Evaluating Insecticide Resistance Mechanisms in Anopheles gambiae Populations From Malaria-Endemic Communities in Akwa Ibom State, South South Nigeria

Insecticide resistance in Anopheles gambiae sensu lato populations threatens the effectiveness of pyrethroid-based insecticide-treated nets and indoor residual spraying, the two principal vector control tools deployed in Nigeria's malaria elimination strategy. This study evaluates insecticide resistance mechanisms in A. gambiae populations from malaria-endemic communities in Akwa Ibom State, South South Nigeria. An analytical entomological study was conducted across three communities in Uyo, Eket, and Ikot Abasi Local Government Areas. Adult female mosquitoes were collected using CDC light traps and reared one generation to produce F1 adult offspring for insecticide susceptibility bioassays. WHO tube bioassay tests with deltamethrin, permethrin, malathion, and bendiocarb were performed per standardised protocols. Synergist bioassays using piperonyl butoxide were conducted to implicate metabolic resistance. Molecular analysis was performed for the L1014F and L1014S kdr mutations associated with target site resistance. Cytochrome P450 and glutathione-S-transferase activity assays assessed enzyme-based metabolic resistance. Evidence from 2020 to 2024 confirms that pyrethroid resistance is near-universal in A. gambiae populations across southern Nigeria, driven by the co-occurrence of kdr mutations and metabolic resistance. This study characterises the specific resistance profile for Akwa Ibom State, informing the selection of insecticide formulations for IRS campaigns. Findings will be submitted to the Akwa Ibom State Malaria Elimination Programme and the National Malaria Elimination Programme insecticide resistance monitoring committee. Keywords: insecticide resistance, Anopheles gambiae, kdr mutations, Akwa Ibom State, vector control.