Ndifreke Daniel Ekpo *1 
, Asanga Edet Effiong2 , Eteng Ofem Effiom3 , Emmanuel Ating4 , Essien Ubong Benard5 , Udeme Udo Afia5 , Akon Umoekeyo Uno6 , Nworie Chika John5 , Akpan Bassey Effiong5 , Lawrence Usip5
, Asanga Edet Effiong2 , Eteng Ofem Effiom3 , Emmanuel Ating4 , Essien Ubong Benard5 , Udeme Udo Afia5 , Akon Umoekeyo Uno6 , Nworie Chika John5 , Akpan Bassey Effiong5 , Lawrence Usip5
1- Department of Animal and Environmental Biology, University of Uyo, Uyo, Nigeria. , ndifrekeekpo@uniuyo.edu.ng
2- Department of Biochemistry, Arthur Jarvis University, Akpabuyo, Cross River State, Nigeria.
3- Department of Biochemistry, College of Biosciences, Federal University of Agriculture, Abeokuta, Nigeria.
4- School of Nautical Studies, Maritime Academy of Nigeria, Oron, Nigeria.
5- Department of Animal and Environmental Biology, University of Uyo, Uyo, Nigeria.
6- Federal University of Technology, Minna, Nigeria.
2- Department of Biochemistry, Arthur Jarvis University, Akpabuyo, Cross River State, Nigeria.
3- Department of Biochemistry, College of Biosciences, Federal University of Agriculture, Abeokuta, Nigeria.
4- School of Nautical Studies, Maritime Academy of Nigeria, Oron, Nigeria.
5- Department of Animal and Environmental Biology, University of Uyo, Uyo, Nigeria.
6- Federal University of Technology, Minna, Nigeria.
Abstract: (82 Views)
Background: Sustained insecticide toxicity against malaria vectors is crucial for effective vector control. Some mosquito populations have become resistant to commonly used insecticides for their control. Resistance, however, is often localized as it is shaped by local environmental factors that drive physiological and biochemical changes in local mosquito populations. This study examined insecticide resistance and biochemical changes in adult female Anopheles mosquitoes from crude oil-polluted areas in Akwa Ibom State, Nigeria (March–November 2024).
Methodology: Physico-chemical parameters of breeding sites were assessed using standard hydrobiological methods. Insecticide and piperonyl butoxide (PBO) bioassays, along with enzyme activity assays, followed standard protocols.
Results: Breeding sites were contaminated with hydrocarbons and other pollutants. Vectors showed substantial resistance to permethrin (16 – 71% mortality) but only marginal resistance to other pyrethroids (90 – 97% mortality). A strong negative correlation was observed between permethrin mortality and hydrocarbon levels (r = -0.831, p = 0.011), suggesting that pollution reduced insecticide efficacy. Pre-exposure to PBO remarkably raised permethrin mortality to 92 – 98%, implicating metabolic enzymes in the resistance dynamics. Local mosquito populations exhibited elevated detoxifying enzyme activities—especially mixed function oxidase (MFO)—compared to Kisumu strains. These enzyme levels correlated significantly and positively with hydrocarbon content (r = 0.766 – 0.985; p = 0.000 – 0.027).
Conclusion: The findings suggest that crude oil pollution of anopheles breeding sites in Ibeno LGA, Akwa Ibom State, fosters enzyme-driven pyrethroid resistance in the local adult malaria vector populations. This presents a major challenge to pyrethroid-based interventions, threatening malaria control efforts in the region
Methodology: Physico-chemical parameters of breeding sites were assessed using standard hydrobiological methods. Insecticide and piperonyl butoxide (PBO) bioassays, along with enzyme activity assays, followed standard protocols.
Results: Breeding sites were contaminated with hydrocarbons and other pollutants. Vectors showed substantial resistance to permethrin (16 – 71% mortality) but only marginal resistance to other pyrethroids (90 – 97% mortality). A strong negative correlation was observed between permethrin mortality and hydrocarbon levels (r = -0.831, p = 0.011), suggesting that pollution reduced insecticide efficacy. Pre-exposure to PBO remarkably raised permethrin mortality to 92 – 98%, implicating metabolic enzymes in the resistance dynamics. Local mosquito populations exhibited elevated detoxifying enzyme activities—especially mixed function oxidase (MFO)—compared to Kisumu strains. These enzyme levels correlated significantly and positively with hydrocarbon content (r = 0.766 – 0.985; p = 0.000 – 0.027).
Conclusion: The findings suggest that crude oil pollution of anopheles breeding sites in Ibeno LGA, Akwa Ibom State, fosters enzyme-driven pyrethroid resistance in the local adult malaria vector populations. This presents a major challenge to pyrethroid-based interventions, threatening malaria control efforts in the region
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