Molecular detection of insecticide resistance markers in <i>Aedes aegypti</i> (Diptera: Culicidae) populations from Haiti

Aedes aegypti (Linnaeus, 1762) mosquitoes are the primary vectors of several arboviruses of major public health importance, including dengue virus, Zika virus, chikungunya virus, and yellow fever virus. In Haiti, Ae. aegypti mosquitoes are highly abundant and linked to the transmission and spread of these pathogens. As the use of pesticides for control of mosquitoes increases, there is heightened selection pressure for insecticide-resistant (IR) mosquitoes, mitigating the efficacy of pesticides and leading to an increased risk of continual pathogen transmission. To this end, active surveillance of resistance status can inform more effective operational control strategies. In this study, we screened 421 individual Ae. aegypti mosquitoes collected from the Ouest department of Haiti between 2018 and 2019 for the presence of IR mutations S989P, F1534C, V1016I, and V1016G. We observed IR-conferring alleles in all study sites, including a high prevalence of the homozygous resistance variant of F1534C across time, an increased prevalence of the homozygous resistance variant V1016I across time (an estimated 12.27% higher odds across time), and the absence of resistance-associated alleles for S989P. Our results indicate that pyrethroid resistance is prevalent and increasing in Ae. aegypti populations within this region of Haiti.