Pyrethroid Resistance in Anopheles gambiae s.l.: A Focus on Permethrin and Deltamethrin for Malaria Vector Control.

BACKGROUND: Malaria remains a major public health concern, and sub-Saharan Africa accounts for a significant proportion of global cases. A key challenge in malaria control is the increasing resistance of malaria vectors to commonly used insecticides, particularly pyrethroids. This study assessed the susceptibility of Anopheles gambiae s.l. to permethrin and deltamethrin in Zuba, located in the Gwagwalada Area Council of Abuja, Nigeria. METHODS: Mosquito larvae were collected in June 2024 and reared under controlled insectary conditions until adulthood. Adult mosquitoes were then tested using the Centers for Disease Control and Prevention bottle bioassays, and exposed to both standard World Health Organization recommended doses (21.5 µg/bottle for permethrin and 12.5 µg/bottle for deltamethrin) and lower, sub-lethal concentrations. Mortality rates were monitored up to 24 h post-exposure, and the results were analyzed using one-way analysis of variance at a significance level of P < 0.05. RESULTS: At the standard dose, permethrin induced a mortality rate of 84.4% (21.10 ± 0.50) after 30 min, significantly higher (P = 0.031) than that observed at 15.0 µg/bottle (18.00 ± 0.00, 72%). Complete mortality was achieved only after 35 min. Deltamethrin caused a mortality rate of 76% at 30 min (19.00 ± 0.30), with 100% mortality observed after 40 min (P = 0.04). No mortality was recorded for sub-lethal doses (≤0.8 µg/bottle) after 24 h (P = 0.061). CONCLUSIONS: These findings highlight the resistance levels of permethrin and deltamethrin in An. gambiae s.l. population in Zuba. Routine resistance surveillance and tailored mosquito control strategies are essential for sustaining mosquito control efforts in this region.