineCenters for Disease ...

  14. Automated innovative diagnostic, data management and communication tool, for improving malaria vector control in endemic settings.

    Science.gov (United States)

    Vontas, John; Mitsakakis, Konstantinos; Zengerle, Roland; Yewhalaw, Delenasaw; Sikaala, Chadwick Haadezu; Etang, Josiane; Fallani, Matteo; Carman, Bill; Müller, Pie; Chouaïbou, Mouhamadou; Coleman, Marlize; Coleman, Michael

    2016-01-01

    Malaria is a life-threatening disease that caused more than 400,000 deaths in sub-Saharan Africa in 2015. Mass prevention of the disease is best achieved by vector control which heavily relies on the use of insecticides. Monitoring mosquito vector populations is an integral component of control programs and a prerequisite for effective interventions. Several individual methods are used for this task; however, there are obstacles to their uptake, as well as challenges in organizing, interpreting and communicating vector population data. The Horizon 2020 project "DMC-MALVEC" consortium will develop a fully integrated and automated multiplex vector-diagnostic platform (LabDisk) for characterizing mosquito populations in terms of species composition, Plasmodium infections and biochemical insecticide resistance markers. The LabDisk will be interfaced with a Disease Data Management System (DDMS), a custom made data management software which will collate and manage data from routine entomological monitoring activities providing information in a timely fashion based on user needs and in a standardized way. The ResistanceSim, a serious game, a modern ICT platform that uses interactive ways of communicating guidelines and exemplifying good practices of optimal use of interventions in the health sector will also be a key element. The use of the tool will teach operational end users the value of quality data (relevant, timely and accurate) to make informed decisions. The integrated system (LabDisk, DDMS & ResistanceSim) will be evaluated in four malaria endemic countries, representative of the vector control challenges in sub-Saharan Africa, (Cameroon, Ivory Coast, Ethiopia and Zambia), highly representative of malaria settings with different levels of endemicity and vector control challenges, to support informed decision-making in vector control and disease management.

  15. A nonintegrative lentiviral vector-based vaccine provides long-term sterile protection against malaria.

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    Frédéric Coutant

    Full Text Available Trials testing the RTS,S candidate malaria vaccine and radiation-attenuated sporozoites (RAS have shown that protective immunity against malaria can be induced and that an effective vaccine is not out of reach. However, longer-term protection and higher protection rates are required to eradicate malaria from the endemic regions. It implies that there is still a need to explore new vaccine strategies. Lentiviral vectors are very potent at inducing strong immunological memory. However their integrative status challenges their safety profile. Eliminating the integration step obviates the risk of insertional oncogenesis. Providing they confer sterile immunity, nonintegrative lentiviral vectors (NILV hold promise as mass pediatric vaccine by meeting high safety standards. In this study, we have assessed the protective efficacy of NILV against malaria in a robust pre-clinical model. Mice were immunized with NILV encoding Plasmodium yoelii Circumsporozoite Protein (Py CSP and challenged with sporozoites one month later. In two independent protective efficacy studies, 50% (37.5-62.5 of the animals were fully protected (p = 0.0072 and p = 0.0008 respectively when compared to naive mice. The remaining mice with detectable parasitized red blood cells exhibited a prolonged patency and reduced parasitemia. Moreover, protection was long-lasting with 42.8% sterile protection six months after the last immunization (p = 0.0042. Post-challenge CD8+ T cells to CSP, in contrast to anti-CSP antibodies, were associated with protection (r = -0.6615 and p = 0.0004 between the frequency of IFN-g secreting specific T cells in spleen and parasitemia. However, while NILV and RAS immunizations elicited comparable immunity to CSP, only RAS conferred 100% of sterile protection. Given that a better protection can be anticipated from a multi-antigen vaccine and an optimized vector design, NILV appear as a promising malaria vaccine.

  16. Extensive introgression in a malaria vector species complex revealed by phylogenomics

    Science.gov (United States)

    Fontaine, Michael C.; Pease, James B.; Steele, Aaron; Waterhouse, Robert M.; Neafsey, Daniel E.; Sharakhov, Igor V.; Jiang, Xiaofang; Hall, Andrew B.; Catteruccia, Flaminia; Kakani, Evdoxia; Mitchell, Sara N.; Wu, Yi-Chieh; Smith, Hilary A.; Love, R. Rebecca; Lawniczak, Mara K.; Slotman, Michel A.; Emrich, Scott J.; Hahn, Matthew W.; Besansky, Nora J.

    2015-01-01

    Introgressive hybridization is now recognized as a widespread phenomenon, but its role in evolution remains contested. Here we use newly available reference genome assemblies to investigate phylogenetic relationships and introgression in a medically important group of Afrotropical mosquito sibling species. We have identified the correct species branching order to resolve a contentious phylogeny, and show that lineages leading to the principal vectors of human malaria were among the first to split. Pervasive autosomal introgression between these malaria vectors means that only a small fraction of the genome, mainly on the X chromosome, has not crossed species boundaries. Our results suggest that traits enhancing vectorial capacity may be gained through interspecific gene flow, including between non-sister species. PMID:25431491

  17. Larvicidal and IGR activity of extract of Tanzanian plants against malaria vector mosquitoes

    OpenAIRE

    Erich Kleinpeter; Matthias Heydenreich; Magesa, Stephen M; Ahmed Hassanali; Joseph, Cosam C.; Nkunya, Mayunga H. H.; Charles Kihampa

    2009-01-01

    Background & objectives: This paper reports the larvicidal activity of seventeen Tanzanian plantspecies against the malaria vector, Anopheles gambiae s.s. Giles larvae. Some of the plants are usedtraditionally as sources of insecticidal materials.Methods: The crude extracts from the leaves, stem and root barks of the investigated plants wereobtained by solvent extraction and then bio-assayed following WHO protocols showed LC50 values10 to 400 ppm after 24 h exposure. The structures were deter...

  18. Ecology of the Malaria Vector, Anopheles (Nyssorhynchus) Marajoara Galvao and Damasceno in Trinidad, West Indies

    Science.gov (United States)

    2006-01-01

    1995b) (RAPDs) and Li and Wilkerson (2005) OTS2-based PCR primers ). RESULTS A total of 1.157 AI/opheles females were cap- lUred during the experimental...intragenomic variation in all 4 species. However. it was possible to design spe- cies-specific primers based on constant sites to make reliable...de-Souza-Rai- mundo -TL. Schlichling CD. Wirtz RA. Povoa MM. 2002. Emergence of a new Neotropical malaria vector facilitated by human migration and

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

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    Denis Leen

    2008-06-01

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

  20. Impact of urban agriculture on malaria vectors in Accra, Ghana.

    Science.gov (United States)

    Klinkenberg, Eveline; McCall, Pj; Wilson, Michael D; Amerasinghe, Felix P; Donnelly, Martin J

    2008-08-04

    To investigate the impact of urban agriculture on malaria transmission risk in urban Accra larval and adult stage mosquito surveys, were performed. Local transmission was implicated as Anopheles spp. were found breeding and infected Anopheles mosquitoes were found resting in houses in the study sites. The predominant Anopheles species was Anopheles gambiae s.s.. The relative proportion of molecular forms within a subset of specimens was 86% S-form and 14% M-form. Anopheles spp. and Culex quinquefasciatus outdoor biting rates were respectively three and four times higher in areas around agricultural sites (UA) than in areas far from agriculture (U). The annual Entomological Inoculation Rate (EIR), the number of infectious bites received per individual per year, was 19.2 and 6.6 in UA and U sites, respectively. Breeding sites were highly transitory in nature, which poses a challenge for larval control in this setting. The data also suggest that the epidemiological importance of urban agricultural areas may be the provision of resting sites for adults rather than an increased number of larval habitats. Host-seeking activity peaked between 2-3 am, indicating that insecticide-treated bednets should be an effective control method.

  1. Effect of artemether-lumefantrine policy and improved vector control on malaria burden in KwaZulu-Natal, South Africa.

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    Karen I Barnes

    2005-11-01

    Full Text Available BACKGROUND: Between 1995 and 2000, KwaZulu-Natal province, South Africa, experienced a marked increase in Plasmodium falciparum malaria, fuelled by pyrethroid and sulfadoxine-pyrimethamine resistance. In response, vector control was strengthened and artemether-lumefantrine (AL was deployed in the first Ministry of Health artemisinin-based combination treatment policy in Africa. In South Africa, effective vector and parasite control had historically ensured low-intensity malaria transmission. Malaria is diagnosed definitively and treatment is provided free of charge in reasonably accessible public-sector health-care facilities. METHODS AND FINDINGS: We reviewed four years of malaria morbidity and mortality data at four sentinel health-care facilities within KwaZulu-Natal's malaria-endemic area. In the year following improved vector control and implementation of AL treatment, malaria-related admissions and deaths both declined by 89%, and outpatient visits decreased by 85% at the sentinel facilities. By 2003, malaria-related outpatient cases and admissions had fallen by 99%, and malaria-related deaths had decreased by 97%. There was a concomitant marked and sustained decline in notified malaria throughout the province. No serious adverse events were associated causally with AL treatment in an active sentinel pharmacovigilance survey. In a prospective study with 42 d follow up, AL cured 97/98 (99% and prevented gametocyte developing in all patients. Consistent with the findings of focus group discussions, a household survey found self-reported adherence to the six-dose AL regimen was 96%. CONCLUSION: Together with concurrent strengthening of vector control measures, the antimalarial treatment policy change to AL in KwaZulu-Natal contributed to a marked and sustained decrease in malaria cases, admissions, and deaths, by greatly improving clinical and parasitological cure rates and reducing gametocyte carriage.

  2. Vector capacity of Anopheles sinensis in malaria outbreak areas of central China

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    Pan Jia-Yun

    2012-07-01

    Full Text Available Abstract Background Both falciparum and vivax malaria were historically prevalent in China with high incidence. With the control efforts, the annual incidence in the whole country has reduced to 0.0001% except in some areas in the southern borders after 2000. Despite this, the re-emergence or outbreak of malaria was unavoidable in central China during 2005–2007. In order to understand the role of the vector in the transmission of malaria during the outbreak period, the vector capacity of An. sinensis in Huanghuai valley of central China was investigated. Findings The study was undertaken in two sites, namely Huaiyuan county of Anhui province and Yongcheng county of Henan province. In each county, malaria cases were recorded for recent years, and transmission risk factors for each study village including anti-mosquito facilities and total number of livestock were recorded by visiting each household in the study sites. The specimens of mosquitoes were collected in two villages, and population density and species in each study site were recorded after the identification of different species, and the blood-fed mosquitoes were tested by ring precipitation test. Finally, various indicators were calculated to estimate vector capacity or dynamics, including mosquito biting rate (MBR, human blood index (HBI, and the parous rates (M. Finally, the vector capacity, as an important indicator of malaria transmission to predict the potential recurrence of malaria, was estimated and compared in each study site. About 93.0% of 80 households in Huaiyuan and 89.3% of 192 households in Yongcheng had anti-mosquito facilities. No cattle or pigs were found, only less than 10 sheep were found in each study village. A total of 94 and 107 Anopheles spp. mosquitos were captured in two study sites, respectively, and all of An. sinensis were morphologically identified. It was found that mosquito blood-feeding peak was between 9:00 pm and 12:00 pm. Man biting rate of

  3. High effective coverage of vector control interventions in children after achieving low malaria transmission in Zanzibar, Tanzania

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    Beer Netta

    2013-01-01

    Full Text Available Abstract Background Formerly a high malaria transmission area, Zanzibar is now targeting malaria elimination. A major challenge is to avoid resurgence of malaria, the success of which includes maintaining high effective coverage of vector control interventions such as bed nets and indoor residual spraying (IRS. In this study, caretakers' continued use of preventive measures for their children is evaluated, following a sharp reduction in malaria transmission. Methods A cross-sectional community-based survey was conducted in June 2009 in North A and Micheweni districts in Zanzibar. Households were randomly selected using two-stage cluster sampling. Interviews were conducted with 560 caretakers of under-five-year old children, who were asked about perceptions on the malaria situation, vector control, household assets, and intention for continued use of vector control as malaria burden further decreases. Results Effective coverage of vector control interventions for under-five children remains high, although most caretakers (65%; 363/560 did not perceive malaria as presently being a major health issue. Seventy percent (447/643 of the under-five children slept under a long-lasting insecticidal net (LLIN and 94% (607/643 were living in houses targeted with IRS. In total, 98% (628/643 of the children were covered by at least one of the vector control interventions. Seasonal bed-net use for children was reported by 25% (125/508 of caretakers of children who used bed nets. A high proportion of caretakers (95%; 500/524 stated that they intended to continue using preventive measures for their under-five children as malaria burden further reduces. Malaria risk perceptions and different perceptions of vector control were not found to be significantly associated with LLIN effective coverage. Conclusions While the majority of caretakers felt that malaria had been reduced in Zanzibar, effective coverage of vector control interventions remained high. Caretakers

  4. Tumor Necrosis Factor and Lymphotoxin-α Polymorphisms and Severe Malaria in African Populations

    Science.gov (United States)

    Clark, Taane G.; Diakite, Mahamadou; Auburn, Sarah; Campino, Susana; Fry, Andrew E.; Green, Angela; Richardson, Anna; Small, Kerrin; Teo, Yik Y.; Wilson, Jonathan; Jallow, Muminatou; Sisay-Joof, Fatou; Pinder, Margaret; Griffiths, Michael J.; Peshu, Norbert; Williams, Thomas N.; Marsh, Kevin; Molyneux, Malcolm E.; Taylor, Terrie E.; Rockett, Kirk A.; Kwiatkowski, Dominic P.

    2009-01-01

    The tumor necrosis factor gene (TNF) and lymphotoxin-α gene (LTA) have long attracted attention as candidate genes for susceptibility traits for malaria, and several of their polymorphisms have been found to be associated with severe malaria (SM) phenotypes. In a large study involving > 10,000 individuals and encompassing 3 African populations, we found evidence to support the reported associations between the TNF −238 polymorphism and SM in The Gambia. However, no TNF/LTA polymorphisms were found to be associated with SM in cohorts in Kenya and Malawi. It has been suggested that the causal polymorphisms regulating the TNF and LTA responses may be located some distance from the genes. Therefore, more-detailed mapping of variants across TNF/LTA genes and their flanking regions in the Gambian and allied populations may need to be undertaken to find any causal polymorphisms. PMID:19281305

  5. Successful malaria elimination strategies require interventions that target changing vector behaviours

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    Russell Tanya L

    2013-02-01

    Full Text Available Abstract Background The ultimate long-term goal of malaria eradication was recently placed back onto the global health agenda. When planning for this goal, it is important to remember why the original Global Malaria Eradication Programme (GMEP, conducted with DDT-based indoor residual spraying (IRS, did not achieve its goals. One of the technical reasons for the failure to eliminate malaria was over reliance on a single intervention and subsequently the mosquito vectors developed behavioural resistance so that they did not come into physical contact with the insecticide. Hypothesis and how to test it Currently, there remains a monolithic reliance on indoor vector control. It is hypothesized that an outcome of long-term, widespread control is that vector populations will change over time, either in the form of physiological resistance, changes in the relative species composition or behavioural resistance. The potential for, and consequences of, behavioural resistance was explored by reviewing the literature regarding vector behaviour in the southwest Pacific. Discussion Here, two of the primary vectors that were highly endophagic, Anopheles punctulatus and Anopheles koliensis, virtually disappeared from large areas where DDT was sprayed. However, high levels of transmission have been maintained by Anopheles farauti, which altered its behaviour to blood-feed early in the evening and outdoors and, thereby, avoiding exposure to the insecticides used in IRS. This example indicates that the efficacy of programmes relying on indoor vector control (IRS and long-lasting, insecticide-treated nets [LLINs] will be significantly reduced if the vectors change their behaviour to avoid entering houses. Conclusions Behavioural resistance is less frequently seen compared with physiological resistance (where the mosquito contacts the insecticide but is not killed, but is potentially more challenging to control programmes because the intervention effectiveness

  6. Malaria.

    Science.gov (United States)

    Dupasquier, Isabelle

    1989-01-01

    Malaria, the greatest pandemia in the world, claims an estimated one million lives each year in Africa alone. While it may still be said that for the most part malaria is found in what is known as the world's poverty belt, cases are now frequently diagnosed in western countries. Due to resistant strains of malaria which have developed because of…

  7. 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

  8. Benefit of insecticide-treated nets, curtains and screening on vector borne diseases, excluding malaria: a systematic review and meta-analysis.

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    Anne L Wilson

    2014-10-01

    Full Text Available Insecticide-treated nets (ITNs are one of the main interventions used for malaria control. However, these nets may also be effective against other vector borne diseases (VBDs. We conducted a systematic review and meta-analysis to estimate the efficacy of ITNs, insecticide-treated curtains (ITCs and insecticide-treated house screening (ITS against Chagas disease, cutaneous and visceral leishmaniasis, dengue, human African trypanosomiasis, Japanese encephalitis, lymphatic filariasis and onchocerciasis.MEDLINE, EMBASE, LILACS and Tropical Disease Bulletin databases were searched using intervention, vector- and disease-specific search terms. Cluster or individually randomised controlled trials, non-randomised trials with pre- and post-intervention data and rotational design studies were included. Analysis assessed the efficacy of ITNs, ITCs or ITS versus no intervention. Meta-analysis of clinical data was performed and percentage reduction in vector density calculated.Twenty-one studies were identified which met the inclusion criteria. Meta-analysis of clinical data could only be performed for four cutaneous leishmaniasis studies which together showed a protective efficacy of ITNs of 77% (95%CI: 39%-91%. Studies of ITC and ITS against cutaneous leishmaniasis also reported significant reductions in disease incidence. Single studies reported a high protective efficacy of ITS against dengue and ITNs against Japanese encephalitis. No studies of Chagas disease, human African trypanosomiasis or onchocerciasis were identified.There are likely to be considerable collateral benefits of ITN roll out on cutaneous leishmaniasis where this disease is co-endemic with malaria. Due to the low number of studies identified, issues with reporting of entomological outcomes, and few studies reporting clinical outcomes, it is difficult to make strong conclusions on the effect of ITNs, ITCs or ITS on other VBDs and therefore further studies be conducted. Nonetheless, it

  9. Widespread pyrethroid and DDT resistance in the major malaria vector Anopheles funestus in East Africa is driven by metabolic resistance mechanisms.

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    Charles Mulamba

    Full Text Available BACKGROUND: Establishing the extent, geographical distribution and mechanisms of insecticide resistance in malaria vectors is a prerequisite for resistance management. Here, we report a widespread distribution of insecticide resistance in the major malaria vector An. funestus across Uganda and western Kenya under the control of metabolic resistance mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: Female An. funestus collected throughout Uganda and western Kenya exhibited a Plasmodium infection rate between 4.2 to 10.4%. Widespread resistance against both type I (permethrin and II (deltamethrin pyrethroids and DDT was observed across Uganda and western Kenya. All populations remain highly susceptible to carbamate, organophosphate and dieldrin insecticides. Knockdown resistance plays no role in the pyrethroid and DDT resistance as no kdr mutation associated with resistance was detected despite the presence of a F1021C replacement. Additionally, no signature of selection was observed on the sodium channel gene. Synergist assays and qRT-PCR indicated that metabolic resistance plays a major role notably through elevated expression of cytochrome P450s. DDT resistance mechanisms differ from West Africa as the L119F-GSTe2 mutation only explains a small proportion of the genetic variance to DDT resistance. CONCLUSION: The extensive distribution of pyrethroid and DDT resistance in East African An. funestus populations represents a challenge to the control of this vector. However, the observed carbamate and organophosphate susceptibility offers alternative solutions for resistance management.

  10. Effective coverage and systems effectiveness for malaria case management in sub-Saharan African countries.

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    Katya Galactionova

    Full Text Available Scale-up of malaria preventive and control interventions over the last decade resulted in substantial declines in mortality and morbidity from the disease in sub-Saharan Africa and many other parts of the world. Sustaining these gains will depend on the health system performance. Treatment provides individual benefits by curing infection and preventing progression to severe disease as well as community-level benefits by reducing the infectious reservoir and averting emergence and spread of drug resistance. However many patients with malaria do not access care, providers do not comply with treatment guidelines, and hence, patients do not necessarily receive the correct regimen. Even when the correct regimen is administered some patients will not adhere and others will be treated with counterfeit or substandard medication leading to treatment failures and spread of drug resistance. We apply systems effectiveness concepts that explicitly consider implications of health system factors such as treatment seeking, provider compliance, adherence, and quality of medication to estimate treatment outcomes for malaria case management. We compile data for these indicators to derive estimates of effective coverage for 43 high-burden Sub-Saharan African countries. Parameters are populated from the Demographic and Health Surveys and other published sources. We assess the relative importance of these factors on the level of effective coverage and consider variation in these health systems indicators across countries. Our findings suggest that effective coverage for malaria case management ranges from 8% to 72% in the region. Different factors account for health system inefficiencies in different countries. Significant losses in effectiveness of treatment are estimated in all countries. The patterns of inter-country variation suggest that these are system failures that are amenable to change. Identifying the reasons for the poor health system performance and

  11. Time to move from presumptive malaria treatment to laboratory-confirmed diagnosis and treatment in African children with fever.

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    Valérie D'Acremont

    2009-01-01

    Full Text Available BACKGROUND TO THE DEBATE: Current guidelines recommend that all fever episodes in African children be treated presumptively with antimalarial drugs. But declining malarial transmission in parts of sub-Saharan Africa, declining proportions of fevers due to malaria, and the availability of rapid diagnostic tests mean it may be time for this policy to change. This debate examines whether enough evidence exists to support abandoning presumptive treatment and whether African health systems have the capacity to support a shift toward laboratory-confirmed rather than presumptive diagnosis and treatment of malaria in children under five.

  12. Anopheles plumbeus (Diptera: Culicidae in Europe: a mere nuisance mosquito or potential malaria vector?

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    Schaffner Francis

    2012-11-01

    Full Text Available Abstract Background Anopheles plumbeus has been recognized as a minor vector for human malaria in Europe since the beginning of the 20th century. In recent years this tree hole breeding mosquito species appears to have exploited novel breeding sites, including large and organically rich man-made containers, with consequently larger mosquito populations in close vicinity to humans. This lead to investigate whether current populations of An. plumbeus would be able to efficiently transmit Plasmodium falciparum, the parasite responsible for the most deadly form of malaria. Methods Anopheles plumbeus immatures were collected from a liquid manure pit in Switzerland and transferred as adults to the CEPIA (Institut Pasteur, France where they were fed on P. falciparum gametocytes produced in vitro. Anopheles gambiae mosquitoes served as controls. Development of P. falciparum in both mosquito species was followed by microscopical detection of oocysts on mosquito midguts and by sporozoite detection in the head/thorax by PCR and microscopy. Results A total of 293 wild An. plumbeus females from four independent collections successfully fed through a membrane on blood containing P. falciparum gametocytes. Oocysts were observed in mosquito midguts and P. falciparum DNA was detected in head-thorax samples in all four experiments, demonstrating, on a large mosquito sample, that An. plumbeus is indeed receptive to P. falciparum NF54 and able to produce sporozoites. Importantly, the proportion of sporozoites-infected An. plumbeus was almost similar to that of An. gambiae (31 to 88% An. plumbeus versus 67 to 97% An. gambiae. However, the number of sporozoites produced was significantly lower in infected An. plumbeus. Conclusion The results show that a sample of field-caught An. plumbeus has a moderate to high receptivity towards P. falciparum. Considering the increased mobility of humans between Europe and malaria endemic countries and changes in environment and

  13. Mass Spectrometry Based Proteomic Analysis of Salivary Glands of Urban Malaria Vector Anopheles stephensi

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    Sonam Vijay

    2014-01-01

    Full Text Available Salivary gland proteins of Anopheles mosquitoes offer attractive targets to understand interactions with sporozoites, blood feeding behavior, homeostasis, and immunological evaluation of malaria vectors and parasite interactions. To date limited studies have been carried out to elucidate salivary proteins of An. stephensi salivary glands. The aim of the present study was to provide detailed analytical attributives of functional salivary gland proteins of urban malaria vector An. stephensi. A proteomic approach combining one-dimensional electrophoresis (1DE, ion trap liquid chromatography mass spectrometry (LC/MS/MS, and computational bioinformatic analysis was adopted to provide the first direct insight into identification and functional characterization of known salivary proteins and novel salivary proteins of An. stephensi. Computational studies by online servers, namely, MASCOT and OMSSA algorithms, identified a total of 36 known salivary proteins and 123 novel proteins analysed by LC/MS/MS. This first report describes a baseline proteomic catalogue of 159 salivary proteins belonging to various categories of signal transduction, regulation of blood coagulation cascade, and various immune and energy pathways of An. stephensi sialotranscriptome by mass spectrometry. Our results may serve as basis to provide a putative functional role of proteins in concept of blood feeding, biting behavior, and other aspects of vector-parasite host interactions for parasite development in anopheline mosquitoes.

  14. Exogenous gypsy insulator sequences modulate transgene expression in the malaria vector mosquito, Anopheles stephensi.

    Science.gov (United States)

    Carballar-Lejarazú, Rebeca; Jasinskiene, Nijole; James, Anthony A

    2013-04-30

    Malaria parasites are transmitted to humans by mosquitoes of the genus Anopheles, and these insects are the targets of innovative vector control programs. Proposed approaches include the use of genetic strategies based on transgenic mosquitoes to suppress or modify vector populations. Although substantial advances have been made in engineering resistant mosquito strains, limited efforts have been made in refining mosquito transgene expression, in particular attenuating the effects of insertions sites, which can result in variations in phenotypes and impacts on fitness due to the random integration of transposon constructs. A promising strategy to mitigate position effects is the identification of insulator or boundary DNA elements that could be used to isolate transgenes from the effects of their genomic environment. We applied quantitative approaches that show that exogenous insulator-like DNA derived from the Drosophila melanogaster gypsy retrotransposon can increase and stabilize transgene expression in transposon-mediated random insertions and recombinase-catalyzed, site-specific integrations in the malaria vector mosquito, Anopheles stephensi. These sequences can contribute to precise expression of transgenes in mosquitoes engineered for both basic and applied goals.

  15. Microbial control of malaria: biological warfare against the parasite and its vector.

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    Abdul-Ghani, Rashad; Al-Mekhlafi, Abdulsalam M; Alabsi, Mogeeb S

    2012-02-01

    Microbial applications in malaria transmission control have drawn global attention. Mosquito midgut microbiota can modulate vector immunity and block Plasmodium development. Paratransgenic manipulation of bacterial symbionts and Wolbachia can affect reproductive characteristics of mosquitoes. Bacillus-based biolarvicides can control mosquito larvae in different breeding habitats, but their effectiveness differs according to the type of formulation applied, and the physical and ecological conditions of the environment. Entomopathogenic fungi show promise as effective and evolution-proof agents against adult mosquitoes. In addition, transgenic fungi can express anti-plasmodial effector molecules that can target the parasite inside its vector. Despite showing effectiveness in domestic environments as well as against insecticide-resistant mosquitoes, claims towards their deployability in the field and their possible use in integrated vector management programmes have yet to be investigated. Viral pathogens show efficacy in the interruption of sporogonic development of the parasite, and protozoal pathogens exert direct pathogenic potential on larvae and adults with substantial effects on mosquito longevity and fecundity. However, the technology required for their isolation and maintenance impedes their field application. Many agents show promising findings; however, the question remains about the epidemiologic reality of these approaches because even those that have been tried under field conditions still have certain limitations. This review addresses aspects of the microbial control of malaria between proof-of-concept and epidemiologic reality.

  16. Comparative genomic analysis of chitinase and chitinase-like genes in the African malaria mosquito (Anopheles gambiae.

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    Jianzhen Zhang

    Full Text Available Chitinase is an important enzyme responsible for chitin metabolism in a wide range of organisms including bacteria, yeasts and other fungi, nematodes and arthropods. However, current knowledge on chitinolytic enzymes, especially their structures, functions and regulation is very limited. In this study we have identified 20 chitinase and chitinase-like genes in the African malaria mosquito, Anopheles gambiae, through genome-wide searching and transcript profiling. We assigned these genes into eight different chitinase groupings (groups I-VIII. Domain analysis of their predicted proteins showed that all contained at least one catalytic domain. However, only seven (AgCht4, AgCht5-1, AgCht6, AgCht7, AgCht8, AgCht10 and AgCht23 displayed one or more chitin-binding domains. Analyses of stage- and tissue-specific gene expression revealed that most of these genes were expressed in larval stages. However, AgCht8 was mainly expressed in the pupal and adult stages. AgCht2 and AgCht12 were specifically expressed in the foregut, whereas AgCht13 was only expressed in the midgut. The high diversity and complexity of An. gambiae chitinase and chitinase-like genes suggest their diverse functions during different developmental stages and in different tissues of the insect. A comparative genomic analysis of these genes along with those present in Drosophila melanogaster, Tribolium castaneum and several other insect species led to a uniform classification and nomenclature of these genes. Our investigation also provided important information for conducting future studies on the functions of chitinase and chitinase-like genes in this important malaria vector and other species of arthropods.

  17. 1.45 Å resolution structure of SRPN18 from the malaria vector Anopheles gambiae

    Energy Technology Data Exchange (ETDEWEB)

    Meekins, David A.; Zhang, Xin; Battaile, Kevin P.; Lovell, Scott; Michel, Kristin (Kansas); (KSU); (HWMRI)

    2016-11-19

    Serine protease inhibitors (serpins) in insects function within development, wound healing and immunity. The genome of the African malaria vector,Anopheles gambiae, encodes 23 distinct serpin proteins, several of which are implicated in disease-relevant physiological responses.A. gambiaeserpin 18 (SRPN18) was previously categorized as non-inhibitory based on the sequence of its reactive-center loop (RCL), a region responsible for targeting and initiating protease inhibition. The crystal structure ofA. gambiaeSRPN18 was determined to a resolution of 1.45 Å, including nearly the entire RCL in one of the two molecules in the asymmetric unit. The structure reveals that the SRPN18 RCL is extremely short and constricted, a feature associated with noncanonical inhibitors or non-inhibitory serpin superfamily members. Furthermore, the SRPN18 RCL does not contain a suitable protease target site and contains a large number of prolines. The SRPN18 structure therefore reveals a unique RCL architecture among the highly conserved serpin fold.

  18. Larvicidal activity of synthesized silver nanoparticles using Eclipta prostrata leaf extract against filariasis and malaria vectors.

    Science.gov (United States)

    Rajakumar, G; Abdul Rahuman, A

    2011-06-01

    Mosquitoes transmit serious human diseases, causing millions of deaths every year. 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 this study, larvicidal activity of synthesized silver nanoparticles (AgNPs) utilizing aqueous extract from Eclipta prostrata, a member of the Asteraceae was investigated against fourth instar larvae of filariasis vector, Culex quinquefasciatus say and malaria vector, Anopheles subpictus Grassi (Diptera: Culicidae). The synthesized AgNPs characterized by UV-vis spectrum, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and X-ray diffraction (XRD). SEM analyses of the synthesized AgNPs were clearly distinguishable measured 35-60 nm in size. Larvae were exposed to varying concentrations of aqueous extract of synthesized AgNPs for 24h. The maximum efficacy was observed in crude aqueous, and synthesized AgNPs against C. quinquefasciatus (LC(50)=27.49 and 4.56 mg/L; LC(90)=70.38 and 13.14 mg/L), and against A. subpictus (LC(50)=27.85 and 5.14 mg/L; LC(90)=71.45 and 25.68 mg/L) respectively. The chi-square value were significant at pmosquito larvicidal activity of synthesized AgNPs against vectors.

  19. Characteristics of malaria vector breeding habitats in Sri Lanka: relevance for environmental management

    DEFF Research Database (Denmark)

    Hoek, Wim van der; Amerasinghe, F P; Konradsen, F;

    1998-01-01

    In and around a village in the Anuradhapura District of Sri Lanka anopheline larvae were sampled from July 1994 to April 1996 in all surface water bodies. Samples positive for Anopheles culicifacies, the established vector of malaria in Sri Lanka, and for An. barbirostris, An. vagus, and An. varuna......, potential secondary vectors, were characterized by site, exposure to sunlight, substratum, turbidity of the water, presence of vegetation, and presence of fauna. Availability of pools of stagnant water in the stream near the village and along the edge of the village tank was highly predictive for presence...... of An. culicifacies larvae, independent from the other characteristics that were included in the study. The biological and physical characteristics could not very well explain the preference for certain habitats, but it was of interest that An. culicifacies, generally considered to bread in sun exposed...

  20. Vectors and malaria transmission in deforested, rural communities in north-central Vietnam

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    Do Manh Cuong

    2010-09-01

    Full Text Available Abstract Background Malaria is still prevalent in rural communities of central Vietnam even though, due to deforestation, the primary vector Anopheles dirus is uncommon. In these situations little is known about the secondary vectors which are responsible for maintaining transmission. Basic information on the identification of the species in these rural communities is required so that transmission parameters, such as ecology, behaviour and vectorial status can be assigned to the appropriate species. Methods In two rural villages - Khe Ngang and Hang Chuon - in Truong Xuan Commune, Quang Binh Province, north central Vietnam, a series of longitudinal entomological surveys were conducted during the wet and dry seasons from 2003 - 2007. In these surveys anopheline mosquitoes were collected in human landing catches, paired human and animal bait collections, and from larval surveys. Specimens belonging to species complexes were identified by PCR and sequence analysis, incrimination of vectors was by detection of circumsporozoite protein using an enzyme-linked immunosorbent assay. Results Over 80% of the anopheline fauna was made up of Anopheles sinensis, Anopheles aconitus, Anopheles harrisoni, Anopheles maculatus, Anopheles sawadwongporni, and Anopheles philippinensis. PCR and sequence analysis resolved identification issues in the Funestus Group, Maculatus Group, Hyrcanus Group and Dirus Complex. Most species were zoophilic and while all species could be collected biting humans significantly higher densities were attracted to cattle and buffalo. Anopheles dirus was the most anthropophilic species but was uncommon making up only 1.24% of all anophelines collected. Anopheles sinensis, An. aconitus, An. harrisoni, An. maculatus, An. sawadwongporni, Anopheles peditaeniatus and An. philippinensis were all found positive for circumsporozoite protein. Heterogeneity in oviposition site preference between species enabled vector densities to be high in both

  1. Design of a Two-level Adaptive Multi-Agent System for Malaria Vectors driven by an ontology

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    Etang Josiane

    2007-07-01

    Full Text Available Abstract Background The understanding of heterogeneities in disease transmission dynamics as far as malaria vectors are concerned is a big challenge. Many studies while tackling this problem don't find exact models to explain the malaria vectors propagation. Methods To solve the problem we define an Adaptive Multi-Agent System (AMAS which has the property to be elastic and is a two-level system as well. This AMAS is a dynamic system where the two levels are linked by an Ontology which allows it to function as a reduced system and as an extended system. In a primary level, the AMAS comprises organization agents and in a secondary level, it is constituted of analysis agents. Its entry point, a User Interface Agent, can reproduce itself because it is given a minimum of background knowledge and it learns appropriate "behavior" from the user in the presence of ambiguous queries and from other agents of the AMAS in other situations. Results Some of the outputs of our system present a series of tables, diagrams showing some factors like Entomological parameters of malaria transmission, Percentages of malaria transmission per malaria vectors, Entomological inoculation rate. Many others parameters can be produced by the system depending on the inputted data. Conclusion Our approach is an intelligent one which differs from statistical approaches that are sometimes used in the field. This intelligent approach aligns itself with the distributed artificial intelligence. In terms of fight against malaria disease our system offers opportunities of reducing efforts of human resources who are not obliged to cover the entire territory while conducting surveys. Secondly the AMAS can determine the presence or the absence of malaria vectors even when specific data have not been collected in the geographical area. In the difference of a statistical technique, in our case the projection of the results in the field can sometimes appeared to be more general.

  2. Larvicidal Activity of Essential Oils of Apiaceae Plants Against Malaria Vector, Anopheles Stephensi

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    Y Salim Abadi

    2011-12-01

    Full Text Available Background: Plant extracts and oils may act as alternatives to conventional pesticides for malaria vector control. The aim of this study was to evaluate the larvicidal activity of essential oils of three plants of Apiaceae family against Anophe­les stephensi, the main malaria vector in Iran. Methods: Essential oils from Heracleum persicum, Foeniculum vulgare and Coriandrum sativum seeds were hydro distil­lated, then their larvicidal activity were evaluated against laboratory-reared larvae of An. stephensi according to stan­dard method of WHO. After susceptibility test, results were analysis using Probit program.Results: Essential oils were separated from H. persicum, F. vulgare and C. sativum plants and their larvicidal activi­ties were tested. Result of this study showed that F. vulgare oil was the most effective against An. stephensi with LC50 and LC90 values of 20.10 and 44.51 ppm, respectively.Conclusion: All three plants essential oil can serve as a natural larvicide against An. stephensi. F. vulgare oil exhib­ited more larvicidal properties.

  3. On the efficacy of malaria DNA vaccination with magnetic gene vectors.

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    Nawwab Al-Deen, Fatin; Ma, Charles; Xiang, Sue D; Selomulya, Cordelia; Plebanski, Magdalena; Coppel, Ross L

    2013-05-28

    We investigated the efficacy and types of immune responses from plasmid malaria DNA vaccine encoding VR1020-PyMSP119 condensed on the surface of polyethyleneimine (PEI)-coated SPIONs. In vivo mouse studies were done firstly to determine the optimum magnetic vector composition, and then to observe immune responses elicited when magnetic vectors were introduced via different administration routes. Higher serum antibody titers against PyMSP119 were observed with intraperitoneal and intramuscular injections than subcutaneous and intradermal injections. Robust IgG2a and IgG1 responses were observed for intraperitoneal administration, which could be due to the physiology of peritoneum as a major reservoir of macrophages and dendritic cells. Heterologous DNA prime followed by single protein boost vaccination regime also enhanced IgG2a, IgG1, and IgG2b responses, indicating the induction of appropriate memory immunity that can be elicited by protein on recall. These outcomes support the possibility to design superparamagnetic nanoparticle-based DNA vaccines to optimally evoke desired antibody responses, useful for a variety of diseases including malaria.

  4. Indication of pyrethroid resistance in the main malaria vectorAnopheles stephensi from Iran

    Institute of Scientific and Technical Information of China (English)

    Hassan Vatandoost; Ahmad Ali Hanafi-Bojd

    2012-01-01

    Objective:To investiagte insecticide resistance in target species for better insecticide resistance managemnet in malaria control programs.Methods:The status of insecticide resistance to different imagicides inAnopheles stephensi(An. stephensi) includingDDT4%, lambdacyhalothrin 0.50%, deltamethrin0.05%, permethrin0.75%, cyfluthrin0.15% and etofenprox0.50% was performed according toWHO standard method.Results:The mortality rate to lambdacyhalothrin, permethrin, cyfluthrin, deltamethrin, etofenprox andDDT was(88.0±3.2),(92.0±2.7),(52.0±5.0),(96.0±2.2),(90.0±3.0) and(41.0±5.7) percent, respectively at diagnostic dose for one hour exposure time followed by24 h recovery period.Conclusions:These results showed first indication of pyrethroid resistance inAn. stephensiin a malarious area, from southernIran.There is widespread, multiple resistances in the country inAn. stephensi to organochlorine and some report of tolerance to organophosphate insecticides and recently to pyrethroids.However, results of this paper will provide a clue for monitoring and mapping of insecticide resistance in the main malaria vector for implementation of any vector control.

  5. Evaluation of new tools for malaria vector control in Cameroon: focus on long lasting insecticidal nets.

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    Josiane Etang

    Full Text Available BACKGROUND: From 2006 to 2011, biological activity of insecticides for Indoor Residual Spraying (IRS, conventional treatment of nets (CTNs or long lasting insecticidal nets (LLINs was evaluated before their approval in Cameroon. The objective of the study was to select the best tools for universal malaria vector control coverage. METHODOLOGY: Bioassays were performed using WHO cones and the Kisumu susceptible strain of Anopheles gambiae s.s.. Among tested products, residual activity and wash resistance of Alpha-cypermethrin LLINs (Interceptor and CTNs (Fendona were assessed during 5 months in the Ntougou neighborhood. PRINCIPAL FINDINGS: All the 14 tested products were found effective (95-100% knockdown and mortality rates, although a significant decrease of efficacy was seen with lambda-cyhalothrinWP IRS, alpha-cypermethrin CTNs and LLINs (p< 0.05. However, the efficacy of Interceptor nets did not decrease during the 5 months evaluation, even after 25 washes (0.07malaria vector control in Cameroon.

  6. High malaria transmission in a forested malaria focus in French Guiana: How can exophagic Anopheles darlingi thwart vector control and prevention measures?

    Science.gov (United States)

    Vezenegho, Samuel B; Adde, Antoine; de Santi, Vincent Pommier; Issaly, Jean; Carinci, Romuald; Gaborit, Pascal; Dusfour, Isabelle; Girod, Romain; Briolant, Sébastien

    2016-01-01

    In French Guiana, malaria vector control and prevention relies on indoor residual spraying and distribution of long lasting insecticidal nets. These measures are based on solid epidemiological evidence but reveal a poor understanding of the vector. The current study investigated the behaviour of both vectors and humans in relation to the ongoing prevention strategies. In 2012 and 2013, Anopheles mosquitoes were sampled outdoors at different seasons and in various time slots. The collected mosquitoes were identified and screened for Plasmodium infection. Data on human behaviour and malaria episodes were obtained from an interview. A total of 3,135 Anopheles mosquitoes were collected, of which Anopheles darlingi was the predominant species (96.2%). For the December 2012-February 2013 period, the Plasmodium vivax infection rate for An. darlingi was 7.8%, and the entomological inoculation rate was 35.7 infective bites per person per three-month span. In spite of high bednet usage (95.7%) in 2012 and 2013, 52.2% and 37.0% of the participants, respectively, had at least one malaria episode. An. darlingi displayed heterogeneous biting behaviour that peaked between 20:30 and 22:30; however, 27.6% of the inhabitants were not yet protected by bednets by 21:30. The use of additional individual and collective protective measures is required to limit exposure to infective mosquito bites and reduce vector densities. PMID:27653361

  7. High malaria transmission in a forested malaria focus in French Guiana: How can exophagic Anopheles darlingi thwart vector control and prevention measures?

    Science.gov (United States)

    Vezenegho, Samuel B; Adde, Antoine; Pommier de Santi, Vincent; Issaly, Jean; Carinci, Romuald; Gaborit, Pascal; Dusfour, Isabelle; Girod, Romain; Briolant, Sébastien

    2016-09-01

    In French Guiana, malaria vector control and prevention relies on indoor residual spraying and distribution of long lasting insecticidal nets. These measures are based on solid epidemiological evidence but reveal a poor understanding of the vector. The current study investigated the behaviour of both vectors and humans in relation to the ongoing prevention strategies. In 2012 and 2013, Anopheles mosquitoes were sampled outdoors at different seasons and in various time slots. The collected mosquitoes were identified and screened for Plasmodium infection. Data on human behaviour and malaria episodes were obtained from an interview. A total of 3,135 Anopheles mosquitoes were collected, of which Anopheles darlingi was the predominant species (96.2%). For the December 2012-February 2013 period, the Plasmodium vivax infection rate for An. darlingi was 7.8%, and the entomological inoculation rate was 35.7 infective bites per person per three-month span. In spite of high bednet usage (95.7%) in 2012 and 2013, 52.2% and 37.0% of the participants, respectively, had at least one malaria episode. An. darlingi displayed heterogeneous biting behaviour that peaked between 20:30 and 22:30; however, 27.6% of the inhabitants were not yet protected by bednets by 21:30. The use of additional individual and collective protective measures is required to limit exposure to infective mosquito bites and reduce vector densities.

  8. Using the entomological inoculation rate to assess the impact of vector control on malaria parasite transmission and elimination

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    McKenzie F Ellis

    2010-05-01

    Full Text Available Abstract Background Prior studies have shown that annual entomological inoculation rates (EIRs must be reduced to less than one to substantially reduce the prevalence of malaria infection. In this study, EIR values were used to quantify the impact of insecticide-treated bed nets (ITNs, indoor residual spraying (IRS, and source reduction (SR on malaria transmission. The analysis of EIR was extended through determining whether available vector control tools can ultimately eradicate malaria. Method The analysis is based primarily on a review of all controlled studies that used ITN, IRS, and/or SR and reported their effects on the EIR. To compare EIRs between studies, the percent difference in EIR between the intervention and control groups was calculated. Results Eight vector control intervention studies that measured EIR were found: four ITN studies, one IRS study, one SR study, and two studies with separate ITN and IRS intervention groups. In both the Tanzania study and the Solomon Islands study, one community received ITNs and one received IRS. In the second year of the Tanzania study, EIR was 90% lower in the ITN community and 93% lower in the IRS community, relative to the community without intervention; the ITN and IRS effects were not significantly different. In contrast, in the Solomon Islands study, EIR was 94% lower in the ITN community and 56% lower in the IRS community. The one SR study, in Dar es Salaam, reported a lower EIR reduction (47% than the ITN and IRS studies. All of these vector control interventions reduced EIR, but none reduced it to zero. Conclusion These studies indicate that current vector control methods alone cannot ultimately eradicate malaria because no intervention sustained an annual EIR less than one. While researchers develop new tools, integrated vector management may make the greatest impact on malaria transmission. There are many gaps in the entomological malaria literature and recommendations for future

  9. Malaria vector control by indoor residual insecticide spraying on the tropical island of Bioko, Equatorial Guinea

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    Kuklinski Jaime

    2007-05-01

    Full Text Available Abstract Background A comprehensive malaria control intervention was initiated in February 2004 on Bioko Island, Equatorial Guinea. This manuscript reports on the continuous entomological monitoring of the indoor residual spray (IRS programme during the first two years of its implementation. Methods Mosquitoes were captured daily using window traps at 16 sentinel sites and analysed for species identification, sporozoite rates and knockdown resistance (kdr using polymerase chain reaction (PCR to assess the efficacy of the vector control initiative from December 2003 to December 2005. Results A total of 2,807 and 10,293 Anopheles funestus and Anopheles gambiae s.l. respectively were captured throughout the study period. Both M and S molecular forms of An. gambiae s.s. and Anopheles melas were identified. Prior to the first round of IRS, sporozoite rates were 6.0, 8.3 and 4.0 for An. gambiae s.s., An. melas and An. funestus respectively showing An. melas to be an important vector in areas in which it occurred. After the third spray round, no infective mosquitoes were identified. After the first spray round using a pyrethroid spray the number of An. gambiae s.s. were not reduced due to the presence of the kdr gene but An funestus and An. melas populations declined from 23.5 to 3.1 and 5.3 to 0.8 per trap per 100 nights respectively. After the introduction of a carbamate insecticide in the second round, An. gambiae s.s. reduced from 25.5 to 1.9 per trap per 100 nights and An. funestus and An. melas remained at very low levels. Kdr was found only in the M-form of An. gambiae s.s. with the highest frequency at Punta Europa (85%. Conclusion All three vectors that were responsible for malaria transmission before the start of the intervention were successfully controlled once an effective insecticide was used. Continuous entomological surveillance including resistance monitoring is of critical importance in any IRS based malaria vector control programme

  10. Chlorfenapyr: a new insecticide with novel mode of action can control pyrethroid resistant malaria vectors

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    Srivastava Harish C

    2011-01-01

    Full Text Available Abstract Background Malaria vectors have acquired widespread resistance to many of the currently used insecticides, including synthetic pyrethroids. Hence, there is an urgent need to develop alternative insecticides for effective management of insecticide resistance in malaria vectors. In the present study, chlorfenapyr was evaluated against Anopheles culicifacies and Anopheles stephensi for its possible use in vector control. Methods Efficacy of chlorfenapyr against An. culicifacies and An. stephensi was assessed using adult bioassay tests. In the laboratory, determination of diagnostic dose, assessment of residual activity on different substrates, cross-resistance pattern with different insecticides and potentiation studies using piperonyl butoxide were undertaken by following standard procedures. Potential cross-resistance patterns were assessed on field populations of An. culicifacies. Results A dose of 5.0% chlorfenapyr was determined as the diagnostic concentration for assessing susceptibility applying the WHO tube test method in anopheline mosquitoes with 2 h exposure and 48 h holding period. The DDT-resistant/malathion-deltamethrin-susceptible strain of An. culicifacies species C showed higher LD50 and LD99 (0.67 and 2.39% respectively values than the DDT-malathion-deltamethrin susceptible An. culicifacies species A (0.41 and 2.0% respectively and An. stephensi strains (0.43 and 2.13% respectively and there was no statistically significant difference in mortalities among the three mosquito species tested (p > 0.05. Residual activity of chlorfenapyr a.i. of 400 mg/m2 on five fabricated substrates, namely wood, mud, mud+lime, cement and cement + distemper was found to be effective up to 24 weeks against An. culicifacies and up to 34 weeks against An. stephensi. No cross-resistance to DDT, malathion, bendiocarb and deltamethrin was observed with chlorfenapyr in laboratory-reared strains of An. stephensi and field-caught An. culicifacies

  11. Resting behaviour, ecology and genetics of malaria vectors in large scale agricultural areas of Western Kenya.

    Science.gov (United States)

    Githeko, A K; Service, M W; Mbogo, C M; Atieli, F K

    1996-12-01

    In Kenya indoor and outdoor resting densities of Anopheles arabiensis and Anopheles funestus at the Ahero rice irrigation scheme, and Anopheles gambiae s.s., An. arabiensis and An. funestus at the Miwani sugar belt were assessed for 13 months by pyrethrum spray collections in houses and granaries. The vector's house leaving behaviour was evaluated with exit traps and it was noted that early exophily (i.e., deliberate) was not detected in any of the vectors. Assortative indoor/outdoor resting behaviour was studied by a capture-mark-release-recapture method and showed that in An. arabiensis both indoor and outdoor resting traits were present in the same individuals. Samples of half-gravid female An. gambiae s.l. were chromosomally identified either as Anopheles gambiae s.s. or An. arabiensis and in a subsample chromosomal inversions were read. Anopheles gambiae s.s. and An. arabiensis had the 2Rb inversion but in addition the 2La inversion was found in An. gambiae s.s. and this is an indication of low chromosomal variation. At Ahero An. arabiensis was most abundant when the rice crop was immature and An. funestus when the crop was mature. This succession of vectors facilitated the transmission of malaria throughout the year. At Miwani, An. gambiae s.l. population peaked during the long rains but the proportion of An. arabiensis was highest during the dry season. The indoor resting density of males of the three vector species was less than half of the females.

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

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    Yan G

    2002-08-01

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

  13. The genetic risk of acute seizures in African children with falciparum malaria

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    Kariuki, Symon M; Rockett, Kirk; Clark, Taane G; Reyburn, Hugh; Agbenyega, Tsiri; Taylor, Terrie E; Birbeck, Gretchen L; Williams, Thomas N; Newton, Charles R J C

    2013-01-01

    Purpose It is unclear why some children with falciparum malaria develop acute seizures and what determines the phenotype of seizures. We sought to determine if polymorphisms of malaria candidate genes are associated with acute seizures. Methods Logistic regression was used to investigate genetic associations with malaria-associated seizures (MAS) and complex MAS (repetitive, prolonged, or focal seizures) in four MalariaGEN African sites, namely: Blantyre, Malawi; Kilifi, Kenya; Kumasi, Ghana; and Muheza, Tanzania. The analysis was repeated for five inheritance models (dominant, heterozygous, recessive, additive, and general) and adjusted for potential confounders and multiple testing. Key Findings Complex phenotypes of seizures constituted 71% of all admissions with MAS across the sites. MAS were strongly associated with cluster of differentiation-ligand-rs3092945 in females in Kilifi (p = 0.00068) and interleukin (IL)-17 receptor E-rs708567 in the pooled analysis across the sites (p = 0.00709). Complex MAS were strongly associated with epidermal growth factor module-containing mucin-like hormone receptor (EMR)1-rs373533 in Kumasi (p = 0.00033), but none in the pooled analysis. Focal MAS were strongly associated with IL-20 receptor A-rs1555498 in Muheza (p = 0.00016), but none in the pooled analysis. Prolonged MAS were strongly associated with complement receptor 1-rs17047660 in Kilifi (p = 0.00121) and glucose-6-phosphate dehydrogenase-rs1050828 in females in the pooled analysis (p = 0.00155). Repetitive MAS were strongly associated with EMR1-rs373533 in Kumasi (p = 0.00003) and cystic fibrosis transmembrane conductance receptor-rs17140229 in the pooled analysis (p = 0.00543). MAS with coma/cerebral malaria were strongly associated with EMR1-rs373533 in Kumasi (p = 0.00019) and IL10-rs3024500 in the pooled analysis across the sites (p = 0.00064). Significance We have identified a number of genetic associations that may explain the risk of seizures in >2,000 cases

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

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    Cetron Martin S

    2011-06-01

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

  15. Declining malaria, rising of dengue and Zika virus: insights for mosquito vector control.

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    Benelli, Giovanni; Mehlhorn, Heinz

    2016-05-01

    The fight against mosquito-borne diseases is a challenge of huge public health importance. To our mind, 2015 was an extraordinary year for malaria control, due to three hot news: the Nobel Prize to Youyou Tu for the discovery of artemisinin, the development of the first vaccine against Plasmodium falciparum malaria [i.e. RTS,S/AS01 (RTS,S)], and the fall of malaria infection rates worldwide, with special reference to sub-Saharan Africa. However, there are major challenges that still deserve attention, in order to boost malaria prevention and control. Indeed, parasite strains resistant to artemisinin have been detected, and RTS,S vaccine does not offer protection against Plasmodium vivax malaria, which predominates in many countries outside of Africa. Furthermore, the recent outbreaks of Zika virus infections, occurring in South America, Central America and the Caribbean, represent the most recent of four arrivals of important arboviruses in the Western Hemisphere, over the last 20 years. Zika virus follows dengue (which slyly arrived in the hemisphere over decades and became more aggressive in the 1990s), West Nile virus (emerged in 1999) and chikungunya (emerged in 2013). Notably, there are no specific treatments for these arboviruses. The emerging scenario highlights that the effective and eco-friendly control of mosquito vectors, with special reference to highly invasive species such as Aedes aegypti and Aedes albopictus, is crucial. The concrete potential of screening plant species as sources of metabolites for parasitological purposes is worthy of attention, as elucidated by the Y. Tu's example. Notably, plant-borne molecules are often effective at few parts per million against Aedes, Ochlerotatus, Anopheles and Culex young instars, can be used for the rapid synthesis of mosquitocidal nanoformulations and even employed to prepare cheap repellents with low human toxicity. In addition, behaviour-based control tools relying to the employ of sound traps and the

  16. Monitoring of Plasmodium infection in humans and potential vectors of malaria in a newly emerged focus in southern Iran.

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    Kalantari, Mohsen; Soltani, Zahra; Ebrahimi, Mostafa; Yousefi, Masoud; Amin, Masoumeh; Shafiei, Ayda; Azizi, Kourosh

    2017-02-01

    Despite control programs, which aim to eliminate malaria from Iran by 2025, transmission of malaria has not been removed from the country. This study aimed to monitor malaria from asymptomatic parasitaemia and clinical cases from about one year of active case surveillance and potential vectors of malaria in the newly emerged focus of Mamasani and Rostam, southern Iran during 2014-2015. Samples were collected and their DNAs were extracted for Polymerase Chain Reaction (PCR) assay using specific primers for detection of Plasmodium species. The Annual Parasite Incidence rate (API) was three cases per 1,000 population from 2,000 individuals in three villages. Parasites species were detected in 9 out of the 4,000 blood smear samples among which, 6 cases were indigenous and had no history of travels to endemic areas of malaria. Also, the prevalence rate of asymptomatic parasites was about 0.3%. Overall, 1073 Anopheles spp. were caught from 9 villages. Totally, 512 female samples were checked by PCR, which indicated that none of them was infected with Plasmodium. Despite new malaria local transmission in humans in Mamasani and Rostam districts, no infection with Plasmodium was observed in Anopheles species. Because of neighboring of the studied area to the re-emerged focus in Fars province (Kazerun) and important endemic foci of malaria in other southern provinces, such as Hormozgan and Kerman, monitoring of the vectors and reservoir hosts of Plasmodium species would be unavoidable. Application of molecular methods, such as PCR, can simplify access to the highest level of accuracy in malaria researches.

  17. Imported malaria among African immigrants: is there still a relationship between developed countries and their ex-colonies?

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    Muñoz José

    2009-05-01

    Full Text Available Abstract Background The objective of this study was to compare cases of imported malaria originating from the Spanish ex-colony of Equatorial Guinea (EG with those originating from the rest of Africa (RA. Methods All the African cases detected in Barcelona between 1989 and 2007 were investigated in a retrospective analysis. Clinical-epidemiological variables such as sex, age, visiting friends and relatives (VFR, species, hospital admission and chemo-prophylaxis were compared. Data were analysed by logistic regression, calculating the Odds Ratio (OR and 95% Confidence Intervals (95% CI. Results Of the 489 African patients, 279 (57,1% had been born in EG and 210 (42,9% in the rest of Africa. The cumulative incidence of imported malaria among those from EG was 179.6 per thousand inhabitants, while in those from the RA it was 33.7 per thousand (p visiting friends and relatives (VFR category, and more individuals younger than 15 years or older than 37 years, and more women. They also visited a traveller's health centre more often, had fewer hospital admissions and were less likely to reside in the inner city. Conclusion Cases of imported malaria originating in Africa, are more likely to come from the Spanish ex-colony of EG, and VFR are more likely to be affected. It is recommended that developed countries promote prevention programmes, such as CP advice directed at African immigrants, and develop programmes of cooperation against malaria in their ex-colonies.

  18. Field evaluation of picaridin repellents reveals differences in repellent sensitivity between Southeast Asian vectors of malaria and arboviruses.

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    Karel Van Roey

    2014-12-01

    Full Text Available Scaling up of insecticide treated nets has contributed to a substantial malaria decline. However, some malaria vectors, and most arbovirus vectors, bite outdoors and in the early evening. Therefore, topically applied insect repellents may provide crucial additional protection against mosquito-borne pathogens. Among topical repellents, DEET is the most commonly used, followed by others such as picaridin. The protective efficacy of two formulated picaridin repellents against mosquito bites, including arbovirus and malaria vectors, was evaluated in a field study in Cambodia. Over a period of two years, human landing collections were performed on repellent treated persons, with rotation to account for the effect of collection place, time and individual collector. Based on a total of 4996 mosquitoes collected on negative control persons, the overall five hour protection rate was 97.4% [95%CI: 97.1-97.8%], not decreasing over time. Picaridin 20% performed equally well as DEET 20% and better than picaridin 10%. Repellents performed better against Mansonia and Culex spp. as compared to aedines and anophelines. A lower performance was observed against Aedes albopictus as compared to Aedes aegypti, and against Anopheles barbirostris as compared to several vector species. Parity rates were higher in vectors collected on repellent treated person as compared to control persons. As such, field evaluation shows that repellents can provide additional personal protection against early and outdoor biting malaria and arbovirus vectors, with excellent protection up to five hours after application. The heterogeneity in repellent sensitivity between mosquito genera and vector species could however impact the efficacy of repellents in public health programs. Considering its excellent performance and potential to protect against early and outdoor biting vectors, as well as its higher acceptability as compared to DEET, picaridin is an appropriate product to evaluate the

  19. Field evaluation of picaridin repellents reveals differences in repellent sensitivity between Southeast Asian vectors of malaria and arboviruses.

    Science.gov (United States)

    Van Roey, Karel; Sokny, Mao; Denis, Leen; Van den Broeck, Nick; Heng, Somony; Siv, Sovannaroth; Sluydts, Vincent; Sochantha, Tho; Coosemans, Marc; Durnez, Lies

    2014-12-01

    Scaling up of insecticide treated nets has contributed to a substantial malaria decline. However, some malaria vectors, and most arbovirus vectors, bite outdoors and in the early evening. Therefore, topically applied insect repellents may provide crucial additional protection against mosquito-borne pathogens. Among topical repellents, DEET is the most commonly used, followed by others such as picaridin. The protective efficacy of two formulated picaridin repellents against mosquito bites, including arbovirus and malaria vectors, was evaluated in a field study in Cambodia. Over a period of two years, human landing collections were performed on repellent treated persons, with rotation to account for the effect of collection place, time and individual collector. Based on a total of 4996 mosquitoes collected on negative control persons, the overall five hour protection rate was 97.4% [95%CI: 97.1-97.8%], not decreasing over time. Picaridin 20% performed equally well as DEET 20% and better than picaridin 10%. Repellents performed better against Mansonia and Culex spp. as compared to aedines and anophelines. A lower performance was observed against Aedes albopictus as compared to Aedes aegypti, and against Anopheles barbirostris as compared to several vector species. Parity rates were higher in vectors collected on repellent treated person as compared to control persons. As such, field evaluation shows that repellents can provide additional personal protection against early and outdoor biting malaria and arbovirus vectors, with excellent protection up to five hours after application. The heterogeneity in repellent sensitivity between mosquito genera and vector species could however impact the efficacy of repellents in public health programs. Considering its excellent performance and potential to protect against early and outdoor biting vectors, as well as its higher acceptability as compared to DEET, picaridin is an appropriate product to evaluate the epidemiological

  20. The use of digital spaceborne SAR data for the delineation of surface features indicative of malaria vector breeding habitats

    Science.gov (United States)

    Imhoff, M. L.; Vermillion, C. H.; Khan, F. A.

    1984-01-01

    An investigation to examine the utility of spaceborne radar image data to malaria vector control programs is described. Specific tasks involve an analysis of radar illumination geometry vs information content, the synergy of radar and multispectral data mergers, and automated information extraction techniques.

  1. First report of the infection of insecticide-resistant malaria vector mosquitoes with an entomopathogenic fungus under field conditions

    NARCIS (Netherlands)

    Howard, A.F.V.; N'Guessan, R.; Koenraadt, C.J.M.; Asidi, A.; Farenhorst, M.; Akogbeto, M.; Knols, B.G.J.; Takken, W.

    2011-01-01

    Background - Insecticide-resistant mosquitoes are compromising the ability of current mosquito control tools to control malaria vectors. A proposed new approach for mosquito control is to use entomopathogenic fungi. These fungi have been shown to be lethal to both insecticide-susceptible and insecti

  2. Development and assessment of plant-based synthetic odor baits for surveillance and control of Malaria vectors

    Science.gov (United States)

    Recent malaria vector control measures have considerably reduced indoor biting mosquito populations. However, reducing the outdoor biting populations remains a challenge because of the unavailability of appropriate lures to achieve this. This study sought to test the efficacy of plant-based syntheti...

  3. Larvicidal and repellent activity of Vetiveria zizaniodes (Poaceae) essential oil against the malaria vector Anopheles stephensi (Liston) (Diptera: Culicidae)

    Science.gov (United States)

    Essential oil extracted by steam distillation of Vetiveria zizanioides (L.) Nash (Poaceae) was evaluated for larvicidal and adult repellent activity against the malaria vector Anopheles stephensi (Liston). Median lethal concentrations (LC50) at 24 h post treatment for instars 1-4 were, respectively,...

  4. Anopheles (Anopheles) Calderoni n.sp., A Malaria Vector of the Arribalzagia Series from Peru (Diptera: Culicidae)

    Science.gov (United States)

    1991-08-01

    ountered only at elevations below 250 m. The larvae are found in small streams, small ir- rigation canals and swamps, mostly in dense emergent...tions. REFERENCES CITED Calderon, G., A. Curaca, J. Llancari, M. Napan and F. Sipan. 1974. Distribucion geografica de los vectores de malaria en el

  5. House design modifications reduce indoor resting malaria vector densities in rice irrigation scheme area in western Kenya

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    Githeko Andrew

    2009-05-01

    Full Text Available Abstract Background Simple modifications of typical rural house design can be an effective and relatively inexpensive method of reducing indoor mosquito vector densities and consequently decreasing malaria transmission. Public health scientists have shown the potential for house design to protect people against malaria, yet this type of intervention remains virtually ignored. A randomized-controlled study was, therefore, undertaken to determine the effects of this method of vector control on the density of indoor resting malaria vectors in a rice irrigation scheme area in lowlands of western Kenya. Methods Ten treatment houses were modified with ceilings of papyrus mats and insecticide-treated netting (ITN and tested against ten control houses without papyrus ceilings. To determine densities of mosquitoes resting in homes, the pyrethrum spray method was used to simultaneously collect indoor resting malaria vectors in intervention and control houses. Each house was sampled a total of eight times over a period of four months, resulting in a total of 80 sampling efforts for each treatment. Community response to such intervention was investigated by discussions with residents. Results Papyrus mats ceiling modification reduced house entry by Anopheles gambiae s.l and Anopheles funestus densities by between 78–80% and 86% respectively compared to unmodified houses. Geometric mean density of Anopheles gambiae s.l. and Anopheles funestus in modified houses were significantly lower (t18 = 7.174, P 18 = 2.52, P = 0.02, respectively compared to controls. Unmodified houses were associated with relatively higher densities of malaria vectors. There was a 84% (OR 0.16, 95% CI 0.07–0.39, P Anopheles gambiae s.l. and Anopheles funestus presence in modified houses, respectively, compared with unmodified houses. Residents responded favourably to this mode of vector control. Conclusion House modifications involving insect screen ceilings made from locally

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

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    Ali Zakia M I

    2012-12-01

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

  7. Biosynthesized silver nanoparticles using floral extract of Chrysanthemum indicum L.--potential for malaria vector control.

    Science.gov (United States)

    Arokiyaraj, Selvaraj; Dinesh Kumar, Vannam; Elakya, Vijay; Kamala, Tamilselvan; Park, Sung Kwon; Ragam, Muthiah; Saravanan, Muthupandian; Bououdina, Mohomad; Arasu, Mariadhas Valan; Kovendan, Kalimuthu; Vincent, Savariar

    2015-07-01

    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 synthesized of natural products for vector control have been a priority in this area. In the present study, silver nanoparticles (Ag NPs) were green-synthesized using a floral extract of Chrysanthemum indicum screened for larvicidal and pupicidal activity against the first to fourth instar larvae and pupae of the malaria vector Anopheles stephensi mosquitoes. The synthesized Ag NPs were characterized by using UV-vis absorption, X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy techniques. The textures of the yielded Ag NPs were found to be spherical and polydispersed with a mean size in the range of 25-59 nm. Larvae and pupae were exposed to various concentrations of aqueous extract of C. indicum and synthesized Ag NPs for 24 h, and the maximum mortality was observed from the synthesized Ag NPs against the vector A. stephensi (LC50 = 5.07, 10.35, 14.19, 22.81, and 35.05 ppm; LC90 = 29.18, 47.15, 65.53, 87.96, and 115.05 ppm). These results suggest that the synthesized Ag NPs have the potential to be used as an ideal eco-friendly approach for the control of A. stephensi. Additionally, this study provides the larvicidal and pupicidal properties of green-synthesized Ag NPs with the floral extract of C. indicum against vector mosquito species from the geographical location of India.

  8. Ecological study of avian malaria vectors on the island of Minami-Daito, Japan.

    Science.gov (United States)

    Tsuda, Yoshio; Matsui, Shin; Saito, Atsushi; Akatani, Kana; Sato, Yukita; Takagi, Masaoki; Murata, Koichi

    2009-09-01

    The seasonal prevalence and spatial distribution of mosquitoes were examined as part of an avian malaria study on the oceanic island of Minami-Daito Island, Japan. Because dry ice was not available in this study, yeast-generated CO2 was used to attract biting mosquitoes. Adult mosquitoes were collected biweekly using battery-operated traps enhanced with yeast-generated CO2 and a gravid trap from March 2006 to February 2007. The CO2-baited traps were distributed in 4 different habitats: sugar cane field, forest and vegetation ring, residential area, and swamp area. At 3 collection sites beside sugar cane fields, traps were fixed at 2 different heights (3 and 6 m above the ground). A total of 1,437 mosquitoes of the following 9 species were collected: Culex quinquefasciatus, Aedes albopictus, Coquillettidia sp., Mansonia uniformis, Culex rubithoracis, Armigeres subalbatus, Lutzia fuscanus, Aedes daitensis, and Aedes togoi. Among them, Cx. quinquefasciatus, Ae. albopictus, and Coquillettidia sp. were dominant. The high density and wide distribution of Cx. quinquefasciatus throughout the island suggested the importance of this species as a principal vector of avian malaria on the island.

  9. “Highly evolvable malaria vectors: the genomes of 16 Anopheles mosquitoes”

    Science.gov (United States)

    Neafsey, Daniel E.; Waterhouse, Robert M.; Abai, Mohammad R.; Aganezov, Sergey S.; Alekseyev, Max A.; Allen, James E.; Amon, James; Arcà, Bruno; Arensburger, Peter; Artemov, Gleb; Assour, Lauren A.; Basseri, Hamidreza; Berlin, Aaron; Birren, Bruce W.; Blandin, Stephanie A.; Brockman, Andrew I.; Burkot, Thomas R.; Burt, Austin; Chan, Clara S.; Chauve, Cedric; Chiu, Joanna C.; Christensen, Mikkel; Costantini, Carlo; Davidson, Victoria L.M.; Deligianni, Elena; Dottorini, Tania; Dritsou, Vicky; Gabriel, Stacey B.; Guelbeogo, Wamdaogo M.; Hall, Andrew B.; Han, Mira V.; Hlaing, Thaung; Hughes, Daniel S.T.; Jenkins, Adam M.; Jiang, Xiaofang; Jungreis, Irwin; Kakani, Evdoxia G.; Kamali, Maryam; Kemppainen, Petri; Kennedy, Ryan C.; Kirmitzoglou, Ioannis K.; Koekemoer, Lizette L.; Laban, Njoroge; Langridge, Nicholas; Lawniczak, Mara K.N.; Lirakis, Manolis; Lobo, Neil F.; Lowy, Ernesto; MacCallum, Robert M.; Mao, Chunhong; Maslen, Gareth; Mbogo, Charles; McCarthy, Jenny; Michel, Kristin; Mitchell, Sara N.; Moore, Wendy; Murphy, Katherine A.; Naumenko, Anastasia N.; Nolan, Tony; Novoa, Eva M.; O'Loughlin, Samantha; Oringanje, Chioma; Oshaghi, Mohammad A.; Pakpour, Nazzy; Papathanos, Philippos A.; Peery, Ashley N.; Povelones, Michael; Prakash, Anil; Price, David P.; Rajaraman, Ashok; Reimer, Lisa J.; Rinker, David C.; Rokas, Antonis; Russell, Tanya L.; Sagnon, N'Fale; Sharakhova, Maria V.; Shea, Terrance; Simão, Felipe A.; Simard, Frederic; Slotman, Michel A.; Somboon, Pradya; Stegniy, Vladimir; Struchiner, Claudio J.; Thomas, Gregg W.C.; Tojo, Marta; Topalis, Pantelis; Tubio, José M.C.; Unger, Maria F.; Vontas, John; Walton, Catherine; Wilding, Craig S.; Willis, Judith H.; Wu, Yi-Chieh; Yan, Guiyun; Zdobnov, Evgeny M.; Zhou, Xiaofan; Catteruccia, Flaminia; Christophides, George K.; Collins, Frank H.; Cornman, Robert S.; Crisanti, Andrea; Donnelly, Martin J.; Emrich, Scott J.; Fontaine, Michael C.; Gelbart, William; Hahn, Matthew W.; Hansen, Immo A.; Howell, Paul I.; Kafatos, Fotis C.; Kellis, Manolis; Lawson, Daniel; Louis, Christos; Luckhart, Shirley; Muskavitch, Marc A.T.; Ribeiro, José M.; Riehle, Michael A.; Sharakhov, Igor V.; Tu, Zhijian; Zwiebel, Laurence J.; Besansky, Nora J.

    2015-01-01

    Variation in vectorial capacity for human malaria among Anopheles mosquito species is determined by many factors, including behavior, immunity, and life history. To investigate the genomic basis of vectorial capacity and explore new avenues for vector control, we sequenced the genomes of 16 anopheline mosquito species from diverse locations spanning ~100 million years of evolution. Comparative analyses show faster rates of gene gain and loss, elevated gene shuffling on the X chromosome, and more intron losses, relative to Drosophila. Some determinants of vectorial capacity, such as chemosensory genes, do not show elevated turnover, but instead diversify through protein-sequence changes. This dynamism of anopheline genes and genomes may contribute to their flexible capacity to take advantage of new ecological niches, including adapting to humans as primary hosts. PMID:25554792

  10. Target product profile choices for intra-domiciliary malaria vector control pesticide products: repel or kill?

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    Moore Sarah J

    2011-07-01

    Full Text Available Abstract Background The most common pesticide products for controlling malaria-transmitting mosquitoes combine two distinct modes of action: 1 conventional insecticidal activity which kills mosquitoes exposed to the pesticide and 2 deterrence of mosquitoes away from protected humans. While deterrence enhances personal or household protection of long-lasting insecticidal nets and indoor residual sprays, it may also attenuate or even reverse communal protection if it diverts mosquitoes to non-users rather than killing them outright. Methods A process-explicit model of malaria transmission is described which captures the sequential interaction between deterrent and toxic actions of vector control pesticides and accounts for the distinctive impacts of toxic activities which kill mosquitoes before or after they have fed upon the occupant of a covered house or sleeping space. Results Increasing deterrency increases personal protection but consistently reduces communal protection because deterrent sub-lethal exposure inevitably reduces the proportion subsequently exposed to higher lethal doses. If the high coverage targets of the World Health Organization are achieved, purely toxic products with no deterrence are predicted to generally provide superior protection to non-users and even users, especially where vectors feed exclusively on humans and a substantial amount of transmission occurs outdoors. Remarkably, this is even the case if that product confers no personal protection and only kills mosquitoes after they have fed. Conclusions Products with purely mosquito-toxic profiles may, therefore, be preferable for programmes with universal coverage targets, rather than those with equivalent toxicity but which also have higher deterrence. However, if purely mosquito-toxic products confer little personal protection because they do not deter mosquitoes and only kill them after they have fed, then they will require aggressive "catch up" campaigns, with

  11. Lethal effect ofStreptomyces citreofluorescens against larvae of malaria, filaria and dengue vectors

    Institute of Scientific and Technical Information of China (English)

    Gavendra Singh; Soam Prakash

    2012-01-01

    Objective:To investigate lethal effect of culture filtrates ofStreptomyces citreofluorescens (S. citreofluorescens)againstAnopheles stephensi (An. stephensi), Culex quinquefasciatus (Cx. quinquefasciatus), andAedes aegypti (Ae. aegypti) larvae vectors for malaria, filarial and dengue. Methods:The culture filtrates obtained fromS. citreofluorescens2528 was grown inPotato DextroseBroth(PDB), filtrated and used for the bioassay after a growth of15 days.Results:The results demonstrated that theAn. stephensi shows mortalities withLC50,LC90 values of first instar 46.8 μL/mL,79.5 μL/mL, second instar79.0μL/mL,95.6μL/mL, third instar79.0 μL/mL,136.9 μL/mL, and fourth instar122.6 μL/mL,174.5 μL/mL.Whereas,TheCx. quinquefasciatus were found effective on first instar40.0 μL/mL,138.03 μL/mL, second instar80.0 μL/mL,181.97 μL/mL, third instar100.0 μL/mL,309.2 μL/mL, and fourth instar60.0 μL/mL,169.82 μL/mL.The Ae. aegypti were successfully achieved susceptible with higher concentrations in comparisons ofAn. stephensi andCx. quinquefasciatus larvae.These outcomes of the investigations have compared with theChitinase of Streptomyces griseus (S. griseus)C6137 that shows90%-95% mortality.Conclusions:These new findings significantly permitted that the culture filtrates ofS. citreofluorescens can be used as bacterial larvicides.This is an environmentally safe approach to control the vectors of malaria, dengue and filariasis of tropical areas.

  12. Role of An. culicifacies as a vector of malaria in changing ecological scenario of Northeastern states of India

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    Nasreen Akhtar

    2016-01-01

    Full Text Available Background & objectives: Malaria has become endemic and subject of concern in most part of the India especially Northeastern states of India. Surveys before 2000 revealed that Anopheles minimus was major vector responsible for transmission of malaria in this region followed by An. dirus and An. fluviatilis. However, recent studies indicate replacement of An. minimus vector by An. culicifacies due to different ecological changes and change in landuse pattern etc. The objective of present study was to explore the vectorial role of An. culicifacies in transmission of malaria in four malaria endemic states, viz. Assam, Meghalaya, Manipur and Sikkim of India. Methods: The seven surveys were conducted in 176 selected villages belonging to eight districts of the four states in both pre-monsoon (March-April and post-monsoon (September-October seasons from 2010 to 2013. However, in 2011 surveys could not be carried out due to public inconvenience in pre-monsoon season. For vectorial role of all vector species collected, ELISA and PCR were assayed. Results: A total of 19,173 specimens belonging to 30 anopheline species were collected, out of which 4315 belonged to four established vector species. In total, 4183 specimens were processed through ELISA, out of which 236 specimens were found positive for circumsporozoite (CS protein. Further, infectivity was confirmed by PCR in 35 samples, of which 12 samples were found positive for Plasmodium falciparum and three for P. vivax. Out of 12 Plasmodium falciparum positive samples, nine samples were positive for An. culicifacies, two for An. fluviatilis and one for An. minimus. While out of three Plasmodium vivax positive samples, two samples were positive for An. dirus and one sample was positive for An. culicifacies. Interpretation & conclusion: Anopheles culicifacies replaced the An. minimus, the vector of malaria in Northeastern states of India, as it was found to be highly infected with malaria parasite as

  13. 西藏自治区疟疾流行区传疟媒介研究%Study on malaria vectors in malaria endemic areas of Tibet Autonomous Region

    Institute of Scientific and Technical Information of China (English)

    武松; 黄芳; 周水森; 汤林华

    2012-01-01

    The malaria situation in Tibet has been in an active status and the malaria incidence reached the second in China in 2010. Malaria vector prevention and control is one of the important methods for malaria control, while the malaria vectors are still unknown in Tibet. The author summarized the past researches on malaria vectors in Tibet, so as to provide the evidence for improving malaria control investigation in malaria endemic areas of Tibet, with hopes to provide useful vector message for other researcher.%近年西藏自治区(简称西藏)林芝地区疟疾疫情一直处于不稳定状态,2010年疟疾发病率跃居全国第二.媒介防制是疟疾综合防治的重要手段,然而西藏疟疾流行区的传疟媒介尚未定论.本文对既往西藏林芝疟疾流行区的传疟媒介相关研究进行综述,以期为西藏疟疾防治提供媒介方面基础的研究信息.

  14. Is housing quality associated with malaria incidence among young children and mosquito vector numbers? Evidence from Korogwe, Tanzania.

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    Jenny X Liu

    Full Text Available BACKGROUND: Several studies conducted in Northeast Tanzania have documented declines in malaria transmission even before interventions were scaled up. One explanation for these reductions may be the changes in socio-environmental conditions associated with economic development, and in particular improvements in housing construction. OBJECTIVE: This analysis seeks to identify (1 risk factors for malaria incidence among young children and (2 household and environmental factors associated with mosquito vector numbers collected in the child's sleeping area. Both analyses focus on housing construction quality as a key determinant. METHODOLOGY: For 435 children enrolled in a larger trial of intermittent preventive treatment for malaria in infants in the Korogwe District in Tanga, Northeastern Tanzania, detailed information on their dwelling characteristics were collected in the last year of the trial. Principal components analysis was used to construct an index of housing structure quality and converted to quintile units for regression analysis. Univariate and multivariate random effects negative binomial regressions were used to predict risk factors for child malaria incidence and the mean total number of indoor female Anopheles gambiae and funestus mosquitoes collected per household across three occasions. FINDINGS: Building materials have substantially improved in Korogwe over time. Multivariate regressions showed that residing in rural areas (versus urban increased malaria incidence rates by over three-fold and mean indoor female A. gambiae and funestus numbers by nearly two-fold. Compared to those residing in the lowest quality houses, children residing in the highest quality houses had one-third lower malaria incidence rates, even when wealth and rural residence were controlled for. Living in the highest quality houses reduced vector numbers while having cattle near the house significantly increased them. CONCLUSIONS: Results corroborate

  15. Changes in vector species composition and current vector biology and behaviour will favour malaria elimination in Santa Isabel Province, Solomon Islands

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    Beebe Nigel W

    2011-09-01

    Full Text Available Abstract Background In 2009, Santa Isabel Province in the Solomon Islands embarked on a malaria elimination programme. However, very little is known in the Province about the anopheline fauna, which species are vectors, their bionomics and how they may respond to intensified intervention measures. The purpose of this study was to provide baseline data on the malaria vectors and to ascertain the possibility of successfully eliminating malaria using the existing conventional vector control measures, such as indoor residual spraying (IRS and long-lasting insecticidal nets (LLIN. Methods Entomological surveys were undertaken during October 2009. To determine species composition and distribution larval surveys were conducted across on the whole island. For malaria transmission studies, adult anophelines were sampled using human landing catches from two villages - one coastal and one inland. Results Five Anopheles species were found on Santa Isabel: Anopheles farauti, Anopheles hinesorum, Anopheles lungae, Anopheles solomonis, and Anopheles nataliae. Anopheles hinesorum was the most widespread species. Anopheles farauti was abundant, but found only on the coast. Anopheles punctulatus and Anopheles koliensis were not found. Anopheles farauti was the only species found biting in the coastal village, it was incriminated as a vector in this study; it fed early in the night but equally so indoors and outdoors, and had a low survival rate. Anopheles solomonis was the main species biting humans in the inland village, it was extremely exophagic, with low survival rates, and readily fed on pigs. Conclusion The disappearance of the two major vectors, An. punctulatus and An. koliensis, from Santa Isabel and the predominance of An. hinesorum, a non-vector species may facilitate malaria elimination measures. Anopheles farauti was identified as the main coastal vector with An. solomonis as a possible inland vector. The behaviour of An. solomonis is novel as it has

  16. A note on the insecticide susceptibility status of principal malaria vector Anopheles culicifacies in four states of India

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    Kamaraju Raghavendra

    2014-08-01

    Full Text Available Background & objectives: The major malaria vector, Anopheles culicifacies Giles is reported to contribute ~ 65% of the malaria cases in India. This species developed resistance to DDT and later to HCH, malathion and also to pyrethroids in some states due to their use in the national malaria control programme. In the present study, insecticide susceptibility of this species was monitored in four states of India. Methods: To determine insecticide susceptibility status of the major malaria vector An. culicifacies, adult mosquitoes were collected from different localities of 32 tribal districts in the states of Andhra Pradesh, Odisha, Jharkhand and West Bengal during October/November 2009-10. Mosquitoes were collected from stratified ecotypes comprising a group of districts in West Bengal and individual districts in three other states. Mosquitoes were exposed to papers treated with WHO diagnostic dose: 4% DDT, 5% malathion and 0.05% deltamethrin following the WHO tube method. Results: Results provided the susceptibility status of An. culicifacies to different insecticides used in the public health programme in 32 districts in four states. An. culicifacies was found resistant to DDT (mortality range 0-36% in all the 32 districts; to malathion it was resistant in 14 districts, verification required in 10 districts and susceptible in eight districts (mortality range 32.2-100%. It was resistant to deltamethrin in four districts, verification required in 11 districts and susceptible in 17 districts (mortality range 43.3-100%. Interpretation & conclusion: Development of widespread resistance to insecticides used in public health sprays for vector control including to pyrethroids in An. culicifacies in the surveyed districts is of great concern for the malaria control programme as the major interventions for vector control are heavily reliant on chemical insecticides, mainly synthetic pyrethroids used both for indoor residual spraying and for long

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

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    Coetzee M

    2010-08-01

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

  18. Identification and analysis of Single Nucleotide Polymorphisms (SNPs in the mosquito Anopheles funestus, malaria vector

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    Hemingway Janet

    2007-01-01

    Full Text Available Abstract Background Single nucleotide polymorphisms (SNPs are the most common source of genetic variation in eukaryotic species and have become an important marker for genetic studies. The mosquito Anopheles funestus is one of the major malaria vectors in Africa and yet, prior to this study, no SNPs have been described for this species. Here we report a genome-wide set of SNP markers for use in genetic studies on this important human disease vector. Results DNA fragments from 50 genes were amplified and sequenced from 21 specimens of An. funestus. A third of specimens were field collected in Malawi, a third from a colony of Mozambican origin and a third form a colony of Angolan origin. A total of 494 SNPs including 303 within the coding regions of genes and 5 indels were identified. The physical positions of these SNPs in the genome are known. There were on average 7 SNPs per kilobase similar to that observed in An. gambiae and Drosophila melanogaster. Transitions outnumbered transversions, at a ratio of 2:1. The increased frequency of transition substitutions in coding regions is likely due to the structure of the genetic code and selective constraints. Synonymous sites within coding regions showed a higher polymorphism rate than non-coding introns or 3' and 5'flanking DNA with most of the substitutions in coding regions being observed at the 3rd codon position. A positive correlation in the level of polymorphism was observed between coding and non-coding regions within a gene. By genotyping a subset of 30 SNPs, we confirmed the validity of the SNPs identified during this study. Conclusion This set of SNP markers represents a useful tool for genetic studies in An. funestus, and will be useful in identifying candidate genes that affect diverse ranges of phenotypes that impact on vector control, such as resistance insecticide, mosquito behavior and vector competence.

  19. Increased proportions of outdoor feeding among residual malaria vector populations following increased use of insecticide-treated nets in rural Tanzania

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    Azizi Salum

    2011-04-01

    Full Text Available Abstract Background Insecticide-treated nets (ITNs and indoor residual spraying (IRS represent the front-line tools for malaria vector control globally, but are optimally effective where the majority of baseline transmission occurs indoors. In the surveyed area of rural southern Tanzania, bed net use steadily increased over the last decade, reducing malaria transmission intensity by 94%. Methods Starting before bed nets were introduced (1997, and then after two milestones of net use had been reached-75% community-wide use of untreated nets (2004 and then 47% use of ITNs (2009-hourly biting rates of malaria vectors from the Anopheles gambiae complex and Anopheles funestus group were surveyed. Results In 1997, An. gambiae s.l. and An. funestus mosquitoes exhibited a tendency to bite humans inside houses late at night. For An. gambiae s.l., by 2009, nocturnal activity was less (p = 0.0018. At this time, the sibling species composition of the complex had shifted from predominantly An. gambiae s.s. to predominantly An. arabiensis. For An. funestus, by 2009, nocturnal activity was less (p = 0.0054 as well as the proportion biting indoors (p An. funestus s.s. remained the predominant species within this group. As a consequence of these altered feeding patterns, the proportion (mean ± standard error of human contact with mosquitoes (bites per person per night occurring indoors dropped from 0.99 ± 0.002 in 1997 to 0.82 ± 0.008 in 2009 for the An. gambiae complex (p = 0.0143 and from 1.00 ± An. funestus complex (p = 0.0004 over the same time period. Conclusions High usage of ITNs can dramatically alter African vector populations so that intense, predominantly indoor transmission is replaced by greatly lowered residual transmission, a greater proportion of which occurs outdoors. Regardless of the underlying mechanism, the residual, self-sustaining transmission will respond poorly to further insecticidal measures within houses. Additional vector control

  20. Evaluation of the effectiveness of malaria vector control measures in urban settings of Dakar by a specific anopheles salivary biomarker.

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    Papa Makhtar Drame

    Full Text Available Standard entomological methods for evaluating the impact of vector control lack sensitivity in low-malaria-risk areas. The detection of human IgG specific to Anopheles gSG6-P1 salivary antigen reflects a direct measure of human-vector contact. This study aimed to assess the effectiveness of a range of vector control measures (VCMs in urban settings by using this biomarker approach. The study was conducted from October to December 2008 on 2,774 residents of 45 districts of urban Dakar. IgG responses to gSG6-P1 and the use of malaria VCMs highly varied between districts. At the district level, specific IgG levels significantly increased with age and decreased with season and with VCM use. The use of insecticide-treated nets, by drastically reducing specific IgG levels, was by far the most efficient VCM regardless of age, season or exposure level to mosquito bites. The use of spray bombs was also associated with a significant reduction of specific IgG levels, whereas the use of mosquito coils or electric fans/air conditioning did not show a significant effect. Human IgG response to gSG6-P1 as biomarker of vector exposure represents a reliable alternative for accurately assessing the effectiveness of malaria VCM in low-malaria-risk areas. This biomarker tool could be especially relevant for malaria control monitoring and surveillance programmes in low-exposure/low-transmission settings.

  1. Malaria.

    Science.gov (United States)

    Heck, J E

    1991-03-01

    Human malaria is caused by four species of the genus plasmodium. The sexual stage of the parasite occurs in the mosquito and asexual reproduction occurs in man. Symptoms of fever, chills, headache, and myalgia result from the invasion and rupture of erythrocytes. Merozoites are released from erythrocytes and invade other cells, thus propagating the infection. The most vulnerable hosts are nonimmune travelers, young children living in the tropics, and pregnant women. P. falciparum causes the most severe infections because it infects RBCs of all ages and has the propensity to develop resistance to antimalarials. Rapid diagnosis can be made with a malarial smear, and treatment should be initiated promptly. In some regions (Mexico, Central America except Panama, and North Africa) chloroquine phosphate is effective therapy. In subsaharan Africa, South America, and Southeast Asia, chloroquine resistance has become widespread, and other antimalarials are necessary. The primary care physician should have a high index of suspicion for malaria in the traveler returning from the tropics. Malaria should also be suspected in the febrile transfusion recipient and newborns of mothers with malaria.

  2. [Anopheles gambiae, major malaria vector in Logbessou, a peri-urban area of Douala (Cameroon)].

    Science.gov (United States)

    Akono, P Ntonga; Tonga, C; Mbida, J A Mbida; Hondt, O E Ngo; Ambene, P Awono; Ndo, C; Magne, G Tamdem; Peka, M F; Ngaha, R; Lehman, L G

    2015-12-01

    An entomological survey was carried out from August to November 2013, in order to determine the vector system of a building site for social housing in a coastal periurban district of Douala (Cameroon). Mosquito larvae were collected and adult endophilic mosquitoes captured on volunteers, for a total sample of 4897 mosquitoes. Morpho-taxonomic techniques alongside molecular techniques enabled the identification of 4 species, all aggressive to humans: Cx. pipiens (22.3%), Ae. albopictus (0.3%), An. coluzzii and An. gambiae (77.4%). The overall average biting rate recorded was 41.73 bites/person/night (b/p/n). An. gambiae s.l. represents 90.82% of this aggressive fauna, followed by Cx. pipiens (8.58%) and Ae. albopictus (0.6%). The detection of CSP showed that An. gambiae was responsible for 100% of P. falciparum transmission. The overall mean Entomological Inoculation Rate (EIR) was 3.94 ib/p/n. Female An. gambiae mortality rates were 14.47%, 82.5% and 100% respectively with DDT, permethrin and deltamethrin. The proliferation of An. gambiae in this area during raining season, at the detriment of An. coluzzii Coetze & Wilkerson and An. melas Theobald known to be major malaria vectors in island and coastal areas of Africa, may owe to the forest that still colonises this coastal peri-urban locality. Residents should therefore make use of deltamethrin based protective measures.

  3. Comparison of all-cause and malaria-specific mortality from two West African countries with different malaria transmission patterns

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    Kouyaté Bocar

    2008-01-01

    Full Text Available Abstract Background Malaria is a leading cause of death in children below five years of age in sub-Saharan Africa. All-cause and malaria-specific mortality rates for children under-five years old in a mesoendemic malaria area (The Gambia were compared with those from a hyper/holoendemic area (Burkina Faso. Methods Information on observed person-years (PY, deaths and cause of death was extracted from online search, using key words: "Africa, The Gambia, Burkina Faso, malaria, Plasmodium falciparum, mortality, child survival, morbidity". Missing person-years were estimated and all-cause and malaria-specific mortality were calculated as rates per 1,000 PY. Studies were classified as longitudinal/clinical studies or surveys/censuses. Linear regression was used to investigate mortality trends. Results Overall, 39 and 18 longitudinal/clinical studies plus 10 and 15 surveys and censuses were identified for The Gambia and Burkina Faso respectively (1960–2004. Model-based estimates for under-five all-cause mortality rates show a decline from 1960 to 2000 in both countries (Burkina Faso: from 71.8 to 39.0, but more markedly in The Gambia (from 104.5 to 28.4. The weighted-average malaria-specific mortality rate per 1000 person-years for Burkina Faso (15.4, 95% CI: 13.0–18.3 was higher than that in The Gambia (9.5, 95% CI: 9.1–10.1. Malaria mortality rates did not decline over time in either country. Conclusion Child mortality in both countries declined significantly in the period 1960 to 2004, possibly due to socio-economic development, improved health services and specific intervention projects. However, there was little decline in malaria mortality suggesting that there had been no major impact of malaria control programmes during this period. The difference in malaria mortality rates across countries points to significant differences in national disease control policies and/or disease transmission patterns.

  4. Neem by-products in the fight against mosquito-borne diseases: Biotoxicity of neem cake fractions towards the rural malaria vector Anopheles culicifacies (Diptera: Culicidae

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    Balamurugan Chandramohan

    2016-06-01

    Conclusions: Overall, this study suggests that the methanolic fractions of neem cake may be considered as a new and cheap source of highly effective compounds against the rural malaria vector An. culicifacies.

  5. Malaria

    Science.gov (United States)

    2011-06-01

    glands , and are inoculated into host during subsequent blood meal. 7. In human host, sporozoites leave blood and infect hepatocytes. 8-10...reach the mosquito’s salivary glands lodge there and are inoculated into a new host when the mosquito takes an- other blood meal. In humans...from 53-year-old patient who died of chloroquine-resistant falciparum malaria. x600 Figure 10.77 Mature schizont (arrow) in capillary in parathyroid

  6. Persistence and residue activity of deltamethrin on indoor residual spraying surfaces against malaria vectors in southeastern Iran

    Institute of Scientific and Technical Information of China (English)

    Abtahi Mohammad; Shayeghi Mansoreh; Khoobdel Mehdi; Vatandoost Hasan; Abaei Mohammad Reza; Akbarzadeh Kamran

    2011-01-01

    Objective:To evaluate the efficacy of deltamethrin and find a relation between persistence and residue of this insecticide on the prevalent surfaces against malaria vectors in southeastern Iran. Methods:After indoor residual spraying on prevalent surfaces in studied areas (plaster and mud as absorbent surfaces, wood as non absorbent surface and filter paper as control) for malaria control, conical tests as a bioassay method and chromatographic method as an analytical method were used for evolution of persistence and residue of deltamethrin insecticide. Results were investigated statistically by ANOVA and Tukey-HSD tests for determining relations or differences between residue and persistence of deltamethrin. Results:According to the results, there was no significant difference between mortality rates from bioassay tests on different surfaces, and deltamethrin kept its utility to malaria vector control until 120 days after indoor residual spraying on these surfaces. In the case of residue, there was no significant relation between residue amounts and mortality rates on different surfaces, whereas this relation existed between residual amounts on filter papers and mortality rates from bioassay tests. Conclusions: This study shows that measurement of residue in filter papers is a suitable tool for evolution and dictum of efficiency of deltamethrin insecticide in indoor residual spraying for malaria control.

  7. Ovicidal, repellent, adulticidal and field evaluations of plant extract against dengue, malaria and filarial vectors.

    Science.gov (United States)

    Kovendan, Kalimuthu; Murugan, Kadarkarai; Mahesh Kumar, Palanisamy; Thiyagarajan, Perumal; John William, Samuel

    2013-03-01

    Mosquitoes are insect vectors responsible for the transmission of parasitic and viral infections to millions of people worldwide, with substantial morbidity and mortality. Infections transmitted by mosquitoes include malaria, yellow fever, chikungunya, filariasis and other arboviruses. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. The adulticidal activities of crude hexane, benzene, ethyl acetate, acetone and methanol leaf extracts of Acalypha alnifolia were assayed for their toxicity against three important vector mosquitoes, viz., Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. The adult mortality was observed after 24 h of exposure. All extracts showed moderate adulticide effects; however, the highest adult mortality was found in methanol extract were observed. The LC(50) values of A. alnifolia leaf extracts against adulticidal activity of (hexane, benzene, ethyl acetate, acetone and methanol) A. aegypti, A. stephensi and C. quinquefasciatus were the following: A. aegypti values were 371.87, 342.97, 320.17, 300.86 and 279.75 ppm; A. stephensi values were 358.35, 336.64, 306.10, 293.01 and 274.76 ppm; C. quinquefasciatus values were 383.59, 354.13, 327.74, 314.33 and 291.71 ppm. The results of the repellent activity of hexane, benzene, ethyl acetate, acetone and methanol extract of A. alnifolia plant at three different concentrations of 1.0, 3.0, and 5.0 mg/cm(2) were applied on skin of forearm in man and exposed against adult female mosquitoes. In this observation, this plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the repellent activity is dependent on the strength of the plant extracts. Mean percent hatchability of the ovicidal activity was observed 48 h post-treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. Mortality of 100

  8. Use of Bacillus thuringiensis var israelensis as a viable option in an Integrated Malaria Vector Control Programme in the Kumasi Metropolis, Ghana

    OpenAIRE

    Nartey, Rita; Owusu-Dabo, Ellis; Kruppa, Thomas; Baffour-Awuah, Sandra; Annan, Augustina; Oppong, Samuel; Becker, Norbert; Obiri-Danso, Kwasi

    2013-01-01

    Background Integrated Vector Control (IVC) remains the approach for managing the malaria-causing vector. The study investigated the contribution of Bacillus thuringiensis israelensis (Bti) in the control of malaria by targeting the larvae and also mapped and documented major breeding sites in the Kumasi metropolis, Ghana. Methods Using a hand held GPS receiver unit, major breeding sites within the metropolis were mapped out during the larval survey. Mosquito larvae were then collected from th...

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

    OpenAIRE

    Kayode David Ileke; Olaniyi Charles Ogungbite

    2015-01-01

    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 an...

  10. Agriculture and the promotion of insect pests: rice cultivation in river floodplains and malaria vectors in The Gambia

    Directory of Open Access Journals (Sweden)

    Louca Vasilis

    2009-07-01

    Full Text Available Abstract Background Anthropogenic modification of natural habitats can create conditions in which pest species associated with humans can thrive. In order to mitigate for these changes, it is necessary to determine which aspects of human management are associated with the promotion of those pests. Anopheles gambiae, the main Africa malaria vector, often breeds in rice fields. Here the impact of the ancient practice of 'swamp rice' cultivation, on the floodplains of the Gambia River, on the production of anopheline mosquitoes was investigated. Methods Routine surveys were carried out along 500 m transects crossing rice fields from the landward edge of the floodplains to the river during the 2006 rainy season. Aquatic invertebrates were sampled using area samplers and emergence traps and fish sampled using nets. Semi-field experiments were used to investigate whether nutrients used for swamp rice cultivation affected mosquito larval abundance. Results At the beginning of the rainy season rice is grown on the landward edge of the floodplain; the first area to flood with fresh water and one rich in cattle dung. Later, rice plants are transplanted close to the river, the last area to dry out on the floodplain. Nearly all larval and adult stages of malaria vectors were collected 0–100 m from the landward edge of the floodplains, where immature rice plants were grown. These paddies contained stagnant freshwater with high quantities of cattle faeces. Semi-field studies demonstrated that cattle faeces nearly doubled the number of anopheline larvae compared with untreated water. Conclusion Swamp rice cultivation creates ideal breeding sites for malaria vectors. However, only those close to the landward edge harboured vectors. These sites were productive since they were large areas of standing freshwater, rich in nutrients, protected from fish, and situated close to human habitation, where egg-laying mosquitoes from the villages had short distances to

  11. Aquaporin water channel AgAQP1 in the malaria vector mosquito Anopheles gambiae during blood feeding and humidity adaptation.

    Science.gov (United States)

    Liu, Kun; Tsujimoto, Hitoshi; Cha, Sung-Jae; Agre, Peter; Rasgon, Jason L

    2011-04-12

    Altered patterns of malaria endemicity reflect, in part, changes in feeding behavior and climate adaptation of mosquito vectors. Aquaporin (AQP) water channels are found throughout nature and confer high-capacity water flow through cell membranes. The genome of the major malaria vector mosquito Anopheles gambiae contains at least seven putative AQP sequences. Anticipating that transmembrane water movements are important during the life cycle of A. gambiae, we identified and characterized the A. gambiae aquaporin 1 (AgAQP1) protein that is homologous to AQPs known in humans, Drosophila, and sap-sucking insects. When expressed in Xenopus laevis oocytes, AgAQP1 transports water but not glycerol. Similar to mammalian AQPs, water permeation of AgAQP1 is inhibited by HgCl(2) and tetraethylammonium, with Tyr185 conferring tetraethylammonium sensitivity. AgAQP1 is more highly expressed in adult female A. gambiae mosquitoes than in males. Expression is high in gut, ovaries, and Malpighian tubules where immunofluorescence microscopy reveals that AgAQP1 resides in stellate cells but not principal cells. AgAQP1 expression is up-regulated in fat body and ovary by blood feeding but not by sugar feeding, and it is reduced by exposure to a dehydrating environment (42% relative humidity). RNA interference reduces AgAQP1 mRNA and protein levels. In a desiccating environment (adaptation of A. gambiae, a major mosquito vector of human malaria in sub-Saharan Africa.

  12. An online operational rainfall-monitoring resource for epidemic malaria early warning systems in Africa

    Science.gov (United States)

    Grover-Kopec, Emily; Kawano, Mika; Klaver, Robert W.; Blumenthal, Benno; Ceccato, Pietro; Connor, Stephen J.

    2005-01-01

    Periodic epidemics of malaria are a major public health problem for many sub-Saharan African countries. Populations in epidemic prone areas have a poorly developed immunity to malaria and the disease remains life threatening to all age groups. The impact of epidemics could be minimized by prediction and improved prevention through timely vector control and deployment of appropriate drugs. Malaria Early Warning Systems are advocated as a means of improving the opportunity for preparedness and timely response.

  13. Predicting the effect of climate change on African trypanosomiasis: integrating epidemiology with parasite and vector biology.

    Science.gov (United States)

    Moore, Sean; Shrestha, Sourya; Tomlinson, Kyle W; Vuong, Holly

    2012-05-07

    Climate warming over the next century is expected to have a large impact on the interactions between pathogens and their animal and human hosts. Vector-borne diseases are particularly sensitive to warming because temperature changes can alter vector development rates, shift their geographical distribution and alter transmission dynamics. For this reason, African trypanosomiasis (sleeping sickness), a vector-borne disease of humans and animals, was recently identified as one of the 12 infectious diseases likely to spread owing to climate change. We combine a variety of direct effects of temperature on vector ecology, vector biology and vector-parasite interactions via a disease transmission model and extrapolate the potential compounding effects of projected warming on the epidemiology of African trypanosomiasis. The model predicts that epidemics can occur when mean temperatures are between 20.7°C and 26.1°C. Our model does not predict a large-range expansion, but rather a large shift of up to 60 per cent in the geographical extent of the range. The model also predicts that 46-77 million additional people may be at risk of exposure by 2090. Future research could expand our analysis to include other environmental factors that influence tsetse populations and disease transmission such as humidity, as well as changes to human, livestock and wildlife distributions. The modelling approach presented here provides a framework for using the climate-sensitive aspects of vector and pathogen biology to predict changes in disease prevalence and risk owing to climate change.

  14. Vector competence in West African Aedes aegypti Is Flavivirus species and genotype dependent.

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    Laura B Dickson

    2014-10-01

    Full Text Available Vector competence of Aedes aegypti mosquitoes is a quantitative genetic trait that varies among geographic locations and among different flavivirus species and genotypes within species. The subspecies Ae. aegypti formosus, found mostly in sub-Saharan Africa, is considered to be refractory to both dengue (DENV and yellow fever viruses (YFV compared to the more globally distributed Ae. aegypti aegypti. Within Senegal, vector competence varies with collection site and DENV-2 viral isolate, but knowledge about the interaction of West African Ae. aegypti with different flaviviruses is lacking. The current study utilizes low passage isolates of dengue-2 (DENV-2-75505 sylvatic genotype and yellow fever (YFV BA-55 -West African Genotype I, or YFV DAK 1279-West African Genotype II from West Africa and field derived Ae. aegypti collected throughout Senegal to determine whether vector competence is flavivirus or virus genotype dependent.Eight collections of 20-30 mosquitoes from different sites were fed a bloodmeal containing either DENV-2 or either isolate of YFV. Midgut and disseminated infection phenotypes were determined 14 days post infection. Collections varied significantly in the rate and intensity of midgut and disseminated infection among the three viruses.Overall, vector competence was dependent upon both viral and vector strains. Importantly, contrary to previous studies, sylvatic collections of Ae. aegypti showed high levels of disseminated infection for local isolates of both DENV-2 and YFV.

  15. [Comparison of the effectiveness of artemether and quinine for treatment of severe malaria in children, Bangui, Central African Republic].

    Science.gov (United States)

    Bobossi-Serengbe, G; Gody, J-C; Fioboy, R; Elowa, J-B; Manirakiza, A

    2015-03-01

    The management of severe malaria is a major challenge in the health care services in sub-Saharan Africa. This study aimed to assess the efficacy and safety of artemether and quinine in severe malaria at Complexe pédiatrique of Bangui, Central African Republic. A total of 212 children among 1125 hospital admissions (18.8%), and aged 6 to 59 months were randomly treated with artemether and quinine. Anemia (58.5%) and seizures (33.5%) were the major syndromes observed. On the third day of follow up, a regression of clinical signs and parasite clearance were observed in 98.1% of children treated with artemether and 97.1% of children treated with quinine. The death rate was 2.3% due to anemic and neurological forms. These findings show that the artemether and quinine have similar efficacy. Hence, associated with adequate intensive health care, the use of these antimalarial drugs can significantly reduce mortality from severe malaria in the Central African Republic.

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

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    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.

  17. Strong association between house characteristics and malaria vectors in Sri Lanka

    DEFF Research Database (Denmark)

    Konradsen, Flemming; Amerasinghe, Priyanie; van der Hoek, Wim

    2003-01-01

    The objective of this study was to determine whether house characteristics could be used to further refine the residual insecticide-spraying program in Sri Lanka. Indoor-resting mosquito densities were estimated in 473 houses based on fortnightly collections over a two-and-a-half-year period....... The type of house construction and the exact location of all houses were determined. In a multivariate analysis, distance of less than 750 meters between a house and the main vector-breeding site was strongly associated with the presence of Anopheles culicifacies in the house (odds ratio [OR] 4.8, 95......% confidence interval [CI] 3.4-6.8) and to a lesser extent with the presence of An. subpictus (OR 1.4, 95% CI 1.1-1.7). Poor housing construction also was an independent risk factor (OR for An. culicifacies 1.3, 95% CI 1.0-1.9; OR for An. subpictus 1.3, 95% CI 1.0-1.6). It is recommended that a malaria control...

  18. Larvicidal activity of essential oil and methanol extract of Nepeta menthoides against malaria vector Anopheles stephensi

    Institute of Scientific and Technical Information of China (English)

    Khanavi Mahnaz; Fallah Alireza; Vatandoost Hassan; Sedaghat Mahdi; Abai Mohammad Reza; Hadjiakhoondi Abbas

    2012-01-01

    Objective: To investigate the larvicidal activity of essential oil and methanol extract of theNepeta menthoides (N. menthoides) against main malaria vector, Anopheles stephensi (An. stephensi). Methods: The essential oil of plant was obtained by Clevenger type apparatus and the methanol extract was supplied with Percolation method. Larvicidal activity was tested by WHO method. Twenty five fourth-instar larvae of An. stephensi were used in the larvicidal assay and four replicates were tested for each concentration. Five different concentrations of the oil and extract were tested for calculation of LC50 and LC90 values. Results: The LC50 and LC90 values were determined by probit analysis. LC50 was 69.5 and 234.3 ppm and LC90 was 175.5 and 419.9 ppm for the extract and essential oil respectively. Conclusions: According to the results of this study methanolic extract of plant exhibited more larvicidal activity than essential oil. This could be useful for investigation of new natural larvicidal compounds.

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

    Institute of Scientific and Technical Information of China (English)

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

    2010-01-01

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

  20. Larvicidal and IGR activity of extract of Tanzanian plants against malaria vector mosquitoes

    Directory of Open Access Journals (Sweden)

    Erich Kleinpeter

    2009-06-01

    Full Text Available Background & objectives: This paper reports the larvicidal activity of seventeen Tanzanian plantspecies against the malaria vector, Anopheles gambiae s.s. Giles larvae. Some of the plants are usedtraditionally as sources of insecticidal materials.Methods: The crude extracts from the leaves, stem and root barks of the investigated plants wereobtained by solvent extraction and then bio-assayed following WHO protocols showed LC50 values10 to 400 ppm after 24 h exposure. The structures were determined on interpretation of spectroscopicdata.Results: The most active extracts were those from the stem and root barks of Annona squamosa,Uvaria faulknerae, U. kirkii and Uvariodendron pycnophyllum, all of which had LC50 values between10 and 100 ppm. Long-term exposure beyond 24 h also showed more susceptibility of the larvae tothe extracts. Larvae deformities by forming tail-like structures were observed for the methanolextracts of Tessmannia martiniana var pauloi.Interpretation & conclusion: The results suggest that the investigated plant extracts are promisingas larvicides against An. gambiae s.s. Giles mosquitoes and could be useful leads in the search fornew and biodegradable plant derived larvicide products.

  1. Suboptimal Larval Habitats Modulate Oviposition of the Malaria Vector Mosquito Anopheles coluzzii.

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    Eunho Suh

    Full Text Available Selection of oviposition sites by gravid females is a critical behavioral step in the reproductive cycle of Anopheles coluzzii, which is one of the principal Afrotropical malaria vector mosquitoes. Several studies suggest this decision is mediated by semiochemicals associated with potential oviposition sites. To better understand the chemosensory basis of this behavior and identify compounds that can modulate oviposition, we examined the generally held hypothesis that suboptimal larval habitats give rise to semiochemicals that negatively influence the oviposition preference of gravid females. Dual-choice bioassays indicated that oviposition sites conditioned in this manner do indeed foster significant and concentration dependent aversive effects on the oviposition site selection of gravid females. Headspace analyses derived from aversive habitats consistently noted the presence of dimethyl disulfide (DMDS, dimethyl trisulfide (DMTS and 6-methyl-5-hepten-2-one (sulcatone each of which unitarily affected An. coluzzii oviposition preference. Electrophysiological assays across the antennae, maxillary palp, and labellum of gravid An. coluzzii revealed differential responses to these semiochemicals. Taken together, these findings validate the hypothesis in question and suggest that suboptimal environments for An. coluzzii larval development results in the release of DMDS, DMTS and sulcatone that impact the response valence of gravid females.

  2. Lethal effects of Aspergillus niger against mosquitoes vector of filaria, malaria, and dengue: a liquid mycoadulticide.

    Science.gov (United States)

    Singh, Gavendra; Prakash, Soam

    2012-01-01

    Aspergillus niger is a fungus of the genus Aspergillus. It has caused a disease called black mold on certain fruits and vegetables. The culture filtrates released from the A. niger ATCC 66566 were grown in Czapek dox broth (CDB) then filtered with flash chromatograph and were used for the bioassay after a growth of thirty days. The result demonstrated these mortalities with LC(50), LC(90), and LC(99) values of Culex quinquefasciatus 0.76, 3.06, and 4.75, Anopheles stephensi 1.43, 3.2, and 3.86, and Aedes aegypti 1.43, 2.2, and 4.1 μl/cm(2), after exposure of seven hours. We have calculated significant LT(90) values of Cx. quinquefasciatus 4.5, An. stephensi 3.54, and Ae. aegypti 6.0 hrs, respectively. This liquid spray of fungal culture isolate of A. niger can reduce malaria, dengue, and filarial transmission. These results significantly support broadening the current vector control paradigm beyond chemical adulticides.

  3. Lethal Effects of Aspergillus niger against Mosquitoes Vector of Filaria, Malaria, and Dengue: A Liquid Mycoadulticide

    Directory of Open Access Journals (Sweden)

    Gavendra Singh

    2012-01-01

    Full Text Available Aspergillus niger is a fungus of the genus Aspergillus. It has caused a disease called black mold on certain fruits and vegetables. The culture filtrates released from the A. niger ATCC 66566 were grown in Czapek dox broth (CDB then filtered with flash chromatograph and were used for the bioassay after a growth of thirty days. The result demonstrated these mortalities with LC50, LC90, and LC99 values of Culex quinquefasciatus 0.76, 3.06, and 4.75, Anopheles stephensi 1.43, 3.2, and 3.86, and Aedes aegypti 1.43, 2.2, and 4.1 μl/cm2, after exposure of seven hours. We have calculated significant LT90 values of Cx. quinquefasciatus 4.5, An. stephensi 3.54, and Ae. aegypti 6.0 hrs, respectively. This liquid spray of fungal culture isolate of A. niger can reduce malaria, dengue, and filarial transmission. These results significantly support broadening the current vector control paradigm beyond chemical adulticides.

  4. The role of proboscis of the malaria vector mosquito Anopheles stephensi in host-seeking behavior

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    Yoshimura Aya

    2011-01-01

    Full Text Available Abstract Background The proboscis is an essential head appendage in insects that processes gustatory code during food intake, particularly useful considering that blood-sucking arthropods routinely reach vessels under the host skin using this proboscis as a probe. Results Here, using an automated device able to quantify CO2-activated thermo (35°C-sensing behavior of the malaria vector Anopheles stephensi, we uncovered that the protruding proboscis of mosquitoes contributes unexpectedly to host identification from a distance. Ablation experiments indicated that not only antennae and maxillary palps, but also proboscis were required for the identification of pseudo-thermo targets. Furthermore, the function of the proboscis during this behavior can be segregated from CO2 detection required to evoke mosquito activation, suggesting that the proboscis of mosquitoes divide the proboscis into a "thermo-antenna" in addition to a "thermo-probe". Conclusions Our findings support an emerging view with a possible role of proboscis as important equipment during host-seeking, and give us an insight into how these appendages likely evolved from a common origin in order to function as antenna organs.

  5. Artificial activation of mature unfertilized eggs in the malaria vector mosquito, Anopheles stephensi (Diptera, Culicidae).

    Science.gov (United States)

    Yamamoto, Daisuke S; Hatakeyama, Masatsugu; Matsuoka, Hiroyuki

    2013-08-01

    In the past decade, many transgenic lines of mosquitoes have been generated and analyzed, whereas the maintenance of a large number of transgenic lines requires a great deal of effort and cost. In vitro fertilization by an injection of cryopreserved sperm into eggs has been proven to be effective for the maintenance of strains in mammals. The technique of artificial egg activation is a prerequisite for the establishment of in vitro fertilization by sperm injection. We demonstrated that artificial egg activation is feasible in the malaria vector mosquito, Anopheles stephensi (Diptera, Culicidae). Nearly 100% of eggs dissected from virgin females immersed in distilled water darkened, similar to normally oviposited fertilized eggs. It was revealed by the cytological examination of chromosomes that meiotic arrest was relieved in these eggs approximately 20 min after incubation in water. Biochemical examinations revealed that MAPK (mitogen-activated protein kinase)/ERK (extracellular signal-regulated protein kinase) and MEK (MAPK/ERK kinase) were dephosphorylated similar to that in fertilized eggs. These results indicate that dissected unfertilized eggs were activated in distilled water and started development. Injection of distilled water into body cavity of the virgin blood-fed females also induced activation of a portion of eggs in the ovaries. The technique of artificial egg activation is expected to contribute to the success of in vitro fertilization in A. stephensi.

  6. Status of pesticide management in the practice of vector control: a global survey in countries at risk of malaria or other major vector-borne diseases

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    Tan Soo

    2011-05-01

    Full Text Available Abstract Background It is critical that vector control pesticides are used for their acceptable purpose without causing adverse effects on health and the environment. This paper provides a global overview of the current status of pesticides management in the practice of vector control. Methods A questionnaire was distributed to WHO member states and completed either by the director of the vector-borne disease control programme or by the national manager for vector control. In all, 113 countries responded to the questionnaire (80% response rate, representing 94% of the total population of the countries targeted. Results Major gaps were evident in countries in pesticide procurement practices, training on vector control decision making, certification and quality control of pesticide application, monitoring of worker safety, public awareness programmes, and safe disposal of pesticide-related waste. Nevertheless, basic conditions of policy and coordination have been established in many countries through which the management of vector control pesticides could potentially be improved. Most countries responded that they have adopted relevant recommendations by the WHO. Conclusions Given the deficiencies identified in this first global survey on public health pesticide management and the recent rise in pesticide use for malaria control, the effectiveness and safety of pesticide use are being compromised. This highlights the urgent need for countries to strengthen their capacity on pesticide management and evidence-based decision making within the context of an integrated vector management approach.

  7. Multiple Insecticide Resistance in the Malaria Vector Anopheles funestus from Northern Cameroon Is Mediated by Metabolic Resistance Alongside Potential Target Site Insensitivity Mutations

    Science.gov (United States)

    Menze, Benjamin D.; Riveron, Jacob M.; Ibrahim, Sulaiman S.; Irving, Helen; Antonio-Nkondjio, Christophe; Awono-Ambene, Parfait H.; Wondji, Charles S.

    2016-01-01

    Background Despite the recent progress in establishing the patterns of insecticide resistance in the major malaria vector Anopheles funestus, Central African populations of this species remain largely uncharacterised. To bridge this important gap and facilitate the implementation of suitable control strategies against this vector, we characterised the resistance patterns of An. funestus population from northern Cameroon. Methods and Findings Collection of indoor-resting female mosquitoes in Gounougou (northern Cameroon) in 2012 and 2015 revealed a predominance of An. funestus during dry season. WHO bioassays performed using F1 An. funestus revealed that the population was multiple resistant to several insecticide classes including pyrethroids (permethrin, deltamethrin, lambda-cyhalothrin and etofenprox), carbamates (bendiocarb) and organochlorines (DDT and dieldrin). However, a full susceptibility was observed against the organophosphate malathion. Bioassays performed with 2015 collection revealed that resistance against pyrethroids and DDT is increasing. PBO synergist assays revealed a significant recovery of susceptibility for all pyrethroids but less for DDT. Analysis of the polymorphism of a portion of the voltage-gated sodium channel gene (VGSC) revealed the absence of the L1014F/S kdr mutation but identified 3 novel amino acid changes I877L, V881L and A1007S. However, no association was established between VGSC polymorphism and pyrethroid/DDT resistance. The DDT resistant 119F-GSTe2 allele (52%) and the dieldrin resistant 296S-RDL allele (45%) were detected in Gounougou. Temporal analysis between 2006, 2012 and 2015 collections revealed that the 119F-GSTe2 allele was relatively stable whereas a significant decrease is observed for 296S-RDL allele. Conclusion This multiple resistance coupled with the temporal increased in resistance intensity highlights the need to take urgent measures to prolong the efficacy of current insecticide-based interventions against

  8. Distribution of the Habitat Suitability of the Main Malaria Vector in French Guiana Using Maximum Entropy Modeling.

    Science.gov (United States)

    Moua, Yi; Roux, Emmanuel; Girod, Romain; Dusfour, Isabelle; de Thoisy, Benoit; Seyler, Frédérique; Briolant, Sébastien

    2016-12-22

    Malaria is an important health issue in French Guiana. Its principal mosquito vector in this region is Anopheles darlingi Root. Knowledge of the spatial distribution of this species is still very incomplete due to the extent of French Guiana and the difficulty to access most of the territory. Species distribution modeling based on the maximal entropy procedure was used to predict the spatial distribution of An. darlingi using 39 presence sites. The resulting model provided significantly high prediction performances (mean 10-fold cross-validated partial area under the curve and continuous Boyce index equal to, respectively, 1.11-with a level of omission error of 20%-and 0.42). The model also provided a habitat suitability map and environmental response curves in accordance with the known entomological situation. Several environmental characteristics that had a positive correlation with the presence of An. darlingi were highlighted: nonpermanent anthropogenic changes of the natural environment, the presence of roads and tracks, and opening of the forest. Some geomorphological landforms and high altitude landscapes appear to be unsuitable for An. darlingi The species distribution modeling was able to reliably predict the distribution of suitable habitats for An. darlingi in French Guiana. Results allowed completion of the knowledge of the spatial distribution of the principal malaria vector in this Amazonian region, and identification of the main factors that favor its presence. They should contribute to the definition of a necessary targeted vector control strategy in a malaria pre-elimination stage, and allow extrapolation of the acquired knowledge to other Amazonian or malaria-endemic contexts.

  9. Malaria vectors in the Republic of Benin: distribution of species and molecular forms of the Anopheles gambiae complex.

    Science.gov (United States)

    Djogbénou, Luc; Pasteur, Nicole; Bio-Bangana, Sahabi; Baldet, Thierry; Irish, Seth R; Akogbeto, Martin; Weill, Mylène; Chandre, Fabrice

    2010-05-01

    Members of the Anopheles gambiae complex are among the best malaria vectors in the world, but their vectorial capacities vary between species and populations. A large-scale sampling of An. gambiae sensu lato was carried out in 2006 and 2007 in various bioclimatic areas of Benin (West Africa). The objective of this study was to collate data on the relative frequencies of species and forms within the An. gambiae complex and to produce a map of their spatial distribution. Sampling took place at 30 sites and 2122 females were analyzed. Two species were identified through molecular methods. The overall collection showed a preponderance of An. gambiae s.s., but unexpectedly, An. arabiensis was reported in the coastal-Guinean bioclimatic area characterized by a mean annual rainfall of >1500 mm where only An. gambiae s.s. was reported previously. Our study of Benin indicates that An. arabiensis would be adapted not only to the urban areas but also to the rural humid regions. Among 1717 An. gambiae s.s., 26.5% were of the M form and 73.3% were S form. Few hybrid specimens between the M and S forms were observed (0.2%). Only the spatial distribution of the M form appears to be mainly a function of bioclimatic area. Factors that influence the distribution of these malaria vectors are discussed. This study underlines the need of further investigations of biological, ecological, and behavioral traits of these species and forms to better appreciate their vectorial capacities. Acquisition of entomological field data appears essential to better estimate the stratification of malaria risk and help improve malaria vector control interventions.

  10. Malaria Transmission Risk Factor In West Java (Epidemiology Study About Vector, Plasmodium parasite and Environmental Risk Factors For Malaria Cases

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    Lukman Hakim

    2010-06-01

    Full Text Available Since the territory is divided with the province of Banten, in West Java there are five regencies that defined as malaria endemic area, there are Ciamis, Tasikmalaya, Garut, Cianjur and Sukabumi. Sufferer, concentrated in southern coastal areas (Indonesian Ocean starting from the beach of Kalipucang at Ciamis up to coast of Cikakak at Sukabumi which borders the province of Banten and also mountain and plantations areas. Malaria morbidity incidence risk factors is differ in each of these endemic areas. In general is the presence of malaria patients without symptoms who can be a source of infection that so difficult to know its existence. Still the number of standing water that can become mosqui-to breeding places of Anopheles spp, such as fish pond, small puddle on the riverside, shrimp pond, mangrove forests that potentially at the beginning of the rainy season, the fields during rice that potential when the rice growing and the river that potential in the dry season. The existence of high population mobility and also the number of vegetation in the surrounding residential population and the existence of cattle are placed close to settle-ments.

  11. Diagnosing severe falciparum malaria in parasitaemic African children: a prospective evaluation of plasma PfHRP2 measurement.

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    Ilse C E Hendriksen

    Full Text Available BACKGROUND: In African children, distinguishing severe falciparum malaria from other severe febrile illnesses with coincidental Plasmodium falciparum parasitaemia is a major challenge. P. falciparum histidine-rich protein 2 (PfHRP2 is released by mature sequestered parasites and can be used to estimate the total parasite burden. We investigated the prognostic significance of plasma PfHRP2 and used it to estimate the malaria-attributable fraction in African children diagnosed with severe malaria. METHODS AND FINDINGS: Admission plasma PfHRP2 was measured prospectively in African children (from Mozambique, The Gambia, Kenya, Tanzania, Uganda, Rwanda, and the Democratic Republic of the Congo aged 1 month to 15 years with severe febrile illness and a positive P. falciparum lactate dehydrogenase (pLDH-based rapid test in a clinical trial comparing parenteral artesunate versus quinine (the AQUAMAT trial, ISRCTN 50258054. In 3,826 severely ill children, Plasmadium falciparum PfHRP2 was higher in patients with coma (p = 0.0209, acidosis (p<0.0001, and severe anaemia (p<0.0001. Admission geometric mean (95%CI plasma PfHRP2 was 1,611 (1,350-1,922 ng/mL in fatal cases (n = 381 versus 1,046 (991-1,104 ng/mL in survivors (n = 3,445, p<0.0001, without differences in parasitaemia as assessed by microscopy. There was a U-shaped association between log(10 plasma PfHRP2 and risk of death. Mortality increased 20% per log(10 increase in PfHRP2 above 174 ng/mL (adjusted odds ratio [AOR] 1.21, 95%CI 1.05-1.39, p = 0.009. A mechanistic model assuming a PfHRP2-independent risk of death in non-malaria illness closely fitted the observed data and showed malaria-attributable mortality less than 50% with plasma PfHRP2≤174 ng/mL. The odds ratio (OR for death in artesunate versus quinine-treated patients was 0.61 (95%CI 0.44-0.83, p = 0.0018 in the highest PfHRP2 tertile, whereas there was no difference in the lowest tertile (OR 1.05; 95%CI 0.69-1.61; p = 0.82. A

  12. Safety and efficacy of re-treatments with pyronaridine-artesunate in African patients with malaria: a substudy of the WANECAM randomised trial

    OpenAIRE

    Sagara, Issaka; Beavogui, Abdoul Habib; Zongo, Issaka; Soulama, Issiaka; Borghini-Fuhrer, Isabelle; Fofana, Bakary; Camara, Daouda; Somé, Anyirékun F; Coulibaly, Aboubacar S; Traore, Oumar B; Dara, Niawanlou; Kabore, Moïse J T; Thera, Ismaila; Compaore, Yves D; Sylla, Malick Minkael

    2016-01-01

    Summary Background Sparse data on the safety of pyronaridine-artesunate after repeated treatment of malaria episodes restrict its clinical use. We therefore compared the safety of pyronaridine-artesunate after treatment of the first episode of malaria versus re-treatment in a substudy analysis. Methods This planned substudy analysis of the randomised, open-label West African Network for Clinical Trials of Antimalarial Drugs (WANECAM) phase 3b/4 trial was done at six health facilities in Mali,...

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

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    Coetzee Maureen

    2010-12-01

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

  14. How human practices have affected vector-borne diseases in the past: a study of malaria transmission in Alpine valleys

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    Lemperière Guy

    2007-08-01

    Full Text Available Abstract Background Malaria was endemic in the Rhône-Alpes area of eastern France in the 19th century and life expectancy was particularly shortened in Alpine valleys. This study was designed to determine how the disease affected people in the area and to identify the factors influencing malaria transmission. Methods Demographic data of the 19th century were collected from death registers of eight villages of the flood-plain of the river Isère. Correlations were performed between these demographic data and reconstructed meteorological data. Archive documents from medical practitioners gave information on symptoms of ill people. Engineer reports provided information on the hydraulic project developments in the Isère valley. Results Description of fevers was highly suggestive of endemic malaria transmission in the parishes neighbouring the river Isère. The current status of anopheline mosquitoes in the area supports this hypothesis. Mean temperature and precipitation were poorly correlated with demographic data, whereas the chronology of hydrological events correlated with fluctuations in death rates in the parishes. Conclusion Nowadays, most of the river development projects involve the creation of wet areas, enabling controlled flooding events. Flood-flow risk and the re-emergence of vector-borne diseases would probably be influenced by the climate change. The message is not to forget that human disturbance of any functioning hydrosystem has often been linked to malaria transmission in the past.

  15. Impact assessment of malaria vector control using routine surveillance data in Zambia: implications for monitoring and evaluation

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    Chanda Emmanuel

    2012-12-01

    Full Text Available Abstract Background Malaria vector control using long-lasting insecticidal nets (LLINs and indoor residual spraying (IRS, with pyrethroids and DDT, to reduce malaria transmission has been expansively implemented in Zambia. The impact of these interventions on malaria morbidity and mortality has not previously been formally assessed at the population level in Zambia. Methods The impact of IRS (15 urban districts and LLINs (15 rural districts implementation on severe malaria cases, deaths and case fatality rates in children below the age of five years were compared. Zambian national Health Management Information System data from 2007 to 2008 were retrospectively analysed to assess the epidemiological impact of the two interventions using odds ratios to compare the pre-scaling up year 2007 with the scaling-up year 2008. Results Overall there were marked reductions in morbidity and mortality, with cases, deaths and case fatality rates (CFR of severe malaria decreasing by 31%, 63% and 62%, respectively between 2007 and 2008. In urban districts with IRS introduction there was a significant reduction in mortality (Odds Ratio [OR] = 0.37, 95% CI = 0.31-0.43, P = 0.015, while the reduction in mortality in rural districts with LLINs implementation was not significant (OR = 0.83, 95% CI = 0.67-1.04, P = 0.666. A similar pattern was observed for case fatality rates with a significant reduction in urban districts implementing IRS (OR = 0.34, 95% CI = 0.33-0.36, P = 0.005, but not in rural districts implementing LLINs (OR = 0.96, 95% CI = 0.91-1.00, P = 0.913. No substantial difference was detected in overall reduction of malaria cases between districts implementing IRS and LLINs (P = 0.933. Conclusion Routine surveillance data proved valuable for determining the temporal effects of malaria control with two strategies, IRS and LLINs on severe malaria disease in different types of Zambian districts. However, this analysis did not take into account the effect

  16. Development and assessment of plant-based synthetic odor baits for surveillance and control of malaria vectors.

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    Vincent O Nyasembe

    Full Text Available BACKGROUND: Recent malaria vector control measures have considerably reduced indoor biting mosquito populations. However, reducing the outdoor biting populations remains a challenge because of the unavailability of appropriate lures to achieve this. This study sought to test the efficacy of plant-based synthetic odor baits in trapping outdoor populations of malaria vectors. METHODOLOGY AND PRINCIPAL FINDING: Three plant-based lures ((E-linalool oxide [LO], (E-linalool oxide and (E-β-ocimene [LO + OC], and a six-component blend comprising (E-linalool oxide, (E-β-ocimene, hexanal, β-pinene, limonene, and (E-β-farnesene [Blend C], were tested alongside an animal/human-based synthetic lure (comprising heptanal, octanal, nonanal, and decanal [Blend F] and worn socks in a malaria endemic zone in the western part of Kenya. Mosquito Magnet-X (MM-X and lightless Centre for Disease Control (CDC light traps were used. Odor-baited traps were compared with traps baited with either solvent alone or solvent + carbon dioxide (controls for 18 days in a series of randomized incomplete-block designs of days × sites × treatments. The interactive effect of plant and animal/human odor was also tested by combining LO with either Blend F or worn socks. Our results show that irrespective of trap type, traps baited with synthetic plant odors compared favorably to the same traps baited with synthetic animal odors and worn socks in trapping malaria vectors, relative to the controls. Combining LO and worn socks enhanced trap captures of Anopheles species while LO + Blend F recorded reduced trap capture. Carbon dioxide enhanced total trap capture of both plant- and animal/human-derived odors. However, significantly higher proportions of male and engorged female Anopheles gambiae s.l. were caught when the odor treatments did not include carbon dioxide. CONCLUSION AND SIGNIFICANCE: The results highlight the potential of plant-based odors and specifically linalool oxide

  17. Alternative treatments for indoor residual spraying for malaria control in a village with pyrethroid- and DDT-resistant vectors in The Gambia

    NARCIS (Netherlands)

    Tangena, J.A.A.; Adiamoh, M.; Alessandro, D' U.; Jarju, L.; Jawara, M.; Jeffries, D.; Malik, N.; Nwakanma, D.; Kaur, H.; Takken, W.; Lindsay, S.W.; Pinder, M.

    2013-01-01

    Background: Malaria vector control is threatened by resistance to pyrethroids, the only class of insecticides used for treating bed nets. The second major vector control method is indoor residual spraying with pyrethroids or the organochloride DDT. However, resistance to pyrethroids frequently confe

  18. Screening mosquito house entry points as a potential method for integrated control of endophagic filariasis, arbovirus and malaria vectors.

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    Sheila B Ogoma

    Full Text Available BACKGROUND: Partial mosquito-proofing of houses with screens and ceilings has the potential to reduce indoor densities of malaria mosquitoes. We wish to measure whether it will also reduce indoor densities of vectors of neglected tropical diseases. METHODOLOGY: The main house entry points preferred by anopheline and culicine vectors were determined through controlled experiments using specially designed experimental huts and village houses in Lupiro village, southern Tanzania. The benefit of screening different entry points (eaves, windows and doors using PVC-coated fibre glass netting material in terms of reduced indoor densities of mosquitoes was evaluated compared to the control. FINDINGS: 23,027 mosquitoes were caught with CDC light traps; 77.9% (17,929 were Anopheles gambiae sensu lato, of which 66.2% were An. arabiensis and 33.8% An. gambiae sensu stricto. The remainder comprised 0.2% (50 An. funestus, 10.2% (2359 Culex spp. and 11.6% (2664 Mansonia spp. Screening eaves reduced densities of Anopheles gambiae s. l. (Relative ratio (RR = 0.91; 95% CI = 0.84, 0.98; P = 0.01; Mansonia africana (RR = 0.43; 95% CI = 0.26, 0.76; P<0.001 and Mansonia uniformis (RR = 0.37; 95% CI = 0.25, 0.56; P<0.001 but not Culex quinquefasciatus, Cx. univittatus or Cx. theileri. Numbers of these species were reduced by screening windows and doors but this was not significant. SIGNIFICANCE: This study confirms that across Africa, screening eaves protects households against important mosquito vectors of filariasis, Rift Valley Fever and O'Nyong nyong as well as malaria. While full house screening is required to exclude Culex species mosquitoes, screening of eaves alone or fitting ceilings has considerable potential for integrated control of other vectors of filariasis, arbovirus and malaria.

  19. 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.

  20. Polyamidoamine nanoparticles as nanocarriers for the drug delivery to malaria parasite stages in the mosquito vector

    OpenAIRE

    Urbán, Patricia; Ranucci, Elisabetta; Fernàndez Busquets, Xavier

    2015-01-01

    Malaria is arguably one of the main medical concerns worldwide because of the numbers of people affected, the severity of the disease and the complexity of the life cycle of its causative agent, the protist Plasmodium spp. With the advent of nanoscience, renewed hopes have appeared of finally obtaining the long sought-after magic bullet against malaria in the form of a nanovector ...

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

    NARCIS (Netherlands)

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

    2014-01-01

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

  2. Laboratory evaluation of Indian medicinal plants as repellents against malaria, dengue, and filariasis vector mosquitoes.

    Science.gov (United States)

    Govindarajan, Marimuthu; Sivakumar, Rajamohan

    2015-02-01

    Mosquito-borne diseases have an economic impact, including loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates; however, no part of the world is free from vector-borne diseases. Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue fever, chikungunya fever, West Nile virus, and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticides, in the present study, the repellent activity of crude hexane, ethyl acetate, benzene, chloroform, and methanol extracts of leaf of Erythrina indica and root of Asparagus racemosus were assayed for their repellency against three important vector mosquitoes, viz., Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. The crude extract was applied on a membrane used for membrane feeding of unfed mosquitoes in a 1-ft cage. About 50 unfed 3-4-day-old laboratory-reared pathogen-free strains of A. stephensi, A. aegypti, and C. quinquefasciatus were introduced in a 1-ft cage fitted with a membrane with blood for feeding with temperature maintained at 37 °C through circulating water bath maintained at 40-45 °C. Three concentrations (1.0, 2.0, and 5.0 mg/cm(2)) of the crude extracts were evaluated. Repellents in E. indica afforded longer protection time against A. stephensi, A. aegypti, and C. quinquefasciatus than those in A. racemosus at 5.0 mg/cm(2) concentration, and the mean complete protection time ranged from 120 to 210 min with the different extracts tested. In this observation, these two plant crude extracts gave protection against mosquito bites; also, the repellent activity is dependent on the strength of the plant extracts. These results suggest that the leaf extract of E. indica and root extract of A. racemosus have the potential to

  3. Parasites and vectors carry no passport: how to fund cross-border and regional efforts to achieve malaria elimination

    Directory of Open Access Journals (Sweden)

    Gueye Cara

    2012-10-01

    multi-country proposals showed that applicants described their projects in one of two ways: a regional ‘network approach’ by which benefits are derived from economies of scale or from enhanced opportunities for mutual support and learning or the development of common policies and approaches; or a ‘cross-border’ approach for enabling activities to be more effectively delivered towards border-crossing populations or vectors. In Round 10, only those with a ‘network approach’ were recommended for funding. The Global Fund has only ever approved six malaria multi-country applications. Four approved applications stated strong arguments for a multi-country initiative, combining both ‘cross-border’ and ‘network’ approaches. Conclusion With the cancellation of Round 11 and the proposal that the Global Fund adopt a more targeted and strategic approach to funding, the time is opportune for the Global Fund to develop a clear consensus about the key factors and criteria for funding malaria specific multi-country initiatives. This study found that currently there was a lack of guidance on the key features that a successful multi-country proposal needs to be approved and that applications directed towards the ‘network’ approach were most successful in Round 10. This type of multi-country proposal may favour other diseases such as HIV, whereas the need for malaria control and elimination is different, focusing on cross-border coordination and delivery of interventions to specific groups. The Global Fund should seek to address these issues and give better guidance to countries and regions and investigate disease-specific calls for multi-country and regional applications.

  4. Epidemic malaria and warmer temperatures in recent decades in an East African highland

    NARCIS (Netherlands)

    Alonso, David; Bouma, Menno J.; Pascual, Mercedes

    2011-01-01

    Climate change impacts on malaria are typically assessed with scenarios for the long-term future. Here we focus instead on the recent past (1970-2003) to address whether warmer temperatures have already increased the incidence of malaria in a highland region of East Africa. Our analyses rely on a ne

  5. Stunting may determine the severity of malaria-associated anemia in African children

    NARCIS (Netherlands)

    Verhoef, H.; West, C.E.; Veenemans, J.; Beguin, Y.; Kok, F.J.

    2002-01-01

    OBJECTIVE: Evidence from previous studies that malnourished children are protected against malaria is controversial. In individuals repeatedly exposed to malaria, immunity may develop first against severe disease, then against pyrogens, and last, against parasites. If this is true, this would sugges

  6. A phase 3 trial of RTS,S/AS01 malaria vaccine in African infants

    DEFF Research Database (Denmark)

    Agnandji, Selidji Todagbe; Lell, Bertrand; Fernandes, José Francisco;

    2012-01-01

    The candidate malaria vaccine RTS,S/AS01 reduced episodes of both clinical and severe malaria in children 5 to 17 months of age by approximately 50% in an ongoing phase 3 trial. We studied infants 6 to 12 weeks of age recruited for the same trial....

  7. Host population persistence in the face of introduced vector-borne diseases: Hawaii amakihi and avian malaria

    Science.gov (United States)

    Woodworth, B.L.; Atkinson, C.T.; Lapointe, D.A.; Hart, P.J.; Spiegel, C.S.; Tweed, E.J.; Henneman, C.; LeBrun, J.; Denette, T.; DeMots, R.; Kozar, K.L.; Triglia, D.; Lease, D.; Gregor, A.; Smith, T.; Duffy, D.

    2005-01-01

    The past quarter century has seen an unprecedented increase in the number of new and emerging infectious diseases throughout the world, with serious implications for human and wildlife populations. We examined host persistence in the face of introduced vector-borne diseases in Hawaii, where introduced avian malaria and introduced vectors have had a negative impact on most populations of Hawaiian forest birds for nearly a century. We studied birds, parasites, and vectors in nine study areas from 0 to 1,800 m on Mauna Loa Volcano, Hawaii from January to October, 2002. Contrary to predictions of prior work, we found that Hawaii amakihi (Hemignathus virens), a native species susceptible to malaria, comprised from 24.5% to 51.9% of the avian community at three low-elevation forests (55-270 m). Amakihi were more abundant at low elevations than at disease-free high elevations, and were resident and breeding there. Infection rates were 24-40% by microscopy and 55-83% by serology, with most infected individuals experiencing low-intensity, chronic infections. Mosquito trapping and diagnostics provided strong evidence for year-round local transmission. Moreover, we present evidence that Hawaii amakihi have increased in low elevation habitats on south-eastern Hawaii Island over the past decade. The recent emergent phenomenon of recovering amakihi populations at low elevations, despite extremely high prevalence of avian malaria, suggests that ecological or evolutionary processes acting on hosts or parasites have allowed this species to recolonize low-elevation habitats. A better understanding of the mechanisms allowing coexistence of hosts and parasites may ultimately lead to tools for mitigating disease impacts on wildlife and human populations.

  8. Feasibility and acceptability of ACT for the community case management of malaria in urban settings in five African sites

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    Traoré Abdoulaye

    2011-08-01

    Full Text Available Abstract Background The community case management of malaria (CCMm is now an established route for distribution of artemisinin-based combination therapy (ACT in rural areas, but the feasibility and acceptability of the approach through community medicine distributors (CMD in urban areas has not been explored. It is estimated that in 15 years time 50% of the African population will live in urban areas and transmission of the malaria parasite occurs in these densely populated areas. Methods Pre- and post-implementation studies were conducted in five African cities: Ghana, Burkina Faso, Ethiopia and Malawi. CMDs were trained to educate caregivers, diagnose and treat malaria cases in Results Qualitative findings: In all sites, interviews revealed that caregivers' knowledge of malaria signs and symptoms improved after the intervention. Preference for CMDs as preferred providers for malaria increased in all sites. Quantitative findings: 9001 children with an episode of fever were treated by 199 CMDs in the five study sites. Results from the CHWs registers show that of these, 6974 were treated with an ACT and 6933 (99% were prescribed the correct dose for their age. Fifty-four percent of the 3,025 children for which information about the promptness of treatment was available were treated within 24 hours from the onset of symptoms. From the household survey 3700 children were identified who had an episode of fever during the preceding two weeks. 1480 (40% of them sought treatment from a CMD and 1213 of them (82% had received an ACT. Of these, 1123 (92.6% were administered the ACT for the correct number of doses and days; 773 of the 1118 (69.1% children for which information about the promptness of treatment was available were treated within 24 hours from onset of symptoms, and 768 (68.7% were treated promptly and correctly. Conclusions The concept of CCMm in an urban environment was positive, and caregivers were generally satisfied with the services

  9. Single concentration tests show synergism among Bacillus thuringiensis subsp. israelensis toxins against the malaria vector mosquito Anopheles albimanus.

    Science.gov (United States)

    Fernández-Luna, María Teresa; Tabashnik, Bruce E; Lanz-Mendoza, Humberto; Bravo, Alejandra; Soberón, Mario; Miranda-Ríos, Juan

    2010-07-01

    Bioassays of insecticidal proteins from Bacillus thuringiensis subsp. israelensis with larvae of the malaria vector mosquito Anopheles albimanus showed that the cytolytic protein Cyt1Aa was not toxic alone, but it increased the toxicity of the crystalline proteins Cry4Ba and Cry11Aa. Synergism also occurred between Cry4Ba and Cry11Aa toxins. Whereas many previous analyses of synergism have been based on a series of toxin concentrations leading to comparisons between expected and observed values for the concentration killing 50% of insects tested (LC(50)), we describe and apply a method here that enables testing for synergism based on single concentrations of toxins.

  10. Human antibody response to Anopheles saliva for comparing the efficacy of three malaria vector control methods in Balombo, Angola.

    Directory of Open Access Journals (Sweden)

    Laura Brosseau

    Full Text Available Human antibody (Ab response to Anopheles whole saliva, used as biomarker of Anopheles exposure, was investigated over a period of two years (2008-2009, in children between 2 to 9 years old, before and after the introduction of three different malaria vector control methods; deltamethrin treated long lasting impregnated nets (LLIN and insecticide treated plastic sheeting (ITPS--Zero Fly® (ITPS-ZF, deltamethrin impregnated Durable (Wall Lining (ITPS-DL--Zerovector® alone, and indoor residual spraying (IRS with lambdacyhalothrin alone. These different vector control methods resulted in considerable decreases in all three entomological (82.4%, parasitological (54.8% and immunological criteria analyzed. The highest reductions in the number of Anopheles collected and number of positive blood smears, respectively 82.1% and 58.3%, were found in Capango and Canjala where LLIN and ITPS-ZF were implemented. The immunological data based on the level of anti-saliva IgG Ab in children of all villages dropped significantly from 2008 to 2009, except in Chissequele. These results indicated that these three vector control methods significantly reduced malaria infections amongst the children studied and IRS significantly reduced the human-Anopheles contact. The number of Anopheles, positive blood smears, and the levels of anti-saliva IgG Ab were most reduced when LLIN and ITPS-ZF were used in combination, compared to the use of one vector control method alone, either ITPS-DL or IRS. Therefore, as a combination of two vector control methods is significantly more effective than one control method only, this control strategy should be further developed at a more global scale.

  11. 传疟按蚊抗药性研究进展%Research advance on insecticide resistance of malaria vector mosquito Anopheles

    Institute of Scientific and Technical Information of China (English)

    秦茜; 闫桂云; 陈晓光

    2014-01-01

    In May 2010,the Ministry of Health and Chinese Government issued Action Plan of China Malaria Elimination (2010-2020),aiming at complete elimination of malaria in P.R.China by 2020.Vector control is a fundamental element of the existing global strategy to fight malaria.Anopheles is the main malaria vector mosquito.However,rapidly increasing insecticide resistance of mosquitoes threatens current malaria vector control efforts.In order to understand current status of mosquito resistance to insecticide and resistance mechanisms of the malaria vector,the current status of insecticide resistance in malaria vector mosquito Anopheles,the resistance mechanisms and the detection methods on resistance were reviewed in this paper.%我国卫生部于2010年5月印发《中国消除疟疾行动计划(2010-2020年)》,提出在2020年,将全面彻底消除疟疾.控制及消除疟疾的关键在于传播媒介的控制,而按蚊为疟疾主要传播媒介,传疟媒介对杀虫剂的抗药性直接导致了疟疾发病的死灰复燃.为了全面了解疟疾蚊媒的抗药性现状和产生机制,该文对国内外传疟按蚊抗药性现状、产生机制和检测方法进行综述.

  12. Re-Emerging Malaria Vectors in Rural Sahel (nouna, Burkina Faso): the Paluclim Project

    Science.gov (United States)

    Vignolles, Cécile; Sauerborn, Rainer; Dambach, Peter; Viel, Christian; Soubeyroux, Jean-Michel; Sié, Ali; Rogier, Christophe; Tourre, Yves M.

    2016-06-01

    The Paluclim project applied the tele-epidemiology approach, linking climate, environment and public health (CNES, 2008), to rural malaria in Nouna (Burkina Faso). It was to analyze the climate impact on vectorial risks, and its consequences on entomological risks forecast. The objectives were to: 1) produce entomological risks maps in the Nouna region, 2) produce dynamic maps on larvae sites and their productivity, 3) study the climate impact on malaria risks, and 4) evaluate the feasibility of strategic larviciding approach.

  13. Malaria Matters

    Centers for Disease Control (CDC) Podcasts

    2008-04-18

    This podcast gives an overview of malaria, including prevention and treatment, and what CDC is doing to help control and prevent malaria globally.  Created: 4/18/2008 by National Center for Zoonotic, Vector-Borne, and Enteric Diseases (NCZVED).   Date Released: 4/18/2008.

  14. Amazonian malaria: asymptomatic human reservoirs, diagnostic challenges, environmentally driven changes in mosquito vector populations, and the mandate for sustainable control strategies.

    Science.gov (United States)

    da Silva-Nunes, Mônica; Moreno, Marta; Conn, Jan E; Gamboa, Dionicia; Abeles, Shira; Vinetz, Joseph M; Ferreira, Marcelo U

    2012-03-01

    Across the Americas and the Caribbean, nearly 561,000 slide-confirmed malaria infections were reported officially in 2008. The nine Amazonian countries accounted for 89% of these infections; Brazil and Peru alone contributed 56% and 7% of them, respectively. Local populations of the relatively neglected parasite Plasmodium vivax, which currently accounts for 77% of the regional malaria burden, are extremely diverse genetically and geographically structured. At a time when malaria elimination is placed on the public health agenda of several endemic countries, it remains unclear why malaria proved so difficult to control in areas of relatively low levels of transmission such as the Amazon Basin. We hypothesize that asymptomatic parasite carriage and massive environmental changes that affect vector abundance and behavior are major contributors to malaria transmission in epidemiologically diverse areas across the Amazon Basin. Here we review available data supporting this hypothesis and discuss their implications for current and future malaria intervention policies in the region. Given that locally generated scientific evidence is urgently required to support malaria control interventions in Amazonia, we briefly describe the aims of our current field-oriented malaria research in rural villages and gold-mining enclaves in Peru and a recently opened agricultural settlement in Brazil.

  15. A Randomized Longitudinal Factorial Design to Assess Malaria Vector Control and Disease Management Interventions in Rural Tanzania

    Directory of Open Access Journals (Sweden)

    Randall A. Kramer

    2014-05-01

    Full Text Available The optimization of malaria control strategies is complicated by constraints posed by local health systems, infrastructure, limited resources, and the complex interactions between infection, disease, and treatment. The purpose of this paper is to describe the protocol of a randomized factorial study designed to address this research gap. This project will evaluate two malaria control interventions in Mvomero District, Tanzania: (1 a disease management strategy involving early detection and treatment by community health workers using rapid diagnostic technology; and (2 vector control through community-supported larviciding. Six study villages were assigned to each of four groups (control, early detection and treatment, larviciding, and early detection and treatment plus larviciding. The primary endpoint of interest was change in malaria infection prevalence across the intervention groups measured during annual longitudinal cross-sectional surveys. Recurring entomological surveying, household surveying, and focus group discussions will provide additional valuable insights. At baseline, 962 households across all 24 villages participated in a household survey; 2,884 members from 720 of these households participated in subsequent malariometric surveying. The study design will allow us to estimate the effect sizes of different intervention mixtures. Careful documentation of our study protocol may also serve other researchers designing field-based intervention trials.

  16. A randomized longitudinal factorial design to assess malaria vector control and disease management interventions in rural Tanzania.

    Science.gov (United States)

    Kramer, Randall A; Mboera, Leonard E G; Senkoro, Kesheni; Lesser, Adriane; Shayo, Elizabeth H; Paul, Christopher J; Miranda, Marie Lynn

    2014-05-16

    The optimization of malaria control strategies is complicated by constraints posed by local health systems, infrastructure, limited resources, and the complex interactions between infection, disease, and treatment. The purpose of this paper is to describe the protocol of a randomized factorial study designed to address this research gap. This project will evaluate two malaria control interventions in Mvomero District, Tanzania: (1) a disease management strategy involving early detection and treatment by community health workers using rapid diagnostic technology; and (2) vector control through community-supported larviciding. Six study villages were assigned to each of four groups (control, early detection and treatment, larviciding, and early detection and treatment plus larviciding). The primary endpoint of interest was change in malaria infection prevalence across the intervention groups measured during annual longitudinal cross-sectional surveys. Recurring entomological surveying, household surveying, and focus group discussions will provide additional valuable insights. At baseline, 962 households across all 24 villages participated in a household survey; 2,884 members from 720 of these households participated in subsequent malariometric surveying. The study design will allow us to estimate the effect sizes of different intervention mixtures. Careful documentation of our study protocol may also serve other researchers designing field-based intervention trials.

  17. Green synthesis and characterization of silver nanoparticles fabricated using Anisomeles indica: Mosquitocidal potential against malaria, dengue and Japanese encephalitis vectors.

    Science.gov (United States)

    Govindarajan, Marimuthu; Rajeswary, Mohan; Veerakumar, Kaliyan; Muthukumaran, Udaiyan; Hoti, S L; Benelli, Giovanni

    2016-02-01

    Mosquitoes (Diptera: Culicidae) represent a key threat for millions of people worldwide, since they act as vectors for devastating parasites and pathogens. In this scenario, eco-friendly control tools against mosquito vectors are a priority. Green synthesis of silver nanoparticles (AgNP) using a cheap, aqueous leaf extract of Anisomeles indica by reduction of Ag(+) ions from silver nitrate solution has been investigated. Bio-reduced AgNP were characterized by UV-visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDX) and X-ray diffraction analysis (XRD). The acute toxicity of A. indica leaf extract and biosynthesized AgNP was evaluated against larvae of the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. Both the A. indica leaf extract and AgNP showed dose dependent larvicidal effect against all tested mosquito species. Compared to the leaf aqueous extract, biosynthesized AgNP showed higher toxicity against An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus with LC50 values of 31.56, 35.21 and 38.08 μg/mL, respectively. Overall, this study firstly shed light on the mosquitocidal potential of A. indica, a potential bioresource for rapid, cheap and effective AgNP synthesis.

  18. Cytokine response during non-cerebral and cerebral malaria: evidence of a failure to control inflammation as a cause of death in African adults

    Directory of Open Access Journals (Sweden)

    Yakhya Dieye

    2016-05-01

    Full Text Available Background. With 214 million cases and 438,000 deaths in 2015, malaria remains one of the deadliest infectious diseases in tropical countries. Several species of the protozoan Plasmodium cause malaria. However, almost all the fatalities are due to Plasmodium falciparum, a species responsible for the severest cases including cerebral malaria. Immune response to Plasmodium falciparum infection is mediated by the production of pro-inflammatory cytokines, chemokines and growth factors whose actions are crucial for the control of the parasites. Following this response, the induction of anti-inflammatory immune mediators downregulates the inflammation thus preventing its adverse effects such as damages to various organs and death. Methods. We performed a retrospective, nonprobability sampling study using clinical data and sera samples from patients, mainly adults, suffering of non-cerebral or cerebral malaria in Dakar, Sénégal. Healthy individuals residing in the same area were included as controls. We measured the serum levels of 29 biomarkers including growth factors, chemokines, inflammatory and anti-inflammatory cytokines. Results. We found an induction of both pro- and anti-inflammatory immune mediators during malaria. The levels of pro-inflammatory biomarkers were higher in the cerebral malaria than in the non-cerebral malaria patients. In contrast, the concentrations of anti-inflammatory cytokines were comparable in these two groups or lower in CM patients. Additionally, four pro-inflammatory biomarkers were significantly increased in the deceased of cerebral malaria compared to the survivors. Regarding organ damage, kidney failure was significantly associated with death in adults suffering of cerebral malaria. Conclusions. Our results suggest that a poorly controlled inflammatory response determines a bad outcome in African adults suffering of cerebral malaria.

  19. Identifying malaria vector breeding habitats with remote sensing data and terrain-based landscape indices in Zambia

    Directory of Open Access Journals (Sweden)

    Shiff Clive

    2010-11-01

    Full Text Available Abstract Background Malaria, caused by the parasite Plasmodium falciparum, is a significant source of morbidity and mortality in southern Zambia. In the Mapanza Chiefdom, where transmission is seasonal, Anopheles arabiensis is the dominant malaria vector. The ability to predict larval habitats can help focus control measures. Methods A survey was conducted in March-April 2007, at the end of the rainy season, to identify and map locations of water pooling and the occurrence anopheline larval habitats; this was repeated in October 2007 at the end of the dry season and in March-April 2008 during the next rainy season. Logistic regression and generalized linear mixed modeling were applied to assess the predictive value of terrain-based landscape indices along with LandSat imagery to identify aquatic habitats and, especially, those with anopheline mosquito larvae. Results Approximately two hundred aquatic habitat sites were identified with 69 percent positive for anopheline mosquitoes. Nine species of anopheline mosquitoes were identified, of which, 19% were An. arabiensis. Terrain-based landscape indices combined with LandSat predicted sites with water, sites with anopheline mosquitoes and sites specifically with An. arabiensis. These models were especially successful at ruling out potential locations, but had limited ability in predicting which anopheline species inhabited aquatic sites. Terrain indices derived from 90 meter Shuttle Radar Topography Mission (SRTM digital elevation data (DEM were better at predicting water drainage patterns and characterizing the landscape than those derived from 30 m Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER DEM. Conclusions The low number of aquatic habitats available and the ability to locate the limited number of aquatic habitat locations for surveillance, especially those containing anopheline larvae, suggest that larval control maybe a cost-effective control measure in the fight

  20. Assessing the Role of Climate Change in Malaria Transmission in Africa

    Directory of Open Access Journals (Sweden)

    E. T. Ngarakana-Gwasira

    2016-01-01

    Full Text Available The sensitivity of vector borne diseases like malaria to climate continues to raise considerable concern over the implications of climate change on future disease dynamics. The problem of malaria vectors shifting from their traditional locations to invade new zones is of important concern. A mathematical model incorporating rainfall and temperature is constructed to study the transmission dynamics of malaria. The reproduction number obtained is applied to gridded temperature and rainfall datasets for baseline climate and future climate with aid of GIS. As a result of climate change, malaria burden is likely to increase in the tropics, the highland regions, and East Africa and along the northern limit of falciparum malaria. Falciparum malaria will spread into the African highlands; however it is likely to die out at the southern limit of the disease.

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

    Science.gov (United States)

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

    2015-12-08

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

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

    Directory of Open Access Journals (Sweden)

    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.

  3. Lack of association of interferon regulatory factor 1 with severe malaria in affected child-parental trio studies across three African populations.

    Directory of Open Access Journals (Sweden)

    Valentina D Mangano

    Full Text Available Interferon Regulatory Factor 1 (IRF-1 is a member of the IRF family of transcription factors, which have key and diverse roles in the gene-regulatory networks of the immune system. IRF-1 has been described as a critical mediator of IFN-gamma signalling and as the major player in driving TH1 type responses. It is therefore likely to be crucial in both innate and adaptive responses against intracellular pathogens such as Plasmodium falciparum. Polymorphisms at the human IRF1 locus have been previously found to be associated with the ability to control P. falciparum infection in populations naturally exposed to malaria. In order to test whether genetic variation at the IRF1 locus also affects the risk of developing severe malaria, we performed a family-based test of association for 18 Single Nucleotide Polymorphisms (SNPs across the gene in three African populations, using genotype data from 961 trios consisting of one affected child and his/her two parents (555 from The Gambia, 204 from Kenya and 202 from Malawi. No significant association with severe malaria or severe malaria subphenotypes (cerebral malaria and severe malaria anaemia was observed for any of the SNPs/haplotypes tested in any of the study populations. Our results offer no evidence that the molecular pathways regulated by the transcription factor IRF-1 are involved in the immune-based pathogenesis of severe malaria.

  4. Lack of Association of Interferon Regulatory Factor 1 with Severe Malaria in Affected Child-Parental Trio Studies across Three African Populations

    Science.gov (United States)

    Mangano, Valentina D.; Clark, Taane G.; Green, Angela; Richardson, Anna; Jallow, Muminatou; Sisay-Joof, Fatou; Pinder, Margaret; Griffiths, Michael J.; Newton, Charles; Peshu, Norbert; Williams, Thomas N.; Marsh, Kevin; Molyneux, Malcolm E.; Taylor, Terrie E.; Modiano, David; Kwiatkowski, Dominic P.; Rockett, Kirk A.

    2009-01-01

    Interferon Regulatory Factor 1 (IRF-1) is a member of the IRF family of transcription factors, which have key and diverse roles in the gene-regulatory networks of the immune system. IRF-1 has been described as a critical mediator of IFN-gamma signalling and as the major player in driving TH1 type responses. It is therefore likely to be crucial in both innate and adaptive responses against intracellular pathogens such as Plasmodium falciparum. Polymorphisms at the human IRF1 locus have been previously found to be associated with the ability to control P. falciparum infection in populations naturally exposed to malaria. In order to test whether genetic variation at the IRF1 locus also affects the risk of developing severe malaria, we performed a family-based test of association for 18 Single Nucleotide Polymorphisms (SNPs) across the gene in three African populations, using genotype data from 961 trios consisting of one affected child and his/her two parents (555 from The Gambia, 204 from Kenya and 202 from Malawi). No significant association with severe malaria or severe malaria subphenotypes (cerebral malaria and severe malaria anaemia) was observed for any of the SNPs/haplotypes tested in any of the study populations. Our results offer no evidence that the molecular pathways regulated by the transcription factor IRF-1 are involved in the immune-based pathogenesis of severe malaria. PMID:19145247

  5. Man biting rate seasonal variation of malaria vectors in Roraima, Brazil

    Directory of Open Access Journals (Sweden)

    Fábio Saito Monteiro de Barros

    2007-06-01

    Full Text Available Malaria control has been directed towards regional actions where more detailed knowledge of local determinants of transmission is of primary importance. This is a short report on range distribution and biting indices for Anopheles darlingi and An. albitarsis during the dry and rainy season that follows river level variation in a savanna/alluvial forest malaria system area in the Northern Amazon Basin. Distribution range and adult biting indices were at their highest during the rainy season for both An. darlingi and An. albitarsis. During the rainy season the neighboring alluvial forest was extensively flooded. This coincided with highest rates in malaria transmission with case clustering near the river. As the river receded, anopheline distribution range and density decreased. This decrease in distribution and density corresponded to a malaria decrease in the near area. An exponential regression function was derived to permit estimations of An. darlingi distribution over specified distances. Anopheline spatio-temporal variations lead to uneven malaria case distribution and are of important implications for control strategies.

  6. Does malaria epidemiology project Cameroon as `Africa in miniature'?

    Indian Academy of Sciences (India)

    Huguette Gaelle Ngassa Mbenda; Gauri Awasthi; Poonam K Singh; Inocent Gouado; Aparup Das

    2014-09-01

    Cameroon, a west-central African country with a ∼20 million population, is commonly regarded as ‘Africa in miniature’ due to the extensive biological and cultural diversities of whole Africa being present in a single-country setting. This country is inhabited by ancestral human lineages in unique eco-climatic conditions and diverse topography. Over 90% Cameroonians are at risk of malaria infection, and ∼41% have at least one episode of malaria each year. Historically, the rate of malaria infection in Cameroon has fluctuated over the years; the number of cases was about 2 million in 2010 and 2011. The Cameroonian malaria control programme faces an uphill task due to high prevalence of multidrug-resistant parasites and insecticide-resistant malaria vectors. Above all, continued human migration from the rural to urban areas as well as population exchange with adjoining countries, high rate of ecological instabilities caused by deforestation, poor housing, lack of proper sanitation and drainage system might have resulted in the recent increase in incidences of malaria and other vector-borne diseases in Cameroon. The available data on eco-environmental variability and intricate malaria epidemiology in Cameroon reflect the situation in the whole of Africa, and warrant the need for in-depth study by using modern surveillance tools for meaningful basic understanding of the malaria triangle (host-parasite-vector-environment).

  7. Vector bionomics and malaria transmission in the Upper Orinoco River, Southern Venezuela

    Directory of Open Access Journals (Sweden)

    Magda Magris

    2007-06-01

    Full Text Available A longitudinal epidemiological and entomological study was carried out in Ocamo, Upper Orinoco River, between January 1994 and February 1995 to understand the dynamics of malaria transmission in this area. Malaria transmission occurs throughout the year with a peak in June at the beginning of the rainy season. The Annual Parasite Index was 1,279 per 1,000 populations at risk. Plasmodium falciparum infections accounted for 64% of all infections, P. vivax for 28%, and P. malariae for 4%. Mixed P. falciparum/P. vivax infections were diagnosed in 15 people representing 4% of total cases. Children under 10 years accounted for 58% of the cases; the risk for malaria in this age group was 77% higher than for those in the greater than 50 years age group. Anopheles darlingi was the predominant anopheline species landing on humans indoors with a biting peak between midnight and dawn. A significant positive correlation was found between malaria monthly incidence and mean number of An. darlingi caught. There was not a significant relationship between mean number of An. darlingi and rainfall or between incidence and rainfall. A total of 7295 anophelines were assayed by ELISA for detection of Plasmodium circumsporozoite (CS protein. Only An. darlingi (55 was positive for CS proteins of P. falciparum (0.42%, P. malariae (0.25%, and P. vivax-247 (0.1%. The overall estimated entomological inoculation rate was 129 positive bites/person/year. The present study was the first longitudinal entomological and epidemiological study conducted in this area and set up the basic ground for subsequent intervention with insecticide-treated nets.

  8. Effects of Microclimate Condition Changes Due to Land Use and Land Cover Changes on the Survivorship of Malaria Vectors in China-Myanmar Border Region.

    Directory of Open Access Journals (Sweden)

    Daibin Zhong

    Full Text Available In the past decade, developing countries have been experiencing rapid land use and land cover changes, including deforestation and cultivation of previously forested land. However, little is known about the impact of deforestation and land-use changes on the life history of malaria vectors and their effects on malaria transmission. This study examined the effects of deforestation and crop cultivation on the adult survivorship of major malaria mosquitoes, Anopheles sinensis and An. minimus in the China-Myanmar border region. We examined three conditions: indoor, forested, and banana plantation. Mean survival time of An. sinensis in banana plantation environment was significantly longer than those in forested environment, and mosquitoes exhibited the longest longevity in the indoor environment. This pattern held for both males and females, and also for An. minimus. To further test the effect of temperature on mosquito survival, we used two study sites with different elevation and ambient temperatures. Significantly higher survivorship of both species was found in sites with lower elevation and higher ambient temperature. Increased vector survival in the deforested area could have an important impact on malaria transmission in Southeast Asia. Understanding how deforestation impacts vector survivorship can help combat malaria transmission.

  9. Effects of Microclimate Condition Changes Due to Land Use and Land Cover Changes on the Survivorship of Malaria Vectors in China-Myanmar Border Region.

    Science.gov (United States)

    Zhong, Daibin; Wang, Xiaoming; Xu, Tielong; Zhou, Guofa; Wang, Ying; Lee, Ming-Chieh; Hartsel, Joshua A; Cui, Liwang; Zheng, Bin; Yan, Guiyun

    2016-01-01

    In the past decade, developing countries have been experiencing rapid land use and land cover changes, including deforestation and cultivation of previously forested land. However, little is known about the impact of deforestation and land-use changes on the life history of malaria vectors and their effects on malaria transmission. This study examined the effects of deforestation and crop cultivation on the adult survivorship of major malaria mosquitoes, Anopheles sinensis and An. minimus in the China-Myanmar border region. We examined three conditions: indoor, forested, and banana plantation. Mean survival time of An. sinensis in banana plantation environment was significantly longer than those in forested environment, and mosquitoes exhibited the longest longevity in the indoor environment. This pattern held for both males and females, and also for An. minimus. To further test the effect of temperature on mosquito survival, we used two study sites with different elevation and ambient temperatures. Significantly higher survivorship of both species was found in sites with lower elevation and higher ambient temperature. Increased vector survival in the deforested area could have an important impact on malaria transmission in Southeast Asia. Understanding how deforestation impacts vector survivorship can help combat malaria transmission.

  10. Chemical composition and larvicidal activity of Elaeagnus indica Servett. (Elaeagnaceae plant leaf extracts against dengue and malaria vectors

    Directory of Open Access Journals (Sweden)

    Ramalingam Srinivasan

    2014-12-01

    Full Text Available MMosquito control is facing a threat due to the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. The acetone, chloroform, ethyl acetate, hexane, methanol and petroleum benzene leaf extracts of E. indica were tested against fourth instar larvae of malaria vector, Anopheles stephensi and dengue vector, Aedes aegypti. The larval mortality was observed after 24 h of exposure. Highest larval mortality was found in acetone leaf extracts against A. aegypti (LC50 and LC90 values of 2.97027and 5.9820 mg/ml and A. stephensi (LC50 and LC90 values of 3.92501 and 68.3250 mg/ml respectively. GC-MS analysis of plant extracts of acetone solvent revealed 19 compounds, of which the major compounds were -Thujone 1-Isopropyl-4-Methylbicyclo(3.1.0Hexan-3-One 1- (6.71%, 1,6- Cyclodecadiene, 1-Methyl-5-Methylene-8-(1-Methylethyl-, [S-(E,E]-Germacra-1(10,4(15,5-Trie N (3.11%, L-(+-Ascorbic Acid 2,6-Dihexadecanoate (4.06%, 2-Cyclohexylcyclohexanol [1,1'-Bicyclohexyl]-2-Ol (3.16%, Dotriacontane N- Bicetyl (58.7% and Tetrapentacontane (3.85%. E. indica offers promise as potential biocontrol agent against major dengue and malaria mosquitoes particularly in larvicidal effect. Our results shows acetone leaf extracts of E. indica have the potential to be used as an ideal eco-friendly approach for control of mosquito vectors.

  11. Tsetse Flies (Glossina) as Vectors of Human African Trypanosomiasis: A Review.

    Science.gov (United States)

    Wamwiri, Florence Njeri; Changasi, Robert Emojong

    2016-01-01

    Human African Trypanosomiasis (HAT) transmitted by the tsetse fly continues to be a public health issue, despite more than a century of research. There are two types of the disease, the chronic gambiense and the acute rhodesiense-HAT. Fly abundance and distribution have been affected by changes in land-use patterns and climate. However, disease transmission still continues. Here, we review some aspects of HAT ecoepidemiology in the context of altered infestation patterns and maintenance of the transmission cycle as well as emerging options in disease and vector control.

  12. Tsetse Flies (Glossina as Vectors of Human African Trypanosomiasis: A Review

    Directory of Open Access Journals (Sweden)

    Florence Njeri Wamwiri

    2016-01-01

    Full Text Available Human African Trypanosomiasis (HAT transmitted by the tsetse fly continues to be a public health issue, despite more than a century of research. There are two types of the disease, the chronic gambiense and the acute rhodesiense-HAT. Fly abundance and distribution have been affected by changes in land-use patterns and climate. However, disease transmission still continues. Here, we review some aspects of HAT ecoepidemiology in the context of altered infestation patterns and maintenance of the transmission cycle as well as emerging options in disease and vector control.

  13. Exploiting the behaviour of wild malaria vectors to achieve high infection with fungal biocontrol agents

    NARCIS (Netherlands)

    Mnyone, L.L.; Lyimo, I.N.; Lwetoijera, D.W.; Mpingwa, M.W.; Nchimbi, N.; Hancock, P.A.; Russell, T.L.; Kirby, M.J.; Takken, W.; Koenraadt, C.J.M.

    2012-01-01

    Background Control of mosquitoes that transmit malaria has been the mainstay in the fight against the disease, but alternative methods are required in view of emerging insecticide resistance. Entomopathogenic fungi are candidate alternatives, but to date, few trials have translated the use of these

  14. Efficacy of Aquatain, a Monomolecular Film, for the Control of Malaria Vectors in Rice Paddies

    NARCIS (Netherlands)

    Bukhari, S.T.; Takken, W.; Githeko, A.K.; Koenraadt, C.J.M.

    2011-01-01

    Background Rice paddies harbour a large variety of organisms including larvae of malaria mosquitoes. These paddies are challenging for mosquito control because their large size, slurry and vegetation make it difficult to effectively apply a control agent. Aquatain, a monomolecular surface film, can

  15. Fitness consequences of larval exposure to Beauveria bassiana on adults of the malaria vector Anopheles stephensi

    NARCIS (Netherlands)

    Vogels, C.B.F.; Bukhari, T.; Koenraadt, C.J.M.

    2014-01-01

    Entomopathogenic fungi have shown to be effective in biological control of both larval and adult stages of malaria mosquitoes. However, a small fraction of mosquitoes is still able to emerge after treatment with fungus during the larval stage. It remains unclear whether fitness of these adults is af

  16. Molecular tools for studying the major malaria vector Anopheles funestus: improving the utility of the genome using a comparative poly(A) and Ribo-Zero RNAseq analysis

    OpenAIRE

    WEEDALL, GARETH D.; Irving, Helen; Hughes, Margaret A.; Wondji, Charles S.

    2015-01-01

    Background Next-generation sequencing (NGS) offers great opportunities for studying the biology of insect vectors of disease. Prerequisites for successful analyses include high quality annotated genome assemblies and that techniques designed for use with model organisms be tested and optimised for use with these insects. We aimed to test and improve genomic tools for studying the major malaria vector Anopheles funestus. Results To guide future RNAseq transcriptomic studies of An. funestus, we...

  17. Genome sequence of the tsetse fly (Glossina morsitans ): Vector of African trypanosomiasis

    KAUST Repository

    Watanabe, Junichi

    2014-04-24

    Tsetse flies are the sole vectors of human African trypanosomiasis throughout sub-Saharan Africa. Both sexes of adult tsetse feed exclusively on blood and contribute to disease transmission. Notable differences between tsetse and other disease vectors include obligate microbial symbioses, viviparous reproduction, and lactation. Here, we describe the sequence and annotation of the 366-megabase Glossina morsitans morsitans genome. Analysis of the genome and the 12,308 predicted protein-encoding genes led to multiple discoveries, including chromosomal integrations of bacterial (Wolbachia) genome sequences, a family of lactation-specific proteins, reduced complement of host pathogen recognition proteins, and reduced olfaction/chemosensory associated genes. These genome data provide a foundation for research into trypanosomiasis prevention and yield important insights with broad implications for multiple aspects of tsetse biology.

  18. A randomized controlled Phase Ib trial of the malaria vaccine candidate GMZ2 in African children

    DEFF Research Database (Denmark)

    Bélard, Sabine; Issifou, Saadou; Hounkpatin, Aurore B

    2011-01-01

    GMZ2 is a fusion protein of Plasmodium falciparum merozoite surface protein 3 (MSP3) and glutamate rich protein (GLURP) that mediates an immune response against the blood stage of the parasite. Two previous phase I clinical trials, one in naïve European adults and one in malaria-exposed Gabonese ...... adults showed that GMZ2 was well tolerated and immunogenic. Here, we present data on safety and immunogenicity of GMZ2 in one to five year old Gabonese children, a target population for future malaria vaccine efficacy trials....

  19. The fine-scale genetic structure of the malaria vectors Anopheles funestus and Anopheles gambiae (Diptera: Culicidae) in the north-eastern part of Tanzania

    NARCIS (Netherlands)

    Gélin, P.; Magalon, H.; Drakeley, C.; Maxwell, C.; Magesa, S.; Takken, W.; Boëte, C.

    2016-01-01

    Understanding the impact of altitude and ecological heterogeneity at a fine scale on the populations of malaria vectors is essential to better understand and anticipate eventual epidemiological changes. It could help to evaluate the spread of alleles conferring resistance to insecticides and also

  20. Benefit of insecticide-treated nets, curtains and screening on vector borne diseases, excluding malaria: a systematic review and meta-analysis

    NARCIS (Netherlands)

    Wilson, A.L.; Dhiman, R.C.; Kitron, U.; Scott, T.W.; Berg, van den H.; Lindsay, S.W.

    2014-01-01

    Introduction Insecticide-treated nets (ITNs) are one of the main interventions used for malaria control. However, these nets may also be effective against other vector borne diseases (VBDs). We conducted a systematic review and meta-analysis to estimate the efficacy of ITNs, insecticide-treated curt

  1. Spatial and temporal distribution of the malaria mosquito Anopheles arabiensis in northern Sudan: influence of environmental factors and implications for vector control

    NARCIS (Netherlands)

    Ageep, T.B.; Cox, J.; Hassan, M.M.; Knols, B.G.J.; Benedict, M.Q.; Malcolm, C.A.; Babiker, A.; Sayed, El B.B.

    2009-01-01

    Background - Malaria is an important public health problem in northern Sudan, but little is known about the dynamics of its transmission. Given the characteristic low densities of Anopheles arabiensis and the difficult terrain in this area, future vector control strategies are likely to be based on

  2. Translating research into policy: lessons learned from eclampsia treatment and malaria control in three southern African countries

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    Matinhure Sheillah

    2009-12-01

    Full Text Available Abstract Background Little is known about the process of knowledge translation in low- and middle-income countries. We studied policymaking processes in Mozambique, South Africa and Zimbabwe to understand the factors affecting the use of research evidence in national policy development, with a particular focus on the findings from randomized control trials (RCTs. We examined two cases: the use of magnesium sulphate (MgSO4 in the treatment of eclampsia in pregnancy (a clinical case; and the use of insecticide treated bed nets and indoor residual household spraying for malaria vector control (a public health case. Methods We used a qualitative case-study methodology to explore the policy making process. We carried out key informants interviews with a range of research and policy stakeholders in each country, reviewed documents and developed timelines of key events. Using an iterative approach, we undertook a thematic analysis of the data. Findings Prior experience of particular interventions, local champions, stakeholders and international networks, and the involvement of researchers in policy development were important in knowledge translation for both case studies. Key differences across the two case studies included the nature of the evidence, with clear evidence of efficacy for MgSO4 and ongoing debate regarding the efficacy of bed nets compared with spraying; local researcher involvement in international evidence production, which was stronger for MgSO4 than for malaria vector control; and a long-standing culture of evidence-based health care within obstetrics. Other differences were the importance of bureaucratic processes for clinical regulatory approval of MgSO4, and regional networks and political interests for malaria control. In contrast to treatment policies for eclampsia, a diverse group of stakeholders with varied interests, differing in their use and interpretation of evidence, was involved in malaria policy decisions in the three

  3. Prevalence of Plasmodium spp. in malaria asymptomatic African migrants assessed by nucleic acid sequence based amplification

    NARCIS (Netherlands)

    M. Marangi; R. Di Tullio; P.F. Mens; D. Martinelli; V. Fazio; G. Angarano; H.D.F.H. Schallig; A. Giangaspero; G. Scotto

    2009-01-01

    Background: Malaria is one of the most important infectious diseases in the world. Although most cases are found distributed in the tropical regions of Africa, Asia, Central and South Americas, there is in Europe a significant increase in the number of imported cases in non-endemic countries, in par

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

    Science.gov (United States)

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

    2016-01-01

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

  5. Evaluation of silver nanoparticles toxicity of Arachis hypogaea peel extracts and its larvicidal activity against malaria and dengue vectors.

    Science.gov (United States)

    Velu, Kuppan; Elumalai, Devan; Hemalatha, Periaswamy; Janaki, Arumugam; Babu, Muthu; Hemavathi, Maduraiveeran; Kaleena, Patheri Kunyil

    2015-11-01

    Silver nanoparticles (AgNPs) were successfully synthesised from aqueous silver nitrate using the extracts of Arachis hypogaea peels. The synthesised SNPs were characterized by Fourier transform-infrared spectroscopy analysis, X-ray diffraction, transmission electron microscopy analysis and high-resonance scanning electron microscopy, and energy dispersive X-ray spectroscopy. AgNPs were well defined and measured 20 to 50 nm in size. The nanoparticles were crystallized with a face-centered cubic structure. Larvicidal activity of synthesised AgNPs from A. hypogaea peels was tested for their larvicidal activity against the fourth instar larvae of Aedes aegypti (Yellow fever), Anopheles stephensi (Human malaria). The results suggest that the synthesised AgNPs have the potential to be used as an ideal eco-friendly resource for the control of A. aegypti and A. stephensi. This study provides the first report on the mosquito larvicidal activity of synthesised AgNPs from A. hypogaea peels against vectors of malaria and dengue.

  6. 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.

  7. Using nylon strips to dispense mosquito attractants for sampling the malaria vector Anopheles gambiae s.s.

    Science.gov (United States)

    Okumu, F; Biswaro, L; Mbeleyela, E; Killeen, G F; Mukabana, R; Moore, S J

    2010-03-01

    Synthetic versions of human derived kairomones can be used as baits when trapping host seeking mosquitoes. The effectiveness of these lures depends not only on their attractiveness to the mosquitoes but also on the medium from which they are dispensed. We report on the development and evaluation of nylon strips as a method of dispensing odorants attractive to the malaria vector, Anopheles gambiae s.s. (Giles). When a synthetic blend of attractants was dispensed using this method, significantly more mosquitoes were trapped than when two previous methods, open glass vials or low density polyethylene sachets were used. We conclude that the nylon strips are suitable for dispensing odorants in mosquito trapping operations and can be adopted for use in rural and remote areas. The nylon material required is cheap and widely available and the strips can be prepared without specialized equipment or electricity.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. "SUSCEPTIBILITY AND IRRITABILITY LEVELS OF MAIN MALARIA VECTORS TO SYNTHETIC PYRETHROIDS IN THE ENDEMIC AREAS OF IRAN"

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    H. Vatandosst N. Borhani

    2004-09-01

    Full Text Available The rational use of insecticides largely depends on a broad knowledge of the susceptibility and irritability levels of malaria vectors to currently used insecticides especially pyrethroids. In this study the susceptibility and irritability levels of Anopheles stephensi and An.culicifacies to DDT 4%,malathion 5%, propoxur 0.1%, deltamethrin 0.025%, lambdacyhalothrin 0.1%, cyfluthrin 0.1% and permethrin 0.25% were determined. Susceptibility and irritability tests on adult mosquitoes were carried out according to WHO methods. The results showed that An.stephensi was resistant to DDT 4% and mortality rates to this insecticide in Gavdary and Abtar areas were 64.2%±3.9 and 61.8%±4.36, respectively. An.stephensi was assumed susceptible to other insecticides. An.culicifacies was found susceptible to all the tested insecticides. The irritability tests carried out with pyrethroids exhibited that permethrin 0.25% had the highest irritancy effect against both species. Lambdacyhalothrin 0.1% and deltamethrin 0.025% had the least irritancy effect against An.stephensi and An.culicifacies, respectively. Average numbers of take offs/females/minute of An.stephensi to permethrin, deltamethrin, cyfluthrin and lambdacyhalothrin were 6.64±1.04, 3.11±0.67, 2.73±0.61 and 2.57±0.67, respectively. These figures for An.culicifacies were 2.24±0.37, 1.44±0.38, 1.59±0.35 and 1.46±0.5, respectively. Irritancy effect of pyrethroids should come in consideration while they are used for control of malaria vectors.

  10. Earth observation in support of malaria control and epidemiology: MALAREO monitoring approaches

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    Jonas Franke

    2015-06-01

    Full Text Available Malaria affects about half of the world’s population, with the vast majority of cases occuring in Africa. National malaria control programmes aim to reduce the burden of malaria and its negative, socioeconomic effects by using various control strategies (e.g. vector control, environmental management and case tracking. Vector control is the most effective transmission prevention strategy, while environmental factors are the key parameters affecting transmission. Geographic information systems (GIS, earth observation (EO and spatial modelling are increasingly being recognised as valuable tools for effective management and malaria vector control. Issues previously inhibiting the use of EO in epidemiology and malaria control such as poor satellite sensor performance, high costs and long turnaround times, have since been resolved through modern technology. The core goal of this study was to develop and implement the capabilities of EO data for national malaria control programmes in South Africa, Swaziland and Mozambique. High- and very high resolution (HR and VHR land cover and wetland maps were generated for the identification of potential vector habitats and human activities, as well as geoinformation on distance to wetlands for malaria risk modelling, population density maps, habitat foci maps and VHR household maps. These products were further used for modelling malaria incidence and the analysis of environmental factors that favour vector breeding. Geoproducts were also transferred to the staff of national malaria control programmes in seven African countries to demonstrate how EO data and GIS can support vector control strategy planning and monitoring. The transferred EO products support better epidemiological understanding of environmental factors related to malaria transmission, and allow for spatio-temporal targeting of malaria control interventions, thereby improving the cost-effectiveness of interventions.

  11. Other vector-borne parasitic diseases: animal helminthiases, bovine besnoitiosis and malaria.

    Science.gov (United States)

    Duvallet, G; Boireau, P

    2015-08-01

    The parasitic diseases discussed elsewhere in this issue of the Scientific and Technical Review are not the only ones to make use of biological vectors (such as mosquitoes or ticks) or mechanical vectors (such as horse flies or Stomoxys flies). The authors discuss two major groups of vector-borne parasitic diseases: firstly, helminthiasis, along with animal filariasis and onchocerciasis, which are parasitic diseases that often take a heavytoll on artiodactylsthroughoutthe world; secondly, parasitic diseases caused by vector-borne protists, foremost of which is bovine besnoitiosis (or anasarca of cattle), which has recently spread through Europe by a dual mode of transmission (direct and by vector). Other protists, such as Plasmodium and Hepatozoon, are also described briefly.

  12. Vaccination and Malaria Prevention among International Travelers Departing from Athens International Airport to African Destinations.

    Science.gov (United States)

    Pavli, Androula; Spilioti, Athina; Smeti, Paraskevi; Patrinos, Stavros; Maltezou, Helena C

    2014-01-01

    Background. International travel to Africa has grown dramatically over the last decade along with an increasing need to understand the health issues for travelers. The current survey aimed to assess vaccination and malaria prevention of travelers visiting Africa. Methods. A questionnaire-based survey was conducted from of November 1, 2011 to of April 30, 2013 at Athens International Airport. Results. A total of 360 travelers were studied; 68% were men. Their mean age was 39.9 years. Previous travel to tropical countries was reported by 71.9% of them. Most frequent destination was sub-Saharan Africa (60%). Most of them traveled for ≥1 month (62%). The main reason for travel was work (39.7%). Only 47% sought pretravel consultation. Hepatitis A, typhoid, and meningococcal vaccines were administered to 49.8%, 28%, and 26.6%, respectively, and malaria chemoprophylaxis to 66.8% of those who visited sub-Saharan Africa. A history of previous travel to a tropical country, elementary level of education, and traveling for visiting friends and relatives, and for short duration were significant determinants for not pursuing pretravel consultation. Conclusions. The current survey revealed important inadequacies in vaccine and malaria prophylaxis of travelers departing to Africa. Educational tools should be developed in order to improve awareness of travelers to risk destinations.

  13. Vaccination and Malaria Prevention among International Travelers Departing from Athens International Airport to African Destinations

    Directory of Open Access Journals (Sweden)

    Androula Pavli

    2014-01-01

    Full Text Available Background. International travel to Africa has grown dramatically over the last decade along with an increasing need to understand the health issues for travelers. The current survey aimed to assess vaccination and malaria prevention of travelers visiting Africa. Methods. A questionnaire-based survey was conducted from of November 1, 2011 to of April 30, 2013 at Athens International Airport. Results. A total of 360 travelers were studied; 68% were men. Their mean age was 39.9 years. Previous travel to tropical countries was reported by 71.9% of them. Most frequent destination was sub-Saharan Africa (60%. Most of them traveled for ≥1 month (62%. The main reason for travel was work (39.7%. Only 47% sought pretravel consultation. Hepatitis A, typhoid, and meningococcal vaccines were administered to 49.8%, 28%, and 26.6%, respectively, and malaria chemoprophylaxis to 66.8% of those who visited sub-Saharan Africa. A history of previous travel to a tropical country, elementary level of education, and traveling for visiting friends and relatives, and for short duration were significant determinants for not pursuing pretravel consultation. Conclusions. The current survey revealed important inadequacies in vaccine and malaria prophylaxis of travelers departing to Africa. Educational tools should be developed in order to improve awareness of travelers to risk destinations.

  14. [Particularities and stratification of malaria in Madagascar].

    Science.gov (United States)

    Mouchet, J; Blanchy, S

    1995-01-01

    The first factor is the malaria parasite, for which the species P. falciparum and P. vivax are important. Secondly, the transmission determines the disease stability and challenges the host's immunity. The third factor is the human host, consisting of people of both African and Asiatic origin, the latter of whom are more susceptible to P. vivax. Human activities such as cultivating rice fields are of paramount importance for the proliferation of the vectors. The vectors A. gambiae, A. arabiensis and A. funestus are very similar to those of the African continent. These vectors are not endemic on Madagascar, suggesting that they were recently introduced to the island where 95% of the fauna species are endemic. On the Plateau and in the South, the rice fields provide most of the breeding places for A. gambiae s.l. and A. funestus. Five epidemiological belts are found in Madagascar which are very similar to their analogs on continental Africa (fig. 1). These facies include the equatorial belt on the east coast and the tropical belt on the west coast north of Morondava, the Plateau belt analogous to the southern African continent, the southern Madagascar belt which is similar to the Sahelian areas, and finally the zones above 1,500m, which are essentially free of malaria. The first two facies have a stable type of malaria, and in the following two, malaria is unstable. These areas include the Plateau, the area of the severe epidemics which occurred between 1985 and 1988 with more than 50,00 deaths. Malaria control is based on a variety of strategies to respond to the epidemiological heterogeneity of the disease. Spraying within the homes with DDT, used on the Plateau after 1988, was and still is very successful.

  15. Patterns of irrigated rice growth and malaria vector breeding in Mali using multi-temporal ERS-2 synthetic aperture radar.

    Science.gov (United States)

    Diuk-Wasser, M A; Dolo, G; Bagayoko, M; Sogoba, N; Toure, M B; Moghaddam, M; Manoukis, N; Rian, S; Traore, S F; Taylor, C E

    2006-02-01

    We explored the use of the European Remote Sensing Satellite 2 Synthetic Aperture Radar (ERS-2 SAR) to trace the development of rice plants in an irrigated area near Niono, Mali and relate that to the density of anopheline mosquitoes, especially An. gambiae. This is important because such mosquitoes are the major vectors of malaria in sub-Saharan Africa, and their development is often coupled to the cycle of rice development. We collected larval samples, mapped rice fields using GPS and recorded rice growth stages simultaneously with eight ERS-2 SAR acquisitions. We were able to discriminate among rice growth stages using ERS-2 SAR backscatter data, especially among the early stages of rice growth, which produce the largest numbers of larvae. We could also distinguish between basins that produced high and low numbers of anophelines within the stage of peak production. After the peak, larval numbers dropped as rice plants grew taller and thicker, reducing the amount of light reaching the water surface. ERS-2 SAR backscatter increased concomitantly. Our data support the belief that ERS-2 SAR data may be helpful for mapping the spatial patterns of rice growth, distinguishing different agricultural practices, and monitoring the abundance of vectors in nearby villages.

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

    Science.gov (United States)

    Deletre, Emilie; Martin, Thibaud; Campagne, Pascal; Bourguet, Denis; Cadin, Andy; Menut, Chantal; Bonafos, Romain; Chandre, Fabrice

    2013-01-01

    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.

  17. DNA barcoding reveals both known and novel taxa in the Albitarsis Group (Anopheles: Nyssorhynchus of Neotropical malaria vectors

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    Ruiz-Lopez Freddy

    2012-02-01

    Full Text Available Abstract Background Mosquitoes belonging to the Albitarsis Group (Anopheles: Nyssorhynchus are of importance as malaria vectors across the Neotropics. The Group currently comprises six known species, and recent studies have indicated further hidden biodiversity within the Group. DNA barcoding has been proposed as a highly useful tool for species recognition, although its discriminatory utility has not been verified in closely related taxa across a wide geographic distribution. Methods DNA barcodes (658 bp of the mtDNA Cytochrome c Oxidase - COI were generated for 565 An. albitarsis s.l. collected in Argentina, Brazil, Colombia, Paraguay, Trinidad and Venezuela over the past twenty years, including specimens from type series and type localities. Here we test the utility of currently advocated barcoding methodologies, including the Kimura-two-parameter distance model (K2P and Neighbor-joining analysis (NJ, for determining species delineation within mosquitoes of the Neotropical Albitarsis Group of malaria vectors (Anopheles: Nyssorhynchus, and compare results with Bayesian analysis. Results Species delineation through barcoding analysis and Bayesian phylogenetic analysis, fully concur. Analysis of 565 sequences (302 unique haplotypes resolved nine NJ tree clusters, with less than 2% intra-node variation. Mean intra-specific variation (K2P was 0.009 (range 0.002 - 0.014, whereas mean inter-specific divergence were several-fold higher at 0.041 (0.020 - 0.056, supporting the reported "barcoding gap". These results show full support for separate species status of the six known species in the Albitarsis Group (An. albitarsis s.s., An. albitarsis F, An. deaneorum, An. janconnae, An. marajoara and An. oryzalimnetes, and also support species level status for two previously detected lineages - An. albitarsis G &An. albitarsis I (designated herein. In addition, we highlight the presence of a unique mitochondrial lineage close to An. deaneorum and An

  18. A historical perspective on malaria control in Brazil.

    Science.gov (United States)

    Griffing, Sean Michael; Tauil, Pedro Luiz; Udhayakumar, Venkatachalam; Silva-Flannery, Luciana

    2015-09-01

    Malaria has always been an important public health problem in Brazil. The early history of Brazilian malaria and its control was powered by colonisation by Europeans and the forced relocation of Africans as slaves. Internal migration brought malaria to many regions in Brazil where, given suitable Anopheles mosquito vectors, it thrived. Almost from the start, officials recognised the problem malaria presented to economic development, but early control efforts were hampered by still developing public health control and ignorance of the underlying biology and ecology of malaria. Multiple regional and national malaria control efforts have been attempted with varying success. At present, the Amazon Basin accounts for 99% of Brazil's reported malaria cases with regional increases in incidence often associated with large scale public works or migration. Here, we provide an exhaustive summary of primary literature in English, Spanish and Portuguese regarding Brazilian malaria control. Our goal was not to interpret the history of Brazilian malaria control from a particular political or theoretical perspective, but rather to provide a straightforward, chronological narrative of the events that have transpired in Brazil over the past 200 years and identify common themes.

  19. Insecticide resistance in Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) and Anopheles gambiae Giles (Diptera: Culicidae) could compromise the sustainability of malaria vector control strategies in West Africa.

    Science.gov (United States)

    Gnankiné, Olivier; Bassolé, Imael H N; Chandre, Fabrice; Glitho, Isabelle; Akogbeto, Martin; Dabiré, Roch K; Martin, Thibaud

    2013-10-01

    Insecticides from the organophosphate (OP) and pyrethroid (PY) chemical families, have respectively, been in use for 50 and 30 years in West Africa, mainly against agricultural pests, but also against vectors of human disease. The selection pressure, with practically the same molecules year after year (mainly on cotton), has caused insecticide resistance in pest populations such as Bemisia tabaci, vector of harmful phytoviruses on vegetables. The evolution toward insecticide resistance in malaria vectors such as Anopheles gambiae sensus lato (s.l.) is probably related to the current use of these insecticides in agriculture. Thus, successful pest and vector control in West Africa requires an investigation of insect susceptibility, in relation to the identification of species and sub species, such as molecular forms or biotypes. Identification of knock down resistance (kdr) and acetylcholinesterase gene (Ace1) mutations modifying insecticide targets in individual insects and measure of enzymes activity typically involved in insecticide metabolism (oxidase, esterase and glutathion-S-transferase) are indispensable in understanding the mechanisms of resistance. Insecticide resistance is a good example in which genotype-phenotype links have been made successfully. Insecticides used in agriculture continue to select new resistant populations of B. tabaci that could be from different biotype vectors of plant viruses. As well, the evolution of insecticide resistance in An. gambiae threatens the management of malaria vectors in West Africa. It raises the question of priority in the use of insecticides in health and/or agriculture, and more generally, the question of sustainability of crop protection and vector control strategies in the region. Here, we review the susceptibility tests, biochemical and molecular assays data for B. tabaci, a major pest in cotton and vegetable crops, and An. gambiae, main vector of malaria. The data reviewed was collected in Benin and Burkina

  20. A randomized controlled phase Ib trial of the malaria vaccine candidate GMZ2 in African children.

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    Sabine Bélard

    Full Text Available BACKGROUND: GMZ2 is a fusion protein of Plasmodium falciparum merozoite surface protein 3 (MSP3 and glutamate rich protein (GLURP that mediates an immune response against the blood stage of the parasite. Two previous phase I clinical trials, one in naïve European adults and one in malaria-exposed Gabonese adults showed that GMZ2 was well tolerated and immunogenic. Here, we present data on safety and immunogenicity of GMZ2 in one to five year old Gabonese children, a target population for future malaria vaccine efficacy trials. METHODOLOGY/PRINCIPAL FINDINGS: Thirty children one to five years of age were randomized to receive three doses of either 30 µg or 100 µg of GMZ2, or rabies vaccine. GMZ2, adjuvanted in aluminum hydroxide, was administered on Days 0, 28 and 56. All participants received a full course of their respective vaccination and were followed up for one year. Both 30 µg and 100 µg GMZ2 vaccine doses were well tolerated and induced antibodies and memory B-cells against GMZ2 as well as its antigenic constituents MSP3 and GLURP. After three doses of vaccine, the geometric mean concentration of antibodies to GMZ2 was 19-fold (95%CI: 11,34 higher in the 30 µg GMZ2 group than in the rabies vaccine controls, and 16-fold (7,36 higher in the 100 µg GMZ2 group than the rabies group. Geometric mean concentration of antibodies to MSP3 was 2.7-fold (1.6,4.6 higher in the 30 µg group than in the rabies group and 3.8-fold (1.5,9.6 higher in the 100 µg group. Memory B-cells against GMZ2 developed in both GMZ2 vaccinated groups. CONCLUSIONS/SIGNIFICANCE: Both 30 µg as well as 100 µg intramuscular GMZ2 are immunogenic, well tolerated, and safe in young, malaria-exposed Gabonese children. This result confirms previous findings in naïve and malaria-exposed adults and supports further clinical development of GMZ2. TRIAL REGISTRATION: ClinicalTrials.gov NCT00703066.

  1. 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.

  2. How much does malaria vector control quality matter: the epidemiological impact of holed nets and inadequate indoor residual spraying.

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    Andrea M Rehman

    Full Text Available BACKGROUND: Insecticide treated nets (ITN and indoor residual spraying (IRS are the two pillars of malaria vector control in Africa, but both interventions are beset by quality and coverage concerns. Data from three control programs were used to investigate the impact of: 1 the physical deterioration of ITNs, and 2 inadequate IRS spray coverage, on their respective protective effectiveness. METHODS: Malaria indicator surveys were carried out in 2009 and 2010 in Bioko Island, mainland Equatorial Guinea and Malawi to monitor infection with P. falciparum in children, mosquito net use, net condition and spray status of houses. Nets were classified by their condition. The association between infection and quality and coverage of interventions was investigated. RESULTS: There was reduced odds of infection with P. falciparum in children sleeping under ITNs that were intact (Odds ratio (OR: 0.65, 95% CI: 0.55-0.77 and OR: 0.81, 95% CI: 0.56-1.18 in Equatorial Guinea and in Malawi respectively, but the protective effect became less with increasingly worse condition of the net. There was evidence for a linear trend in infection per category increase in deterioration of nets. In Equatorial Guinea IRS offered protection to those in sprayed and unsprayed houses alike when neighbourhood spray coverage was high (≥80% compared to those living in areas of low IRS coverage (<20%, regardless of whether the house they lived in was sprayed or not (adjusted OR = 0.54, 95% CI 0.33-0.89. ITNs provided only personal protection, offering no protection to non users. Although similar effects were seen in Malawi, the evidence was much weaker than in Equatorial Guinea. CONCLUSIONS: Universal coverage strategies should consider policies for repair and replacement of holed nets and promote the care of nets by their owners. IRS programs should ensure high spray coverage since inadequate coverage gives little or no protection at all.

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

    Science.gov (United States)

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

    2015-12-01

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

  4. Chemical composition, toxicity and non-target effects of Pinus kesiya essential oil: An eco-friendly and novel larvicide against malaria, dengue and lymphatic filariasis mosquito vectors.

    Science.gov (United States)

    Govindarajan, Marimuthu; Rajeswary, Mohan; Benelli, Giovanni

    2016-07-01

    Mosquitoes (Diptera: Culicidae) are vectors of important parasites and pathogens causing death, poverty and social disability worldwide, with special reference to tropical and subtropical countries. The overuse of synthetic insecticides to control mosquito vectors lead to resistance, adverse environmental effects and high operational costs. Therefore, the development of eco-friendly control tools is an important public health challenge. In this study, the mosquito larvicidal activity of Pinus kesiya leaf essential oil (EO) was evaluated against the malaria vector Anopheles stephensi, the dengue vector Aedes aegypti and the lymphatic filariasis vector Culex quinquefasciatus. The chemical composition of the EO was analyzed by gas chromatography-mass spectroscopy. GC-MS revealed that the P. kesiya EO contained 18 compounds. Major constituents were α-pinene, β-pinene, myrcene and germacrene D. In acute toxicity assays, the EO showed significant toxicity against early third-stage larvae of An. stephensi, Ae. aegypti and Cx. quinquefasciatus, with LC50 values of 52, 57, and 62µg/ml, respectively. Notably, the EO was safer towards several aquatic non-target organisms Anisops bouvieri, Diplonychus indicus and Gambusia affinis, with LC50 values ranging from 4135 to 8390µg/ml. Overall, this research adds basic knowledge to develop newer and safer natural larvicides from Pinaceae plants against malaria, dengue and filariasis mosquito vectors.

  5. Predicting the potential distribution of main malaria vectors Anopheles stephensi, An. culicifacies s.l. and An. fluviatilis s.l. in Iran based on maximum entropy model.

    Science.gov (United States)

    Pakdad, Kamran; Hanafi-Bojd, Ahmad Ali; Vatandoost, Hassan; Sedaghat, Mohammad Mehdi; Raeisi, Ahmad; Moghaddam, Abdolreza Salahi; Foroushani, Abbas Rahimi

    2017-05-01

    Malaria is considered as a major public health problem in southern areas of Iran. The goal of this study was to predict best ecological niches of three main malaria vectors of Iran: Anopheles stephensi, Anopheles culicifacies s.l. and Anopheles fluviatilis s.l. A databank was created which included all published data about Anopheles species of Iran from 1961 to 2015. The suitable environmental niches for the three above mentioned Anopheles species were predicted using maximum entropy model (MaxEnt). AUC (area under Roc curve) values were 0.943, 0.974 and 0.956 for An. stephensi, An. culicifacies s.l. and An. fluviatilis s.l respectively, which are considered as high potential power of model in the prediction of species niches. The biggest bioclimatic contributor for An. stephensi and An. fluviatilis s.l. was bio 15 (precipitation seasonality), 25.5% and 36.1% respectively, followed by bio 1 (annual mean temperature), 20.8% for An. stephensi and bio 4 (temperature seasonality) with 49.4% contribution for An. culicifacies s.l. This is the first step in the mapping of the country's malaria vectors. Hence, future weather situation can change the dispersal maps of Anopheles. Iran is under elimination phase of malaria, so that such spatio-temporal studies are essential and could provide guideline for decision makers for IVM strategies in problematic areas.

  6. Efficacy of the Olyset Duo net against insecticide-resistant mosquito vectors of malaria.

    Science.gov (United States)

    Ngufor, Corine; N'Guessan, Raphael; Fagbohoun, Josias; Todjinou, Damien; Odjo, Abibath; Malone, David; Ismail, Hanafy; Akogbeto, Martin; Rowland, Mark

    2016-09-14

    Olyset Duo is a new long-lasting insecticidal net treated with permethrin (a pyrethroid) and pyriproxyfen, an insect growth regulator that disrupts the maturation of oocytes in mosquitoes exposed to the net. We tested the Olyset Duo net against pyrethroid-resistant Anopheles gambiae mosquitoes, which transmit malaria parasites, in laboratory bioassays and in a trial in Benin using experimental huts that closely resemble local habitations. Host-seeking mosquitoes that entered to feed were free to contact the occupied nets and were collected the next morning from exit traps. Surviving blood-fed mosquitoes were observed for effects on reproduction. Control nets were treated with pyrethroid only or pyriproxyfen only, and nets were tested unwashed and after 20 standardized washes. The Olyset Duo net showed improved efficacy and wash resistance relative to the pyrethroid-treated net in terms of mosquito mortality and prevention of blood feeding. The production of offspring among surviving blood-fed A. gambiae in the hut trial was reduced by the pyriproxyfen-treated net and the Olyset Duo net both before washing (90 and 71% reduction, respectively) and after washing (38 and 43% reduction, respectively). The degree of reproductive suppression in the hut trial was predicted by laboratory tunnel tests but not by cone bioassays. The overall reduction in reproductive rate of A. gambiae with the Olyset Duo net in the trial was 94% with no washing and 78% after 20 washes. The Olyset Duo net has the potential to provide community control of mosquito populations and reduce malaria transmission in areas of high insecticide resistance.

  7. Fitness consequences of larval exposure to Beauveria bassiana on adults of the malaria vector Anopheles stephensi.

    Science.gov (United States)

    Vogels, Chantal B F; Bukhari, Tullu; Koenraadt, Constantianus J M

    2014-06-01

    Entomopathogenic fungi have shown to be effective in biological control of both larval and adult stages of malaria mosquitoes. However, a small fraction of mosquitoes is still able to emerge after treatment with fungus during the larval stage. It remains unclear whether fitness of these adults is affected by the treatment during the larval stage and whether they are still susceptible for another treatment during the adult stage. Therefore, we tested the effects of larval exposure to the entomopathogenic fungus Beauveria bassiana on fitness of surviving Anopheles stephensi females. Furthermore, we tested whether larval exposed females were still susceptible to re-exposure to the fungus during the adult stage. Sex ratio, survival and reproductive success were compared between non-exposed and larval exposed A. stephensi. Comparisons were also made between survival of non-exposed and larval exposed females that were re-exposed to B. bassiana during the adult stage. Larval treatment did not affect sex ratio of emerging mosquitoes. Larval exposed females that were infected died significantly faster and laid equal numbers of eggs from which equal numbers of larvae hatched, compared to non-exposed females. Larval exposed females that were uninfected had equal survival, but laid a significantly larger number of eggs from which a significantly higher number of larvae hatched, compared to non-exposed females. Larval exposed females which were re-exposed to B. bassiana during the adult stage had equal survival as females exposed only during the adult stage. Our results suggest that individual consequences for fitness of larval exposed females depended on whether a fungal infection was acquired during the larval stage. Larval exposed females remained susceptible to re-exposure with B. bassiana during the adult stage, indicating that larval and adult control of malaria mosquitoes with EF are compatible.

  8. Imputation-based meta-analysis of severe malaria in three African populations.

    Directory of Open Access Journals (Sweden)

    Gavin Band

    2013-05-01

    Full Text Available Combining data from genome-wide association studies (GWAS conducted at different locations, using genotype imputation and fixed-effects meta-analysis, has been a powerful approach for dissecting complex disease genetics in populations of European ancestry. Here we investigate the feasibility of applying the same approach in Africa, where genetic diversity, both within and between populations, is far more extensive. We analyse genome-wide data from approximately 5,000 individuals with severe malaria and 7,000 population controls from three different locations in Africa. Our results show that the standard approach is well powered to detect known malaria susceptibility loci when sample sizes are large, and that modern methods for association analysis can control the potential confounding effects of population structure. We show that pattern of association around the haemoglobin S allele differs substantially across populations due to differences in haplotype structure. Motivated by these observations we consider new approaches to association analysis that might prove valuable for multicentre GWAS in Africa: we relax the assumptions of SNP-based fixed effect analysis; we apply Bayesian approaches to allow for heterogeneity in the effect of an allele on risk across studies; and we introduce a region-based test to allow for heterogeneity in the location of causal alleles.

  9. Imputation-Based Meta-Analysis of Severe Malaria in Three African Populations

    Science.gov (United States)

    Band, Gavin; Le, Quang Si; Jostins, Luke; Pirinen, Matti; Kivinen, Katja; Jallow, Muminatou; Sisay-Joof, Fatoumatta; Bojang, Kalifa; Pinder, Margaret; Sirugo, Giorgio; Conway, David J.; Nyirongo, Vysaul; Kachala, David; Molyneux, Malcolm; Taylor, Terrie; Ndila, Carolyne; Peshu, Norbert; Marsh, Kevin; Williams, Thomas N.; Alcock, Daniel; Andrews, Robert; Edkins, Sarah; Gray, Emma; Hubbart, Christina; Jeffreys, Anna; Rowlands, Kate; Schuldt, Kathrin; Clark, Taane G.; Small, Kerrin S.; Teo, Yik Ying; Kwiatkowski, Dominic P.; Rockett, Kirk A.; Barrett, Jeffrey C.; Spencer, Chris C. A.

    2013-01-01

    Combining data from genome-wide association studies (GWAS) conducted at different locations, using genotype imputation and fixed-effects meta-analysis, has been a powerful approach for dissecting complex disease genetics in populations of European ancestry. Here we investigate the feasibility of applying the same approach in Africa, where genetic diversity, both within and between populations, is far more extensive. We analyse genome-wide data from approximately 5,000 individuals with severe malaria and 7,000 population controls from three different locations in Africa. Our results show that the standard approach is well powered to detect known malaria susceptibility loci when sample sizes are large, and that modern methods for association analysis can control the potential confounding effects of population structure. We show that pattern of association around the haemoglobin S allele differs substantially across populations due to differences in haplotype structure. Motivated by these observations we consider new approaches to association analysis that might prove valuable for multicentre GWAS in Africa: we relax the assumptions of SNP–based fixed effect analysis; we apply Bayesian approaches to allow for heterogeneity in the effect of an allele on risk across studies; and we introduce a region-based test to allow for heterogeneity in the location of causal alleles. PMID:23717212

  10. High diversity of West African bat malaria parasites and a tight link with rodent Plasmodium taxa.

    Science.gov (United States)

    Schaer, Juliane; Perkins, Susan L; Decher, Jan; Leendertz, Fabian H; Fahr, Jakob; Weber, Natalie; Matuschewski, Kai

    2013-10-22

    As the only volant mammals, bats are captivating for their high taxonomic diversity, for their vital roles in ecosystems--particularly as pollinators and insectivores--and, more recently, for their important roles in the maintenance and transmission of zoonotic viral diseases. Genome sequences have identified evidence for a striking expansion of and positive selection in gene families associated with immunity. Bats have also been known to be hosts of malaria parasites for over a century, and as hosts, they possess perhaps the most phylogenetically diverse set of hemosporidian genera and species. To provide a molecular framework for the study of these parasites, we surveyed bats in three remote areas of the Upper Guinean forest ecosystem. We detected four distinct genera of hemosporidian parasites: Plasmodium, Polychromophilus, Nycteria, and Hepatocystis. Intriguingly, the two species of Plasmodium in bats fall within the clade of rodent malaria parasites, indicative of multiple host switches across mammalian orders. We show that Nycteria species form a very distinct phylogenetic group and that Hepatocystis parasites display an unusually high diversity and prevalence in epauletted fruit bats. The diversity and high prevalence of novel lineages of chiropteran hemosporidians underscore the exceptional position of bats among all other mammalian hosts of hemosporidian parasites and support hypotheses of pathogen tolerance consistent with the exceptional immunology of bats.

  11. The rediscovery of malaria parasites of ungulates.

    Science.gov (United States)

    Templeton, Thomas J; Martinsen, Ellen; Kaewthamasorn, Morakot; Kaneko, Osamu

    2016-10-01

    Over a hundred years since their first description in 1913, the sparsely described malaria parasites (genus Plasmodium) of ungulates have been rediscovered using molecular typing techniques. In the span of weeks, three studies have appeared describing the genetic characterization and phylogenetic analyses of malaria parasites from African antelope (Cephalophus spp.) and goat (Capra aegagrus hircus), Asian water buffalo (Bubalus bubalis), and North American white-tailed deer (Odocoileus virginianus). Here we unify the contributions from those studies with the literature on pre-molecular characterizations of ungulate malaria parasites, which are largely based on surveys of Giemsa-reagent stained blood smears. We present a phylogenetic tree generated from all available ungulate malaria parasite sequence data, and show that parasites from African duiker antelope and goat, Asian water buffalo and New World white-tailed deer group together in a clade, which branches early in Plasmodium evolution. Anopheline mosquitoes appear to be the dominant, if not sole vectors for parasite transmission. We pose questions for future phylogenetic studies, and discuss topics that we hope will spur further molecular and cellular studies of ungulate malaria parasites.

  12. Malaria vectors in the changing environment of the southern Punjab, Pakistan

    DEFF Research Database (Denmark)

    Klinkenberg, Eveline; Konradsen, Flemming; Herrel, Nathaly

    2004-01-01

    in the Pakistani Punjab may have been influenced by a change in vector species abundance or composition, possibly induced by environmental changes. To investigate this question, routinely-collected government entomological data for the period 1970 to 1999 for the district of Bahawalnagar, in the Indus Basin......, where irrigation-induced waterlogging of soil with related salinization has created an environment favourable for the more salt-tolerant A. stephensi. Some biotypes of A. stephensi are suspected of being less efficient vectors and, therefore, the shift in species dominance might have played a role...

  13. Pilot study on the combination of an organophosphate-based insecticide paint and pyrethroid-treated long lasting nets against pyrethroid resistant malaria vectors in Burkina Faso.

    Science.gov (United States)

    Mosqueira, Beatriz; Soma, Dieudonné D; Namountougou, Moussa; Poda, Serge; Diabaté, Abdoulaye; Ali, Ouari; Fournet, Florence; Baldet, Thierry; Carnevale, Pierre; Dabiré, Roch K; Mas-Coma, Santiago

    2015-08-01

    A pilot study to test the efficacy of combining an organophosphate-based insecticide paint and pyrethroid-treated Long Lasting Insecticide Treated Nets (LLINs) against pyrethroid-resistant malaria vector mosquitoes was performed in a real village setting in Burkina Faso. Paint Inesfly 5A IGR™, comprised of two organophosphates (OPs) and an Insect Growth Regulator (IGR), was tested in combination with pyrethroid-treated LLINs. Efficacy was assessed in terms of mortality for 12 months using Early Morning Collections of malaria vectors and 30-minute WHO bioassays. Resistance to pyrethroids and OPs was assessed by detecting the frequency of L1014F and L1014S kdr mutations and Ace-1(R)G119S mutation, respectively. Blood meal origin was identified using a direct enzyme-linked immunosorbent assay (ELISA). The combination of Inesfly 5A IGR™ and LLINs was effective in killing 99.9-100% of malaria vector populations for 6 months regardless of the dose and volume treated. After 12 months, mortality rates decreased to 69.5-82.2%. The highest mortality rates observed in houses treated with 2 layers of insecticide paint and a larger volume. WHO bioassays supported these results: mortalities were 98.8-100% for 6 months and decreased after 12 months to 81.7-97.0%. Mortality rates in control houses with LLINs were low. Collected malaria vectors consisted exclusively of Anopheles coluzzii and were resistant to pyrethroids, with a L1014 kdr mutation frequency ranging from 60 to 98% through the study. About 58% of An. coluzzii collected inside houses had bloodfed on non-human animals. Combining Inesfly 5A IGR™ and LLINs yielded a one year killing efficacy against An. coluzzii highly resistant to pyrethroids but susceptible to OPs that exhibited an anthropo-zoophilic behaviour in the study area. The results obtained in a real setting supported previous work performed in experimental huts and underscore the need to study the impact that this novel strategy may have on clinical

  14. Use of DNA barcoding to distinguish the malaria vector Anopheles neivai in Colombia.

    Science.gov (United States)

    López-Rubio, Andrés; Suaza-Vasco, Juan; Marcet, Paula L; Ruíz-Molina, Natalia; Cáceres, Lorenzo; Porter, Charles; Uribe, Sandra

    2016-10-17

    A reference 535 bp barcode sequence from a fragment of the mitochondrial gene cytochrome oxidase I (COI), acquired from specimens of An. neivai Howard, Dyar & Knab, 1913 from its type locality in Panama, was used as a tool for distinguishing this species from others in the subgenus Kerteszia. Comparisons with corresponding regions of COI between An. neivai and other species in the subgenus (An. bellator Dyar & Knab 1906, An. homunculus Komp 1937, An cruzii Dyar & Knab, 1908 and An. laneanus Corrêa & Cerqueira, 1944) produced K2P genetic distances of 8.3-12.6%, values well above those associated with intraspecific variation. In contrast, genetic distances among 55 specimens from five municipalities in the Colombian Pacific coastal state of Chocó were all within the range of 0-2.5%, with an optimized barcode threshold of 1.3%, the limit for unambiguous differentiation of An. neivai. Among specimens from the Chocó region, 18 haplotypes were detected, two of which were widely distributed over the municipalities sampled. The barcode sequence permits discrimination of An. neivai from sympatric species and indicates genetic variability within the species; aspects key to malaria surveillance and control as well as defining geographic distribution and dispersion patterns.

  15. Use of DNA barcoding to distinguish the malaria vector Anopheles neivai in Colombia

    Science.gov (United States)

    LÓPEZ-RUBIO, ANDRÉS; SUAZA-VASCO, JUAN; MARCET, PAULA L; RUÍZ-MOLINA, NATALIA; CÁCERES, LORENZO; PORTER, CHARLES; URIBE, SANDRA

    2016-01-01

    A reference 535 bp barcode sequence from a fragment of the mitochondrial gene cytochrome oxidase I (COI), acquired from specimens of An. neivai Howard, Dyar & Knab, 1913 from its type locality in Panama, was used as a tool for distinguishing this species from others in the subgenus Kerteszia. Comparisons with corresponding regions of COI between An. neivai and other species in the subgenus (An. bellator Dyar & Knab 1906, An. homunculus Komp 1937, An cruzii Dyar & Knab, 1908 and An. laneanus Corrêa & Cerqueira, 1944) produced K2P genetic distances of 8.3–12.6%, values well above those associated with intraspecific variation. In contrast, genetic distances among 55 specimens from five municipalities in the Colombian Pacific coastal state of Chocó were all within the range of 0–2.5%, with an optimized barcode threshold of 1.3%, the limit for unambiguous differentiation of An. neivai. Among specimens from the Chocó region, 18 haplotypes were detected, two of which were widely distributed over the municipalities sampled. The barcode sequence permits discrimination of An. neivai from sympatric species and indicates genetic variability within the species; aspects key to malaria surveillance and control as well as defining geographic distribution and dispersion patterns. PMID:27811749

  16. Effect of irrigation systems on temporal distribution of malaria vectors in semi-arid regions.

    Science.gov (United States)

    Ohta, Shunji; Kaga, Takumi

    2014-04-01

    Previous research models have used climate data to explain habitat conditions of Anopheles mosquitoes transmitting malaria parasites. Although they can estimate mosquito populations with sufficient accuracy in many areas, observational data show that there is a tendency to underestimate the active growth and reproduction period of mosquitoes in semi-arid agricultural regions. In this study, a new, modified model that includes irrigation as a factor was developed to predict the active growing period of mosquitoes more precisely than the base model for ecophysiological and climatological distribution of mosquito generations (ECD-mg). Five sites with complete sets of observational data were selected in semi-arid regions of India for the comparison. The active growing period of mosquitoes determined from the modified ECD-mg model that incorporated the irrigation factor was in agreement with the observational data, whereas the active growing period was underestimated by the previous ECD-mg model that did not incorporate irrigation. This suggests that anthropogenic changes in the water supply due to extensive irrigation can encourage the growth of Anopheles mosquitoes through the alteration of the natural water balance in their habitat. In addition, it was found that the irrigation systems not only enable the active growth of mosquitoes in dry seasons but also play an important role in stabilizing the growth in rainy seasons. Consequently, the irrigation systems could lengthen the annual growing period of Anopheles mosquitoes and increase the maximum generation number of mosquitoes in semi-arid subtropical regions.

  17. Bioefficacy of Morinda tinctoria and Pongamia glabra plant extracts against the malaria vector Anopheles stephensi (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    D. Amerasan

    2015-04-01

    Full Text Available Mosquito-borne diseases have an economic impact, including loss in commercial and labour outputs, particularly in countries with tropical and subtropical climates; however, no part of the world is free from vector-borne diseases. The aim of the present study was to investigate the larvicidal, adulticidal and ovicidal activity of dried leaf chloroform, ethyl acetate, acetone, aqueous, and methanol extracts of Morinda tinctoria and Pongamia glabra against larvae of Anopheles stephensi (Diptera: Culicidae. Larvae were exposed to varying concentrations of plant extracts for 24 h. All extracts showed moderate larvicidal effects after 24 h of exposure; however, the highest larval mortality was found with the leaf methanol extracts of M. tinctoria and P. glabra against the larvae of A. stephensi lethal concentration (LC50=136.24 and 141.05 ppm; LC90=342.67 and 368.89 ppm, respectively. The results of the adulticidal activity assays of chloroform, ethyl acetate, acetone, aqueous, and methanol extracts of M. tinctoria and P. glabra showed significant mortality against larvae of A. stephensi. The methanol extract showed maximum activity compared with the other extracts. The greatest effect on mean percentage hatch in the ovicidal assays was observed 48 h post-treatment. Percent hatch was inversely proportional to the concentration of extract, and directly proportional to the number of eggs. A mortality of 100% was observed with 100-400 ppm methanol extracts and 200-400 ppm aqueous extracts of M. tinctoria, and 200-400 ppm aqueous and methanol extracts of P. glabra. This study provides the first report of the larvicidal, adulticidal and ovicidal activities of M. tinctoria and P. glabra plant extracts against the malaria vector, A. stephensi, representing an ideal eco-friendly approach for its control.

  18. Eco-friendly microbial route to synthesize cobalt nanoparticles using Bacillus thuringiensis against malaria and dengue vectors.

    Science.gov (United States)

    Marimuthu, Sampath; Rahuman, Abdul Abdul; Kirthi, Arivarasan Vishnu; Santhoshkumar, Thirunavukkarasu; Jayaseelan, Chidambaram; Rajakumar, Govindasamy

    2013-12-01

    The developments of resistance and persistence to chemical insecticides and concerns about the non-target effects have prompted the development of eco-friendly mosquito control agents. The aim of this study was to investigate the larvicidal activities of synthesized cobalt nanoparticles (Co NPs) using bio control agent, Bacillus thuringiensis against malaria vector, Anopheles subpictus and dengue vector, Aedes aegypti (Diptera: Culicidae). The synthesized Co NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Field-emission scanning electron microscopy (FESEM) with energy dispersive X-ray spectroscopy, and Transmission electron microscopy (TEM). XRD analysis showed three distinct diffraction peaks at 27.03°, 31.00°, and 45.58° indexed to the planes 102, 122, and 024, respectively on the face-centered cubic cobalt acetate with an average size of 85.3 nm. FTIR spectra implicated role of the peak at 3,436 cm(-1) for O-H hydroxyl group, 2924 cm(-1) for methylene C-H stretch in the formation of Co NPs. FESEM analysis showed the topological and morphological appearance of NPs which were found to be spherical and oval in shape. TEM analysis showed polydispersed and clustered NPs with an average size of 84.81 nm. The maximum larvicidal mortality was observed in the cobalt acetate solution, B. thuringiensis formulation, and synthesized Co NPs against fourth instar larvae of A. subpictus and A. aegypti with LC50 values of 29.16, 8.12, 3.59 mg/L; 34.61, 6.94, and 2.87 mg/L; r (2) values of 0.986, 0.933, 0.942; 0.962, 0.957, and 0.922, respectively.

  19. Multiple insecticide resistance mechanisms involving metabolic changes and insensitive target sites selected in anopheline vectors of malaria in Sri Lanka

    Directory of Open Access Journals (Sweden)

    Karunaratne SHP Parakrama

    2008-08-01

    Full Text Available Abstract Background The current status of insecticide resistance and the underlying resistance mechanisms were studied in the major vector of malaria, Anopheles culicifacies, and the secondary vector, Anopheles subpictus in five districts (Anuradhapura, Kurunegala, Moneragala, Puttalam and Trincomalee of Sri Lanka. Eight other anophelines, Anopheles annularis, Anopheles barbirostris, Anopheles jamesii, Anopheles nigerrimus, Anopheles peditaeniatus, Anopheles tessellatus, Anopheles vagus and Anopheles varuna from Anuradhapura district were also tested. Methods Adult females were exposed to the WHO discriminating dosages of DDT, malathion, fenitrothion, propoxur, λ-cyhalothrin, cyfluthrin, cypermethrin, deltamethrin, permethrin and etofenprox. The presence of metabolic resistance by esterase, glutathione S-transferase (GST and monooxygenase-based mechanisms, and the sensitivity of the acetylcholinesterase target site were assessed using synergists, and biochemical, and metabolic techniques. Results All the anopheline species had high DDT resistance. All An. culicifacies and An. subpictus populations were resistant to malathion, except An. culicifacies from Kurunegala, where there was no malathion carboxylesterase activity. Kurunegala and Puttalam populations of An. culicifacies were susceptible to fenitrothion. All the An. culicifacies populations were susceptible to carbamates. Both species were susceptible to the discriminating dosages of cypermethrin and cyfluthrin, but had different levels of resistance to other pyrethroids. Of the 8 other anophelines, only An. nigerrimus and An. peditaeniatus were resistant to all the insecticides tested, probably due to their high exposure to the insecticides used in agriculture. An. vagus showed some resistance to permethrin. Esterases, GSTs and monooxygenases were elevated in both An. culicifacies and An. subpictus. AChE was most sensitive to insecticides in Kurunegala and Trincomalee An. culicifacies

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

    Directory of Open Access Journals (Sweden)

    Vera Margarete Scarpassa

    2007-06-01

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

  1. Larvicidal efficacy of Ethiopian ethnomedicinal plant Juniperus procera essential oil against Afrotropical malaria vector Anopheles arabiensis (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Kaliyaperumal Karunamoorthi; Askual Girmay; Samuel Fekadu

    2014-01-01

    Objective: To screen the essential oil of Juniperus procera (J. procera) (Cupressaceae) for larvicidal activity against late third instar larvae of Anopheles arabiensis (An. arabiensis) Patton, the principle malaria vector in Ethiopia.Methods:the laboratory and semi-field conditions by adopting the World Health Organization standard protocols. The larval mortality was observed for 24 h of post exposure.Results:The essential oil of J. procera has demonstrated varying degrees of larvicidal activity The essential oil of J. procera was evaluated against the larvae of An. arabiensis under against An. arabiensis. The LC50 and LC90 values of J. procera were 14.42 and 24.65 mg/L, respectively under the laboratory conditions, and from this data, a Chi-square value 6.662 was observed to be significant at the P=0.05 level. However, under the semi-field conditions the LC50 and LC90 values of J. procera were 24.51 and 34.21 mg/L, respectively and a Chi-square value 4.615 was significant at the P=0.05 level. The observations clearly showed that larval mortality rate is completely time and dose-dependent as compared with the control.Conclusions:This investigation indicates that J. procera could serve as a potential larvicidal agent against insect vector of diseases, particularly An. arabiensis. However further studies are strongly recommended for the identification of the chemical constituents and the mode of action towards the rational design of alternative promising insecticidal agents in the near future.

  2. Mosquito repellent potential ofPithecellobium dulce leaf and seed against malaria vectorAnopheles stephensi (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Mohan Rajeswary; Marimuthu Govindarajan

    2016-01-01

    Objective:To determine the repellent properties of hexane, benzene, ethyl acetate, chloroform and methanol extract ofPithecellobium dulce (P. dulce) leaf and seed against Anopheles stephensi(An. stephensi). Methods:Repellent activity assay was carried out in a net cage (45 cmí30 cmí25 cm) containing 100 blood starved female mosquitoes ofAn. stephensi. This assay was carried out in the laboratory conditions according to theWHO 2009 protocol. Plant crude extracts ofP. 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 ofP. dulceprovided over 180 min and 150 min protection, respectively. Conclusions: Crude extracts ofP. dulceexhibit the potential for controlling malaria vector mosquitoAn. stephensi.

  3. A low-cost repellent for malaria vectors in the Americas: results of two field trials in Guatemala and Peru

    Directory of Open Access Journals (Sweden)

    Sihuincha Moisés

    2007-08-01

    Full Text Available Abstract Background The cost of mosquito repellents in Latin America has discouraged their wider use among the poor. To address this problem, a low-cost repellent was developed that reduces the level of expensive repellent actives by combining them with inexpensive fixatives that appear to slow repellent evaporation. The chosen actives were a mixture of para-menthane-diol (PMD and lemongrass oil (LG. Methods To test the efficacy of the repellent, field trials were staged in Guatemala and Peru. Repellent efficacy was determined by human-landing catches on volunteers who wore the experimental repellents, control, or 15% DEET. The studies were conducted using a balanced Latin Square design with volunteers, treatments, and locations rotated each night. Results In Guatemala, collections were performed for two hours, commencing three hours after repellent application. The repellent provided >98% protection for five hours after application, with a biting pressure of >100 landings per person/hour. The 15% DEET control provided lower protection at 92% (p 46 landings per person/hour. The 20% DEET control provided significantly lower protection at 64% (p Conclusion In both locations, the PMD/LG repellent provided excellent protection up to six hours after application against a wide range of disease vectors including Anopheles darlingi. The addition of fixatives to the repellent extended its longevity while enhancing efficacy and significantly reducing its cost to malaria-endemic communities.

  4. 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).

  5. Aristolochia indica green-synthesized silver nanoparticles: A sustainable control tool against the malaria vector Anopheles stephensi?

    Science.gov (United States)

    Murugan, Kadarkarai; Labeeba, Mohammed Aamina; Panneerselvam, Chellasamy; Dinesh, Devakumar; Suresh, Udaiyan; Subramaniam, Jayapal; Madhiyazhagan, Pari; Hwang, Jiang-Shiou; Wang, Lan; Nicoletti, Marcello; Benelli, Giovanni

    2015-10-01

    Malaria is a life-threatening disease caused by parasites transmitted to people and animals through the bites of infected mosquitoes. We biosynthesized silver nanoparticles (AgNP) using Aristolochia indica extract as reducing and stabilizing agent. AgNP were characterized by UV-vis spectroscopy, FTIR, SEM, EDX and XRD. In laboratory, LC50 of A. indica extract against Anopheles stephensi ranged from 262.66 (larvae I) to 565.02 ppm (pupae). LC50 of AgNP against A. stephensi ranged from 3.94 (larvae I) to 15.65 ppm (pupae). In the field, the application of A. indica extract and AgNP (10 × LC50) leads to 100% larval reduction after 72 h. In laboratory, 24-h predation efficiency of Diplonychus indicus against A. stephensi larvae was 33% (larvae II) and 57% (larvae III). In AgNP-contaminated environment (1 ppm), it was 45.5% (larvae II) and 71.75% (larvae III). Overall, A. indica-synthesized AgNP may be considered as newer and safer control tools against Anopheles vectors.

  6. Assessing the Fauna of Aquatic Insects for Possible Use for Malaria Vector Control in Large River, Central Iran

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    Mansoureh Shayeghi

    2015-10-01

    Full Text Available Insects with over 30,000 aquatic species are known as very successful arthropods in freshwater habitats. Some of them are applied as biological indicators for water quality control, as well as the main food supply for fishes and amphibians. The faunistic studies are the basic step in entomological researches; the current study was carried out emphasizing on the fauna of aquatic insects in Karaj River, northern Iran. A field study was carried out in six various sampling site of Karaj River during spring 2013. The aquatic insects were collected using several methods such as D-frame nets, dipping and direct search on river floor stones. Specimens were collected and preserved in Ethanol and identified by standard identification keys. Totally, 211 samples were collected belonging to three orders; Plecoptera, Trichoptera and Ephemeroptera. Seven genuses (Perla, Isoperla, Hydropsyche, Cheumatopsyche, Baetis, Heptagenia and Maccafferium from five families (Perlidae, Perlodidae, Hydropsychidae, Batidae, Heptagenidae were identified. The most predominant order was Plecoptera followed by Trichoptera. Karaj River is a main and important river, which provides almost all of water of Karaj dam. So, identification of aquatic species which exist in this river is vital and further studies about systematic and ecological investigations should be performed. Also, monitoring of aquatic biota by trained health personnel can be a critical step to describe water quality in this river. Understanding the fauna of aquatic insects will provide a clue for possible biological control of medically important aquatic insects such as Anopheles as the malaria vectors.

  7. Larvicidal activity of Cymbopogon citratus (DC) Stapf. and Croton macrostachyus Del. against Anopheles arabiensis Patton, a potent malaria vector.

    Science.gov (United States)

    Karunamoorthi, K; Ilango, K

    2010-01-01

    Methanol leaf extracts of two Ethiopian traditional medicinal plants viz., Lomisar [vernacular name (local native language, Amharic); Cymbopogon citratus (DC) Stapf. (Poaceae)] and Bisana [vernacular name (local native language, Amharic); Croton macrostachyus Del. (Euphorbiaceae)] were screened for larvicidal activity against late third instar larvae of Anopheles arabiensis Patton, a potent malaria vector in Ethiopia. The larval mortality was observed 24 h of post treatment. Both plant extracts demonstrated varying degrees of larvicidal activity against Anopheles arabiensis. Cymbopogon citratus extract has exhibited potent larvicidal activity than Croton macrostachyus at lower concentrations. The LC50 and LC90 values of Cymbopogon citratus were 74.02 and 158.20 ppm, respectively. From this data, a chi-square value 2.760 is significant at the P < 0.05 level. While, the LC50 and LC90 values of Croton macrostachyus were 89.25 and 224.98 ppm, respectively and the chi-square value 1.035 is significant at the P < 0.05 level. The present investigation establishes that these plant extracts could serve as potent mosquito larvicidal agents against Anopheles arabiensis. However, their mode of actions and larvicidal efficiency under the field conditions should be scrutinized and determined in the near future.

  8. Assessing the Fauna of Aquatic Insects for Possible Use for Malaria Vector Control in Large River, Central Iran.

    Science.gov (United States)

    Shayeghi, Mansoureh; Nejati, Jalil; Shirani-Bidabadi, Leila; Koosha, Mona; Badakhshan, Mehdi; Mohammadi Bavani, Mulood; Arzamani, Kourosh; Choubdar, Nayyereh; Bagheri, Fatemeh; Saghafipour, Abedin; Veysi, Arshad; Karimian, Fateh; Akhavan, Amir Ahamd; Vatandoost, Hassan

    2015-01-01

    Insects with over 30,000 aquatic species are known as very successful arthropods in freshwater habitats. Some of them are applied as biological indicators for water quality control, as well as the main food supply for fishes and amphibians. The faunistic studies are the basic step in entomological researches; the current study was carried out emphasizing on the fauna of aquatic insects in Karaj River, northern Iran. A field study was carried out in six various sampling site of Karaj River during spring 2013. The aquatic insects were collected using several methods such as D-frame nets, dipping and direct search on river floor stones. Specimens were collected and preserved in Ethanol and identified by standard identification keys. Totally, 211 samples were collected belonging to three orders; Plecoptera, Trichoptera and Ephemeroptera. Seven genuses (Perla, Isoperla, Hydropsyche, Cheumatopsyche, Baetis, Heptagenia and Maccafferium) from five families (Perlidae, Perlodidae, Hydropsychidae, Batidae, Heptagenidae) were identified. The most predominant order was Plecoptera followed by Trichoptera. Karaj River is a main and important river, which provides almost all of water of Karaj dam. So, identification of aquatic species which exist in this river is vital and further studies about systematic and ecological investigations should be performed. Also, monitoring of aquatic biota by trained health personnel can be a critical step to describe water quality in this river. Understanding the fauna of aquatic insects will provide a clue for possible biological control of medically important aquatic insects such as Anopheles as the malaria vectors.

  9. Cost effective malaria risk control using remote sensing and environmental data

    Science.gov (United States)

    Rahman, Md. Z.; Roytman, Leonid; Kadik, Abdel Hamid

    2012-06-01

    Malaria transmission in many part of the world specifically in Bangladesh and southern African countries is unstable and epidemic. An estimate of over a million cases is reported annually. Malaria is heterogeneous, potentially due to variations in ecological settings, socio-economic status, land cover, and agricultural practices. Malaria control only relies on treatment and supply of bed networks. Drug resistance to these diseases is widespread. Vector control is minimal. Malaria control in those countries faces many formidable challenges such as inadequate accessibility to effective treatment, lack of trained manpower, inaccessibility of endemic areas, poverty, lack of education, poor health infrastructure and low health budgets. Health facilities for malaria management are limited, surveillance is inadequate, and vector control is insufficient. Control can only be successful if the right methods are used at the right time in the right place. This paper aims to improve malaria control by developing malaria risk maps and risk models using satellite remote sensing data by identifying, assessing, and mapping determinants of malaria associated with environmental, socio-economic, malaria control, and agricultural factors.

  10. An eco-hydrologic model of malaria outbreaks

    Directory of Open Access Journals (Sweden)

    E. Montosi

    2012-03-01

    Full Text Available Malaria is a geographically widespread infectious disease that is well known to be affected by climate variability at both seasonal and interannual timescales. In an effort to identify climatic factors that impact malaria dynamics, there has been considerable research focused on the development of appropriate disease models for malaria transmission and their consideration alongside climatic datasets. These analyses have focused largely on variation in temperature and rainfall as direct climatic drivers of malaria dynamics. Here, we further these efforts by considering additionally the role that soil water content may play in driving malaria incidence. Specifically, we hypothesize that hydro-climatic variability should be an important factor in controlling the availability of mosquito habitats, thereby governing mosquito growth rates. To test this hypothesis, we reduce a nonlinear eco-hydrologic model to a simple linear model through a series of consecutive assumptions and apply this model to malaria incidence data from three South African provinces. Despite the assumptions made in the reduction of the model, we show that soil water content can account for a significant portion of malaria's case variability beyond its seasonal patterns, whereas neither temperature nor rainfall alone can do so. Future work should therefore consider soil water content as a simple and computable variable for incorporation into climate-driven disease models of malaria and other vector-borne infectious diseases.

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

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    Roger François

    2008-02-01

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

  12. Nutrient vectors and riparian nutrient processing in African semiarid savanna ecosystems

    Science.gov (United States)

    Jacobs, Shayne M.; Bechtold, J.S.; Biggs, Harry C.; Grimm, N. B.; McClain, M.E.; Naiman, R.J.; Perakis, Steven S.; Pinay, G.; Scholes, M.C.

    2007-01-01

    This review article describes vectors for nitrogen and phosphorus delivery to riparian zones in semiarid African savannas, the processing of nutrients in the riparian zone and the effect of disturbance on these processes. Semiarid savannas exhibit sharp seasonality, complex hillslope hydrology and high spatial heterogeneity, all of which ultimately impact nutrient fluxes between riparian, upland and aquatic environments. Our review shows that strong environmental drivers such as fire and herbivory enhance nitrogen, phosphorus and sediment transport to lower slope positions by shaping vegetative patterns. These vectors differ significantly from other arid and semiarid ecosystems, and from mesic ecosystems where the impact of fire and herbivory are less pronounced and less predictable. Also unique is the presence of sodic soils in certain hillslopes, which substantially alters hydrological flowpaths and may act as a trap where nitrogen is immobilized while sediment and phosphorus transport is enhanced. Nutrients and sediments are also deposited in the riparian zone during seasonal, intermittent floods while, during the dry season, subsurface movement of water from the stream into riparian soils and vegetation further enrich riparian zones with nutrients. As is found in mesic ecosystems, nutrients are immobilized in semiarid riparian corridors through microbial and plant uptake, whereas dissimilatory processes such as denitrification may be important where labile nitrogen and carbon are in adequate supply and physical conditions are suitablea??such as in seeps, wallows created by animals, ephemeral wetlands and stream edges. Interaction between temporal hydrologic connectivity and spatial heterogeneity are disrupted by disturbances such as large floods and extended droughts, which may convert certain riparian patches from sinks to sources for nitrogen and phosphorus. In the face of increasing anthropogenic pressure, the scientific challenges are to provide a basic

  13. Efficacy of aquatain, a monomolecular film, for the control of malaria vectors in rice paddies.

    Directory of Open Access Journals (Sweden)

    Tullu Bukhari

    Full Text Available BACKGROUND: Rice paddies harbour a large variety of organisms including larvae of malaria mosquitoes. These paddies are challenging for mosquito control because their large size, slurry and vegetation make it difficult to effectively apply a control agent. Aquatain, a monomolecular surface film, can be considered a suitable mosquito control agent for such breeding habitats due to its physical properties. The properties allow Aquatain to self-spread over a water surface and affect multiple stages of the mosquito life cycle. METHODOLOGY/PRINCIPAL FINDINGS: A trial based on a pre-test/post-test control group design evaluated the potential of Aquatain as a mosquito control agent at Ahero rice irrigation scheme in Kenya. After Aquatain application at a dose of 2 ml/m(2 on rice paddies, early stage anopheline larvae were reduced by 36%, and late stage anopheline larvae by 16%. However, even at a lower dose of 1 ml/m(2 there was a 93.2% reduction in emergence of anopheline adults and 69.5% reduction in emergence of culicine adults. No pupation was observed in treated buckets that were part of a field bio-assay carried out parallel to the trial. Aquatain application saved nearly 1.7 L of water in six days from a water surface of 0.2 m(2 under field conditions. Aquatain had no negative effect on rice plants as well as on a variety of non-target organisms, except backswimmers. CONCLUSIONS/SIGNIFICANCE: We demonstrated that Aquatain is an effective agent for the control of anopheline and culicine mosquitoes in irrigated rice paddies. The agent reduced densities of aquatic larval stages and, more importantly, strongly impacted the emergence of adult mosquitoes. Aquatain also reduced water loss due to evaporation. No negative impacts were found on either abundance of non-target organisms, or growth and development of rice plants. Aquatain, therefore, appears a suitable mosquito control tool for use in rice agro-ecosystems.

  14. ECOLOGICAL STUDIES ON VECTORS OF MALARIA, JAPANESE ENCEPHALITIS AND FILARIASIS IN RURAL AREAS OF WEST JAVA

    Directory of Open Access Journals (Sweden)

    L. S. Self

    2012-09-01

    Full Text Available Penangkapan rutin nyamuk dewasa dilakukan dua kali sebulan selama 1 jam pada waktu senja pada badan kerbau, babi dan manusia dan juga dikerjakan penangkapan dengan light trap. Daerah penangkapan meliputi satu daerah dataran rendah Jakarta (semi urban dan empat daerah pedalaman di Jawa Barat yang ekologinya berbeda-beda dan dimana sawahnya 2 kali panen dalam satu tahun. Penangkapan nyamuk satu malam penuh dari jam 18.00 - 16.00 dikerjakan disalah satu daerah pedalaman tersebut. Kira-kira 90.000 specimen dari 27 species nyamuk telah ditangkap antara bulan Juni 1973 sampai bulan Juli 1974. Penangkapan pada badan binatang dan manusia menghasilkan keterangan-keterangan yang berguna, mengetahui kepadatan musiman dari vektor malaria, Japanese encephalitis dan filaria.A. aconitus adalah satu Anopheline yang terdapat dalam jumlah banyak menggigit manusia dan kepadatan yang tinggi terdapat didaerah pegunungan dimana sawahnya bertingkat-tingkat (terrace. Di Jakarta dan didaerah yang sawahnya datar nyamuk ini praktis tidak diketemukan Puncak kepadatan dari species ini berhubungan dengan musin padi yaitu pada bulan Mei dan Juni, dan pada penangkapan satu malam penuh dengan umpan manusia nyamuk ini terdapat dalam jumlah banyak pada waktu-waktu sebelum tengah malam.Cu. tritaemorrhynchus, Cu. gelidus, Cu. fuscocephalus dan Cu. vishnui menunjukkan kecen­derungan senang terhadap manusia dan babi. Untuk Cu. tritaeniorrhynchus kepadatan dalam jumlah banyak diseluruh kelima daerah penelitian. Puncak kepadatan nyamuk-nyamuk tersebut sangat pendek yaitu beberapa hari sesudah panen. Cu. vishnui lebih senang menggigit manusia bila dibandingkan species lainnya. Di Jakarta terdapat vektor Japanese encephalitis dalam jumlah yang cukup banyak sehingga kemungkinan terjadi penularan didaerah tersebut lebih besar terutama didaerah dimana diketemukan banyak peternakan babu Dua species lainnya yang banyak menggigit manusia adalah Cu. bitaeniorrhynchus dan M. uniformis.  

  15. Multiple origins and regional dispersal of resistant dhps in African Plasmodium falciparum malaria.

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    Richard J Pearce

    2009-04-01

    Full Text Available BACKGROUND: Although the molecular basis of resistance to a number of common antimalarial drugs is well known, a geographic description of the emergence and dispersal of resistance mutations across Africa has not been attempted. To that end we have characterised the evolutionary origins of antifolate resistance mutations in the dihydropteroate synthase (dhps gene and mapped their contemporary distribution. METHODS AND FINDINGS: We used microsatellite polymorphism flanking the dhps gene to determine which resistance alleles shared common ancestry and found five major lineages each of which had a unique geographical distribution. The extent to which allelic lineages were shared among 20 African Plasmodium falciparum populations revealed five major geographical groupings. Resistance lineages were common to all sites within these regions. The most marked differentiation was between east and west African P. falciparum, in which resistance alleles were not only of different ancestry but also carried different resistance mutations. CONCLUSIONS: Resistant dhps has emerged independently in multiple sites in Africa during the past 10-20 years. Our data show the molecular basis of resistance differs between east and west Africa, which is likely to translate into differing antifolate sensitivity. We have also demonstrated that the dispersal patterns of resistance lineages give unique insights into recent parasite migration patterns.

  16. A 20-year longitudinal study of Plasmodium ovale and Plasmodium malariae prevalence and morbidity in a West African population.

    Directory of Open Access Journals (Sweden)

    Clémentine Roucher

    Full Text Available BACKGROUND: Plasmodium ovale and Plasmodium malariae have long been reported to be widely distributed in tropical Africa and in other major malaria-endemic areas of the world. However, little is known about the burden caused by these two malaria species. METHODS AND FINDINGS: We did a longitudinal study of the inhabitants of Dielmo village, Senegal, between June, 1990, and December, 2010. We monitored the inhabitants for fever during this period and performed quarterly measurements of parasitemia. We analyzed parasitological and clinical data in a random-effect logistic regression model to investigate the relationship between the level of parasitemia and the risk of fever and to establish diagnostic criteria for P. ovale and P. malariae clinical attacks. The prevalence of P. ovale and P. malariae infections in asymptomatic individuals were high during the first years of the project but decreased after 2004 and almost disappeared in 2010 in relation to changes in malaria control policies. The average incidence densities of P. ovale and P. malariae clinical attacks were 0.053 and 0.093 attacks per person per year in children <15 years and 0.024 and 0.009 attacks per person per year in adults ≥ 15 years, respectively. These two malaria species represented together 5.9% of the malaria burden. CONCLUSIONS: P. ovale and P. malariae were a common cause of morbidity in Dielmo villagers until the recent dramatic decrease of malaria that followed the introduction of new malaria control policies. P. ovale and P. malariae may constitute an important cause of morbidity in many areas of tropical Africa.

  17. Vectores

    OpenAIRE

    2016-01-01

    Documento que contiene la explicación sobre las temáticas de Sistemas coordenados, Cantidades vectoriales y escalares, Algunas propiedades de los vectores, Componentes de un vector y vectores unitarios

  18. Electric nets and sticky materials for analysing oviposition behaviour of gravid malaria vectors

    Directory of Open Access Journals (Sweden)

    Dugassa Sisay

    2012-11-01

    Full Text Available Abstract Background Little is known about how malaria mosquitoes locate oviposition sites in nature. Such knowledge is important to help devise monitoring and control measures that could be used to target gravid females. This study set out to develop a suite of tools that can be used to study the attraction of gravid Anopheles gambiae s.s. towards visual or olfactory cues associated with aquatic habitats. Methods Firstly, the study developed and assessed methods for using electrocuting nets to analyse the orientation of gravid females towards an aquatic habitat. Electric nets (1m high × 0.5m wide were powered by a 12V battery via a spark box. High and low energy settings were compared for mosquito electrocution and a collection device developed to retain electrocuted mosquitoes when falling to the ground. Secondly, a range of sticky materials and a detergent were tested to quantify if and where gravid females land to lay their eggs, by treating the edge of the ponds and the water surface. A randomized complete block design was used for all experiments with 200 mosquitoes released each day. Experiments were conducted in screened semi-field systems using insectary-reared An. gambiae s.s. Data were analysed by generalized estimating equations. Results An electric net operated at the highest spark box energy of a 400 volt direct current made the net spark, creating a crackling sound, a burst of light and a burning smell. This setting caught 64% less mosquitoes than a net powered by reduced voltage output that could neither be heard nor seen (odds ratio (OR 0.46; 95% confidence interval (CI 0.40-0.53, p Conclusion A square of four e-nets with yellow sticky boards as a collection device can be used for quantifying the numbers of mosquitoes approaching a small oviposition site. Shiny sticky surfaces attract gravid females possibly because they are visually mistaken as aquatic habitats. These materials might be developed further as gravid traps

  19. 非洲猪瘟的生物媒介%Biological Vectors of African Swine Fever

    Institute of Scientific and Technical Information of China (English)

    陈泽; 罗建勋; 殷宏

    2011-01-01

    非洲猪瘟(ASF)存在多种传播途径,但其生物媒介--钝缘蜱是ASF病毒在疫源地传播、长期保存甚至发生变异的关键因素,也是ASF在很多地区和国家久控不绝的重要原因.为此作者将从钝缘蜱的生物学特性和生态学特性、与ASF的相互关系、该类蜱的防控及其在中国的分布现状等角度进行论述,为非洲猪瘟的有效防控奠定基础.%There are several transmission routes of African swine fever (ASF) , and the biological vector is the most important factor to transmit and maintain the local foci of ASFV, and even induces the genetic diversity of this virus. This is the main reason that ASF has not been eradicated from many regions or countries. Therefore, this review will describe the biological and ecological characteristics of Ornithodoros ticks, virus-tick interaction, Ornithodoros ticks control and their distribution in China, in order to lay the foundation for effective control of ASF.

  20. An extra-domiciliary method of delivering entomopathogenic fungus, Metharizium anisopliae IP 46 for controlling adult populations of the malaria vector, Anopheles arabiensis

    Directory of Open Access Journals (Sweden)

    Mnyone Ladslaus L

    2010-03-01

    Full Text Available Abstract Fungal biopesticides have the potential to significantly reduce densities of malaria vectors as well as associated malaria transmission. In previous field trials, entomopathogenic fungus was delivered from within human dwellings, where its efficacy was limited by low infection rates of target mosquitoes, high costs of spraying fungus inside houses, and potential public health concerns associated with introducing fungal conidia inside houses. Here we have demonstrated that Metarhizium anisopliae IP 46, delivered within an extra-domiciliary odor-baited station (OBS, can infect and slowly-kill a high proportion of the wild adult malaria vector, Anopheles arabiensis which entered and exited the OBS. This study, carried out in rural Tanzania, showed that by using a concentration of 3.9 × 1010 conidia/m2, more than 95% of mosquitoes that flew in and out of the OBS died within 14 days post-exposure. At least 86% infection of mosquito cadavers was recorded with a significant reduction in the probability of daily survival of exposed An. arabiensis in both treatments tested: low quantity of conidia (eave baffles plus one cotton panel; HR = 2.65, P P

  1. Distribution of the species of the Anopheles gambiae complex and first evidence of Anopheles merus as a malaria vector in Madagascar

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    Le Goff Gilbert

    2003-10-01

    Full Text Available Abstract Background Members of the Anopheles gambiae complex are amongst the best malaria vectors in the world, but their vectorial capacities vary between species and populations. A large-scale sampling of An. gambiae sensu lato was carried out in various bioclimatic domains of Madagascar. Local abundance of an unexpected member of this complex raised questions regarding its role in malaria transmission. Methods Sampling took place at 38 sites and 2,067 females were collected. Species assessment was performed using a PCR targeting a sequence in the IGS of the rDNA. Analysis focused on the relative prevalence of the species per site, bioclimatic domain and altitude. Infectivity of Anopheles merus was assessed using an ELISA to detect the presence of malarial circumsporozoite protein in the head-thorax. Results Three species were identified: An. gambiae, Anopheles arabiensis and An. merus. The distribution of each species is mainly a function of bioclimatic domains and, to a lesser extent, altitude. An. arabiensis is present in all bioclimatic domains with highest prevalence in sub-humid, dry and sub-arid domains. An. gambiae has its highest prevalence in the humid domain, is in the minority in dry areas, rare in sub-humid and absent in sub-arid domains. An. merus is restricted to the coastal fringe in the south and west; it was in the majority in one southern village. The majority of sites were sympatric for at least two of the species (21/38 and two sites harboured all three species. The role of An. merus as malaria vector was confirmed in the case of two human-biting females, which were ELISA-positive for Plasmodium falciparum. Conclusion Despite the huge environmental (mainly man-made changes in Madagascar, the distribution of An. gambiae and An. arabiensis appears unchanged for the past 35 years. The distribution of An. merus is wider than was previously known, and its effectiveness as a malaria vector has been shown for the first time; this

  2. Storage and persistence of a candidate fungal biopesticide for use against adult malaria vectors

    Directory of Open Access Journals (Sweden)

    Blanford Simon

    2012-10-01

    Full Text Available Abstract Background New products aimed at augmenting or replacing chemical insecticides must have operational profiles that include both high efficacy in reducing vector numbers and/or blocking parasite transmission and be long lasting following application. Research aimed at developing fungal spores as a biopesticide for vector control have shown considerable potential yet have not been directly assessed for their viability after long-term storage or following application in the field. Methods Spores from a single production run of the entomopathogenic fungi Beauveria bassiana were dried and then stored under refrigeration at 7°C. After 585 days these spores were sub-sampled and placed at either 22°C, 26°C or 32°C still sealed in packaging (closed storage or in open beakers and exposed to the 80% relative humidity of the incubator they were kept in. Samples were subsequently taken from these treatments over a further 165 days to assess viability. Spores from the same production run were also used to test their persistence following application to three different substrates, clay, cement and wood, using a hand held sprayer. The experiments were conducted at two different institutes with one using adult female Anopheles stephensi and the other adult female Anopheles gambiae. Mosquitoes were exposed to the treated substrates for one hour before being removed and their survival monitored for the next 14 days. Assays were performed at monthly intervals over a maximum seven months. Results Spore storage under refrigeration resulted in no loss of spore viability over more than two years. Spore viability of those samples kept under open and closed storage was highly dependent on the incubation temperature with higher temperatures decreasing viability more rapidly than cooler temperatures. Mosquito survival following exposure was dependent on substrate type. Spore persistence on the clay substrate was greatest achieving 80% population reduction for

  3. Synthesis and characterization of silver nanoparticles using Gmelina asiatica leaf extract against filariasis, dengue, and malaria vector mosquitoes.

    Science.gov (United States)

    Muthukumaran, Udaiyan; Govindarajan, Marimuthu; Rajeswary, Mohan; Hoti, S L

    2015-05-01

    Mosquitoes are blood-feeding insects and serve as the most important vectors for spreading human diseases such as malaria, yellow fever, dengue fever, and filariasis. The continued use of synthetic insecticides has resulted in resistance in mosquitoes. Synthetic insecticides are toxic and affect the environment by contaminating soil, water, and air, and then natural products may be an alternative to synthetic insecticides because they are effective, biodegradable, eco-friendly, and safe to environment. Botanical origin may serve as suitable alternative biocontrol techniques in the future. The present study was carried out to establish the larvicidal potential of leaf extracts of Gmelina asiatica and synthesized silver nanoparticles using aqueous leaf extract against late third instar larvae of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. Larvae were exposed to varying concentrations of plant extracts and synthesized AgNPs for 24 h. The results were recorded from UV-visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy analysis support the biosynthesis and characterization of AgNPs. The maximum efficacy was observed in synthesized AgNPs against the larvae of An. stephensi (lethal dose (LC₅₀) = 22.44 μg/mL; LC₉₀ 40.65 μg/mL), Ae. aegypti (LC₅₀ = 25.77 μg/mL; LC₉₀ 45.98 μg/mL), and C. quinquefasciatus (LC₅₀ = 27.83 μg/mL; LC₉₀ 48.92 μg/mL), respectively. No mortality was observed in the control. This is the first report on mosquito larvicidal activity of plant-synthesized nanoparticles. Thus, the use of G. asiatica to synthesize silver nanoparticles is a rapid, eco-friendly, and a single-step approach and the AgNps formed can be potential mosquito larvicidal agents.

  4. Eco-friendly larvicides from Indian plants: Effectiveness of lavandulyl acetate and bicyclogermacrene on malaria, dengue and Japanese encephalitis mosquito vectors.

    Science.gov (United States)

    Govindarajan, Marimuthu; Benelli, Giovanni

    2016-11-01

    Mosquitoes (Diptera: Culicidae) are a key threat for millions of people and animals worldwide, since they act as vectors for devastating pathogens and parasites, including malaria, dengue, Japanese encephalitis, filiariasis and Zika virus. Mosquito young instars are usually targeted using organophosphates, insect growth regulators and microbial agents. Indoor residual spraying and insecticide-treated bed nets are also employed. However, these chemicals have negative effects on human health and the environment and induce resistance in a number of vectors. In this scenario, newer and safer tools have been recently implemented to enhance mosquito control. The concrete potential of screening plant species as sources of metabolites for entomological and parasitological purposes is worthy of attention, as recently elucidated by the Y. Tu's example. Here we investigated the toxicity of Heracleum sprengelianum (Apiaceae) leaf essential oil and its major compounds toward third instar larvae of the malaria vector Anopheles subpictus, the arbovirus vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. GC-MS analysis showed that EO major components were lavandulyl acetate (17.8%) and bicyclogermacrene (12.9%). The EO was toxic to A. subpictus, A. albopictus, and C. tritaeniorhynchus, with LC50 of 33.4, 37.5 and 40.9µg/ml, respectively. Lavandulyl acetate was more toxic to mosquito larvae if compared to bicyclogermacrene. Their LC50 were 4.17 and 10.3µg/ml for A. subpictus, 4.60 and 11.1µg/ml for A. albopictus, 5.11 and 12.5µg/ml for C. tritaeniorhynchus. Notably, the EO and its major compounds were safer to three non-target mosquito predators, Anisops bouvieri, Diplonychus indicus and Gambusia affinis, with LC50 ranging from 206 to 4219µg/ml. Overall, this study highlights that H. sprengelianum EO is a promising source of eco-friendly larvicides against three important mosquito vectors with moderate toxicity against non-target aquatic

  5. Single-step biosynthesis and characterization of silver nanoparticles using Zornia diphylla leaves: A potent eco-friendly tool against malaria and arbovirus vectors.

    Science.gov (United States)

    Govindarajan, Marimuthu; Rajeswary, Mohan; Muthukumaran, Udaiyan; Hoti, S L; Khater, Hanem F; Benelli, Giovanni

    2016-08-01

    Mosquitoes (Diptera: Culicidae) are vectors of important pathogens and parasites, including malaria, dengue, chikungunya, Japanese encephalitis, lymphatic filariasis and Zika virus. The application of synthetic insecticides causes development of resistance, biological magnification of toxic substances through the food chain, and adverse effects on the environment and human health. In this scenario, eco-friendly control tools of mosquito vectors are a priority. Here single-step fabrication of silver nanoparticles (AgNP) using a cheap aqueous leaf extract of Zornia diphylla as reducing and capping agent pf Ag(+) ions has been carried out. Biosynthesized AgNP were characterized by UV-visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDX) and X-ray diffraction analysis (XRD). The acute toxicity of Z. diphylla leaf extract and biosynthesized AgNP was evaluated against larvae of the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. Both the Z. diphylla leaf extract and Ag NP showed dose dependent larvicidal effect against all tested mosquito species. Compared to the leaf aqueous extract, biosynthesized Ag NP showed higher toxicity against An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus with LC50 values of 12.53, 13.42 and 14.61μg/ml, respectively. Biosynthesized Ag NP were found safer to non-target organisms Chironomus circumdatus, Anisops bouvieri and Gambusia affinis, with the respective LC50 values ranging from 613.11 to 6903.93μg/ml, if compared to target mosquitoes. Overall, our results highlight that Z. diphylla-fabricated Ag NP are a promising and eco-friendly tool against larval populations of mosquito vectors of medical and veterinary importance, with negligible toxicity against other non-target organisms.

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

    Directory of Open Access Journals (Sweden)

    Sarma Devojit K

    2012-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Achee Nicole L

    2008-03-01

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

  8. Infection of the malaria mosquito Anopheles gambiae with the entomopathogenic fungus Metarhizium anisopliae reduces blood feeding and fecundity

    NARCIS (Netherlands)

    Scholte, E.J.; Knols, B.G.J.; Takken, W.

    2006-01-01

    The entomopathogenic fungus Metarhizium anisopliae is being considered as a biocontrol agent against adult African malaria vectors. In addition to causing significant mortality, this pathogen is known to cause reductions in feeding and fecundity in a range of insects. In the present study we investi

  9. The effect of larval nutritional deprivation on the life history and DDT resistance phenotype in laboratory strains of the malaria vector Anopheles arabiensis

    Directory of Open Access Journals (Sweden)

    Oliver Shüné V

    2013-02-01

    Full Text Available Abstract Background Anopheles arabiensis is a major malaria vector in Africa. It thrives in agricultural areas and has been associated with increased malaria incidence in areas under rice and maize cultivation. This effect may be due to increased adult size and abundance as a consequence of optimal larval nutrition. The aim of this study was to examine the effect of larval nutrition on the life history and expression of insecticide resistance in adults of laboratory reared An. arabiensis. Methods Larvae drawn from an insecticide susceptible An. arabiensis strain (SENN as well as a DDT-resistant strain (SENN-DDT were subjected to three fasting regimes: 1 mg of food per larva offered once per day, once every second day and once every third day. Control cohorts included larvae offered 1 mg food thrice per day. The rate of larval development was compared between matched cohorts from each strain as well as between fasted larvae and their respective controls. The expression of DDT resistance/tolerance in adults was compared between the starved cohorts and their controls by strain. Factors potentially affecting variation in DDT resistance/tolerance were examined including: adult body size (wing length, knock-down resistance (kdr status and levels of detoxification enzyme activity. Results and conclusion Anopheles arabiensis larval development is prolonged by nutrient deprivation and adults that eclose from starved larvae are smaller and less tolerant to DDT intoxication. This effect on DDT tolerance in adults is also associated with reduced detoxification enzyme activity. Conversely, well fed larvae develop comparatively quickly into large, more DDT tolerant (SENN or resistant (SENN-DDT adults. This is important in those instances where cereal farming is associated with increased An. arabiensis transmitted malaria incidence, because large adult females with high teneral reserves and decreased susceptibility to insecticide intoxication may also

  10. Nutritional zinc deficiency, immune capacity and malaria : a study on mediators of immunity to malaria caused by Plasmodium falciparum in African children

    NARCIS (Netherlands)

    Mbugi, E.V.

    2009-01-01

    This thesis aimed at investigating the role of genetic and nutritional factors that affect the immune response to malaria in Tanzanian children. The introductory chapter (Chapter 1) reviews the importance of nutritional deficiencies, particularly of zinc, and presents the hypothesis that such defici

  11. Plant-Mediated Effects on Mosquito Capacity to Transmit Human Malaria.

    Science.gov (United States)

    Hien, Domonbabele F D S; Dabiré, Kounbobr R; Roche, Benjamin; Diabaté, Abdoulaye; Yerbanga, Rakiswende S; Cohuet, Anna; Yameogo, Bienvenue K; Gouagna, Louis-Clément; Hopkins, Richard J; Ouedraogo, Georges A; Simard, Frédéric; Ouedraogo, Jean-Bosco; Ignell, Rickard; Lefevre, Thierry

    2016-08-01

    The ecological context in which mosquitoes and malaria parasites interact has received little attention, compared to the genetic and molecular aspects of malaria transmission. Plant nectar and fruits are important for the nutritional ecology of malaria vectors, but how the natural diversity of plant-derived sugar sources affects mosquito competence for malaria parasites is unclear. To test this, we infected Anopheles coluzzi, an important African malaria vector, with sympatric field isolates of Plasmodium falciparum, using direct membrane feeding assays. Through a series of experiments, we then examined the effects of sugar meals from Thevetia neriifolia and Barleria lupilina cuttings that included flowers, and fruit from Lannea microcarpa and Mangifera indica on parasite and mosquito traits that are key for determining the intensity of malaria transmission. We found that the source of plant sugar meal differentially affected infection prevalence and intensity, the development duration of the parasites, as well as the survival and fecundity of the vector. These effects are likely the result of complex interactions between toxic secondary metabolites and the nutritional quality of the plant sugar source, as well as of host resource availability and parasite growth. Using an epidemiological model, we show that plant sugar source can be a significant driver of malaria transmission dynamics, with some plant species exhibiting either transmission-reducing or -enhancing activities.

  12. Plant-Mediated Effects on Mosquito Capacity to Transmit Human Malaria

    Science.gov (United States)

    Hien, Domonbabele F. d. S.; Roche, Benjamin; Diabaté, Abdoulaye; Yerbanga, Rakiswende S.; Cohuet, Anna; Yameogo, Bienvenue K.; Gouagna, Louis-Clément; Hopkins, Richard J.; Ouedraogo, Georges A.; Simard, Frédéric; Ignell, Rickard; Lefevre, Thierry

    2016-01-01

    The ecological context in which mosquitoes and malaria parasites interact has received little attention, compared to the genetic and molecular aspects of malaria transmission. Plant nectar and fruits are important for the nutritional ecology of malaria vectors, but how the natural diversity of plant-derived sugar sources affects mosquito competence for malaria parasites is unclear. To test this, we infected Anopheles coluzzi, an important African malaria vector, with sympatric field isolates of Plasmodium falciparum, using direct membrane feeding assays. Through a series of experiments, we then examined the effects of sugar meals from Thevetia neriifolia and Barleria lupilina cuttings that included flowers, and fruit from Lannea microcarpa and Mangifera indica on parasite and mosquito traits that are key for determining the intensity of malaria transmission. We found that the source of plant sugar meal differentially affected infection prevalence and intensity, the development duration of the parasites, as well as the survival and fecundity of the vector. These effects are likely the result of complex interactions between toxic secondary metabolites and the nutritional quality of the plant sugar source, as well as of host resource availability and parasite growth. Using an epidemiological model, we show that plant sugar source can be a significant driver of malaria transmission dynamics, with some plant species exhibiting either transmission-reducing or -enhancing activities. PMID:27490374

  13. Investigating associations between biting time in the malaria vector Anopheles arabiensis Patton and single nucleotide polymorphisms in circadian clock genes: support for sub-structure among An. arabiensis in the Kilombero valley of Tanzania

    OpenAIRE

    2016-01-01

    Background There is growing evidence that the widespread use of Long-Lasting Insecticidal Nets (LLINs) is prompting malaria vectors to shift their biting towards times and places where people are not protected, such as earlier in the evening and/or outdoors. It is uncertain whether these behavioural shifts are due to phenotypic plasticity and/or ecological changes within vector communities that favour more exophilic species, or involve genetic factors within vector species to limit their cont...

  14. Vectors

    DEFF Research Database (Denmark)

    Boeriis, Morten; van Leeuwen, Theo

    2017-01-01

    This article revisits the concept of vectors, which, in Kress and van Leeuwen’s Reading Images (2006), plays a crucial role in distinguishing between ‘narrative’, action-oriented processes and ‘conceptual’, state-oriented processes. The use of this concept in image analysis has usually focused...... on the most salient vectors, and this works well, but many images contain a plethora of vectors, which makes their structure quite different from the linguistic transitivity structures with which Kress and van Leeuwen have compared ‘narrative’ images. It can also be asked whether facial expression vectors...... should be taken into account in discussing ‘reactions’, which Kress and van Leeuwen link only to eyeline vectors. Finally, the question can be raised as to whether actions are always realized by vectors. Drawing on a re-reading of Rudolf Arnheim’s account of vectors, these issues are outlined...

  15. Malaria and Tropical Travel

    Centers for Disease Control (CDC) Podcasts

    2008-05-15

    Malaria is a serious mosquito-borne disease that can lead to death. This podcast discusses malaria risk when traveling to tropical areas, as well as how to protect yourself and your family from malaria infection.  Created: 5/15/2008 by National Center for Zoonotic, Vector-Borne, and Enteric Diseases (NCZVED).   Date Released: 5/29/2008.

  16. Larvicidal and repellent activity of medicinal plant extracts from Eastern Ghats of South India against malaria and filariasis vectors

    Institute of Scientific and Technical Information of China (English)

    Chinnaperumal Kamaraj; Abdul Abdul Rahuman; Asokan Bagavan; Gandhi Elango; Abdul Abduz Zahir; Thirunavukkarasu Santhoshkumar

    2011-01-01

    Objective:To evaluate the larvicidal and repellent activities of ethyl acetate and methanol extracts ofAcacia concinna (A. concinna),Cassia siamea(C. siamea),Coriandrum sativum (C. sativum),Cuminum cyminum(C. cyminum),Lantana camara (L. camara),Nelumbo nucifera (N. nucifera)Phyllanthus amarus (P. amarus),Piper nigrum (P. nigrum) andTrachyspermum ammi(T. ammi) againstAnopheles stephensi(An. stephensi) andCulex quinquefasciatus (Cx. quinquefasciatus).Methods:The larvicidal activity of medicinal plant extracts were tested against early fourth-instar larvae of malaria and filariasis vectors. The mortality was observed 24 h and48 h after treatment, data were subjected to probit analysis to determine the lethal concentrations (LC50 andLC90) to kill50 and 90per cent of the treated larvae of the tested species. The repellent efficacy was determined against two mosquito species at five concentrations (31.25, 62.50, 125.00, 250.00, and 500.00 ppm) under the laboratory conditions.Results: All plant extracts showed moderate effects after24h and 48h of exposure; however, the highest activity was observed after24h in the leaf methanol extract ofN. nucifera, seed ethyl acetate and methanol extract ofP. nigrumagainst the larvae of An. stephensi(LC50 =34.76, 24.54 and30.20 ppm) and againstCx. quinquefasciatus (LC50= 37.49, 43.94 and57.39ppm), respectively. The toxic effect of leaf methanol extract ofC. siamea, seed methanol extract ofC. cyminum, leaf ethyl acetate extract ofN. nucifera, leaf ethyl acetate and methanol extract ofP. amarusand seed methanol extract ofT. ammiwere showed100% mortality againstAn. stephensi andCx. quinquefasciatus after48 h exposer. The maximum repellent activity was observed at500 ppm in methanol extracts ofN. nucifera, ethyl acetate and methanol extract ofP. nigrum and methanol extract ofT. ammi and the mean complete protection time ranged from30 to150 min with the different extracts tested. Conclusions:These results suggest that the leaf and seed

  17. A viral vectored prime-boost immunization regime targeting the malaria Pfs25 antigen induces transmission-blocking activity.

    Directory of Open Access Journals (Sweden)

    Anna L Goodman

    Full Text Available The ookinete surface protein Pfs25 is a macrogamete-to-ookinete/ookinete stage antigen of Plasmodium falciparum, capable of exerting high-level anti-malarial transmission-blocking activity following immunization with recombinant protein-in-adjuvant formulations. Here, this antigen was expressed in recombinant chimpanzee adenovirus 63 (ChAd63, human adenovirus serotype 5 (AdHu5 and modified vaccinia virus Ankara (MVA viral vectored vaccines. Two immunizations were administered to mice in a heterologous prime-boost regime. Immunization of mice with AdHu5 Pfs25 at week 0 and MVA Pfs25 at week 10 (Ad-MVA Pfs25 resulted in high anti-Pfs25 IgG titers, consisting of predominantly isotypes IgG1 and IgG2a. A single priming immunization with ChAd63 Pfs25 was as effective as AdHu5 Pfs25 with respect to ELISA titers at 8 weeks post-immunization. Sera from Ad-MVA Pfs25 immunized mice inhibited the transmission of P. falciparum to the mosquito both ex vivo and in vivo. In a standard membrane-feeding assay using NF54 strain P. falciparum, oocyst intensity in Anopheles stephensi mosquitoes was significantly reduced in an IgG concentration-dependent manner when compared to control feeds (96% reduction of intensity, 78% reduction in prevalence at a 1 in 5 dilution of sera. In addition, an in vivo transmission-blocking effect was also demonstrated by direct feeding of immunized mice infected with Pfs25DR3, a chimeric P. berghei line expressing Pfs25 in place of endogenous Pbs25. In this assay the density of Pfs25DR3 oocysts was significantly reduced when mosquitoes were fed on vaccinated as compared to control mice (67% reduction of intensity, 28% reduction in prevalence and specific IgG titer correlated with efficacy. These data confirm the utility of the adenovirus-MVA vaccine platform for the induction of antibodies with transmission-blocking activity, and support the continued development of this alternative approach to transmission-blocking malaria subunit

  18. Seasonality, malaria, and impact of prophylaxis in a West African village I. Effect of anemia in pregnancy.

    Science.gov (United States)

    Bouvier, P; Doumbo, O; Breslow, N; Robert, C F; Mauris, A; Picquet, M; Kouriba, B; Dembele, H K; Delley, V; Rougemont, A

    1997-04-01

    The importance of malaria as a cause of anemia in pregnancy in endemic areas remains controversial. The prevalence of anemia in pregnant women following the dry (May) and the rainy (November) seasons was compared in two successive years in Bougoula village (region of Sikasso, Mali). Phase I (1992) was observational and included 172 pregnant women and 208 controls. In Phase II (1993, 174 pregnant women and 206 controls), malaria prophylaxis with proguanil (200 mg/day) and chloroquine (300 mg/week) was offered to pregnant women. A strong seasonal variation in the prevalence of moderate to severe anemia in pregnant women (hematocrit anemia in pregnancy decreased by 55.5% (22.8-74.3%). We conclude that malaria is the major cause of anemia in pregnancy in this region. A high priority should be given to prevention of malaria in pregnancy.

  19. Impact of Insecticide Resistance on the Effectiveness of Pyrethroid-Based Malaria Vectors Control Tools in Benin: Decreased Toxicity and Repellent Effect.

    Directory of Open Access Journals (Sweden)

    Fiacre R Agossa

    Full Text Available Since the first evidence of pyrethroids resistance in 1999 in Benin, mutations have rapidly increased in mosquitoes and it is now difficult to design a study including a control area where malaria vectors are fully susceptible. Few studies have assessed the after effect of resistance on the success of pyrethroid based prevention methods in mosquito populations. We therefore assessed the impact of resistance on the effectiveness of pyrethroids based indoor residual spraying (IRS in semi-field conditions and long lasting insecticidal nets (LLINs in laboratory conditions. The results observed showed low repulsion and low toxicity of pyrethroids compounds in the test populations. The toxicity of pyrethroids used in IRS was significantly low with An. gambiae s.l (< 46% but high for other predominant species such as Mansonia africana (93% to 97%. There were significant differences in terms of the repellent effect expressed as exophily and deterrence compared to the untreated huts (P<0.001. Furthermore, mortality was 23.71% for OlyseNet® and 39.06% for PermaNet®. However, with laboratory susceptible "Kisumu", mortality was 100% for both nets suggesting a resistance within the wild mosquito populations. Thus treatment with pyrethroids at World Health Organization recommended dose will not be effective at reducing malaria in the coming years. Therefore it is necessary to study how insecticide resistance decreases the efficacy of particular pyrethroids used in pyrethroid-based vector control so that a targeted approach can be adopted.

  20. Neem by-products in the fight against mosquito-borne diseases:Biotoxicity of neem cake fractions towards the rural malaria vector Anopheles culicifacies(Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Balamurugan Chandramohan; Kadarkarai Murugan; Pari Madhiyazhagan; Kalimuthu Kovendan; Palanisamy Mahesh Kumar; Chellasamy Panneerselvam; Devakumar Dinesh; Jayapal Subramaniam; Rajapandian Rajaganesh; Marcello Nicoletti; Angelo Canale; Giovanni Benelli

    2016-01-01

    Objective: To evaluate the ovicidal, larvicidal and adulticidal potential of neem cake fractions of different polarity against the rural malaria vector Anopheles culicifacies(An.culicifacies).Methods: Neem cake fractions’ total methanol extract(NTMeOH), total ethyl acetate extract(NTAc OEt), ethyl acetate fraction after repartition with NTMe OH(NRAc OEt),butanol fraction after repartition with NTMeOH(NRBuOH), and aqueous fraction after repartition of NTMeOH(NRH2O) were tested against An. culicifacies eggs, fourth instar larvae and adults.Results: In larvicidal experiments, NTMeOH, NTAcOEt, NRAcOEt, NRBuOH and NRH2O achieved LC50 values of 1.32, 1.50, 1.81, 1.95 and 2.54 mg/L, respectively. All fractions tested at 150 mg/L were able to reduce egg hatchability of more than 50%, with the exception of NTAc OEt and NRAc OEt. In adulticidal assays, NTMeOH, NTAcOEt,NRAcOEt, NRBuOH and NRH2O achieved LC50 values of 3.01, 2.95, 3.23, 3.63 and3.00 mg/L, respectively.Conclusions: Overall, this study suggests that the methanolic fractions of neem cake may be considered as a new and cheap source of highly effective compounds against the rural malaria vector An. culicifacies.

  1. The reproductive tracts of two malaria vectors are populated by a core microbiome and by gender- and swarm-enriched microbial biomarkers

    Science.gov (United States)

    Segata, Nicola; Baldini, Francesco; Pompon, Julien; Garrett, Wendy S.; Truong, Duy Tin; Dabiré, Roch K.; Diabaté, Abdoulaye; Levashina, Elena A.; Catteruccia, Flaminia

    2016-01-01

    Microbes play key roles in shaping the physiology of insects and can influence behavior, reproduction and susceptibility to pathogens. In Sub-Saharan Africa, two major malaria vectors, Anopheles gambiae and An. coluzzii, breed in distinct larval habitats characterized by different microorganisms that might affect their adult physiology and possibly Plasmodium transmission. We analyzed the reproductive microbiomes of male and female An. gambiae and An. coluzzii couples collected from natural mating swarms in Burkina Faso. 16S rRNA sequencing on dissected tissues revealed that the reproductive tracts harbor a complex microbiome characterized by a large core group of bacteria shared by both species and all reproductive tissues. Interestingly, we detected a significant enrichment of several gender-associated microbial biomarkers in specific tissues, and surprisingly, similar classes of bacteria in males captured from one mating swarm, suggesting that these males originated from the same larval breeding site. Finally, we identified several endosymbiotic bacteria, including Spiroplasma, which have the ability to manipulate insect reproductive success. Our study provides a comprehensive analysis of the reproductive microbiome of important human disease vectors, and identifies a panel of core and endosymbiotic bacteria that can be potentially exploited to interfere with the transmission of malaria parasites by the Anopheles mosquito. PMID:27086581

  2. Neem by-products in the fight against mosquito-borne diseases:Biotoxicity of neem cake fractions towards the rural malaria vector Anopheles culicifacies (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Balamurugan Chandramohan; Marcello Nicoletti; Angelo Canale; Giovanni Benelli; Kadarkarai Murugan; Pari Madhiyazhagan; Kalimuthu Kovendan; Palanisamy Mahesh Kumar; Chellasamy Panneerselvam; Devakumar Dinesh; Jayapal Subramaniam; Rajapandian Rajaganesh

    2016-01-01

    Objective: To evaluate the ovicidal, larvicidal and adulticidal potential of neem cake fractions of different polarity against the rural malaria vector Anopheles culicifacies (An. culicifacies). Methods: Neem cake fractions' total methanol extract (NTMeOH), total ethyl acetate extract (NTAcOEt), ethyl acetate fraction after repartition with NTMeOH (NRAcOEt), butanol fraction after repartition with NTMeOH (NRBuOH), and aqueous fraction after repartition of NTMeOH (NRH2O) were tested against An. culicifacies eggs, fourth instar larvae and adults. Results: In larvicidal experiments, NTMeOH, NTAcOEt, NRAcOEt, NRBuOH and NRH2O achieved LC50 values of 1.32, 1.50, 1.81, 1.95 and 2.54 mg/L, respectively. All fractions tested at 150 mg/L were able to reduce egg hatchability of more than 50%, with the exception of NTAcOEt and NRAcOEt. In adulticidal assays, NTMeOH, NTAcOEt, NRAcOEt, NRBuOH and NRH2O achieved LC50 values of 3.01, 2.95, 3.23, 3.63 and 3.00 mg/L, respectively. Conclusions: Overall, this study suggests that the methanolic fractions of neem cake may be considered as a new and cheap source of highly effective compounds against the rural malaria vector An. culicifacies.

  3. Neem cake as a promising larvicide and adulticide against the rural malaria vector Anopheles culicifacies (Diptera: Culicidae): a HPTLC fingerprinting approach.

    Science.gov (United States)

    Benelli, Giovanni; Chandramohan, Balamurugan; Murugan, Kadarkarai; Madhiyazhagan, Pari; Kovendan, Kalimuthu; Panneerselvam, Chellasamy; Dinesh, Devakumar; Govindarajan, Marimuthu; Higuchi, Akon; Toniolo, Chiara; Canale, Angelo; Nicoletti, Marcello

    2017-05-01

    Mosquitoes are insects of huge public health importance, since they act as vectors for important pathogens and parasites. Here, we focused on the possibility of using the neem cake in the fight against mosquito vectors. The neem cake chemical composition significantly changes among producers, as evidenced by our HPTLC (High performance thin layer chromatography) analyses of different marketed products. Neem cake extracts were tested to evaluate the ovicidal, larvicidal and adulticidal activity against the rural malaria vector Anopheles culicifacies. Ovicidal activity of both types of extracts was statistically significant, and 150 ppm completely inhibited egg hatching. LC50 values were extremely low against fourth instar larvae, ranging from 1.321 (NM1) to 1.818 ppm (NA2). Adulticidal activity was also high, with LC50 ranging from 3.015 (NM1) to 3.637 ppm (NM2). This study pointed out the utility of neem cake as a source of eco-friendly mosquitocides in Anopheline vector control programmes.

  4. Alternative treatments for indoor residual spraying for malaria control in a village with pyrethroid- and DDT-resistant vectors in the Gambia.

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    Julie-Anne A Tangena

    Full Text Available BACKGROUND: Malaria vector control is threatened by resistance to pyrethroids, the only class of insecticides used for treating bed nets. The second major vector control method is indoor residual spraying with pyrethroids or the organochloride DDT. However, resistance to pyrethroids frequently confers resistance to DDT. Therefore, alternative insecticides are urgently needed. METHODOLOGY/PRINCIPAL FINDINGS: Insecticide resistance and the efficacy of indoor residual spraying with different insecticides was determined in a Gambian village. Resistance of local vectors to pyrethroids and DDT was high (31% and 46% mortality, respectively while resistance to bendiocarb and pirimiphos methyl was low (88% and 100% mortality, respectively. The vectors were predominantly Anopheles gambiae s.s. with 94% of them having the putative resistant genotype kdr 1014F. Four groups of eight residential compounds were each sprayed with either (1 bendiocarb, a carbamate, (2 DDT, an organochlorine, (3 microencapsulated pirimiphos methyl, an organophosphate, or (4 left unsprayed. All insecticides tested showed high residual activity up to five months after application. Mosquito house entry, estimated by light traps, was similar in all houses with metal roofs, but was significantly less in IRS houses with thatched roofs (p=0.02. Residents participating in focus group discussions indicated that IRS was considered a necessary nuisance and also may decrease the use of long-lasting insecticidal nets. CONCLUSION/SIGNIFICANCE: Bendiocarb and microencapsulated pirimiphos methyl are viable alternatives for indoor residual spraying where resistance to pyrethroids and DDT is high and may assist in the management of pyrethroid resistance.

  5. 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

    Directory of Open Access Journals (Sweden)

    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

  6. Malaria in Pregnancy

    OpenAIRE

    Apuzzio, Joseph J.; Abdulla Al-Khan; Jesus R. Alvarez

    2005-01-01

    Recently, there has been a resurgence of malaria in densely populated areas of the United States secondary to human migration from endemic areas where factors such as cessation of vector control, vector resistance to insecticides, disease resistance to drugs, environmental changes, political instability, and indifference, have played a role for malaria becoming an overwhelming infection of these tropical underdeveloped countries. It is important for health care providers of gravida to be aler...

  7. Malaria in pregnancy.

    OpenAIRE

    Jesus R. Alvarez; Al-Khan, Abdulla; Apuzzio, Joseph J.

    2005-01-01

    Recently, there has been a resurgence of malaria in densely populated areas of the United States secondary to human migration from endemic areas where factors such as cessation of vector control, vector resistance to insecticides, disease resistance to drugs, environmental changes, political instability, and indifference, have played a role for malaria becoming an overwhelming infection of these tropical underdeveloped countries. It is important for health care providers of gravida to be aler...

  8. Malaria in pregnancy.

    Science.gov (United States)

    Alvarez, Jesus R; Al-Khan, Abdulla; Apuzzio, Joseph J

    2005-12-01

    Recently, there has been a resurgence of malaria in densely populated areas of the United States secondary to human migration from endemic areas where factors such as cessation of vector control, vector resistance to insecticides, disease resistance to drugs, environmental changes, political instability, and indifference, have played a role for malaria becoming an overwhelming infection of these tropical underdeveloped countries. It is important for health care providers of gravida to be alert of the disease and its effects on pregnancy.

  9. Malaria in Pregnancy

    Directory of Open Access Journals (Sweden)

    Jesus R. Alvarez

    2005-01-01

    Full Text Available Recently, there has been a resurgence of malaria in densely populated areas of the United States secondary to human migration from endemic areas where factors such as cessation of vector control, vector resistance to insecticides, disease resistance to drugs, environmental changes, political instability, and indifference, have played a role for malaria becoming an overwhelming infection of these tropical underdeveloped countries. It is important for health care providers of gravida to be alert of the disease and its effects on pregnancy.

  10. Odour-mediated host-seeking behaviour of the Afro-tropical malaria vector Anopheles gambiae Giles.

    NARCIS (Netherlands)

    Knols, B.G.J.

    1996-01-01

    Malaria remains the single most important parasitic disease of man in tropical regions of the world. It is estimated that 40% of the world's population, in 102 countries, is at risk from the disease. Some 100-200 million cases occur annually worldwide, of which 90 million in Africa, with 1-2 millio

  11. Is the current decline in malaria burden in sub-Saharan Africa due to a decrease in vector population?

    DEFF Research Database (Denmark)

    Meyrowitsch, Dan Wolf; Pedersen, Erling Møller; Alifrangis, Michael

    2011-01-01

    ABSTRACT: BACKGROUND: In sub-Saharan Africa (SSA), malaria caused by Plasmodium falciparum has historically been a major contributor to morbidity and mortality. Recent reports indicate a pronounced decline in infection and disease rates which are commonly ascribed to large-scale bed net programme...

  12. Beer Consumption Increases Human Attractiveness to Malaria Mosquitoes

    Science.gov (United States)

    Lefèvre, Thierry; Gouagna, Louis-Clément; Dabiré, Kounbobr Roch; Elguero, Eric; Fontenille, Didier; Renaud, François; Costantini, Carlo; Thomas, Frédéric

    2010-01-01

    Background Malaria and alcohol consumption both represent major public health problems. Alcohol consumption is rising in developing countries and, as efforts to manage malaria are expanded, understanding the links between malaria and alcohol consumption becomes crucial. Our aim was to ascertain the effect of beer consumption on human attractiveness to malaria mosquitoes in semi field conditions in Burkina Faso. Methodology/Principal Findings We used a Y tube-olfactometer designed to take advantage of the whole body odour (breath and skin emanations) as a stimulus to gauge human attractiveness to Anopheles gambiae (the primary African malaria vector) before and after volunteers consumed either beer (n = 25 volunteers and a total of 2500 mosquitoes tested) or water (n = 18 volunteers and a total of 1800 mosquitoes). Water consumption had no effect on human attractiveness to An. gambiae mosquitoes, but beer consumption increased volunteer attractiveness. Body odours of volunteers who consumed beer increased mosquito activation (proportion of mosquitoes engaging in take-off and up-wind flight) and orientation (proportion of mosquitoes flying towards volunteers' odours). The level of exhaled carbon dioxide and body temperature had no effect on human attractiveness to mosquitoes. Despite individual volunteer variation, beer consumption consistently increased attractiveness to mosquitoes. Conclusions/Significance These results suggest that beer consumption is a risk factor for malaria and needs to be integrated into public health policies for the design of control measures. PMID:20209056

  13. Beer consumption increases human attractiveness to malaria mosquitoes.

    Directory of Open Access Journals (Sweden)

    Thierry Lefèvre

    Full Text Available BACKGROUND: Malaria and alcohol consumption both represent major public health problems. Alcohol consumption is rising in developing countries and, as efforts to manage malaria are expanded, understanding the links between malaria and alcohol consumption becomes crucial. Our aim was to ascertain the effect of beer consumption on human attractiveness to malaria mosquitoes in semi field conditions in Burkina Faso. METHODOLOGY/PRINCIPAL FINDINGS: We used a Y tube-olfactometer designed to take advantage of the whole body odour (breath and skin emanations as a stimulus to gauge human attractiveness to Anopheles gambiae (the primary African malaria vector before and after volunteers consumed either beer (n = 25 volunteers and a total of 2500 mosquitoes tested or water (n = 18 volunteers and a total of 1800 mosquitoes. Water consumption had no effect on human attractiveness to An. gambiae mosquitoes, but beer consumption increased volunteer attractiveness. Body odours of volunteers who consumed beer increased mosquito activation (proportion of mosquitoes engaging in take-off and up-wind flight and orientation (proportion of mosquitoes flying towards volunteers' odours. The level of exhaled carbon dioxide and body temperature had no effect on human attractiveness to mosquitoes. Despite individual volunteer variation, beer consumption consistently increased attractiveness to mosquitoes. CONCLUSIONS/SIGNIFICANCE: These results suggest that beer consumption is a risk factor for malaria and needs to be integrated into public health policies for the design of control measures.

  14. Predicting the effect of climate change on African trypanosomiasis: integrating epidemiology with parasite and vector biology

    NARCIS (Netherlands)

    Moore, S.; Shrestha, S.; Tomlinson, K.W.; Vuong, H.

    2012-01-01

    Climate warming over the next century is expected to have a large impact on the interactions between pathogens and their animal and human hosts. Vector-borne diseases are particularly sensitive to warming because temperature changes can alter vector development rates, shift their geographical distri

  15. Status of pesticide management in the practice of vector control: a global survey in countries at risk of malaria or other major vector-borne diseases

    NARCIS (Netherlands)

    Berg, van den H.; Hii, J.; Soares, A.; Mnzava, A.; Ameneshewa, B.; Dash, A.P.; Ejov, M.; Tan, S.H.; Matthews, G.; Yadav, R.S.; Zaim, M.

    2011-01-01

    Background: It is critical that vector control pesticides are used for their acceptable purpose without causing adverse effects on health and the environment. This paper provides a global overview of the current status of pesticides management in the practice of vector control. Methods: A questionna

  16. Participatory mapping of target areas to enable operational larval source management to suppress malaria vector mosquitoes in Dar es Salaam, Tanzania

    Directory of Open Access Journals (Sweden)

    Dongus Stefan

    2007-09-01

    Full Text Available Abstract Background Half of the population of Africa will soon live in towns and cities where it can be protected from malaria by controlling aquatic stages of mosquitoes. Rigorous but affordable and scaleable methods for mapping and managing mosquito habitats are required to enable effective larval control in urban Africa. Methods A simple community-based mapping procedure that requires no electronic devices in the field was developed to facilitate routine larval surveillance in Dar es Salaam, Tanzania. The mapping procedure included (1 community-based development of sketch maps and (2 verification of sketch maps through technical teams using laminated aerial photographs in the field which were later digitized and analysed using Geographical Information Systems (GIS. Results Three urban wards of Dar es Salaam were comprehensively mapped, covering an area of 16.8 km2. Over thirty percent of this area were not included in preliminary community-based sketch mapping, mostly because they were areas that do not appear on local government residential lists. The use of aerial photographs and basic GIS allowed rapid identification and inclusion of these key areas, as well as more equal distribution of the workload of malaria control field staff. Conclusion The procedure developed enables complete coverage of targeted areas with larval control through comprehensive spatial coverage with community-derived sketch maps. The procedure is practical, affordable, and requires minimal technical skills. This approach can be readily integrated into malaria vector control programmes, scaled up to towns and cities all over Tanzania and adapted to urban settings elsewhere in Africa.

  17. A phase 2b randomized, controlled trial of the efficacy of the GMZ2 malaria vaccine in African children

    DEFF Research Database (Denmark)

    Sirima, Sodiomon B; Mordmüller, Benjamin; Milligan, Paul

    2016-01-01

    -value=0.009). In the ITT analysis, age-adjusted VE was 11.3% (95% CI 2.5%, 19%, p-value=0.013). VE was higher in older children. In GMZ2-vaccinated children, the incidence of malaria decreased with increasing vaccine-induced anti-GMZ2 IgG concentration. There were 32 cases of severe malaria (18......BACKGROUND: GMZ2 is a recombinant protein malaria vaccine, comprising two blood-stage antigens of Plasmodium falciparum, glutamate-rich protein and merozoite surface protein 3. We assessed efficacy of GMZ2 in children in Burkina Faso, Gabon, Ghana and Uganda. METHODS: Children 12-60months old were...... children were randomized, 1735 received three doses of vaccine (868 GMZ2, 867 control-vaccine). There were 641 malaria episodes in the GMZ2/Alum group and 720 in the control group. In the ATP analysis, vaccine efficacy (VE), adjusted for age and site was 14% (95% confidence interval [CI]: 3.6%, 23%, p...

  18. Vß profiles in African children with acute cerebral or uncomplicated malaria: very focused changes among a remarkable global stability

    DEFF Research Database (Denmark)

    Loizon, Séverine; Boeuf, Philippe; Tetteh, John K A

    2007-01-01

    T cells are thought to play a critical role in cerebral malaria pathogenesis. However, available evidences are restricted to rodent models in which V beta specific T cell expansion has been associated with neurological syndrome suggesting involvement of superantigens or dominant antigens. Using f...

  19. Structure and function of a G-actin sequestering protein with a vital role in malaria oocyst development inside the mosquito vector.

    Science.gov (United States)

    Hliscs, Marion; Sattler, Julia M; Tempel, Wolfram; Artz, Jennifer D; Dong, Aiping; Hui, Raymond; Matuschewski, Kai; Schüler, Herwig

    2010-04-09

    Cyclase-associated proteins (CAPs) are evolutionary conserved G-actin-binding proteins that regulate microfilament turnover. CAPs have a modular structure consisting of an N-terminal adenylate cyclase binding domain, a central proline-rich segment, and a C-terminal actin binding domain. Protozoan parasites of the phylum Apicomplexa, such as Cryptosporidium and the malaria parasite Plasmodium, express small CAP orthologs with homology to the C-terminal actin binding domain (C-CAP). Here, we demonstrate by reverse genetics that C-CAP is dispensable for the pathogenic Plasmodium blood stages. However, c-cap(-) parasites display a complete defect in oocyst development in the insect vector. By trans-species complementation we show that the Cryptosporidium parvum ortholog complements the Plasmodium gene functions. Purified recombinant C. parvum C-CAP protein binds actin monomers and prevents actin polymerization. The crystal structure of C. parvum C-CAP shows two monomers with a right-handed beta-helical fold intercalated at their C termini to form the putative physiological dimer. Our results reveal a specific vital role for an apicomplexan G-actin-binding protein during sporogony, the parasite replication phase that precedes formation of malaria transmission stages. This study also exemplifies how Plasmodium reverse genetics combined with biochemical and structural analyses of orthologous proteins can offer a fast track toward systematic gene characterization in apicomplexan parasites.

  20. Variations in susceptibility to common insecticides and resistance mechanisms among morphologically identified sibling species of the malaria vector Anopheles subpictus in Sri Lanka

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    Surendran Sinnathamby N

    2012-02-01

    Full Text Available Abstract Background Anopheles subpictus s.l., an important malaria vector in Sri Lanka, is a complex of four morphologically identified sibling species A-D. Species A-D reportedly differ in bio-ecological traits that are important for vector control. We investigated possible variations that had not been reported previously, in the susceptibility to common insecticides and resistance mechanisms among the An. subpictus sibling species. Methods Adult An. subpictus were collected from localities in four administrative districts in the dry zone of Sri Lanka. Single female isoprogeny lines were established and sibling species status determined according to reported egg morphology. World Health Organization's standard protocols were used for insecticide bioassays and biochemical assays to determine insecticide susceptibility and resistance mechanisms. Susceptibility of mosquitoes was tested against DDT (5%, malathion (4%, deltamethrin (0.05% and λ-cyhalothrin (0.05%. Biochemical basis for resistance was determined through assaying for esterase, glutathione-S-transferase and monooxygenase activities and the insensitivity of acetycholinesterase (AChE to propoxur inhibition. Results All sibling species were highly resistant to DDT. However there were significant differences among the sibling species in their susceptibility to the other tested insecticides. Few species A could be collected for testing, and where testing was possible, species A tended to behave more similarly to species C and D than to B. Species B was more susceptible to all the tested insecticides than the other sibling species. This difference may be attributed to the predominance of species B in coastal areas where selection pressure due to indoor residual spraying of insecticides (IRS was lower. However there were significant differences between the more inland species C and D mainly towards pyrethroids. Higher GST activities in species C and D might have contributed to their greater

  1. The Role of Oxidative Stress in the Longevity and Insecticide Resistance Phenotype of the Major Malaria Vectors Anopheles arabiensis and Anopheles funestus.

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    Shüné V Oliver

    Full Text Available Oxidative stress plays numerous biological roles, both functional and pathological. The role of oxidative stress in various epidemiologically relevant biological traits in Anopheles mosquitoes is not well established. In this study, the effects of oxidative stress on the longevity and insecticide resistance phenotype in the major malaria vector species An. arabiensis and An. funestus were examined. Responses to dietary copper sulphate and hydrogen peroxide were used as proxies for the oxidative stress phenotype by determining the effect of copper on longevity and hydrogen peroxide lethal dose. Glutathione peroxidase and catalase activities were determined colorimetrically. Oxidative burden was quantified as protein carbonyl content. Changes in insecticide resistance phenotype were monitored by WHO bioassay. Insecticide resistant individuals showed an increased capacity for coping with oxidative stress, mediated by increased glutathione peroxidase and catalase activity. This effect was observed in both species, as well as in laboratory strains and F1 individuals derived from wild-caught An. funestus mothers. Phenotypic capacity for coping with oxidative stress was greatest in strains with elevated Cytochrome P450 activity. Synergism of oxidative stress defence enzymes by dietary supplementation with haematin, 3-Amino-1, 2, 4-triazole and Sodium diethyldithiocarbamate significantly increased pyrethroid-induced mortality in An. arabiensis and An. funestus. It is therefore concluded that defence against oxidative stress underlies the augmentation of the insecticide resistance phenotype associated with multiple blood-feeding. This is because multiple blood-feeding ultimately leads to a reduction of oxidative stress in insecticide resistant females, and also reduces the oxidative burden induced by DDT and pyrethroids, by inducing increased glutathione peroxidase activity. This study highlights the importance of oxidative stress in the longevity and

  2. An affordable, quality-assured community-based system for high-resolution entomological surveillance of vector mosquitoes that reflects human malaria infection risk patterns

    Directory of Open Access Journals (Sweden)

    Chaki Prosper P

    2012-05-01

    Full Text Available Abstract Background More sensitive and scalable entomological surveillance tools are required to monitor low levels of transmission that are increasingly common across the tropics, particularly where vector control has been successful. A large-scale larviciding programme in urban Dar es Salaam, Tanzania is supported by a community-based (CB system for trapping adult mosquito densities to monitor programme performance. Methodology An intensive and extensive CB system for routine, longitudinal, programmatic surveillance of malaria vectors and other mosquitoes using the Ifakara Tent Trap (ITT-C was developed in Urban Dar es Salaam, Tanzania, and validated by comparison with quality assurance (QA surveys using either ITT-C or human landing catches (HLC, as well as a cross-sectional survey of malaria parasite prevalence in the same housing compounds. Results Community-based ITT-C had much lower sensitivity per person-night of sampling than HLC (Relative Rate (RR [95% Confidence Interval (CI] = 0.079 [0.051, 0.121], P Anopheles gambiae s.l. and 0.153 [0.137, 0.171], P An. gambiae or Culex respectively. Despite the poor sensitivity of the ITT per night of sampling, when CB-ITT was compared with QA-HLC, it proved at least comparably sensitive in absolute terms (171 versus 169 primary vectors caught and cost-effective (153US$ versus 187US$ per An. gambiae caught because it allowed more spatially extensive and temporally intensive sampling (4284 versus 335 trap nights distributed over 615 versus 240 locations with a mean number of samples per year of 143 versus 141. Despite the very low vectors densities (Annual estimate of about 170 An gambiae s.l bites per person per year, CB-ITT was the only entomological predictor of parasite infection risk (Odds Ratio [95% CI] = 4.43[3.027,7. 454] per An. gambiae or Anopheles funestus caught per night, P =0.0373. Discussion and conclusion CB trapping approaches could be improved with more sensitive traps

  3. Spatial and temporal distribution of the malaria mosquito Anopheles arabiensis in northern Sudan: influence of environmental factors and implications for vector control

    Directory of Open Access Journals (Sweden)

    Malcolm Colin A

    2009-06-01

    Full Text Available Abstract Background Malaria is an important public health problem in northern Sudan, but little is known about the dynamics of its transmission. Given the characteristic low densities of Anopheles arabiensis and the difficult terrain in this area, future vector control strategies are likely to be based on area-wide integrated pest management (AW-IPM that may include the sterile insect technique (SIT. To support the planning and implementation of future AW-IPM activities, larval surveys were carried out to provide key data on spatial and seasonal dynamics of local vector populations. Methods Monthly cross-sectional larval surveys were carried out between March 2005 and May 2007 in two localities (Dongola and Merowe adjacent to the river Nile. A stratified random sampling strategy based on the use of Remote Sensing (RS, Geographical Information Systems (GIS and the Global Positioning System (GPS was used to select survey locations. Breeding sites were mapped using GPS and data on larval density and breeding site characteristics were recorded using handheld computers. Bivariate and multivariate logistic regression models were used to identify breeding site characteristics associated with increased risk of presence of larvae. Seasonal patterns in the proportion of breeding sites positive for larvae were compared visually to contemporaneous data on climate and river height. Results Of a total of 3,349 aquatic habitats sampled, 321 (9.6% contained An. arabiensis larvae. The frequency with which larvae were found varied markedly by habitat type. Although most positive sites were associated with temporary standing water around the margins of the main Nile channel, larvae were also found at brickworks and in areas of leaking pipes and canals – often far from the river. Close to the Nile channel, a distinct seasonal pattern in larval populations was evident and appeared to be linked to the rise and fall of the river level. These patterns were not

  4. Field efficacy of a new mosaic long-lasting mosquito net (PermaNet (R) 3.0) against pyrethroid-resistant malaria vectors : a multi centre study in Western and Central Africa

    OpenAIRE

    Corbel, Vincent; Chabi, Joseph; Dabiré, R. K.; Etang, J.; Nwane, P.; Pigeon, O.; Akogbeto, M.; Hougard, Jean-Marc

    2010-01-01

    Background: Due to the spread of pyrethroid-resistance in malaria vectors in Africa, new strategies and tools are urgently needed to better control malaria transmission. The aim of this study was to evaluate the performances of a new mosaic long-lasting insecticidal net (LLIN), i.e. PermaNet (R) 3.0, against wild pyrethroid-resistant Anopheles gambiae s.l. in West and Central Africa. Methods: A multi centre experimental hut trial was conducted in Malanville (Benin), Vallee du Kou (Burkina Fas...

  5. Field efficacy of a new mosaic long-lasting mosquito net (PermaNet® 3.0) against pyrethroid-resistant malaria vectors: a multi centre study in Western and Central Africa

    OpenAIRE

    Pigeon Olivier; Nwane Philippe; Etang Josiane; Dabiré Roch K; Chabi Joseph; Corbel Vincent; Akogbeto Martin; Hougard Jean-Marc

    2010-01-01

    Abstract Background Due to the spread of pyrethroid-resistance in malaria vectors in Africa, new strategies and tools are urgently needed to better control malaria transmission. The aim of this study was to evaluate the performances of a new mosaic long-lasting insecticidal net (LLIN), i.e. PermaNet® 3.0, against wild pyrethroid-resistant Anopheles gambiae s.l. in West and Central Africa. Methods A multi centre experimental hut trial was conducted in Malanville (Benin), Vallée du Kou (Burkina...

  6. Eugenol, α-pinene and β-caryophyllene from Plectranthus barbatus essential oil as eco-friendly larvicides against malaria, dengue and Japanese encephalitis mosquito vectors.

    Science.gov (United States)

    Govindarajan, Marimuthu; Rajeswary, Mohan; Hoti, S L; Bhattacharyya, Atanu; Benelli, Giovanni

    2016-02-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. Eco-friendly mosquitocides are a priority. In Ayurvedic medicine, Plectranthus species have been used to treat heart disease, convulsions, spasmodic pain and painful urination. In this research, we evaluated the acute toxicity of essential oil from Plectranthus barbatus and its major constituents, against larvae of the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. The chemical composition of P. barbatus essential oil was analyzed by gas chromatography-mass spectroscopy. Nineteen components were identified. Major constituents were eugenol (31.12%), α-pinene (19.38%) and β-caryophyllene (18.42%). Acute toxicity against early third-instar larvae of An. subpictus, Ae. albopictus and Cx. tritaeniorhynchus was investigated. The essential oil had a significant toxic effect against larvae of An. subpictus, Ae. albopictus and Cx. tritaeniorhynchus, with 50% lethal concentration (LC50) values of 84.20, 87.25 and 94.34 μg/ml and 90% lethal concentration (LC90) values of 165.25, 170.56 and 179.58 μg/ml, respectively. Concerning major constituents, eugenol, α-pinene and β-caryophyllene appeared to be most effective against An. subpictus (LC50 = 25.45, 32.09 and 41.66 μg/ml, respectively), followed by Ae. albopictus (LC50 = 28.14, 34.09 and 44.77 μg/ml, respectively) and Cx. tritaeniorhynchus (LC50 = 30.80, 36.75 and 48.17 μg/ml, respectively). Overall, the chance to use metabolites from P. barbatus essential oil against mosquito vectors seems promising, since they are effective at low doses and could be an advantageous alternative to build newer and safer mosquito control tools.

  7. Combining viral vectored and protein-in-adjuvant vaccines against the blood-stage malaria antigen AMA1: report on a phase 1a clinical trial.

    Science.gov (United States)

    Hodgson, Susanne H; Choudhary, Prateek; Elias, Sean C; Milne, Kathryn H; Rampling, Thomas W; Biswas, Sumi; Poulton, Ian D; Miura, Kazutoyo; Douglas, Alexander D; Alanine, Daniel Gw; Illingworth, Joseph J; de Cassan, Simone C; Zhu, Daming; Nicosia, Alfredo; Long, Carole A; Moyle, Sarah; Berrie, Eleanor; Lawrie, Alison M; Wu, Yimin; Ellis, Ruth D; Hill, Adrian V S; Draper, Simon J

    2014-12-01

    The development of effective vaccines against difficult disease targets will require the identification of new subunit vaccination strategies that can induce and maintain effective immune responses in humans. Here we report on a phase 1a clinical trial using the AMA1 antigen from the blood-stage Plasmodium falciparum malaria parasite delivered either as recombinant protein formulated with Alhydrogel adjuvant with and without CPG 7909, or using recombinant vectored vaccines--chimpanzee adenovirus ChAd63 and the orthopoxvirus MVA. A variety of promising "mixed-modality" regimens were tested. All volunteers were primed with ChAd63, and then subsequently boosted with MVA and/or protein-in-adjuvant using either an 8- or 16-week prime-boost interval. We report on the safety of these regimens, as well as the T cell, B cell, and serum antibody responses. Notably, IgG antibody responses primed by ChAd63 were comparably boosted by AMA1 protein vaccine, irrespective of whether CPG 7909 was included in the Alhydrogel adjuvant. The ability to improve the potency of a relatively weak aluminium-based adjuvant in humans, by previously priming with an adenoviral vaccine vector encoding the same antigen, thus offers a novel vaccination strategy for difficult or neglected disease targets when access to more potent adjuvants is not possible.

  8. Statistical modeling of the abundance of vectors of West African Rift Valley fever in Barkedji, Senegal.

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    Cheikh Talla

    Full Text Available Rift Valley fever is an emerging mosquito-borne disease that represents a threat to human and animal health. The exophilic and exophagic behavior of the two main vector in West Africa (Aedes vexans and Culex poicilipes, adverse events post-vaccination, and lack of treatment, render ineffective the disease control. Therefore it is essential to develop an information system that facilitates decision-making and the implementation of adaptation strategies. In East Africa, RVF outbreaks are linked with abnormally high rainfall, and can be predicted up to 5 months in advance by modeling approaches using climatic and environmental parameters. However, the application of these models in West Africa remains unsatisfactory due to a lack of data for animal and human cases and differences in the dynamics of the disease emergence and the vector species involved in transmission. Models have been proposed for West Africa but they were restricted to rainfall impact analysis without a spatial dimension. In this study, we developed a mixed Bayesian statistical model to evaluate the effects of climatic and ecological determinants on the spatiotemporal dynamics of the two main vectors. Adult mosquito abundance data were generated from July to December every fortnight in 2005-2006 at 79 sites, including temporary ponds, bare soils, shrubby savannah, wooded savannah, steppes, and villages in the Barkédji area. The results demonstrate the importance of environmental factors and weather conditions for predicting mosquito abundance. The rainfall and minimum temperature were positively correlated with the abundance of Cx. poicilipes, whereas the maximum temperature had negative effects. The rainfall was negatively correlated with the abundance of Ae. vexans. After combining land cover classes, weather conditions, and vector abundance, our model was used to predict the areas and periods with the highest risks of vector pressure. This information could support decision

  9. Population structure analyses and demographic history of the malaria vector Anopheles albimanus from the Caribbean and the Pacific regions of Colombia

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    Conn Jan E

    2009-11-01

    Full Text Available Abstract Background Anopheles albimanus is an important malaria vector in some areas throughout its distribution in the Caribbean and the Pacific regions of Colombia, covering three biogeographic zones of the neotropical region, Maracaibo, Magdalena and Chocó. Methods This study was conducted to estimate intra-population genetic diversity, genetic differentiation and demographic history of An. albimanus populations because knowledge of vector population structure is a useful tool to guide malaria control programmes. Analyses were based on mtDNA COI gene sequences and four microsatellite loci of individuals collected in eight populations from the Caribbean and the Pacific regions of Colombia. Results Two distinctive groups were consistently detected corresponding to COI haplotypes from each region. A star-shaped statistical parsimony network, significant and unimodal mismatch distribution, and significant negative neutrality tests together suggest a past demographic expansion or a selective sweep in An. albimanus from the Caribbean coast approximately 21,994 years ago during the late Pleistocene. Overall moderate to low genetic differentiation was observed between populations within each region. However, a significant level of differentiation among the populations closer to Buenaventura in the Pacific region was observed. The isolation by distance model best explained genetic differentiation among the Caribbean region localities: Los Achiotes, Santa Rosa de Lima and Moñitos, but it could not explain the genetic differentiation observed between Turbo (Magdalena providence, and the Pacific region localities (Nuquí, Buenaventura, Tumaco. The patterns of differentiation in the populations from the different biogeographic provinces could not be entirely attributed to isolation by distance. Conclusion The data provide evidence for limited past gene flow between the Caribbean and the Pacific regions, as estimated by mtDNA sequences and current gene

  10. One-pot biogenic fabrication of silver nanocrystals using Quisqualis indica: Effectiveness on malaria and Zika virus mosquito vectors, and impact on non-target aquatic organisms.

    Science.gov (United States)

    Govindarajan, Marimuthu; Vijayan, Periasamy; Kadaikunnan, Shine; Alharbi, Naiyf S; Benelli, Giovanni

    2016-09-01

    Currently, mosquito vector control is facing a number of key challenges, including the rapid development of resistance to synthetic pesticides and the recent spread of aggressive arbovirus outbreaks. The biosynthesis of silver nanoparticles (AgNPs) is currently considered an environmental friendly alternative to the employ of pyrethroids, carbamates and microbial agents (e.g. Bacillus thuringiensis var. israelensis), since AgNPs are easy to produce, effective and stable in the aquatic environment. However, their biophysical features showed wide variations according to the botanical agent using for the green synthesis, outlining the importance of screening local floral resources used as reducing and stabilizing agents. In this study, we focused on the biophysical properties and the mosquitocidal action of Quisqualis indica-fabricated AgNPs. AgNPs were characterized using spectroscopic (UV, FTIR, XRD) and microscopic (AFM, SEM, TEM and EDX) techniques. AFM, SEM and TEM confirmed the synthesis of poly-dispersed AgNPs with spherical shape and size ranging from 1 to 30nm. XRD shed light on the crystalline structure of these AgNPs. The acute toxicity of Quisqualis indica extract and AgNPs was evaluated against malaria, arbovirus, and filariasis vectors, Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus, as well as on three important non-target aquatic organisms. The Q. indica leaf extract showed moderate larvicidal effectiveness on Cx. quinquefasciatus (LC50=220.42), Ae. aegypti (LC50=203.63) and An. stephensi (LC50=185.98). Q. indica-fabricated AgNPs showed high toxicity against Cx. quinquefasciatus (LC50=14.63), Ae. aegypti (LC50=13.55) and An. stephensi (LC50=12.52), respectively. Notably, Q. indica-synthesized AgNPs were moderately toxic to non-target aquatic mosquito predators Anisops bouvieri (LC50=653.05μg/mL), Diplonychus indicus (LC50=860.94μg/mL) and Gambusia affinis (LC50=2183.16μg/mL), if compared to the targeted mosquitoes. Overall, the

  11. Is there an efficient trap or collection method for sampling Anopheles darlingi and other malaria vectors that can describe the essential parameters affecting transmission dynamics as effectively as human landing catches? - A Review

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    José Bento Pereira Lima

    2014-08-01

    Full Text Available Distribution, abundance, feeding behaviour, host preference, parity status and human-biting and infection rates are among the medical entomological parameters evaluated when determining the vector capacity of mosquito species. To evaluate these parameters, mosquitoes must be collected using an appropriate method. Malaria is primarily transmitted by anthropophilic and synanthropic anophelines. Thus, collection methods must result in the identification of the anthropophilic species and efficiently evaluate the parameters involved in malaria transmission dynamics. Consequently, human landing catches would be the most appropriate method if not for their inherent risk. The choice of alternative anopheline collection methods, such as traps, must consider their effectiveness in reproducing the efficiency of human attraction. Collection methods lure mosquitoes by using a mixture of olfactory, visual and thermal cues. Here, we reviewed, classified and compared the efficiency of anopheline collection methods, with an emphasis on Neotropical anthropophilic species, especially Anopheles darlingi, in distinct malaria epidemiological conditions in Brazil.

  12. Knowledge and beliefs about malaria transmission and practices for vector control in Southern Mexico Conocimientos y creencias acerca del paludismo y prácticas para el control de vectores en el sur de México

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    Américo David Rodríguez

    2003-04-01

    Full Text Available OBJECTIVE: To investigate the knowledge and beliefs about malaria transmission and practices for vector control in eight villages on the coastal plain of Chiapas, Mexico. MATERIAL AND METHODS: A cross-sectional survey was conducted during May and June 1995 in Chiapas, Mexico. A questionnaire to investigate family structure, knowledge on malaria transmission, preventive measures and attitudes towards seeking treatment was applied to both family heads of a sample of households. Associations were analyzed by estimating odds ratios with confidence intervals and p values, using bivariate and multivariate logistic regression methods. RESULTS: Malaria knowledge was poor and only 48% associated malaria with mosquito bites. The perceived benefit of indoor residual spraying was associated to a reduction of mosquitoes, a reduction in the numbers of cockroaches and rats, but only 3% associated it directly with the prevention of malaria transmission. Most villagers (97.6% agreed with the indoor residual spraying of insecticides. Ninety nine percent of villagers had mosquito bednets, 75.7% used them all year round. Other measures used by villagers to prevent mosquito bites were smoke and mosquito coils. Above 40% of villagers self-medicated when any member of the family had a fever episode, but 51% attended proper health services (community dispensary, private physician, health worker. About 61% used pesticides for agricultural or livestock purposes and 55% applied them themselves. Women had a greater participation as family health promoters, with 70% of the housewives being in charge of the application of self-protection preventive measures. CONCLUSIONS: Educational programs aimed at increasing awareness on the participation of mosquitoes on malaria transmission could promote community participation in malaria control in the region.OBJETIVO: Investigar el conocimiento, las creencias sobre paludismo y las prácticas para el control de vectores en ocho

  13. Larval habitat for the avian malaria vector culex quinquefasciatus (Diptera: Culicidae) in altered mid-elevation mesic-dry forests in Hawai'i

    Science.gov (United States)

    Reiter, M.E.; Lapointe, D.A.

    2009-01-01

    Effective management of avian malaria (Plasmodium relictum) in Hawai'i's endemic honeycreepers (Drepanidinae) requires the identification and subsequent reduction or treatment of larval habitat for the mosquito vector, Culex quinquefasciatus (Diptera: Culicidae). We conducted ground surveys, treehole surveys, and helicopter aerial surveys from 20012003 to identify all potential larval mosquito habitat within two 100+ ha mesic-dry forest study sites in Hawai'i Volcanoes National Park, Hawai'i; 'Ainahou Ranch and Mauna Loa Strip Road. At 'Ainahou Ranch, anthropogenic sites (43%) were more likely to contain mosquitoes than naturally occurring (8%) sites. Larvae of Cx. quinquefasciatus were predominately found in anthropogenic sites while Aedes albopictus larvae occurred less frequently in both anthropogenic sites and naturally-occurring sites. Additionally, moderate-size (???20-22,000 liters) anthropogenic potential larval habitat had >50% probability of mosquito presence compared to larger- and smaller-volume habitat (<50%). Less than 20% of trees surveyed at ' Ainahou Ranch had treeholes and few mosquito larvae were detected. Aerial surveys at 'Ainahou Ranch detected 56% (95% CI: 42-68%) of the potential larval habitat identified in ground surveys. At Mauna Loa Strip Road, Cx. quinquefasciatus larvae were only found in the rock holes of small intermittent stream drainages that made up 20% (5 of 25) of the total potential larval habitat. The volume of the potential larval habitat did not influence the probability of mosquito occurrence at Mauna Loa Strip Road. Our results suggest that Cx. quinquefasciatus abundance, and subsequently avian malaria, may be controlled by larval habitat reduction in the mesic-dry landscapes of Hawai'i where anthropogenic sources predominate.

  14. Persistence of full-length caspase-12 and its relation to malaria in West and Central African populations.

    NARCIS (Netherlands)

    McCall, M.B.B.; Ferwerda, B.; Hopman, J.; Ploemen, I.H.J.; Maiga, B.; Daou, M.; Dolo, A.; Hermsen, C.C.; Doumbo, O.K.; Bedu-Addo, G.; Meer, J.W.M. van der; Troye-Blomberg, M.; Ven, A.J.A.M. van der; Schumann, R.R.; Sauerwein, R.W.; Mockenhaupt, F.P.; Netea, M.G.

    2010-01-01

    BACKGROUND: The full-length (L-) variant of caspase-12 is believed to predispose to sepsis. It has been replaced in the genome of most human populations by the (S-) variant, which leads to premature termination of translation. Strikingly, the L-allele is still widely prevalent in African populations

  15. Estimation of the sporozoite rate of malaria vectors using the polymerase chain reaction and a mathematical model.

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    Harada M

    2000-08-01

    Full Text Available We developed a sensitive polymerase chain reaction (PCR method for the detection of Plasmodium falciparum DNA from mosquitoes collected in the field. Plasmodium falciparum was detected from 15.2% of 1-parous mosquitoes, Anopheles farauti, in the Solomon Islands through use of the PCR method. A novel mathematical model was developed to estimate the sporozoite rate based on the malaria-positive rate of 1-parous mosquitoes. Using this model, the sporozoite rate of Anopheles farauti in the Solomon Islands was calculated to be 0.09%. This method enables estimation of the sporozoite rate based on a relatively small number (100-200 of mosquitoes compared with the number needed for the ELISA method.

  16. Malaria: Knowledge and prevention practices among school adolescents in a coastal community in Calabar, Nigeria

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    Ndifreke E. Udonwa

    2010-03-01

    Full Text Available Background: Malaria prevention and treatment constitute an unbearable economic burden to most African countries, especially south of the Sahara, where about 500 million cases occur annually. The problem of malaria among adolescents has largely been overshadowed by the huge burden of the disease among young children. Attention to malaria among adolescents has also been diverted by the huge burden of HIV/AIDS among adolescents. Some surveys reveal a lack of knowledge and many misconceptions about the transmission and treatment of malaria, which could adversely affect malaria control measures and antimalarial therapy. Such a knowledge gap could have an adverse effect on school children, who could be used as change agents and as role models for their siblings and peers in the malaria control strategy.Objectives: To determine the malaria prevention practices of school adolescents in the coastal community of Calabar, Nigeria.Method: This was a cross-sectional survey involving secondary schools in southern Calabar. Four hundred adolescents were randomly selected from the 4565 learners in 5 out of 17 secondary schools in southern Calabar, Cross River State, Nigeria. A self-administered, semi-structured questionnaire was administered to the respondents.Results: Most respondents (77.5% were aware that the vector transmits the malaria parasite through biting. Fewer respondents would prevent malaria attacks by clearing the vegetation in the peri-domestic environment (13.5%, filling up potholes (16.9%, opening up drainage (11%, using insecticide-treated nets (25.7% or using antimalarial drugs (11.2%. Less than one-tenth (8% would use various other methods such as not accepting unscreened blood, while only 11% obtained the information from their teachers.Conclusion: The study identified knowledge gaps among school children. There is a need to empower teachers with information about the cause of malaria and prevention strategies.

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

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    Okumu Fredros O

    2013-01-01

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

  18. Mosquitocidal and antibacterial activity of green-synthesized silver nanoparticles from Aloe vera extracts: towards an effective tool against the malaria vector Anopheles stephensi?

    Science.gov (United States)

    Dinesh, Devakumar; Murugan, Kadarkarai; Madhiyazhagan, Pari; Panneerselvam, Chellasamy; Kumar, Palanisamy Mahesh; Nicoletti, Marcello; Jiang, Wei; Benelli, Giovanni; Chandramohan, Balamurugan; Suresh, Udaiyan

    2015-04-01

    Mosquitoes represent an important threat for lives of millions of people worldwide, acting as vectors for devastating pathogens, such as malaria, yellow fever, dengue, and West Nile. In addition, pathogens and parasites polluting water also constitute a severe plague for populations of developing countries. Here, we investigated the mosquitocidal and antibacterial properties of Aloe vera leaf extract and silver nanoparticles synthesized using A. vera extract. Mosquitocidal properties were assessed in laboratory against larvae (I-IV instar) and pupae of the malaria vector Anopheles stephensi. Green-synthesized silver nanoparticles were tested against An. stephensi also in field conditions. Antibacterial properties of nanoparticles were evaluated against Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi using the agar disk diffusion and minimum inhibitory concentration protocol. The synthesized silver nanoparticles were characterized by UV-vis spectrum, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). In laboratory conditions, the A. vera extract was toxic against An. stephensi larvae and pupae, even at low dosages. LC50 were 48.79 ppm (I instar), 59.09 ppm (II instar), 70.88 ppm (III instar), 83.58 ppm (IV instar), and 152.55 ppm (pupae). Green-synthesized silver nanoparticles were highly toxic against An. stephensi. LC50 were 3.825 ppm (I instar), 4.119 ppm (II instar), 4.982 ppm (III instar), 5.711 ppm (IV instar), and 6.113 ppm (pupae). In field conditions, the application of A. vera-synthesized silver nanoparticles (10 × LC50) leads to An. stephensi larval reduction of 74.5, 86.6, and 97.7%, after 24, 48, and 72 h, respectively. Nanoparticles also showed antibacterial properties, and the maximum concentration tested (150 mg/L) evoked an inhibition zone wider than 80 mm in all tested bacterium species. This study adds knowledge about the use of green synthesis of nanoparticles in

  19. Dynamics of multiple insecticide resistance in the malaria vector Anopheles gambiae in a rice growing area in South-Western Burkina Faso

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    Ouédraogo Jean-Bosco

    2008-09-01

    Full Text Available Abstract Background Insecticide resistance of the main malaria vector, Anopheles gambiae, has been reported in south-western Burkina Faso, West Africa. Cross-resistance to DDT and pyrethroids was conferred by alterations at site of action in the sodium channel, the Leu-Phe kdr mutation; resistance to organophosphates and carbamates resulted from a single point mutation in the oxyanion hole of the acetylcholinesterase enzyme designed as ace-1R. Methods An entomological survey was carried out during the rainy season of 2005 at Vallée du Kou, a rice growing area in south-western Burkina Faso. At the Vallée du Kou, both insecticide resistance mechanisms have been previously described in the M and S molecular forms of An. gambiae. This survey aimed i to update the temporal dynamics and the circumsporozoite infection rate of the two molecular forms M and S of An. gambiae ii to update the frequency of the Leu-Phe kdr mutation within these forms and finally iii to investigate the occurrence of the ace-1R mutation. Mosquitoes collected by indoor residual collection and by human landing catches were counted and morphologically identified. Species and molecular forms of An. gambiae, ace-1R and Leu-Phe kdr mutations were determined using PCR techniques. The presence of the circumsporozoite protein of Plasmodium falciparum was determined using ELISA. Results Anopheles gambiae populations were dominated by the M form. However the S form occurred in relative important proportion towards the end of the rainy season with a maximum peak in October at 51%. Sporozoite rates were similar in both forms. The frequency of the Leu-Phe kdr mutation in the S form reached a fixation level while it is still spreading in the M form. Furthermore, the ace-1R mutation prevailed predominately in the S form and has just started spreading in the M form. The two mutations occurred concomitantly both in M and S populations. Conclusion These results showed that the Vallée du Kou

  20. False positive circumsporozoite protein ELISA: a challenge for the estimation of the entomological inoculation rate of malaria and for vector incrimination

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    Trung Ho Dinh

    2011-07-01

    Full Text Available Abstract Background The entomological inoculation rate (EIR is an important indicator in estimating malaria transmission and the impact of vector control. To assess the EIR, the enzyme-linked immunosorbent assay (ELISA to detect the circumsporozoite protein (CSP is increasingly used. However, several studies have reported false positive results in this ELISA. The false positive results could lead to an overestimation of the EIR. The aim of present study was to estimate the level of false positivity among different anopheline species in Cambodia and Vietnam and to check for the presence of other parasites that might interact with the anti-CSP monoclonal antibodies. Methods Mosquitoes collected in Cambodia and Vietnam were identified and tested for the presence of sporozoites in head and thorax by using CSP-ELISA. ELISA positive samples were confirmed by a Plasmodium specific PCR. False positive mosquitoes were checked by PCR for the presence of parasites belonging to the Haemosporidia, Trypanosomatidae, Piroplasmida, and Haemogregarines. The heat-stability and the presence of the cross-reacting antigen in the abdomen of the mosquitoes were also checked. Results Specimens (N = 16,160 of seven anopheline species were tested by CSP-ELISA for Plasmodium falciparum and Plasmodium vivax (Pv210 and Pv247. Two new vector species were identified for the region: Anopheles pampanai (P. vivax and Anopheles barbirostris (Plasmodium malariae. In 88% (155/176 of the mosquitoes found positive with the P. falciparum CSP-ELISA, the presence of Plasmodium sporozoites could not be confirmed by PCR. This percentage was much lower (28% or 5/18 for P. vivax CSP-ELISAs. False positive CSP-ELISA results were associated with zoophilic mosquito species. None of the targeted parasites could be detected in these CSP-ELISA false positive mosquitoes. The ELISA reacting antigen of P. falciparum was heat-stable in CSP-ELISA true positive specimens, but not in the false positives

  1. Predicting Scenarios for Successful Autodissemination of Pyriproxyfen by Malaria Vectors from Their Resting Sites to Aquatic Habitats; Description and Simulation Analysis of a Field-Parameterizable Model.

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    Samson S Kiware

    Full Text Available Large-cage experiments indicate pyriproxifen (PPF can be transferred from resting sites to aquatic habitats by Anopheles arabiensis--malaria vector mosquitoes to inhibit emergence of their own offspring. PPF coverage is amplified twice: (1 partial coverage of resting sites with PPF contamination results in far higher contamination coverage of adult mosquitoes because they are mobile and use numerous resting sites per gonotrophic cycle, and (2 even greater contamination coverage of aquatic habitats results from accumulation of PPF from multiple oviposition events.Deterministic mathematical models are described that use only field-measurable input parameters and capture the biological processes that mediate PPF autodissemination. Recent successes in large cages can be rationalized, and the plausibility of success under full field conditions can be evaluated a priori. The model also defines measurable properties of PPF delivery prototypes that may be optimized under controlled experimental conditions to maximize chances of success in full field trials. The most obvious flaw in this model is the endogenous relationship that inevitably occurs between the larval habitat coverage and the measured rate of oviposition into those habitats if the target mosquito species is used to mediate PPF transfer. However, this inconsistency also illustrates the potential advantages of using a different, non-target mosquito species for contamination at selected resting sites that shares the same aquatic habitats as the primary target. For autodissemination interventions to eliminate malaria transmission or vector populations during the dry season window of opportunity will require comprehensive contamination of the most challenging subset of aquatic habitats [Formula: see text] that persist or retain PPF activity (Ux for only one week [Formula: see text], where Ux = 7 days. To achieve >99% contamination coverage of these habitats will necessitate values for the

  2. Infection of malaria (Anopheles gambiae s.s.) and filariasis (Culex quinquefasciatus) vectors with the entomopathogenic fungus Metarhizium anisopliae

    NARCIS (Netherlands)

    Scholte, E.J.; Njiru, B.N.; Smallegange, R.C.; Takken, W.; Knols, B.G.J.

    2003-01-01

    Background: Current intra-domiciliary vector control depends on the application of residual insecticides and/or repellents. Although biological control agents have been developed against aquatic mosquito stages, none are available for adults. Following successful use of an entomopathogenic fungus ag

  3. Operational efficiency and sustainability of vector control of malaria and dengue: descriptive case studies from the Philippines

    NARCIS (Netherlands)

    Berg, van den H.; Velayudhan, R.; Ebol, A.; Catbagan, B.H.G.; Turingan, R.; Tuso, M.; Hii, J.

    2012-01-01

    Background: Analysis is lacking on the management of vector control systems in disease-endemic countries with respect to the efficiency and sustainability of operations. Methods: Three locations were selected, at the scale of province, municipality and barangay (i.e. village). Data on disease incide

  4. DEET microencapsulation: a slow-release formulation enhancing the residual efficacy of bed nets against malaria vectors

    NARCIS (Netherlands)

    N'Guessan, R.; Knols, B.G.J.; Pennetier, C.; Rowland, M.

    2008-01-01

    Textile materials treated with synthetic repellents have the potential to provide protection against insect disease vectors but lack the residual activity necessary to achieve a prolonged effect or to be cost-effective. DEET MC is a formulation of DEET (N,N diethyl-m-toluamide) in which the repellen

  5. Gene-therapy for malaria prevention.

    Science.gov (United States)

    Rodrigues, Mauricio M; Soares, Irene S

    2014-11-01

    The limited number of tools for malaria prevention and the inability to eradicate the disease have required large investments in vaccine development, as vaccines have been the only foreseeable type of immunoprophylaxis against malaria. An alternative strategy named vectored immunoprophylaxis (VIP) now would allow genetically transduced host cells to assemble and secrete antibodies that neutralize the infectivity of the malaria parasite and prevent disease.

  6. Comparative efficacy of neem and dimethyl phthalate (DMP)against malaria vector,Anopheles stephensi (dip-tera:culicidae)

    Institute of Scientific and Technical Information of China (English)

    HVatandoos; FRafi; AKhazani; JRafinejad; MKhoobdel; AKebriai-Zadeh; MRAbai; AAHanafi Bojd; AAAkhavan; SMAbtahi

    2008-01-01

    Malaria is one of the most important parasitic diseases in the world which is transmitted by the Anopheles mos-quitoes.There are several methods for malaria control.One of them is application of repellents on skin in ma-larious area as an intergrated vectro management measures.This study evaluated two repellents of DMP as a synthtic and locally product of neem oil as a botanical repellent against Anopheles stephensi.The modified method of K &D was used for the tests.Probing/biting rates on the shaved belly of white rabbits were coun-ted.ED50 and ED95 values were calculated by probit statistic software.Calculation of effective dose (ED50, ED90)on human volunteer and white rabbit was performed using regression line.Protection and failure time of DMP and neem oil was also determined.ED50 value of DMP and neem oil was determined as 0.0076 and 0. 159 mg/cm2 respectively on white rabit.The figures of ED90 value of DMP and neem oil was determined as 0. 046 and 1.388 mg/cm2 .DMP and neem oil showed repellency effects against An.stephensi on human volun-teers with ED50 value of 0.0037 and 0.127 mg/cm2 respectively.ED90 value of DMP was determined as 0. 032 mg/cm2 .neem oil exhibited a ED90 value of 1.066 mg/cm2 on human volunteer.The protection time of 6-7 hours for DMP and 31 minute for neem oil was determined.The failure times for DMP and Neem was 9 hours and 65 minutes rspectively on human bait.Our results exhibited that plant-based repellent is generally less effective than synthetic repellents.However,use of locally made botanical materials would be of great ad-vantages for personal protection against mosquito biting.

  7. Utilization of combined remote sensing techniques to detect environmental variables influencing malaria vector densities in rural West Africa

    Science.gov (United States)

    2012-01-01

    Introduction The use of remote sensing has found its way into the field of epidemiology within the last decades. With the increased sensor resolution of recent and future satellites new possibilities emerge for high resolution risk modeling and risk mapping. Methods A SPOT 5 satellite image, taken during the rainy season 2009 was used for calculating indices by combining the image's spectral bands. Besides the widely used Normalized Difference Vegetation Index (NDVI) other indices were tested for significant correlation against field observations. Multiple steps, including the detection of surface water, its breeding appropriateness for Anopheles and modeling of vector imagines abundance, were performed. Data collection on larvae, adult vectors and geographic parameters in the field, was amended by using remote sensing techniques to gather data on altitude (Digital Elevation Model = DEM), precipitation (Tropical Rainfall Measurement Mission = TRMM), land surface temperatures (LST). Results The DEM derived altitude as well as indices calculations combining the satellite's spectral bands (NDTI = Normalized Difference Turbidity Index, NDWI Mac Feeters = Normalized Difference Water Index) turned out to be reliable indicators for surface water in the local geographic setting. While Anopheles larvae abundance in habitats is driven by multiple, interconnected factors - amongst which the NDVI - and precipitation events, the presence of vector imagines was found to be correlated negatively to remotely sensed LST and positively to the cumulated amount of rainfall in the preceding 15 days and to the Normalized Difference Pond Index (NDPI) within the 500 m buffer zone around capture points. Conclusions Remotely sensed geographical and meteorological factors, including precipitations, temperature, as well as vegetation, humidity and land cover indicators could be used as explanatory variables for surface water presence, larval development and imagines densities. This modeling

  8. Evaluation of repellent activities of Cymbopogon essential oils against mosquito vectors of Malaria, Filariasis and Dengue Fever in India.

    Science.gov (United States)

    Tyagi, B K; Shahi, A K; Kaul, B L

    1998-08-01

    Essential oils of four species and two hybrid varieties of Cymbopogon grasses were evaluated for their repellent properties against the major vector mosquitoes, namely, Anopheles stephensi, Culex quinque-fasciatus and Aedes aegypti, both in laboratory and field. The magnitude of repellency in the Cymbopogon essential oils was found to be of moderate to high order. All grass species protected completely from mosquito bites for 4 hrs, whereas C. nardus provided protection for as much as 8-10 hrs overnight.

  9. Utilization of combined remote sensing techniques to detect environmental variables influencing malaria vector densities in rural West Africa

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    Dambach Peter

    2012-03-01

    Full Text Available Abstract Introduction The use of remote sensing has found its way into the field of epidemiology within the last decades. With the increased sensor resolution of recent and future satellites new possibilities emerge for high resolution risk modeling and risk mapping. Methods A SPOT 5 satellite image, taken during the rainy season 2009 was used for calculating indices by combining the image's spectral bands. Besides the widely used Normalized Difference Vegetation Index (NDVI other indices were tested for significant correlation against field observations. Multiple steps, including the detection of surface water, its breeding appropriateness for Anopheles and modeling of vector imagines abundance, were performed. Data collection on larvae, adult vectors and geographic parameters in the field, was amended by using remote sensing techniques to gather data on altitude (Digital Elevation Model = DEM, precipitation (Tropical Rainfall Measurement Mission = TRMM, land surface temperatures (LST. Results The DEM derived altitude as well as indices calculations combining the satellite's spectral bands (NDTI = Normalized Difference Turbidity Index, NDWI Mac Feeters = Normalized Difference Water Index turned out to be reliable indicators for surface water in the local geographic setting. While Anopheles larvae abundance in habitats is driven by multiple, interconnected factors - amongst which the NDVI - and precipitation events, the presence of vector imagines was found to be correlated negatively to remotely sensed LST and positively to the cumulated amount of rainfall in the preceding 15 days and to the Normalized Difference Pond Index (NDPI within the 500 m buffer zone around capture points. Conclusions Remotely sensed geographical and meteorological factors, including precipitations, temperature, as well as vegetation, humidity and land cover indicators could be used as explanatory variables for surface water presence, larval development and imagines

  10. Multipurpose effectiveness of Couroupita guianensis-synthesized gold nanoparticles: high antiplasmodial potential, field efficacy against malaria vectors and synergy with Aplocheilus lineatus predators.

    Science.gov (United States)

    Subramaniam, Jayapal; Murugan, Kadarkarai; Panneerselvam, Chellasamy; Kovendan, Kalimuthu; Madhiyazhagan, Pari; Dinesh, Devakumar; Kumar, Palanisamy Mahesh; Chandramohan, Balamurugan; Suresh, Udaiyan; Rajaganesh, Rajapandian; Alsalhi, Mohamad Saleh; Devanesan, Sandhanasamy; Nicoletti, Marcello; Canale, Angelo; Benelli, Giovanni

    2016-04-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. According to recent estimates, about 3.2 billion people, almost half of the world's population, are at risk of malaria. Malaria control is particularly challenging due to a growing number of chloroquine-resistant Plasmodium and pesticide-resistant Anopheles vectors. Newer and safer control tools are required. In this research, gold nanoparticles (AuNPs) were biosynthesized using a cheap flower extract of Couroupita guianensis as reducing and stabilizing agent. The biofabrication of AuNP was confirmed by UV-vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), zeta potential, and particle size analysis. AuNP showed different shapes including spheres, ovals, and triangles. AuNPs were crystalline in nature with face-centered cubic geometry; mean size was 29.2-43.8 nm. In laboratory conditions, AuNPs were toxic against Anopheles stephensi larvae, pupae, and adults. LC50 was 17.36 ppm (larva I), 19.79 ppm (larva II), 21.69 ppm (larva III), 24.57 ppm (larva IV), 28.78 ppm (pupa), and 11.23 ppm (adult). In the field, a single treatment with C. guianensis flower extract and AuNP (10 × LC50) led to complete larval mortality after 72 h. In standard laboratory conditions, the predation efficiency of golden wonder killifish, Aplocheilus lineatus, against A. stephensi IV instar larvae was 56.38 %, while in an aquatic environment treated with sub-lethal doses of the flower extract or AuNP, predation efficiency was boosted to 83.98 and 98.04 %, respectively. Lastly, the antiplasmodial activity of C. guianensis flower extract and AuNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. IC50 of C. guianensis flower extract was 43.21 μg/ml (CQ-s) and 51.16 μg/ml (CQ-r). AuNP IC50 was 69.47 μg/ml (CQ-s) and 76

  11. 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

    Science.gov (United States)

    HARRISON, BRUCE A.; RUIZ-LOPEZ, FREDDY; FALERO, GUILLERMO CALDERON; SAVAGE, HARRY M.; PECOR, JAMES E.; WILKERSON, RICHARD C.

    2015-01-01

    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 actually An. pholidotus. Our specimens are the first correctly associated females of An. lepidotus, which allow us to provide a new morphological interpretation for the adult habitus of this species. This finding is also corroborated by molecular data from a portion of the Cytochrome Oxidase I (COI) gene and ribosomal DNA Internal Transcribed Spacer 2 (rDNA ITS2). The pupal stage of An. lepidotus is described for the first time, and additional larval characters are also noted. Diagnostic morphological characters for the adult, pupal, and larval stages of An. pholidotus are provided to separate the two species. All stages of An. lepidotus are easily separated from other currently known species in subgenus Kerteszia and a new key to the females of An. (Kerteszia) is given. Previously published distribution, bionomics, and medical significance data are corrected and enhanced. PMID:26726290

  12. Strong larvicidal activity of three species of Spilanthes (Akarkara) against malaria (Anopheles stephensi Liston, Anopheles culicifacies, species C) and filaria vector (Culex quinquefasciatus Say).

    Science.gov (United States)

    Pandey, Vibha; Agrawal, Veena; Raghavendra, K; Dash, A P

    2007-12-01

    A system for biocontrol of malaria and filarial mosquito vectors has been developed using herbal extracts of three Spilanthes species, S. acmella L.var oleraceae Clarke, S. calva L. and S. paniculata Wall ex DC. Cent percent mortalities was achieved against the late third/early fourth instar larvae of A. stephensi Liston, A. culicifacies species C and C. quinquefasciatus Say using crude hexane extract obtained from flower heads of Spilanthes spp. Of the three plant species, S. acmella extract proved to be the most effective in inducing complete lethality at minimum doses, the respective LC50 and LC90 values being 4.57 and 7.83 (A. stephensi), 0.87 and 1.92 (A. culicifacies) and 3.11 and 8.89 ppm (C. quinquefasciatus). This was followed by S. calva and S. paniculata extracts, respectively. This is the first report of achieving cent percent lethality against these mosquito larvae using minimal doses of plant extracts from this or any other plant species.

  13. Eficacia del control de larvas de vectores de la malaria con peces larvívoros nativos en San Martín, Perú

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    Elmer Rojas P

    2004-01-01

    Full Text Available Objetivo: Determinar la eficacia del control larvario de vectores de la malaria con peces larvívoros nativos en San Martín, Perú. Material y métodos: Estudio experimental que se llevó a cabo en las localidades de Yumbatos, Alianza y San Juan de Shanusi con ocho criaderos cada uno, identificándose las especies nativas Rivulus urophtalmus "chuina" y Pyrrulina brevis "achualillo" comparados con la eficacia ejercida por Poecilia reticulata "guppy". Se midieron variables como temperatura, pH, concentración de electrolitos en el agua, densidad de los peces y presencia de otros depredadores. Resultados: Los peces nativos alcanzaron una eficacia de 98% en el control de larvas de Anopheles, cuando se mantuvieron en densidades entre 10 y 15 peces/m²; estos peces alcanzan longitudes hasta de 8 cm, y tienen similar o mayor voracidad que Poecilia reticulata. Asimismo, se evidenció la existencia de peces depredadores, Hoplias malabaricus "fasaco" y Simbranchus marmoratus "atinga", los que se alimentan de estos peces pequeños. Conclusiones: Los peces nativos son eficaces para el control de larvas de Anopheles; asimismo, se deben tener en cuenta la existencia de otras especies depredadoras, así como la limpieza de la maleza de los criaderos para incrementar la eficacia del control.

  14. Protective immunization of horses with a recombinant canarypox virus vectored vaccine co-expressing genes encoding the outer capsid proteins of African horse sickness virus.

    Science.gov (United States)

    Guthrie, Alan J; Quan, Melvyn; Lourens, Carina W; Audonnet, Jean-Christophe; Minke, Jules M; Yao, Jiansheng; He, Ling; Nordgren, Robert; Gardner, Ian A; Maclachlan, N James

    2009-07-16

    We describe the development and preliminary characterization of a recombinant canarypox virus vectored (ALVAC) vaccine for protective immunization of equids against African horse sickness virus (AHSV) infection. Horses (n=8) immunized with either of two concentrations of recombinant canarypox virus vector (ALVAC-AHSV) co-expressing synthetic genes encoding the outer capsid proteins (VP2 and VP5) of AHSV serotype 4 (AHSV-4) developed variable titres (horse immunized with a commercial recombinant canarypox virus vectored vaccine expressing the haemagglutinin genes of two equine influenza H3N8 viruses was seronegative to AHSV and following infection with virulent AHSV-4 developed pyrexia, thrombocytopenia and marked oedema of the supraorbital fossae typical of the "dikkop" or cardiac form of African horse sickness. AHSV was detected by virus isolation and quantitative reverse transcriptase polymerase chain reaction in the blood of the control horse from 8 days onwards after challenge infection whereas AHSV was not detected at any time in the blood of the ALVAC-AHSV vaccinated horses. The control horse seroconverted to AHSV by 2 weeks after challenge infection as determined by both virus neutralization and ELISA assays, whereas six of eight of the ALVAC-AHSV vaccinated horses did not seroconvert by either assay following challenge infection with virulent AHSV-4. These data confirm that the ALVAC-AHSV vaccine will be useful for the protective immunization of equids against African horse sickness, and avoids many of the problems inherent to live-attenuated AHSV vaccines.

  15. Feasibility and acceptability of artemisinin-based combination therapy for the home management of malaria in four African sites

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    Munguti Kaendi

    2008-01-01

    Full Text Available Abstract Background The Home Management of Malaria (HMM strategy was developed using chloroquine, a now obsolete drug, which has been replaced by artemisinin-based combination therapy (ACT in health facility settings. Incorporation of ACT in HMM would greatly expand access to effective antimalarial therapy by the populations living in underserved areas in malaria endemic countries. The feasibility and acceptability of incorporating ACT in HMM needs to be evaluated. Methods A multi-country study was performed in four district-size sites in Ghana (two sites, Nigeria and Uganda, with populations ranging between 38,000 and 60,000. Community medicine distributors (CMDs were trained in each village to dispense pre-packaged ACT to febrile children aged 6–59 months, after exclusion of danger signs. A community mobilization campaign accompanied the programme. Artesunate-amodiaquine (AA was used in Ghana and artemether-lumefantrine (AL in Nigeria and Uganda. Harmonized qualitative and quantitative data collection methods were used to evaluate CMD performance, caregiver adherence and treatment coverage of febrile children with ACTs obtained from CMDs. Results Some 20,000 fever episodes in young children were treated with ACT by CMDs across the four study sites. Cross-sectional surveys identified 2,190 children with fever in the two preceding weeks, of whom 1,289 (59% were reported to have received ACT from a CMD. Coverage varied from 52% in Nigeria to 75% in Ho District, Ghana. Coverage rates did not appear to vary greatly with the age of the child or with the educational level of the caregiver. A very high proportion of children were reported to have received the first dose on the day of onset or the next day in all four sites (range 86–97%, average 90%. The proportion of children correctly treated in terms of dose and duration was also high (range 74–97%, average 85%. Overall, the proportion of febrile children who received prompt treatment and the

  16. Chlorproguanil-dapsone-artesunate versus artemether-lumefantrine: a randomized, double-blind phase III trial in African children and adolescents with uncomplicated Plasmodium falciparum malaria.

    Directory of Open Access Journals (Sweden)

    Zul Premji

    Full Text Available BACKGROUND: Chlorproguanil-dapsone-artesunate (CDA was developed as an affordable, simple, fixed-dose artemisinin-based combination therapy for use in Africa. This trial was a randomized parallel-group, double-blind, double-dummy study to compare CDA and artemether-lumefantrine (AL efficacy in uncomplicated Plasmodium falciparum malaria and further define the CDA safety profile, particularly its hematological safety in glucose-6-phosphate dehydrogenase (G6PD -deficient patients. METHODS AND FINDINGS: The trial was conducted at medical centers at 11 sites in five African countries between June 2006 and August 2007. 1372 patients (> or =1 to <15 years old, median age 3 years with acute uncomplicated P. falciparum malaria were randomized (2:1 to receive CDA 2/2.5/4 mg/kg once daily for three days (N = 914 or six-doses of AL over three days (N = 458. Non-inferiority of CDA versus AL for efficacy was evaluated in the Day 28 per-protocol (PP population using parasitological cure (polymerase chain reaction [PCR]-corrected. Cure rates were 94.1% (703/747 for CDA and 97.4% (369/379 for AL (treatment difference -3.3%, 95%CI -5.6, -0.9. CDA was non-inferior to AL, but there was simultaneous superiority of AL (upper 95%CI limit <0. Adequate clinical and parasitological response at Day 28 (uncorrected for reinfection was 79% (604/765 with CDA and 83% (315/381 with AL. In patients with a G6PD-deficient genotype (94/603 [16%] hemizygous males, 22/598 [4%] homozygous females, CDA had the propensity to cause severe and clinically concerning hemoglobin decreases: the mean hemoglobin nadir was 75 g/L (95%CI 71, 79 at Day 7 versus 97 g/L (95%CI 91, 102 for AL. There were three deaths, unrelated to study medication (two with CDA, one with AL. CONCLUSIONS: Although parasitologically effective at Day 28, the hemolytic potential of CDA in G6PD-deficient patients makes it unsuitable for use in a public health setting in Africa. TRIAL REGISTRATION: ClinicalTrials.Gov NCT

  17. MIGRATION AND MALARIA IN EUROPE

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    Begoña Monge-Maillo

    2012-03-01

    Full Text Available The proportion of imported malaria cases due to immigrants in Europe has increased during the lasts decades, being the higher rates for those settled immigrants who travel to visit friends and relatives (VFRs at their country of origin. Cases are mainly due to P. falciparum and Sub-Saharan Africa is the most common origin. Clinically, malaria in immigrants is characterized by a mild clinical presentation with even asymptomatic o delayed malaria cases and low parasitemic level. These characteristics may be explained by a semi-immunity acquired after long periods of time exposed to stable transmission of malaria. Malaria cases among immigrants, even those asymptomatic patients with sub-microscopic parasitemia, could increase the risk of transmission and reintroduction of malaria in certain areas with the adequate vectors and climate conditions. Moreover imported malaria cases by immigrants can also play an important role in the non-vectorial transmission out of endemic area, by blood transfusions, organ transplantation or congenital or occupational exposures. Probably, out of endemic areas, screening of malaria among recent arrived immigrants coming from malaria endemic countries should be performed. These aim to reduce the risk of clinical malaria in the individual as well as to prevent autochthonous transmission of malaria in areas where it had been eradicated.

  18. Laboratory and field efficacy of Pedalium murex and predatory copepod, Mesocyclops longisetus on rural malaria vector, Anopheles culicifacies

    Science.gov (United States)

    Chitra, Thangadurai; Murugan, Kadarkarai; Kumar, Arjunan Naresh; Madhiyazhagan, Pari; Nataraj, Thiyagarajan; Indumathi, Duraisamy; Hwang, Jiang-Shiou

    2013-01-01

    Objective To test the potentiality of the leaf extract of Pedalium murex (P. murex) and predatory copepod Mesocyclops longisetus (M. longisetus) in individual and combination in controlling the rural malarial vector, Anopheles culicifacies (An. culicifacies) in laboratory and field studies. Methods P. murex leaves were collected from in and around Erode, Tamilnadu, India. The active compounds were extracted with 300 mL of methanol for 8 h in a Soxhlet apparatus. Laboratory studies on larvicidal and pupicidal effects of methanolic extract of P. murex tested against the rural malarial vector, An. culicifacies were significant. Results Evaluated lethal concentrations (LC50) of P. murex extract were 2.68, 3.60, 4.50, 6.44 and 7.60 mg/L for I, II, III, IV and pupae of An. culicifacies, respectively. Predatory copepod, M. longisetus was examined for their predatory efficacy against the malarial vector, An. culicifacies. M. longisetus showed effective predation on the early instar (47% and 36% on I and II instar) when compared with the later ones (3% and 1% on III and IV instar). Predatory efficacy of M. longisetus was increased (70% and 45% on I and II instar) when the application was along with the P. murex extract. Conclusions Predator survival test showed that the methanolic extract of P. murex is non-toxic to the predatory copepod, M. longisetus. Experiments were also conducted to evaluate the efficacy of methanolic extract of P. murex and M. longisetus in the direct breeding sites (paddy fields) of An. culicifacies. Reduction in larval density was very high and sustained for a long time in combined treatment of P. murex and M. longisetus.

  19. 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

    , 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...

  20. Diversity of malaria in rice growing areas of the Afrotropical region.

    Science.gov (United States)

    Carnevale, P; Guillet, P; Robert, V; Fontenille, D; Doannio, J; Coosemans, M; Mouchet, J

    1999-09-01

    It is well known that 'in many instances the rice agrosystem perfectly fits the ecological requirements of pathogens or vectors' and in fact 'malaria, schistosomiasis and Japanese encephalitis are important vector-borne diseases associated with rice production in developing countries' (IRRI, 1987). In spite of these fears, rice cultivation has been on the increase in the African region in response to demographic and economic pressures. However, although rice fields provide suitable breeding places for Anopheles mosquitoes and rice cultivation leads to an increase in the biting rates, the species which are adapted to these sites are not the same in all parts of Africa. Several examples illustrate this phenomenon: An. funestus in the rice fields of Madagascar, An. pharoensis in saline water rice fields in the delta of the Senegal river, An. arabiensis in northern Cameroon and Burundi, An. gambiae Mopti form in the Kou Valley (Burkina Faso) and An. gambiae Savanna form in the rice fields of Kafine near Bouaké (Côte d'Ivoire). The vectorial capacities of these species are not the same and malaria inoculation rates are not necessarily increased in the riceland agroecosystem. The consequences for malaria of introducing rice cultivation depend on the situation before its introduction: it could be worsened in unstable malaria areas but not in stable malaria areas. Therefore, sound epidemiological and entomological knowledge are needed before causing any environmental modifications for agricultural purposes and there should be regular monitoring to avoid any outbreak.

  1. Fresh, dried or smoked? repellent properties of volatiles emitted from ethnomedicinal plant leaves against malaria and yellow fever vectors in Ethiopia

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    Dube Fitsum

    2011-12-01

    Full Text Available Abstract Background In the search for plant-based mosquito repellents, volatile emanations were investigated from five plant species, Corymbia citriodora, Ocimum suave, Ocimum lamiifolium, Olea europaea and Ostostegia integrifolia, traditionally used in Ethiopia as protection against mosquitoes. Methods The behaviour of two mosquitoes, the malaria vector Anopheles arabiensis and the arbovirus vector Aedes aegypti, was assessed towards volatiles collected from the headspace of fresh and dried leaves, and the smoke from burning the dried leaves in a two-choice landing bioassay and in the background of human odour. Results Volatile extracts from the smoke of burning dried leaves were found to be more repellent than those from fresh leaves, which in turn were more repellent to mosquitoes than volatiles from dried leaves. Of all smoke and fresh volatile extracts, those from Co. citriodora (52-76% and Oc. suave (58-68% were found to be the most repellent, Os. integrifolia (29-56% to be intermediate while Ol. europaea (23-40% and Os. integrifolia (19-37% were the least repellent. One volatile present in each of the fresh leaf extracts of Co. citriodora, Oc. suave and Os. integrifolia was ß-ocimene. The levels of ß-ocimene reflected the mosquito repellent activity of these three fresh leaf extracts. Female host-seeking mosquitoes responded dose-dependently to ß-ocimene, both physiologically and behaviourally, with a maximal behavioural repulsion at 14% ß-ocimene. ß-ocimene (14% repels mosquitoes in our 6-minute landing assays comparable to the synthetic insect repellent N,N-diethyl-m-toluamide (10% DEET. Conclusions Volatiles in the smoke of burning as well as fresh leaves of Co. citriodora and Oc. suave have significant repellent properties against host seeking An. arabiensis and Ae. aegypti mosquitoes. ß-ocimene, present in the fresh leaf headspace of Co. citriodora, Oc. suave and Os. integrifolia, is a significantly effective volatile mosquito

  2. Plasmodium falciparum Malaria, Southern Algeria, 2007

    OpenAIRE

    Boubidi, Saïd C; Gassen, Ibrahim; Khechache, Yacine; Lamali, Karima; Tchicha, Boualem; Brengues, Cécile; Menegon, Michela; Severini, Carlo; Fontenille, Didier; Harrat, Zoubir

    2010-01-01

    An outbreak of Plasmodium falciparum malaria occurred in Tinzaouatine in southern Algeria in 2007. The likely vector, Anopheles gambiae mosquitoes, had not been detected in Algeria. Genes for resistance to chloroquine were detected in the parasite. The outbreak shows the potential for an increase in malaria vectors in Algeria.

  3. Host choice and multiple blood feeding behaviour of malaria vectors and other anophelines in Mwea rice scheme, Kenya

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    Jacob Benjamin G

    2008-02-01

    Full Text Available Abstract Background Studies were conducted between April 2004 and February 2006 to determine the blood-feeding pattern of Anopheles mosquitoes in Mwea Kenya. Methods Samples were collected indoors by pyrethrum spay catch and outdoors by Centers for Disease Control light traps and processed for blood meal analysis by an Enzyme-linked Immunosorbent Assay. Results A total of 3,333 blood-fed Anopheles mosquitoes representing four Anopheles species were collected and 2,796 of the samples were assayed, with Anopheles arabiensis comprising 76.2% (n = 2,542 followed in decreasing order by Anopheles coustani 8.9% (n = 297, Anopheles pharoensis 8.2% (n = 272 and Anopheles funestus 6.7% (n = 222. All mosquito species had a high preference for bovine (range 56.3–71.4% over human (range 1.1–23.9% or goat (0.1–2.2% blood meals. Some individuals from all the four species were found to contain mixed blood meals. The bovine blood index (BBI for An. arabiensis was significantly higher for populations collected indoors (71.8%, than populations collected outdoors (41.3%, but the human blood index (HBI did not differ significantly between the two populations. In contrast, BBI for indoor collected An. funestus (51.4% was significantly lower than for outdoor collected populations (78.0% and the HBI was significantly higher indoors (28.7% than outdoors (2.4%. Anthropophily of An. funestus was lowest within the rice scheme, moderate in unplanned rice agro-ecosystem, and highest within the non-irrigated agro-ecosystem. Anthropophily of An. arabiensis was significantly higher in the non-irrigated agro-ecosystem than in the other agro-ecosystems. Conclusion These findings suggest that rice cultivation has an effect on host choice by Anopheles mosquitoes. The study further indicate that zooprophylaxis may be a potential strategy for malaria control, but there is need to assess how domestic animals may influence arboviruses epidemiology before adapting the strategy.

  4. Adulticidal properties of synthesized silver nanoparticles using leaf extracts of Feronia elephantum (Rutaceae) against filariasis, malaria, and dengue vector mosquitoes.

    Science.gov (United States)

    Veerakumar, Kaliyan; Govindarajan, Marimuthu

    2014-11-01

    Mosquito-borne diseases with an economic impact create loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates. Mosquito control is facing a threat because of the emergence of resistance to synthetic insecticides. Extracts from plants may be alternative sources of mosquito control agents because they constitute a rich source of bioactive compounds that are biodegradable into nontoxic products and potentially suitable for use to control mosquitoes. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, in the present study, the adulticidal activity of silver nanoparticles (AgNPs) synthesized using Feronia elephantum plant leaf extract against adults of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus was determined. The range of concentrations of synthesized AgNPs (8, 16, 24, 32, and 40 μg mL(-1)) and aqueous leaf extract (40, 80, 120, 160, and 200 μg mL(-1)) were tested against the adults of A. stephensi, A. aegypti, and C. quinquefasciatus. Adults 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) with energy-dispersive X-ray spectroscopy analysis (EDX), and transmission electron microscopy (TEM). Synthesized AgNPs against the vector mosquitoes A. stephensi, A. aegypti, and C. quinquefasciatus had the following lethal dose (LD)₅₀ and LD₉₀ values: A. stephensi had LD₅₀ and LD₉₀ values of 18

  5. [Malaria in Algerian Sahara].

    Science.gov (United States)

    Hammadi, D; Boubidi, S C; Chaib, S E; Saber, A; Khechache, Y; Gasmi, M; Harrat, Z

    2009-08-01

    Thanks to the malaria eradication campaign launched in Algeria in 1968, the number of malaria cases fell down significantly from 95,424 cases in 1960 to 30 cases in 1978. At that time the northern part of the country was declared free of Plasmodium falciparum. Only few cases belonging to P. vivax persisted in residual foci in the middle part of the country. In the beginning of the eighties, the south of the country was marked by an increase of imported malaria cases. The resurgence of the disease in the oases coincided with the opening of the Trans-Saharan road and the booming trade with the neighbouring southern countries. Several authors insisted on the risk of introduction of malaria or its exotic potential vectors in Algeria via this new road. Now, the totality of malaria autochthonous cases in Algeria are located in the south of the country where 300 cases were declared during the period (1980-2007). The recent outbreak recorded in 2007 at the borders with Mall and the introduction of Anopheles gambiae into the Algerian territory show the vulnerability of this area to malaria which is probably emphasized by the local environmental changes. The authors assess the evolution of malaria in the Sahara region and draw up the distribution of the anopheles in this area.

  6. Laboratory evaluation of traditionally used plant-based insect repellent against the malaria vector Anopheles arabiensis Patton (Diptera: Culicidae).

    Science.gov (United States)

    Karunamoorthi, Kaliyaperumal; Ilango, Kandan; Murugan, Kadarkarai

    2010-04-01

    A laboratory study was carried out to evaluate the repellent efficacy of a methanol-leaf extract of Ethiopian traditionally used insect repellent plant viz., Lomi sar [vernacular name (local native language, Amharic); Cymbopogon citratus (DC) Stapf. (Poaceae)] against Anopheles arabiensis at four different concentrations viz., 1.0, 1.5, 2.0, and 2.5 mg/cm(2). The percentage protection in relation to the dose method was performed. C. citratus extract has shown various degrees of repellency impact against A. arabiensis. It provided the maximum total percentage protection of 78.83% at 2.5 mg/cm(2) and followed 68.06% at 2.0 mg/cm(2) for 12 h. All four tested concentrations of C. citratus extract offered significant protection and Student's t test results shows statistically significant (p value = 0.001) [1.0 mg/cm(2) (t = 22.89; df = 4); 1.5 mg/cm(2) (t = 24.03; df = 4); 2.0 mg/cm(2) (t = 36.92; df = 4); 2.5 mg/cm(2) (t = 22.31; df = 4)] difference between treated and control groups. The result suggests that it could serve as a potent insect repellent against vectors of disease. Globally, C. citratus is renowned for its therapeutic values. Above and beyond, due to its user- as well as environmental-friendly nature, it should be promoted among the marginalized populations in order to reduce man-vector contact. In addition, this appropriate strategy affords the opportunity to minimize chemical repellent usage and the risks associated with adverse side effects. At the end of the day, traditionally used plant-based insect repellents could be viable safer alternative sources for chemical insect repellents.

  7. Field evaluation of traditionally used plant-based insect repellents and fumigants against the malaria vector Anopheles darlingi in Riberalta, Bolivian Amazon.

    Science.gov (United States)

    Moore, Sarah J; Hill, Nigel; Ruiz, Carmen; Cameron, Mary M

    2007-07-01

    Inexpensive insect repellents may be needed to supplement the use of impregnated bed-nets in the Amazon region, where the primary malaria vector, Anopheles darlingi (Root), is exophilic and feeds in the early evening. Three plants that are traditionally used to repel mosquitoes in Riberalta, Bolivian Amazon, were identified by focus group, and then they were tested against An. darlingi as well as Mansonia indubitans (Dyar & Shannon)/Mansonia titillans (Walker). Cymbopogon citratus (Staph), Guatemalan lemongrass, essential oil at 25% was used as a skin repellent, and it provided 74% protection for 2.5 h against predominantly An. darlingi and 95% protection for 2.5 h against Mansonia spp. Attalea princeps (name not verified) husks, burned on charcoal in the traditional way provided 35 and 51% protection against An. darlingi and Mansonia spp., respectively. Kerosene lamps, often used to light rural homes, were used as a heat source to volatilize 100% Mentha arvensis (Malinv ex. Bailey) essential oil, and they reduced biting by 41% inside traditional homes against Mansonia spp., although they were ineffective outdoors against An. darlingi. All three plant-based repellents provided significant protection compared with controls. Plant-based repellents, although less effective than synthetic alternatives, were shown by focus groups to be more culturally acceptable in this setting, in particular para-menthane-3, 8, idol derived from lemon eucalyptus, Corymbia citriodora (Hook). Plant-based repellents have the potential to be produced locally and therefore sold more cheaply than synthetic commercial repellents. Importantly, their low cost may encourage user compliance among indigenous and marginalized populations.

  8. Low-volume application by mist-blower compared with conventional compression sprayer treatment of houses with residual pyrethroid to control the malaria vector Anopheles albimanus in Mexico.

    Science.gov (United States)

    Villarreal, C; Rodriguez, M H; Bown, D N; Arredondo-Jiménez, J I

    1995-04-01

    Village-scale trials were carried out in southern Mexico to compare the efficacy of indoor-spraying of the pyrethroid insecticide lambda-cyhalothrin applied either as low-volume (LV) aqueous emulsion or as wettable-powder (WP) aqueous suspension for residual control of the principal coastal malaria vector Anopheles albimanus. Three indoor spray rounds were conducted at 3-month intervals using back-pack mist-blowers to apply lambda-cyhalothrin 12.5 mg a.i./m2 by LV, whereas the WP was applied by conventional compression sprayer at a mean rate of 26.5 mg a.i./m2. Both treatments caused mosquito mortality indoors and outdoors (collected inside house curtains) as a result of contact with treated surfaces before and after feeding, but had no significant impact on overall population density of An. albimanus resting indoors or assessed by human bait collections. Contact bioassays showed that WP and LV treatments with lambda-cyhalothrin were effective for 12-20 weeks (> 75% mortality) without causing excito-repellency. Compared to the WP treatment (8 houses/man/day), LV treatment (25 houses/man/day) was more than 3 times quicker per house, potentially saving 68% of labour costs. This is offset, however, by the much lower unit price of a compression sprayer (e.g. Hudson 'X-pert' at US$120) than a mist-blower (e.g. 'Super Jolly' at US$350), and higher running costs for LV applications. It was calculated, therefore, that LV becomes more economical than WP after 18.8 treatments/100 houses/10 men at equivalent rates of application, or after 7.6 spray rounds with half-rate LV applications.

  9. Use of integrated malaria management reduces malaria in Kenya.

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    Bernard A Okech

    Full Text Available BACKGROUND: During an entomological survey in preparation for malaria control interventions in Mwea division, the number of malaria cases at the Kimbimbi sub-district hospital was in a steady decline. The underlying factors for this reduction were unknown and needed to be identified before any malaria intervention tools were deployed in the area. We therefore set out to investigate the potential factors that could have contributed to the decline of malaria cases in the hospital by analyzing the malaria control knowledge, attitudes and practices (KAP that the residents in Mwea applied in an integrated fashion, also known as integrated malaria management (IMM. METHODS: Integrated Malaria Management was assessed among community members of Mwea division, central Kenya using KAP survey. The KAP study evaluated community members' malaria disease management practices at the home and hospitals, personal protection measures used at the household level and malaria transmission prevention methods relating to vector control. Concurrently, we also passively examined the prevalence of malaria parasite infection via outpatient admission records at the major referral hospital in the area. In addition we studied the mosquito vector population dynamics, the malaria sporozoite infection status and entomological inoculation rates (EIR over an 8 month period in 6 villages to determine the risk of malaria transmission in the entire division. RESULTS: A total of 389 households in Mwea division were interviewed in the KAP study while 90 houses were surveyed in the entomological study. Ninety eight percent of the households knew about malaria disease while approximately 70% of households knew its symptoms and methods to manage it. Ninety seven percent of the interviewed households went to a health center for malaria diagnosis and treatment. Similarly a higher proportion (81% used anti-malarial medicines bought from local pharmacies. Almost 90% of households reported

  10. Sustainable malaria control: transdisciplinary approaches for translational applications

    Directory of Open Access Journals (Sweden)

    Birkholtz Lyn-Marie

    2012-12-01

    Full Text Available Abstract With the adoption of the Global Malaria Action Plan, several countries are moving from malaria control towards elimination and eradication. However, the sustainability of some of the approaches taken may be questionable. Here, an overview of malaria control and elimination strategies is provided and the sustainability of each in context of vector- and parasite control is assessed. From this, it can be concluded that transdisciplinary approaches are essential for sustained malaria control and elimination in malaria-endemic communities.

  11. Ovicidal, larvicidal and adulticidal properties of Asparagus racemosus (Willd.) (Family: Asparagaceae) root extracts against filariasis (Culex quinquefasciatus), dengue (Aedes aegypti) and malaria (Anopheles stephensi) vector mosquitoes (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, Marimuthu; Sivakumar, Rajamohan

    2014-04-01

    Several diseases are associated to the mosquito-human interaction. Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue fever, chikungunya fever, West Nile virus and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. The present investigation was undertaken to study the ovicidal, larvicidal and adulticidal activities of crude hexane, ethyl acetate, benzene, chloroform and methanol extracts of root of Asparagus racemosus were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera: Culicidae). The mean percent hatchability of the eggs was observed after 48 h post-treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. All the five solvent extracts showed moderate ovicidal activity; however, the methanol extract showed the highest ovicidal activity. The methanol extract of Asparagus racemosus against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi exerted 100% mortality (zero hatchability) at 375, 300 and 225 ppm, respectively. Control eggs showed 99-100% hatchability. The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in methanol extract of root of Asparagus racemosus against the larvae of Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi with the LC50 and LC90 values were 115.13, 97.71 and 90.97 ppm and 210.96, 179.92, and 168.82 ppm, respectively. The adult mortality was observed after 24 h recovery period. The plant crude extracts showed dose-dependent mortality. At higher concentrations, the adult showed restless movement for some times with abnormal wagging and then died. Among the extracts tested, the highest adulticidal activity was observed in

  12. Biolarvicidal compound gymnemagenol isolated from leaf extract of miracle fruit plant, Gymnema sylvestre (Retz) Schult against malaria and filariasis vectors.

    Science.gov (United States)

    Khanna, Venkatesan Gopiesh; Kannabiran, Krishnan; Rajakumar, Govindasamy; Rahuman, Abdul Abdul; Santhoshkumar, Thirunavukkarasu

    2011-11-01

    Owing to the fact that the application of synthetic larvicide has envenomed the surroundings as well as non-target organisms, natural products of plant origin with insecticidal properties have been tried as an indigenous method for the control of a variety of insect pests and vectors in the recent past. Insecticides of plant origin have been extensively used on agricultural pests and, to a very limited extent, against insect vectors of public health importance, which deserve careful and thorough screening. The use of plant extracts for insect control has several appealing features as these are generally more biodegradable, less hazardous and a rich storehouse of chemicals of diverse biological activities. Moreover, herbal sources give a lead for discovering new insecticides. Therefore, biologically active plant materials have attracted considerable interest in mosquito control study in recent times. The crude leaf extracts of Gymnema sylvestre (Retz) Schult (Asclepiadaceae) and purified gymnemagenol compound were studied against the early fourth-instar larvae of Anopheles subpictus Grassi and Culex quinquefasciatus Say (Diptera: Culicidae). In the present study, bioassay-guided fractionation of petroleum ether leaf extract of G. sylvestre led to the separation and identification of gymnemagenol as a potential new antiparasitic compound. Phytochemical analysis of G. sylvestre leaves revealed the presence of active constituents such as carbohydrates, saponins, phytosterols, phenols, flavonoids and tannins. However, cardiac glycosides and phlobatannins are absent in the plant extracts. Quantitative analysis results suggested that saponin (5%) was present in a high concentration followed by tannins (1.0%). The 50 g powder was loaded on silica gel column and eluted with chloroform-methanol-water as eluents. From that, 16 mg pure saponin compound was isolated and analysed by thin layer chromatography using chloroform and methanol as the solvent systems. The structure of

  13. Composition of human skin microbiota affects attractiveness to malaria mosquitoes.

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    Niels O Verhulst

    Full Text Available The African malaria mosquito Anopheles gambiae sensu stricto continues to play an important role in malaria transmission, which is aggravated by its high degree of anthropophily, making it among the foremost vectors of this disease. In the current study we set out to unravel the strong association between this mosquito species and human beings, as it is determined by odorant cues derived from the human skin. Microbial communities on the skin play key roles in the production of human body odour. We demonstrate that the composition of the skin microbiota affects the degree of attractiveness of human beings to this mosquito species. Bacterial plate counts and 16S rRNA sequencing revealed that individuals that are highly attractive to An. gambiae s.s. have a significantly higher abundance, but lower diversity of bacteria on their skin than individuals that are poorly attractive. Bacterial genera that are correlated with the relative degree of attractiveness to mosquitoes were identified. The discovery of the connection between skin microbial populations and attractiveness to mosquitoes may lead to the development of new mosquito attractants and personalized methods for protection against vectors of malaria and other infectious diseases.

  14. Laboratory evaluation of traditional insect/mosquito repellent plants against Anopheles arabiensis, the predominant malaria vector in Ethiopia.

    Science.gov (United States)

    Karunamoorthi, Kaliyaperumal; Mulelam, Adane; Wassie, Fentahun

    2008-08-01

    Laboratory study was carried out to evaluate the repellent efficiency of most commonly known four traditional insect/mosquito repellent plants Wogert [vernacular name (local native language, Amharic); Silene macroserene], Kebercho [vernacular name (local native language, Amharic); Echinops sp.], Tinjut [vernacular name (local native language, Amharic); Ostostegia integrifolia], and Woira[vernacular name (local native language, Amharic); Olea europaea] against Anopheles arabiensis under the laboratory conditions. One hundred (4-5 days old) female A. arabiensis were introduced into the both 'control' and 'test' repellent chamber through the hole on top. Traditional charcoal stoves were used for direct burning. The experiment was conducted by applying the smoke into the repellent "test" mosquito cage by direct burning of 25 gm of dried plant materials (leaves and roots) until plant materials completely burned. The number of mosquitoes driving away from the "test" and "control" cage was recorded for every 5 min. In the present investigation, the results clearly revealed that the roots of S. macroserene has potent repellent efficiency (93.61%) and was the most effective. The leaves of Echinops sp. (92.47%), leaves of O. integrifolia (90.10%) and O. europaea (79.78%) were also effective. Roots of S. macroserene exhibited the highest repellent efficiency by direct burning. The present study identified these four traditional indigenous insect/mosquito repellent plant materials are very promising and can be used as safer alternative to modern synthetic chemical repellents against mosquito vectors of disease. Since people have been using these plants for some medicinal purposes, no side effects have been found.

  15. Efficacy of sunlight-activatable porphyrin formulates on larvae of Anopheles gambiae M and S molecular forms and An. arabiensis: a potential novel biolarvicide for integrated malaria vector control.

    Science.gov (United States)

    Fabris, Clara; Ouédraogo, Robert Kossivi; Coppellotti, Olimpia; Dabiré, Roch K; Diabaté, Abdoulaye; Di Martino, Piera; Guidolin, Laura; Jori, Giulio; Lucantoni, Leonardo; Lupidi, Giulio; Martena, Valentina; Sawadogo, Simon P; Soncin, Marina; Habluetzel, Annette

    2012-09-01

    Biolarvicides, such as microbial formulations based on Bacillus thuringiensis and B. sphaericus, have been found to be highly effective against mosquito larvae and are currently employed as eco-friendly alternatives to synthetic chemical insecticides for vector control. Recently, a porphyrin of natural origin has been suggested as a sunlight-activatable larvicide against the dengue vector Aedes aegypti. In order to validate the approach for the control of the malaria vector, we tested the photo-larvicidal activity of a novel porphyrin, namely meso-tri(N-methyl-pyridyl), mono(N-dodecyl-pyridyl)porphine, C12, associated with two specifically selected carriers, against Anopheles gambiae s.s. and An. arabiensis larvae, both laboratory reared and collected from malaria endemic sites in Burkina Faso. Both C12-porphyrin formulates, when administered to larvae at a 50μM porphyrin dose, were accumulated in the alimentary canal. Subsequent exposure of the porphyrin-loaded larvae to sunlight for short times (0.5-3h) led to a complete mortality. The high efficacy exhibited by a "foodstuff" porphyrin formulate also in the presence of typical larval food particles opens promising perspectives for the development of an effective photocidal larvicide.

  16. Different methodological approaches to the assessment of in vivo efficacy of three artemisinin-based combination antimalarial treatments for the treatment of uncomplicated falciparum malaria in African children

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    Zongo Issaka

    2008-08-01

    Full Text Available Abstract Background Use of different methods for assessing the efficacy of artemisinin-based combination antimalarial treatments (ACTs will result in different estimates being reported, with implications for changes in treatment policy. Methods Data from different in vivo studies of ACT treatment of uncomplicated falciparum malaria were combined in a single database. Efficacy at day 28 corrected by PCR genotyping was estimated using four methods. In the first two methods, failure rates were calculated as proportions with either (1a reinfections excluded from the analysis (standard WHO per-protocol analysis or (1b reinfections considered as treatment successes. In the second two methods, failure rates were estimated using the Kaplan-Meier product limit formula using either (2a WHO (2001 definitions of failure, or (2b failure defined using parasitological criteria only. Results Data analysed represented 2926 patients from 17 studies in nine African countries. Three ACTs were studied: artesunate-amodiaquine (AS+AQ, N = 1702, artesunate-sulphadoxine-pyrimethamine (AS+SP, N = 706 and artemether-lumefantrine (AL, N = 518. Using method (1a, the day 28 failure rates ranged from 0% to 39.3% for AS+AQ treatment, from 1.0% to 33.3% for AS+SP treatment and from 0% to 3.3% for AL treatment. The median [range] difference in point estimates between method 1a (reference and the others were: (i method 1b = 1.3% [0 to24.8], (ii method 2a = 1.1% [0 to21.5], and (iii method 2b = 0% [-38 to19.3]. The standard per-protocol method (1a tended to overestimate the risk of failure when compared to alternative methods using the same endpoint definitions (methods 1b and 2a. It either overestimated or underestimated the risk when endpoints based on parasitological rather than clinical criteria were applied. The standard method was also associated with a 34% reduction in the number of patients evaluated compared to the number of patients enrolled. Only 2% of the sample size

  17. Development of drugs for severe malaria in children

    OpenAIRE

    Cheah, PY; Parker, M.; Dondorp, AM

    2016-01-01

    Over 90% of deaths attributable to malaria are in African children under 5 years old. Yet, new treatments are often tested primarily in adult patients and extrapolations have proven to be sometimes invalid, especially in dosing regimens. For studies in severe malaria an additional complication is that the decline in severe malaria in adult patients precludes sufficiently powered trials in adults, before the intervention can be tested in the ultimate target group, paediatric severe malaria. In...

  18. Statistical methodology for the evaluation of vaccine efficacy in a phase III multi-centre trial of the RTS,S/AS01 malaria vaccine in African children

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    Lievens Marc

    2011-08-01

    Full Text Available Abstract Background There has been much debate about the appropriate statistical methodology for the evaluation of malaria field studies and the challenges in interpreting data arising from these trials. Methods The present paper describes, for a pivotal phase III efficacy of the RTS, S/AS01 malaria vaccine, the methods of the statistical analysis and the rationale for their selection. The methods used to estimate efficacy of the primary course of vaccination, and of a booster dose, in preventing clinical episodes of uncomplicated and severe malaria, and to determine the duration of protection, are described. The interpretation of various measures of efficacy in terms of the potential public health impact of the vaccine is discussed. Conclusions The methodology selected to analyse the clinical trial must be scientifically sound, acceptable to regulatory authorities and meaningful to those responsible for malaria control and public health policy. Trial registration Clinicaltrials.gov NCT00866619

  19. Climate, environment and transmission of malaria.

    Science.gov (United States)

    Rossati, Antonella; Bargiacchi, Olivia; Kroumova, Vesselina; Zaramella, Marco; Caputo, Annamaria; Garavelli, Pietro Luigi

    2016-06-01

    Malaria, the most common parasitic disease in the world, is transmitted to the human host by mosquitoes of the genus Anopheles. The transmission of malaria requires the interaction between the host, the vector and the parasite.The four species of parasites responsible for human malaria are Plasmodium falciparum, Plasmodium ovale, Plasmodium malariae and Plasmodium vivax. Occasionally humans can be infected by several simian species, like Plasmodium knowlesi, recognised as a major cause of human malaria in South-East Asia since 2004. While P. falciparum is responsible for most malaria cases, about 8% of estimated cases globally are caused by P. vivax. The different Plasmodia are not uniformly distributed although there are areas of species overlap. The life cycle of all species of human malaria parasites is characterised by an exogenous sexual phase in which multiplication occurs in several species of Anopheles mosquitoes, and an endogenous asexual phase in the vertebrate host. The time span required for mature oocyst development in the salivary glands is quite variable (7-30 days), characteristic of each species and influenced by ambient temperature. The vector Anopheles includes 465 formally recognised species. Approximately 70 of these species have the capacity to transmit Plasmodium spp. to humans and 41 are considered as dominant vector capable of transmitting malaria. The intensity of transmission is dependent on the vectorial capacity and competence of local mosquitoes. An efficient system for malaria transmission needs strong interaction between humans, the ecosystem and infected vectors. Global warming induced by human activities has increased the risk of vector-borne diseases such as malaria. Recent decades have witnessed changes in the ecosystem and climate without precedent in human history although the emphasis in the role of temperature on the epidemiology of malaria has given way to predisposing conditions such as ecosystem changes, political

  20. Safety and High Level Efficacy of the Combination Malaria Vaccine Regimen of RTS,S/AS01B With Chimpanzee Adenovirus 63 and Modified Vaccinia Ankara Vectored Vaccines Expressing ME-TRAP

    Science.gov (United States)

    Rampling, Tommy; Ewer, Katie J.; Bowyer, Georgina; Bliss, Carly M.; Edwards, Nick J.; Wright, Danny; Payne, Ruth O.; Venkatraman, Navin; de Barra, Eoghan; Snudden, Claudia M.; Poulton, Ian D.; de Graaf, Hans; Sukhtankar, Priya; Roberts, Rachel; Ivinson, Karen; Weltzin, Rich; Rajkumar, Bebi-Yassin; Wille-Reece, Ulrike; Lee, Cynthia K.; Ockenhouse, Christian F.; Sinden, Robert E.; Gerry, Stephen; Lawrie, Alison M.; Vekemans, Johan; Morelle, Danielle; Lievens, Marc; Ballou, Ripley W.; Cooke, Graham S.; Faust, Saul N.; Gilbert, Sarah; Hill, Adrian V. S.

    2016-01-01

    Background. The need for a highly efficacious vaccine against Plasmodium falciparum remains pressing. In this controlled human malaria infection (CHMI) study, we assessed the safety, efficacy and immunogenicity of a schedule combining 2 distinct vaccine types in a staggered immunization regimen: one inducing high-titer antibodies to circumsporozoite protein (RTS,S/AS01B) and the other inducing potent T-cell responses to thrombospondin-related adhesion protein (TRAP) by using a viral vector. Method. Thirty-seven healthy malaria-naive adults were vaccinated with either a chimpanzee adenovirus 63 and modified vaccinia virus Ankara–vectored vaccine expressing a multiepitope string fused to TRAP and 3 doses of RTS,S/AS01B (group 1; n = 20) or 3 doses of RTS,S/AS01B alone (group 2; n = 17). CHMI was delivered by mosquito bites to 33 vaccinated subjects at week 12 after the first vaccination and to 6 unvaccinated controls. Results. No suspected unexpected serious adverse reactions or severe adverse events related to vaccination were reported. Protective vaccine efficacy was observed in 14 of 17 subjects (82.4%) in group 1 and 12 of 16 subjects (75%) in group 2. All control subjects received a diagnosis of blood-stage malaria parasite infection. Both vaccination regimens were immunogenic. Fourteen protected subjects underwent repeat CHMI 6 months after initial CHMI; 7 of 8 (87.5%) in group 1 and 5 of 6 (83.3%) in group 2 remained protected. Conclusions. The high level of sterile efficacy observed in this trial is encouraging for further evaluation of combination approaches using these vaccine types. Clinical Trials Registration. NCT01883609. PMID:27307573

  1. Representación de la dinámica de vectores y humanos en una epidemia de malaria mediante un modelo multi-agentes

    OpenAIRE

    2014-01-01

    Esta tesis presenta un modelo basado en agentes que representa la dinámica de la transmisión de Malaria, considerando factores ambientales, espaciales y la introducción de distintas medidas de control. La presentación del modelo se realiza en dos capítulos: uno relacionado con el desarrollo del modelo de la dinámica de transmisión de la Malaria entre la población de humanos y mosquitos, y otro que describe la representación de medidas de control (IRS - insecticida de acción residual aplicado ...

  2. Scientific Opinion on the Role of Tick Vectors in the Epidemiology of Crimean-Congo Hemorrhagic Fever and African Swine Fever in Eurasia

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Animal Health and Welfare (AHAW

    2010-08-01

    Full Text Available The report provides an update on the role of the tick vectors in the epidemiology of African swine fever (ASF and Crimean and Congo haemorrhagic fever (CCHF in Eurasia, specifically to review of the geographical distribution of the relevant ticks with presentation of maps of their occurrence in Europe and Mediterranean basin; a description of the factors that define the relevant tick population dynamics and identify possible high risk areas in the EU; an update on the role of tick vectors associated with CCHF and ASF in Eurasia; and reviews available methods for the control of the relevant tick vectors. Data were collected through systematic literature review in a database from which maps of geographic distribution of ticks, CCHF virus and ASF virus were issued. The main vectors for CCHF are Hyalomma spp, Increase in the number of fragmented areas and the degradation of agricultural lands to bush lands are the two main factors in the creation of new foci of CCHF in endemic areas. Movement of livestock and wildlife species, which may carry infected ticks, contributes to the spread of the infection. The Middle East and Balkan countries are the most likely sources of introduction of CCHFV into other European countries. All the Ornithodoros species investigated so far can become infective with ASF virus and are perhaps biological vectors. These ticks are important in maintaining the local foci of the ASFV, but do not play an active role in the geographical spread of the virus. Wild boars have never been found infested by Ornithodoros spp. because wild boars normally do not rest inside protected burrows, but above the ground. There is no single ideal solution to the control of ticks relevant for CCHF or ASF. The integrated control approach is probably the most effective.

  3. Malaria (For Parents)

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Malaria KidsHealth > For Parents > Malaria A A A What's ... Prevention Diagnosis and Treatment en español Malaria About Malaria Malaria is a common infection in hot, tropical ...

  4. Where are the horses? With the sheep or cows? Uncertain host location, vector-feeding preferences and the risk of African horse sickness transmission in Great Britain.

    Science.gov (United States)

    Lo Iacono, Giovanni; Robin, Charlotte A; Newton, J Richard; Gubbins, Simon; Wood, James L N

    2013-06-06

    Understanding the influence of non-susceptible hosts on vector-borne disease transmission is an important epidemiological problem. However, investigation of its impact can be complicated by uncertainty in the location of the hosts. Estimating the risk of transmission of African horse sickness (AHS) in Great Britain (GB), a virus transmitted by Culicoides biting midges, provides an insightful example because: (i) the patterns of risk are expected to be influenced by the presence of non-susceptible vertebrate hosts (cattle and sheep) and (ii) incomplete information on the spatial distribution of horses is available because the GB National Equine Database records owner, rather than horse, locations. Here, we combine land-use data with available horse owner distributions and, using a Bayesian approach, infer a realistic distribution for the location of horses. We estimate the risk of an outbreak of AHS in GB, using the basic reproduction number (R0), and demonstrate that mapping owner addresses as a proxy for horse location significantly underestimates the risk. We clarify the role of non-susceptible vertebrate hosts by showing that the risk of disease in the presence of many hosts (susceptible and non-susceptible) can be ultimately reduced to two fundamental factors: first, the abundance of vectors and how this depends on host density, and, second, the differential feeding preference of vectors among animal species.

  5. Eco-friendly control of malaria and arbovirus vectors using the mosquitofish Gambusia affinis and ultra-low dosages of Mimusops elengi-synthesized silver nanoparticles: towards an integrative approach?

    Science.gov (United States)

    Subramaniam, Jayapal; Murugan, Kadarkarai; Panneerselvam, Chellasamy; Kovendan, Kalimuthu; Madhiyazhagan, Pari; Kumar, Palanisamy Mahesh; Dinesh, Devakumar; Chandramohan, Balamurugan; Suresh, Udaiyan; Nicoletti, Marcello; Higuchi, Akon; Hwang, Jiang-Shiou; Kumar, Suresh; Alarfaj, Abdullah A; Munusamy, Murugan A; Messing, Russell H; Benelli, Giovanni

    2015-12-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. However, the use of synthetic insecticides to control Culicidae may lead to high operational costs and adverse non-target effects. Plant-borne compounds have been proposed for rapid extracellular synthesis of mosquitocidal nanoparticles. Their impact against biological control agents of mosquito larval populations has been poorly studied. We synthesized silver nanoparticles (AgNP) using the aqueous leaf extract of Mimusops elengi as a reducing and stabilizing agent. The formation of AgNP was studied using different biophysical methods, including UV-vis spectrophotometry, TEM, XRD, EDX and FTIR. Low doses of AgNP showed larvicidal and pupicidal toxicity against the malaria vector Anopheles stephensi and the arbovirus vector Aedes albopictus. AgNP LC50 against A. stephensi ranged from 12.53 (I instar larvae) to 23.55 ppm (pupae); LC50 against A. albopictus ranged from 11.72 ppm (I) to 21.46 ppm (pupae). In the field, the application of M. elengi extract and AgNP (10 × LC50) led to 100 % larval reduction after 72 h. In adulticidal experiments, AgNP showed LC50 of 13.7 ppm for A. stephensi and 14.7 ppm for A. albopictus. The predation efficiency of Gambusia affinis against A. stephensi and A. albopictus III instar larvae was 86.2 and 81.7 %, respectively. In AgNP-contaminated environments, predation was 93.7 and 88.6 %, respectively. This research demonstrates that M. elengi-synthesized AgNP may be employed at ultra-low doses to reduce larval populations of malaria and arbovirus vectors, without detrimental effects on predation rates of mosquito natural enemies, such as larvivorous fishes.

  6. PENENTUAN VEKTOR MALARIA DI FLORES

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    Harijani A. Marwoto

    2012-09-01

    Full Text Available A field study on entomology has been conducted in 6 villages which were located in coastal and in-land areas of Sikka Regency of Central Flores since April 1990 - October 1991. The results of this study showed that the suspected malaria vectors in those areas were An. sundaicus, An. subpictus, An. barbirostris, An. aconitus and An. maculatus. Only 3 species were confirmed as vector using ELISA test, i.e. An. sundaicus, An. barbirostris and An. subpictus with sporosoite rates of 4.2%, 2.1% and 0.1% respectively. An. aconitus, a potential malaria vector in Java and in some onther places was not confirmed as vector in Flores yet. The 3 confirmed vectors were also found positive with sporozoites in West Flores and also found predominant in East Flores.

  7. Study of the climatic change impact on vector-borne diseases in West Africa: the case of tick-borne borreliosis and malaria; Etude de l'impact du changement climatique sur les maladies a transmission vectorielle en Afrique de l'Ouest: le cas de la borreliose a tiques et du paludisme

    Energy Technology Data Exchange (ETDEWEB)

    Trape, J.F

    2005-04-15

    Malaria and tick-borne borreliosis are the two first causes of morbidity due to vector-borne diseases in a large part of Sudan-sahelian West Africa. They are also the two tropical diseases which have been the most affected by climatic change in recent years. In the case of tick-borne borreliosis it has been shown in Senegal that the persistence of drought since the years 70 has been associated with a considerable extension of the geographic range of diseases and the vector tick A-sonrai, a species that was in the past limited to the Sahara and Sahel. In the case of malaria, drought has strongly reduced in these same regions of Africa the distribution, abundance and infection rate of Anopheline mosquitoes, but without any significant reduction of the burden of malaria for most populations concerned. The emergence and spread of Plasmodium falciparum resistance to antimalarial drugs only explain part of this phenomenon. (A.L.B.)

  8. A multidisciplinary approach to study virulence of the entomopathogenic fungus Beauveria bassiana towards malaria mosquitoes

    NARCIS (Netherlands)

    Valero Jimenez, C.A.

    2016-01-01

    Although globally malaria mortality rates have fallen by 48% between 2000 and 2015, malaria is still killing an estimated 438,000 people each year. An effective way to alleviate the burden of malaria is to control its vector (malaria mosquitoes) using insecticides. Th

  9. [Malaria websites].

    Science.gov (United States)

    Genton, B

    2007-05-16

    One click on google.com, key-word "Malaria", 24,900,000 entries. How to choose among this jungle of websites? Ten sites are proposed to meet the needs of the general practitioner They are categorized by focus of interest, namely 1) detailed information on pre- and post-travel advice and management of travelers with illness upon return, 2) the essential on the parasite, the diagnosis and the treatment, 3) the malaria problem worldwide and 4) malaria maps.

  10. The remarkable journey of adaptation of the Plasmodium falciparum malaria parasite to New World anopheline mosquitoes.

    Science.gov (United States)

    Molina-Cruz, Alvaro; Barillas-Mury, Carolina

    2014-08-01

    Plasmodium falciparum originated in Africa, dispersed around the world as a result of human migration and had to adapt to several different indigenous anopheline mosquitoes. Anophelines from the New World are evolutionary distant form African ones and this probably resulted in a more stringent selection of Plasmodium as it adapted to these vectors. It is thought that Plasmodium has been genetically selected by some anopheline species through unknown mechanisms. The mosquito immune system can greatly limit infection and P. falciparum evolved a strategy to evade these responses, at least in part mediated by Pfs47, a highly polymorphic gene. We propose that adaptation of P. falciparum to new vectors may require evasion of their immune system. Parasites with a Pfs47 haplotype compatible with the indigenous mosquito vector would be able to survive and be transmitted. The mosquito antiplasmodial response could be an important determinant of P. falciparum population structure and could affect malaria transmission in the Americas.

  11. The remarkable journey of adaptation of the Plasmodium falciparum malaria parasite to New World anopheline mosquitoes

    Directory of Open Access Journals (Sweden)

    Alvaro Molina-Cruz

    2014-08-01

    Full Text Available Plasmodium falciparum originated in Africa, dispersed around the world as a result of human migration and had to adapt to several different indigenous anopheline mosquitoes. Anophelines from the New World are evolutionary distant form African ones and this probably resulted in a more stringent selection of Plasmodium as it adapted to these vectors. It is thought that Plasmodium has been genetically selected by some anopheline species through unknown mechanisms. The mosquito immune system can greatly limit infection and P. falciparum evolved a strategy to evade these responses, at least in part mediated by Pfs47, a highly polymorphic gene. We propose that adaptation of P. falciparum to new vectors may require evasion of their immune system. Parasites with a Pfs47 haplotype compatible with the indigenous mosquito vector would be able to survive and be transmitted. The mosquito antiplasmodial response could be an important determinant of P. falciparum population structure and could affect malaria transmission in the Americas.

  12. Field efficacy of a new mosaic long-lasting mosquito net (PermaNet® 3.0 against pyrethroid-resistant malaria vectors: a multi centre study in Western and Central Africa

    Directory of Open Access Journals (Sweden)

    Pigeon Olivier

    2010-04-01

    Full Text Available Abstract Background Due to the spread of pyrethroid-resistance in malaria vectors in Africa, new strategies and tools are urgently needed to better control malaria transmission. The aim of this study was to evaluate the performances of a new mosaic long-lasting insecticidal net (LLIN, i.e. PermaNet® 3.0, against wild pyrethroid-resistant Anopheles gambiae s.l. in West and Central Africa. Methods A multi centre experimental hut trial was conducted in Malanville (Benin, Vallée du Kou (Burkina Faso and Pitoa (Cameroon to investigate the exophily, blood feeding inhibition and mortality induced by PermaNet® 3.0 (i.e. a mosaic net containing piperonyl butoxide and deltamethrin on the roof comparatively to the WHO recommended PermaNet® 2.0 (unwashed and washed 20-times and a conventionally deltamethrin-treated net (CTN. Results The personal protection and insecticidal activity of PermaNet 3.0 and PermaNet® 2.0 were excellent (>80% in the "pyrethroid-tolerant" area of Malanville. In the pyrethroid-resistance areas of Pitoa (metabolic resistance and Vallée du Kou (presence of the L1014F kdr mutation, PermaNet® 3.0 showed equal or better performances than PermaNet® 2.0. It should be noted however that the deltamethrin content on PermaNet® 3.0 was up to twice higher than that of PermaNet® 2.0. Significant reduction of efficacy of both LLIN was noted after 20 washes although PermaNet® 3.0 still fulfilled the WHO requirement for LLIN. Conclusion The use of combination nets for malaria control offers promising prospects. However, further investigations are needed to demonstrate the benefits of using PermaNet® 3.0 for the control of pyrethroid resistant mosquito populations in Africa.

  13. The history of 20th century malaria control in Peru.

    Science.gov (United States)

    Griffing, Sean M; Gamboa, Dionicia; Udhayakumar, Venkatachalam

    2013-08-30

    Malaria has been part of Peruvian life since at least the 1500s. While Peru gave the world quinine, one of the first treatments for malaria, its history is pockmarked with endemic malaria and occasional epidemics. In this review, major increases in Peruvian malaria incidence over the past hundred years are described, as well as the human factors that have facilitated these events, and concerted private and governmental efforts to control malaria. Political support for malaria control has varied and unexpected events like vector and parasite resistance have adversely impacted morbidity and mortality. Though the ready availability of novel insecticides like DDT and efficacious medications reduced malaria to very low levels for a decade after the post eradication era, malaria reemerged as an important modern day challenge to Peruvian public health. Its reemergence sparked collaboration between domestic and international partners towards the elimination of malaria in Peru.

  14. Larval source management for malaria control in Africa: myths and reality

    Directory of Open Access Journals (Sweden)

    Fillinger Ulrike

    2011-12-01

    Full Text Available Abstract As malaria declines in many African countries there is a growing realization that new interventions need to be added to the front-line vector control tools of long-lasting impregnated nets (LLINs and indoor residual spraying (IRS that target adult mosquitoes indoors. Larval source management (LSM provides the dual benefits of not only reducing numbers of house-entering mosquitoes, but, importantly, also those that bite outdoors. Large-scale LSM was a highly effective method of malaria control in the first half of the twentieth century, but was largely disbanded in favour of IRS with DDT. Today LSM continues to be used in large-scale mosquito abatement programmes in North America and Europe, but has only recently been tested in a few trials of malaria control in contemporary Africa. The results from these trials show that hand-application of larvicides can reduce transmission by 70-90% in settings where mosquito larval habitats are defined but is largely ineffectual where habitats are so extensive that not all of them can be covered on foot, such as areas that experience substantial flooding. Importantly recent evidence shows that LSM can be an effective method of malaria control, especially when combined with LLINs. Nevertheless, there are a number of misconceptions or even myths that hamper the advocacy for LSM by leading international institutions and the uptake of LSM by Malaria Control Programmes. Many argue that LSM is not feasible in Africa due to the high number of small and temporary larval habitats for Anopheles gambiae that are difficult to find and treat promptly. Reference is often made to the Ross-Macdonald model to reinforce the view that larval control is ineffective. This paper challenges the notion that LSM cannot be successfully used for malaria control in African transmission settings by highlighting historical and recent successes, discussing its potential in an integrated vector management approach working towards

  15. Emergence and prevalence of human vector-borne diseases in sink vector populations.

    Directory of Open Access Journals (Sweden)

    Guilhem Rascalou

    Full Text Available Vector-borne diseases represent a major public health concern in most tropical and subtropical areas, and an emerging threat for more developed countries. Our understanding of the ecology, evolution and control of these diseases relies predominantly on theory and data on pathogen transmission in large self-sustaining 'source' populations of vectors representative of highly endemic areas. However, there are numerous places where environmental conditions are less favourable to vector populations, but where immigration allows them to persist. We built an epidemiological model to investigate the dynamics of six major human vector borne-diseases in such non self-sustaining 'sink' vector populations. The model was parameterized through a review of the literature, and we performed extensive sensitivity analysis to look at the emergence and prevalence of the pathogen that could be encountered in these populations. Despite the low vector abundance in typical sink populations, all six human diseases were able to spread in 15-55% of cases after accidental introduction. The rate of spread was much more strongly influenced by vector longevity, immigration and feeding rates, than by transmission and virulence of the pathogen. Prevalence in humans remained lower than 5% for dengue, leishmaniasis and Japanese encephalitis, but substantially higher for diseases with longer duration of infection; malaria and the American and African trypanosomiasis. Vector-related parameters were again the key factors, although their influence was lower than on pathogen emergence. Our results emphasize the need for ecology and evolution to be thought in the context of metapopulations made of a mosaic of sink and source habitats, and to design vector control program not only targeting areas of high vector density, but working at a larger spatial scale.

  16. Cerebral malaria Malaria cerebral

    Directory of Open Access Journals (Sweden)

    Silvia Blair Trujillo

    2003-03-01

    Full Text Available Is the most common complication of P. falciparum malaria; nearly 90% of people who have suffered CM can recover without neurological problems. Currently there are four hypotheses that explain pathogenesis of CM: cytoadherence and sequestering of parasitized red blood cells to cerebral capillaries; rosette formation and parasitized red blood cells agglutination; production of cytokines and activation of second messengers and opening of the blood-brain barrier. However the main question remains to be answered; how the host-parasite interaction in the vascular space interferes transiently with cerebral function? Recently, the beta amyloid precursor peptide has been employed as marker of neural injury in CM. It is expected that the beta amyloid precursor peptide will help to understand the pathogenesis of CM in complicated patients of endemic areas of Colombia. La malaria Cerebral (MC es la complicación más frecuente de la malaria por P. falciparum; aproximadamente el 90% de las personas que la han padecido se recuperan completamente sin secuelas neurológicas. Aún no se conoce con claridad su patogénesis pero se han postulado cuatro hipótesis o mecanismos posibles: 1 citoadherencia y secuestro de glóbulos rojos parasitados en la microvasculatura cerebral; 2 formación de rosetas y aglutinación de glóbulos rojos parasitados; 3 producción de citoquinas y activación de segundos mensajeros y, 4 apertura de la barrera hematoencefálica. Sin embargo, queda un interrogante sin resolver aún: ¿qué proceso se lleva a cabo para que el parásito, desde el espacio microvascular, pueda interferir transitoriamente con la función cerebral? Recientemente se ha utilizado el precursor de la proteína b-Amiloide como un marcador de daño neuronal en MC; este precursor será de gran ayuda en futuras investigaciones realizadas en nuestro medio que aporten información para comprender la patogénesis de la MC.

  17. Malaria ecology and climate change

    Science.gov (United States)

    McCord, G. C.

    2016-05-01

    Understanding the costs that climate change will exact on society is crucial to devising an appropriate policy response. One of the channels through while climate change will affect human society is through vector-borne diseases whose epidemiology is conditioned by ambient ecology. This paper introduces the literature on malaria, its cost on society, and the consequences of climate change to the physics community in hopes of inspiring synergistic research in the area of climate change and health. It then demonstrates the use of one ecological indicator of malaria suitability to provide an order-of-magnitude assessment of how climate change might affect the malaria burden. The average of Global Circulation Model end-of-century predictions implies a 47% average increase in the basic reproduction number of the disease in today's malarious areas, significantly complicating malaria elimination efforts.

  18. ENVIRONMENTAL MANAGEMENT FOR MALARIA CONTROL

    Directory of Open Access Journals (Sweden)

    H. A. Rafatjah

    1976-09-01

    Full Text Available Environmental management for malaria control is defined as any planned physical activities that through transformation of land, water and vegetation will result in the prevention, reduction or elimination of malaria. In planning and implementing these activities, full consideration must be given to their long-term effects and benefits and to the preservation of the quality of environment and they need to be fully and closely coordinated with water, land and agricultural development projects. Environmental management activities for malaria control can be classified as source reduction, dealing mainly with physical alteration of the environment; environmental manipulation, introducing temporary environmental changes and the reduction, and prevention of man-vector contact by site selection, mosquito proofing of dwellings and personal protection. For anti-malaria programs to employ these activities they need to re-train the staff, re-orient the services and set up pilot operations for feasibility studies.

  19. The impact of natural and social factors on malaria vector ecology%自然与社会因素对传疟媒介按蚊生态习性的影响

    Institute of Scientific and Technical Information of China (English)

    刘小波; 刘起勇

    2012-01-01

    Malaria is a globally prevalent vector-borne disease, causes great physical and mental suffering, with serious social and economic impacts on the world. Studies suggested that both natural and social factors have an impact on the ecology of Anopheles mosquitoes. This paper reviewed the possible impact of natural factors, such as global climate change, natural disasters, and social factors including insecticide abuse, water pollution, rapid urbanization, land reclamation, deforestation, reservoir construction, and farming practices on the ecology of Anopheles mosquitoes in order to target vector control measures and adopt robust malaria elimination strategies.%疟疾广泛流行,严重危害人类健康,不仅造成沉重的疾病负担,而且产生严重的政治、经济和社会影响.研究认为,自然和社会因素可对媒介按蚊的生态习性产生一定程度的影响.现就气候变化、自然灾害等自然因素,杀虫剂滥用、水体污染、快速城市化、开垦荒地、滥伐森林、水库建设与耕作制度改变等社会因素对媒介按蚊生态习性的影响研究和发现进行综述,以便为全球消除疟疾目标顺利实现采取更具针对性的媒介按蚊防控策略和措施.

  20. A Plasmodium vivax plasmid DNA- and adenovirus-vectored malaria vaccine encoding blood stage antigens AMA1 and MSP142 in a prime/boost heterologous immunization regimen partially protects Aotus monkeys against blood stage challenge.

    Science.gov (United States)

    Obaldia, Nicanor; Stockelman, Michael G; Otero, William; Cockrill, Jennifer A; Ganeshan, Harini; Abot, Esteban N; Zhang, Jianfeng; Limbach, Keith; Charoenvit, Yupin; Doolan, Denise L; Tang, De-Chu C; Richie, Thomas L

    2017-02-08

    Malaria is caused by parasites of the genus Plasmodium that are transmitted to humans by the bites of Anopheles mosquitoes. After the elimination of P. falciparum it is predicted that Plasmodium vivax will remain an important cause of morbidity and mortality outside of Africa, stressing the importance of developing a vaccine against malaria. In this study we assess the immunogenicity and protective efficacy of two P. vivax antigens, AMA1 and MSP142 in a recombinant DNA plasmid prime/adenoviral vector (Ad) boost regimen in Aotus monkeys. Groups of 4 to 5 monkeys were immunized with DNA alone, Ad alone, prime/boost regimens of each antigen, prime/boost with both antigens, and empty vector controls, and then subjected to blood stage challenge. The heterologous immunization regimen with the antigen pair was more protective than either antigen alone or both antigens delivered with a single vaccine platform, based on their ability to induced the longest pre-patent period and time to peak parasitemia; the lowest peak and mean parasitemia; the smallest area under the parasitemia curve and the highest self-cured rate. Overall, pre-challenge MSP1 antibody titers strongly correlated with decreased parasite burden. Nevertheless, a significant proportion of immunized animals developed anemia. In conclusion, P. vivax plasmid DNA/Ad5 vaccine encoding blood stage parasite antigens AMA1 and MSP142 in a heterologous prime/boost immunization regimen, provided significant protection against blood-stage challenge in Aotus monkeys, indicating the suitability of these antigens and regimen for further development.

  1. Quantifying behavioural interactions between humans and mosquitoes: Evaluating the protective efficacy of insecticidal nets against malaria transmission in rural Tanzania

    Directory of Open Access Journals (Sweden)

    Mathenge Evan

    2006-11-01

    Full Text Available Abstract Background African malaria vectors bite predominantly indoors at night so sleeping under an Insecticide-Treated Net (ITN can greatly reduce malaria risk. Behavioural adaptation by mosquitoes to increasing ITN coverage could allow vector mosquitoes to bite outside of peak sleeping hours and undermine efficacy of this key malaria prevention measure. Methods High coverage with largely untreated nets has been achieved in the Kilombero Valley, southern Tanzania through social marketing programmes. Direct surveys of nightly biting activity by An. gambiae Giles were conducted in the area before (1997 and after (2004 implementation of ITN promotion. A novel analytical model was applied to estimate the effective protection provided by an ITN, based on published experimental hut trials combined with questionnaire surveys of human sleeping behaviour and recorded mosquito biting patterns. Results An. gambiae was predominantly endophagic and nocturnal in both surveys: Approximately 90% and 80% of exposure occurred indoors and during peak sleeping hours, respectively. ITNs consistently conferred >70% protection against exposure to malaria transmission for users relative to non-users. Conclusion As ITN coverage increases, behavioural adaptation by mosquitoes remains a future possibility. The approach described allows comparison of mosquito biting patterns and ITN efficacy at multiple study sites and times. Initial results indicate ITNs remain highly effective and should remain a top-priority intervention. Combined with recently developed transmission models, this approach allows rapid, informative and cost-effective preliminary comparison of diverse control strategies in terms of protection against exposure before more costly and intensive clinical trials.

  2. Vetores de malária em duas reservas indígenas da Amazônia Brasileira Vectores de malaria en dos reservas indígenas del Amazonas Brasilero Malaria vectors in two indigenous reserves of the Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Roseli La Corte dos Santos

    2009-10-01

    presentaron comportamiento exofílico e intensa actividad nocturna. La ocurrencia de inmaduros fue poco frecuente y la densidad larvaria fue baja. Las características de comportamiento de los vectores no se mostraron favorables a las actividades usuales de control vectorial.OBJECTIVE: To describe the composition, ecological and behavioral characteristics and infectivity of Anopheles species in indigenous reserves of the Amazon region. METHODS: The study was performed in villages of the Nhamundá-Mapuera and Cuminapanema indigenous reserves, in the state of Pará, Northern Brazil, in 2002. A total of three two-week collections were conducted in each reserve, with the capture of adult and immature forms. Adult Anopheles specimens were captured using a Castro sucking tube with human landing trap in indoor and outdoor environments, from 6.00 pm to 9.00 pm and from 6.00 pm to 6.00 am, and subsequently assessed to verify parity and infectivity by plasmodiums using dissection and ELISA. Water collections near the villages were surveyed using 500 ml ladles, with 20 ladlefuls for each 10 m, covering the maximum extent of 200 m of perimeter around the breeding spot. RESULTS: Adding up the collections from both reserves, a total of 8,668 females were captured. Anopheles darlingi was the most frequent species, with higher frequency around the homes. In the Mapuera reserve, blood feeding activity was concentrated between 8.00 pm and 12.00 am, while, in Cuminapanema, it remained high until 12.00 am, decreasing after this time and increasing again early in the morning. Of all the 6,350 An. darlingi females analyzed, 18 were infected with Plasmodium vivax VK247, VK210, P. falciparum and P. malariae. In addition, other 1,450 females of other species were analyzed, but none was found infected. An. nuneztovari and Chagasia bonnae were the most frequent species in the breeding spots of the Mapuera and Cuminapanema villages, respectively. Immature An. darlingi forms were not located in Mapuera

  3. 非洲学员对我国援非疟疾防治培训的需求分析%Analysis of demands of African students for China-Africa malaria preven-tion training

    Institute of Scientific and Technical Information of China (English)

    王琦; 王玠; 李侗桐; 曹俊; 谢铮

    2016-01-01

    Objective To understand the demands of African students on the China⁃Africa malaria prevention training pro⁃grams as well as explore further suggestions on the student selection and course content design. Methods A self⁃administered questionnaire survey was conducted,and all the students who attended in the malaria prevention training courses in 2014 and 2015 were included. The Chi⁃square test was conducted to analyse the correlations between professional backgrounds ,work stat⁃ues and training needs. Results A total of 161 individuals were sampled eventually. These participants were trained in either English(58.4%)or French(41.6%). Most of the participants were male(69.3%),the major of them were mainly clinical tech⁃nology specialty(40.0%),and most of them worked in malaria area within 10 years(56.4%). Moreover,48.2%of the partici⁃pants used more than 76%of total work time on malaria control,and more than 80%worked in national or provincial/municipal level. The working areas of these participants were focused on clinical field(41.4%)and official field(29.9%),and only a few of them were from research positions(11.9%). The most needed course content in malaria training was strategy and epidemiolo⁃gy knowledge for malaria prevention and control(65.5%),while clinical workers were most needed to be trained(39.2%). The participants who came from French speaking countries preferred strategy training(χ2=12.528,P<0.01),and those worked in the national level were aslo more likely to choose strategies training course(χ2=10.508,P<0.05). Conclusions Currently, the China⁃Africa malaria prevention training programs could basically satisfy African students’needs. However,more aimed courses should be designed according to their professional backgrounds,national situation,work experiences on malaria con⁃trol,and institutional levels.%目的:了解非洲学员对我国援非疟疾防治培训的需求,为援非培训班的对象选择和课程设置提

  4. An online operational rainfall-monitoring resource for epidemic malaria early warning systems in Africa

    Directory of Open Access Journals (Sweden)

    Ceccato Pietro

    2005-01-01

    Full Text Available Abstract Periodic epidemics of malaria are a major public health problem for many sub-Saharan African countries. Populations in epidemic prone areas have a poorly developed immunity to malaria and the disease remains life threatening to all age groups. The impact of epidemics could be minimized by prediction and improved prevention through timely vector control and deployment of appropriate drugs. Malaria Early Warning Systems are advocated as a means of improving the opportunity for preparedness and timely response. Rainfall is one of the major factors triggering epidemics in warm semi-arid and desert-fringe areas. Explosive epidemics often occur in these regions after excessive rains and, where these follow periods of drought and poor food security, can be especially severe. Consequently, rainfall monitoring forms one of the essential elements for the development of integrated Malaria Early Warning Systems for sub-Saharan Africa, as outlined by the World Health Organization. The Roll Back Malaria Technical Resource Network on Prevention and Control of Epidemics recommended that a simple indicator of changes in epidemic risk in regions of marginal transmission, consisting primarily of rainfall anomaly maps, could provide immediate benefit to early warning efforts. In response to these recommendations, the Famine Early Warning Systems Network produced maps that combine information about dekadal rainfall anomalies, and epidemic malaria risk, available via their Africa Data Dissemination Service. These maps were later made available in a format that is directly compatible with HealthMapper, the mapping and surveillance software developed by the WHO's Communicable Disease Surveillance and Response Department. A new monitoring interface has recently been developed at the International Research Institute for Climate Prediction (IRI that enables the user to gain a more contextual perspective of the current rainfall estimates by comparing them to

  5. Malaria and Travelers

    Science.gov (United States)

    ... a CDC Malaria Branch clinician. malaria@cdc.gov Malaria and Travelers Recommend on Facebook Tweet Share Compartir ... may be at risk for infection. Determine if malaria transmission occurs at the destinations Obtain a detailed ...

  6. Malaria Treatment (United States)

    Science.gov (United States)

    ... a CDC Malaria Branch clinician. malaria@cdc.gov Malaria Treatment (United States) Recommend on Facebook Tweet Share Compartir Treatment of Malaria: Guidelines For Clinicians (United States) Download PDF version ...

  7. Insecticide resistance in Bemisia tabaci Gennadius (Homoptera : Aleyrodidae) and Anopheles gambiae Giles (Diptera : Culicidae) could compromise the sustainability of malaria vector control strategies in West Africa

    OpenAIRE

    2013-01-01

    Insecticides from the organophosphate (OP) and pyrethroid (PY) chemical families, have respectively, been in use for 50 and 30 years in West Africa, mainly against agricultural pests, but also against vectors of human disease. The selection pressure, with practically the same molecules year after year (mainly on cotton), has caused insecticide resistance in pest populations such as Bemisia tabaci, vector of harmful phytoviruses on vegetables. The evolution toward insecticide resistance in mal...

  8. Synergy in efficacy of fungal entomopathogens and permethrin against West African insecticide-resistant Anopheles gambiae mosquitoes

    NARCIS (Netherlands)

    Farenhorst, M.; Knols, B.G.J.; Thomas, M.B.; Howard, A.F.V.; Takken, W.; Rowland, M.; N'Guessan, R.

    2010-01-01

    Background Increasing incidences of insecticide resistance in malaria vectors are threatening the sustainable use of contemporary chemical vector control measures. Fungal entomopathogens provide a possible additional tool for the control of insecticide-resistant malaria mosquitoes. This study invest

  9. Malaria-associated rubber plantations in Thailand.

    Science.gov (United States)

    Bhumiratana, Adisak; Sorosjinda-Nunthawarasilp, Prapa; Kaewwaen, Wuthichai; Maneekan, Pannamas; Pimnon, Suntorn

    2013-01-01

    Rubber forestry is intentionally used as a land management strategy. The propagation of rubber plantations in tropic and subtropic regions appears to influence the economical, sociological and ecological aspects of sustainable development as well as human well-being and health. Thailand and other Southeast Asian countries are the world's largest producers of natural rubber products; interestingly, agricultural workers on rubber plantations are at risk for malaria and other vector-borne diseases. The idea of malaria-associated rubber plantations (MRPs) encompasses the complex epidemiological settings that result from interactions among human movements and activities, land cover/land use changes, agri-environmental and climatic conditions and vector population dynamics. This paper discusses apparent issues pertaining to the connections between rubber plantations and the populations at high risk for malaria. The following questions are addressed: (i) What are the current and future consequences of rubber plantations in Thailand and Southeast Asia relative to malaria epidemics or outbreaks of other vector-borne diseases? (ii) To what extent is malaria transmission in Thailand related to the forest versus rubber plantations? and (iii) What are the vulnerabilities of rubber agricultural workers to malaria, and how contagious is malaria in these areas?

  10. Assessing the quality of service of village malaria workers to strengthen community-based malaria control in Cambodia

    Directory of Open Access Journals (Sweden)

    Ly Po

    2010-04-01

    Full Text Available Abstract Background Malaria continues to be a major public health problem in remote forested areas in Cambodia. As a national strategy to strengthen community-based malaria control, the Cambodian government has been running the Village Malaria Worker (VMW project since 2001. This study sought to examine the nature and quality of the VMWs' services. Methods Data collection was carried out in February and March 2008 through interviews with one of the two VMWs who takes the lead in malaria control activities in each of the 315 VMW villages (n = 251. The questionnaire addressed 1 the sociodemographic characteristics of VMWs, 2 service quality, 3 actions for malaria prevention and vector control, and 4 knowledge of malaria epidemiology and vector ecology. Results VMWs were effective in conducting diagnosis with Rapid Diagnostic Tests (RDTs and prescribing anti-malarials to those who had positive RDT results, skills that they had acquired through their training programmes. However, most other services, such as active detection, explanations about compliance, and follow-up of patients, were carried out by only a small proportion of VMWs. The variety of actions that VMWs took for malaria prevention and vector control was small (average action index score 12.8/23, and their knowledge was very limited with less than 20% of the VMWs giving correct answers to six out of seven questions on malaria epidemiology and vector ecology. Knowledge of vector breeding places and malaria transmission were significant determinants of both the quality of VMWs' services and the variety of their actions for malaria prevention and vector control. Conclusions VMWs' services focused primarily on diagnosis and treatment. Their focus needs to be broadened to cover other aspects of malaria control in order to further strengthen community-based malaria control. VMWs' actions and knowledge also need substantial improvement. Strengthening training programmes can help achieve better

  11. On the performance of multiple imputation based on chained equations in tackling missing data of the African α3.7 -globin deletion in a malaria association study.

    Science.gov (United States)

    Sepúlveda, Nuno; Manjurano, Alphaxard; Drakeley, Chris; Clark, Taane G

    2014-07-01

    Multiple imputation based on chained equations (MICE) is an alternative missing genotype method that can use genetic and nongenetic auxiliary data to inform the imputation process. Previously, MICE was successfully tested on strongly linked genetic data. We have now tested it on data of the HBA2 gene which, by the experimental design used in a malaria association study in Tanzania, shows a high missing data percentage and is weakly linked with the remaining genetic markers in the data set. We constructed different imputation models and studied their performance under different missing data conditions. Overall, MICE failed to accurately predict the true genotypes. However, using the best imputation model for the data, we obtained unbiased estimates for the genetic effects, and association signals of the HBA2 gene on malaria positivity. When the whole data set was analyzed with the same imputation model, the association signal increased from 0.80 to 2.70 before and after imputation, respectively. Conversely, postimputation estimates for the genetic effects remained the same in relation to the complete case analysis but showed increased precision. We argue that these postimputation estimates are reasonably unbiased, as a result of a good study design based on matching key socio-environmental factors.

  12. mSpray: a mobile phone technology to improve malaria control efforts and monitor human exposure to malaria control pesticides in Limpopo, South Africa.

    Science.gov (United States)

    Eskenazi, Brenda; Quirós-Alcalá, Lesliam; Lipsitt, Jonah M; Wu, Lemuel D; Kruger, Philip; Ntimbane, Tzundzukani; Nawn, John Burns; Bornman, M S Riana; Seto, Edmund

    2014-07-01

    Recent estimates indicate that malaria has led to over half a million deaths worldwide, mostly to African children. Indoor residual spraying (IRS) of insecticides is one of the primary vector control interventions. However, current reporting systems do not obtain precise location of IRS events in relation to malaria cases, which poses challenges for effective and efficient malaria control. This information is also critical to avoid unnecessary human exposure to IRS insecticides. We developed and piloted a mobile-based application (mSpray) to collect comprehensive information on IRS spray events. We assessed the utility, acceptability and feasibility of using mSpray to gather improved homestead- and chemical-level IRS coverage data. We installed mSpray on 10 cell phones with data bundles, and pilot tested it with 13 users in Limpopo, South Africa. Users completed basic information (number of rooms/shelters sprayed; chemical used, etc.) on spray events. Upon submission, this information as well as geographic positioning system coordinates and time/date stamp were uploaded to a Google Drive Spreadsheet to be viewed in real time. We administered questionnaires, conducted focus groups, and interviewed key informants to evaluate the utility of the app. The low-cost, cell phone-based "mSpray" app was learned quickly by users, well accepted and preferred to the current paper-based method. We recorded 2865 entries (99.1% had a GPS accuracy of 20 m or less) and identified areas of improvement including increased battery life. We also identified a number of logistic and user problems (e.g., cost of cell phones and cellular bundles, battery life, obtaining accurate GPS measures, user errors, etc.) that would need to be overcome before full deployment. Use of cell phone technology could increase the efficiency of IRS malaria control efforts by mapping spray events in relation to malaria cases, resulting in more judicious use of chemicals that are potentially harmful to humans

  13. Ecology of Anopheline (Diptera, Culicidae, malaria vectors around the Serra da Mesa Reservoir, State of Goiás, Brazil: 1 - Frequency and climatic factors

    Directory of Open Access Journals (Sweden)

    Anthony Érico Guimarães

    Full Text Available The ecology of anopheline species (Diptera, Culicidae was studied in the vicinity of the Serra da Mesa Reservoir, State of Goiás, Brazil. Climatic factors and frequency of anopheline populations were analyzed. Bimonthly human-bait and Shannon trap captures were conducted for 36 consecutive months (January 1997 through December 1999. A total of 5,205 adult anophelines belonging to five species were collected. Anopheles darlingi was the most frequently collected anopheline (61.4%, followed by An. albitarsis s.l. (35.4%, An. triannulatus. (2.5%, An. oswaldoi (0.4%, and An. evansae (0.2%. The water level and vegetation along the banks of the reservoir were crucial to the frequency of the various anopheline species. Climatic factors had a secondary influence. The reservoir's water-level stability, increased frequency of An. darlingi, and the arrival of gold prospectors were responsible for the increase in malaria cases.

  14. Efficacy comparison between anti-malarial drugs in Africans presenting with mild malaria in the Central Republic of Africa: a preliminary study

    Directory of Open Access Journals (Sweden)

    Nambei W.S.

    2005-03-01

    Full Text Available Drug resistance to Plasmodium falciparum contributes to major health problems in central Africa and, as a consequence, poverty. We have analyzed the efficacy of three currently available antimalarial drugs to treat symptomatic, uncomplicated P. falciparum malaria in semiimmune adults living in Bangui, Central Republic of Africa. 210 consecutive individuals were enrolled in the survey, of which 45 were excluded. Those having received dihydroartemisin proved significantly less parasitemic than those having received quinine per os or sulfadoxin-pyrimethamin (χ2 = 16.93 ; p < 0.05, and 75 % recovered in two days compared to 57 and 44 %, respectively. The 25 % who did not recover benefited from a second cure with dihydroartemisin, which proved 100 % efficient. The most accurate protocol remains to be established by analyzing clinical and parasitological data and taking into account the economics of the country.

  15. Six New Species of the Anopheles leucosphyrus Group, Reinterpretation of An. elegans and Vector Implications

    Science.gov (United States)

    2005-06-01

    vivax, Wuchereria, Culicidae, filaria vector, forest malaria vectors, malaria