| Summary: | <p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>In the laboratory, both sexes of <it>Anopheles gambiae sensu stricto </it>and <it>Culex quinquefasciatus </it>were passively contaminated with dry conidia of <it>Metarhizium anisopliae</it>. Pathogenicity of this fungus for <it>An. gambiae </it>was further tested for varying exposure times and different doses of oil-formulated conidia.</p> <p>Results</p> <p>Comparison of Gompertz survival curves and LT<sub>50 </sub>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<sub>50 </sub>values were found for different exposure times (24, 48 hrs or continuous exposure) of <it>An. gambiae </it>to dry conidia. Exposure to oil-formulated conidia (doses ranging from 1.6 × 10<sup>7 </sup>to 1.6 × 10<sup>10 </sup>conidia/m<sup>2</sup>) gave LT<sub>50 </sub>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%.</p> <p>Conclusion</p> <p>Our study marks the first to use an entomopathogenic fungus against adult Afrotropical disease vectors. Given its high pathogenicity for both adult <it>Anopheles </it>and <it>Culex </it>mosquitoes we recommend development of novel targeted indoor application methods for the control of endophagic host-seeking females.</p>
|
|---|