Knockdown times in a simple assay determination of insecticide resistance in malaria vectors

Background: Determining the insecticide resistance status of malaria vectors, particularly to insecticides used on mosquito nets, is important but is Limited to a relatively small number of Locations. We describe a simple assay that enables this information to be obtained over a much wider area. Methods: The time to knockdown of mosquitoes in an insecticide-treated netting-covered metal frame cage were recorded. The shape of the curve of the proportion of knocked down mosquitoes provides information on resistance status. Results: Resistant Anopheles funestus took significantly Longer for knockdown than did susceptible Anopheles arabiensis. Conclusions: This simple technique will enable a wide range of Locations to be sampled, enhancing our understanding of the spread of resistance to pyrethroids.