Three years of insecticide resistance evolution and associated mechanisms inAedes aegyptipopulations of Ouagadougou, Burkina Faso

Abstract

AbstractBackgroundResistance to insecticides is spreading among populations ofAedes aegypti, the primary vector of important human arboviruses. The escalating insecticide resistance poses a significant threat to dengue vector control, with an expanding number of countries affected by the disease.To gain a deeper insight into the evolution of insecticide resistance, it is essential to have longitudinal surveillance results, which are currently lacking, particularly from AfricanAe. aegyptipopulations.Here we report on three-years of surveillance ofAe. aegyptisusceptibility to insecticide resistance phenotypes and associated kdr mutations in Burkina Faso, a country with regular dengue outbreaks.MethodsAe.aegyptisusceptibility to insecticides and the V410L, V1016I, and F1534Ckdrtarget site mutations linked to pyrethroid insecticide resistance were monitored in Ouagadougou from 2016 to 2018. Larvae were collected from artificial containers at two sites and reared to adulthood in an insectary. Bioassays were conducted on female adults, alongside with a laboratory-susceptible strain, following standard WHO protocols. Allele-specific PCR genotyping assays were utilized to identify the V410L, V1016I, and F1534Ckdrpyrethroid target site mutations.ResultsBioassays revealed a high level of resistance to permethrin and deltamethrin that progressively increased over the three-year period in both localities. The 1534C mutation was nearly fixed throughout the three years at each locality, and while the closely related 410L and 1016I mutations did not vary between localities, their frequency notably increased from 2016 to 2018. Interestingly,Ae. aegyptipopulations in both areas remained susceptible to bendiocarb, fenitrothion, and malathion. Modeling the mortality data further confirmed the escalating resistance trend over the years and emphasized the significant role played by the three kdr mutations in conferring resistance to pyrethroids.ConclusionMortality rates indicate thatAe. aegyptipopulations from Ouagadougou are becoming increasingly resistant to pyrethroid insecticides, likely due to an increase in the frequencies of the 410L and 1016Ikdr mutations. Organophosphate insecticides are likely to be better alternative options for control.