Detoxification enzymes activities in deltamethrin and bendiocarb resistant and susceptible malarial vectors (<i>Anopheles gambiae</i>) breeding in Bichi agricultural and residential sites, Kano state, Nigeria

Abstract

Insecticide resistance is an important impediment to malaria control effort. Knowledge of insecticides resistance status is an essential tools to governmental, nongovernmental and insecticides producing industries whose daily challenge is minimization of malaria burden across the globe. Larvae of Anopheles gambiae collected from residential and agricultural areas of Bichi LGA, Kano States, North west Nigeria were reared to adults. Resistance and susceptibility status in the adults mosquitoes were studied by WHO paper bioassay impregnated with diagnostic dose of Deltamethrin and Bendiocarb. The insecticides resistance and susceptible adult mosquitoes of Bichi; residential areas (BR) and agricultural areas (BA) were respectively designated as BRr, BRs, BAr and BAs. Specific activities of insecticides detoxifying enzymes glutathione S transferase (GST), esterase and monooxygenase in resistant and susceptible vectors were measured using standard WHO methods. Although the levels of resistance varied with the insecticides and breeding site, high resistance status of malaria vectors to deltamethrin was recorded in both study sites (> 80% mortality) and incipient resistance (Tolerance) to bendiocarb (>97% mortality) based on WHO results interpretation. Significantly elevated (P<0.05) activities of GST, esterase and monooxygenase were recorded in deltamethrin and bendiocarb resistant strains compared to susceptible species in both BA and BR. The finding of the study established high resistance status to deltamethrin and incipient resistance to bendiocarb in all the study sites which could be linked to indiscriminate use of insecticides in residential sites against malarial vector and other flying insects and agrochemicals for pest control in the agricultural sites. Based on this finding, it may be concluded that insecticides resistance to malaria vector exists in both residential and agricultural areas and measures should be taken to curtail it. Keywords : insecticides (deltamethrin and bendiocarb) resistance, Bioassay, Malarial vector, detoxification enzymes.