Species Composition and Emerging Insecticide Resistance in Aedes Mosquitoes from Osun State, Nigeria: Implications for Vector Control
1
Biological Sciences, Fountain University, Osogbo, Nigeria
2
Animal and Environmental Biology, Osun State University, Osogbo, Nigeria
Popul. Med. 2026;8(Supplement Supplement 1):
ABSTRACT
INTRODUCTION:
Aedes mosquitoes are major vectors of arboviral diseases, including dengue, Zika, and chikungunya, which present significant public health threats in Nigeria. Despite the increasing burden of arboviruses, limited information exists on insecticide resistance in Aedes populations in Osun State. This study investigated species composition, resistance status to commonly used insecticides, and the effect of synergists on Aedes populations in Osogbo and Ejigbo Local Government, Osun State.
METHODS:
Larvae were collected from diverse breeding habitats, reared to adulthood, and identified morphologically. Adult female mosquitoes were subjected to WHO-standard bioassays using pyrethroids (permethrin, deltamethrin, alpha-cypermethrin) and organophosphate (pirimiphos-methyl), with and without piperonyl butoxide (PBO) as a synergist.
RESULTS:
A total of 600 adult Aedes mosquitoes were tested, with Aedes aegypti predominating (99.3%) over Aedes albopictus (0.7%) (p < 0.05). Susceptibility was observed for permethrin, deltamethrin, and pirimiphos-methyl (100% mortality). However, reduced mortality (94%) against alpha-cypermethrin suggested emerging resistance (p < 0.05). The addition of PBO restored full susceptibility, achieving 100% mortality across assays.
CONCLUSIONS:
These findings highlight the predominance of Ae. aegypti in Osun State and its generally high susceptibility to pyrethroid and organophosphate insecticides, with early evidence of resistance to alpha-cypermethrin. The demonstrated efficacy of PBO underscores the importance of synergists in mitigating resistance and preserving insecticide effectiveness. Continuous surveillance and integrated vector management, including synergist-based interventions, are essential to sustain control efforts and curb the risk of Aedes-borne arboviral disease outbreaks in Nigeria.
Aedes mosquitoes are major vectors of arboviral diseases, including dengue, Zika, and chikungunya, which present significant public health threats in Nigeria. Despite the increasing burden of arboviruses, limited information exists on insecticide resistance in Aedes populations in Osun State. This study investigated species composition, resistance status to commonly used insecticides, and the effect of synergists on Aedes populations in Osogbo and Ejigbo Local Government, Osun State.
METHODS:
Larvae were collected from diverse breeding habitats, reared to adulthood, and identified morphologically. Adult female mosquitoes were subjected to WHO-standard bioassays using pyrethroids (permethrin, deltamethrin, alpha-cypermethrin) and organophosphate (pirimiphos-methyl), with and without piperonyl butoxide (PBO) as a synergist.
RESULTS:
A total of 600 adult Aedes mosquitoes were tested, with Aedes aegypti predominating (99.3%) over Aedes albopictus (0.7%) (p < 0.05). Susceptibility was observed for permethrin, deltamethrin, and pirimiphos-methyl (100% mortality). However, reduced mortality (94%) against alpha-cypermethrin suggested emerging resistance (p < 0.05). The addition of PBO restored full susceptibility, achieving 100% mortality across assays.
CONCLUSIONS:
These findings highlight the predominance of Ae. aegypti in Osun State and its generally high susceptibility to pyrethroid and organophosphate insecticides, with early evidence of resistance to alpha-cypermethrin. The demonstrated efficacy of PBO underscores the importance of synergists in mitigating resistance and preserving insecticide effectiveness. Continuous surveillance and integrated vector management, including synergist-based interventions, are essential to sustain control efforts and curb the risk of Aedes-borne arboviral disease outbreaks in Nigeria.
| eISSN: | 2654-1459 |
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