Iranian Journal of Toxicology

en Metabolic Enzymes Activities Linked with Decimation of Toxic Pyrethroids in Malaria Vector Populations Breeding in Crude Oil Impacted Communities of Akwa Ibom State, Nigeria. تخصصي Special پژوهشي Research 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. The present 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). Methods: Physico-chemical parameters of breeding sites were assessed using standard hydrobiological methods. Insecticide and piperonyl butoxide (PBO) bioassays, along with enzyme activity assays, were conducted according to 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 between permethrin mortality and hydrocarbon levels (r=-0.831, p=0.011) suggests 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 with 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, Nigeria, fosters enzyme-driven pyrethroid resistance in the local adult malaria vector populations. This presents a significant challenge for pyrethroid-based interventions, threatening malaria control efforts in the region.   Malaria vectors, metabolic enzymes, pyrethriod insecticides, Resistance, crude oil 77 86 http://ijt.arakmu.ac.ir/browse.php?a_code=A-10-1462-1&slc_lang=en&sid=1 Ndifreke Daniel Ekpo ndifrekeekpo@uniuyo.edu.ng 100319475328460018930 100319475328460018930 Yes Department of Animal and Environmental Biology, University of Uyo, Uyo, Nigeria. Asanga Edet Effiong edyasangae1@gmail.com 100319475328460018931 100319475328460018931 No Department of Biochemistry, Arthur Jarvis University, Akpabuyo, Cross River State, Nigeria. Eteng Ofem Effiom ofemeffiom@gmail.com 100319475328460018932 100319475328460018932 No Department of Biochemistry, College of Biosciences, Federal University of Agriculture, Abeokuta, Nigeria. Emmanuel Ating emmanuel.ating@maritimeacademy.edu.ng 100319475328460018933 0009-0004-6112-2738 No School of Nautical Studies, Maritime Academy of Nigeria, Oron, Nigeria. Essien Ubong Benard ubongessien11@gmail.com 100319475328460018934 0009-0009-5227-8403 No Department of Animal and Environmental Biology, University of Uyo, Uyo, Nigeria. Udeme Udo Afia afia_udeme@yahoo.com 100319475328460018935 100319475328460018935 No Department of Animal and Environmental Biology, University of Uyo, Uyo, Nigeria. Akon Umoekeyo Uno destynee.au@gmail.com 100319475328460018936 0009-0003-3346-8072 No Federal University of Technology, Minna, Nigeria. Nworie Chika John chikanworie@uniuyo.edu.ng 100319475328460018937 0009-0003-7990-4925 No Department of Animal and Environmental Biology, University of Uyo, Uyo, Nigeria. Akpan Bassey Effiong bassyakpan2015@gmail.com 100319475328460018938 0009-0001-2391-5727 No Department of Animal and Environmental Biology, University of Uyo, Uyo, Nigeria. Lawrence Usip usiplaw01@gmail.com 100319475328460018939 100319475328460018939 No Department of Animal and Environmental Biology, University of Uyo, Uyo, Nigeria.