SUSCEPTIBILITY OF ANOPHELES FUNESTUS TO PIRIMIPHOS-METHYL: EVIDENCE FOR ITS CONTINUED ROLE IN MALARIA VECTOR CONTROL IN NORTHERN NIGERIA

Abstract

Insecticide resistance in malaria vectors threatens vector control programs in Nigeria. The study assessed the insecticide susceptibility status and molecular identification of An. funestus populations in Gajerar Giwa village, Katsina State, Nigeria. Bioassays were conducted using WHO test protocols with DDT (4%), bendiocarb (0.1%), and pirimiphos-methyl (0.25%). Molecular identification was performed using cocktail PCR assays. Results showed possible resistance to DDT (95% mortality) and bendiocarb (90% mortality), while full susceptibility was observed to pirimiphos-methyl (100% mortality). Knockdown analysis indicated a gradual increase in mortality with exposure duration, suggesting partial resistance mechanisms at play. PCR confirmed the presence of An. funestus s.s. These findings provide crucial insights into insecticide resistance profiles of An. funestus in northern Nigeria and emphasize the importance of routine monitoring to guide malaria vector control. The study further highlights the potential operational benefits of organophosphates in indoor residual spraying, given their sustained efficacy compared to carbamates and organochlorines. Considering the widespread emergence of pyrethroid resistance in northern Nigeria, the continued susceptibility of An. funestus to pirimiphos-methyl offers a valuable opportunity for integrated resistance management and policy decisions in malaria control programs.