Aquatain® Mosquito Formulation (AMF) for the control of immature Anopheles gambiae sensu stricto and Anopheles arabiensis: Dose-responses,persistence and sub-lethal effects

Background: persistent monomolecular surface films could benefit larval source management for malaria control by reducing programme costs and managing insecticide resistance. this study evaluated the efficacy of the silicone-based surface film,aquatain® mosquito formulation (amf),for the control of the afrotropical malaria vectors,anopheles gambiae sensu stricto and anopheles arabiensis in laboratory dose-response assays and standardized field tests. methods: tests were carried out following guidelines made by the world health organization pesticide evaluation scheme (whopes). sub-lethal effects of amf were evaluated by measuring egg-laying and hatching of eggs laid by female an. gambiae s.s. that emerged from habitats treated with a dose that resulted in 50% larval mortality in laboratory tests. results: both vector species were highly susceptible to amf. the estimated lethal doses to cause complete larval mortality in dose-response tests in the laboratory were 1.23 (95% confidence interval (ci) 0.99-1.59) ml/m2 for an. gambiae s.s. and 1.35 (95% ci 1.09-1.75) ml/m2 for an. arabiensis. standardized field tests showed that a single dose of amf at 1 ml/m2 inhibited emergence by 85% (95% ci 82-88%) for six weeks. females exposed as larvae to a sub-lethal dose of amf were 2.2 times less likely (odds ratio (or) 0.45,95% ci 0.26-0.78) to lay eggs compared to those from untreated ponds. however,exposure to sub-lethal doses neither affected the number of eggs laid by females nor the proportion hatching. conclusion: amf provided high levels of larval control for a minimum of six weeks,with sub-lethal doses reducing the ability of female mosquitoes to lay eggs. the application of amf provides a promising novel strategy for larval control interventions against malaria vectors in africa. further field studies in different eco-epidemiological settings are justified to determine the persistence of amf film for mosquito vector control and its potential for inclusion in integrated vector management programmes. © 2014 mbare et al.; licensee biomed central ltd.