Assessing female anopheles mosquito susceptibility to three insecticide classes in Ilorin metropolis Nigeria: Implications for environmental management and effective vector control

This study investigates the environmental factors affecting the susceptibility of Female Anopheles mosquitoes to three classes of insecticides in Ilorin, Kwara State, Nigeria, following WHO standards. The analyzed breeding sites showed severe water pollution, with low dissolved oxygen, high conductivity, and heavy metal contamination. Anopheles mosquito populations at two of the five breeding sites, Akanlanbi and Aminlengbe, were resistant to all three insecticide types tested. The mosquitoes in Aminlengbe exhibited higher resistance to organochlorine (71% mortality), organophosphate (73%), pirimiphos methyl (73%), and carbamates (83%) and bendiocarb (88%) compared to those in Akanlanbi, which had lower resistance to pirimiphos methyl (94%) and carbamates (67%) and bendiocarb (86%). In contrast, mosquitoes from the other three sites (Edun, Niger, Shao-garage) were mostly susceptible (98%-100%) to the organophosphate insecticide pirimiphos methyl but showed varying susceptibility to the two carbamate insecticides tested (propoxur and bendiocarb). Mosquitoes at these sites were 98.4%-99.5% susceptible to bendiocarb, yet resistant to propoxur (88.7%-94.6%). The study attributes environmental pollution at these breeding sites to historical agricultural practices, industrial activities, and improper waste disposal, contributing to insecticide resistance among mosquito populations. This resistance poses significant challenges to malaria vector control efforts in Ilorin. The study emphasizes the urgent need for integrated vector management (IVM) strategies that incorporate environmental management into vector control plans. This study therefore recommends adopting pesticide and fertilizer degradation strategies, improving waste management practices, implementing comprehensive IVM approaches, developing supportive policies, and enhancing community awareness and participation to mitigate mosquito-borne diseases and ensure effective malaria control amidst rising insecticide resistance.