Infection of malaria ( Anopheles gambiae s.s. ) and filariasis ( Culex quinquefasciatus ) vectors with the entomopathogenic fungus Metarhizium anisopliae

Abstract 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 f...

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Bibliographic Details
Published in:Malaria Journal
Main Authors: Smallegange Renate C, Njiru Basilio N, Scholte Ernst-Jan, Takken Willem, Knols Bart GJ
Format: Article in Journal/Newspaper
Language:English
Published: BMC 2003
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Online Access:https://doi.org/10.1186/1475-2875-2-29
https://doaj.org/article/ecab8483fcd44d608317e36d020513f0
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Summary:Abstract 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 against tsetse flies (Diptera: Glossinidae) we investigated the potency of this fungus as a biological control agent for adult malaria and filariasis vector mosquitoes. Methods In the laboratory, both sexes of Anopheles gambiae sensu stricto and Culex quinquefasciatus were passively contaminated with dry conidia of Metarhizium anisopliae . Pathogenicity of this fungus for An. gambiae was further tested for varying exposure times and different doses of oil-formulated conidia. Results Comparison of Gompertz survival curves and LT 50 values for treated and untreated specimens showed that, for both species, infected mosquitoes died significantly earlier (p < 0.0001) than uninfected control groups. No differences in LT 50 values were found for different exposure times (24, 48 hrs or continuous exposure) of An. gambiae to dry conidia. Exposure to oil-formulated conidia (doses ranging from 1.6 × 10 7 to 1.6 × 10 10 conidia/m 2 ) gave LT 50 values of 9.69 ± 1.24 (lowest dose) to 5.89 ± 0.35 days (highest dose), with infection percentages ranging from 4.4–83.7%. Conclusion Our study marks the first to use an entomopathogenic fungus against adult Afrotropical disease vectors. Given its high pathogenicity for both adult Anopheles and Culex mosquitoes we recommend development of novel targeted indoor application methods for the control of endophagic host-seeking females.