Pyretheroids Resistance and Detoxifying Enzymes Activities of Malaria Vector (Anopheles gambiae) Breeding in Auyo Irrigation and Residential Sites, Jigawa State, Nigeria

Aims: The aim of this study is to evaluate the resistance status and detoxification enzymes activities of important malaria vector (Anopheles gambae) to WHO recommended pyretheroids insecticides in a highly malaria endemic country like Nigeria.

Study Design: Mosquitoes larvae collected from Auyo residential (AR), and Auyo irrigation (AI) sites were reared to adults and adult gambae were specifically exposed to Permethrin and Deltamethrin. The insecticides resistant and susceptible mosquitoes of AR and AI were respectively redistributed as ARr, ARs, AIr, and AIs.

Place and Duration of Study: Residential site (AR) and Rice irrigation sites (AI) of Auyo town, in Auyo LGA Jigawa State Nigeria, between July and October, 2014.

Methodology: Pyretheroids resistance status was studied using WHO adult mosquito bioassay protocols. Specific activities of insecticides detoxifying enzymes; GST, esterase and monooxygenase of the resistant and susceptible vectors were determined using standard methods.

Results: The results of the study established high resistant status of malaria vectors to both insecticides tested based on WHO interpretation (< 90% mortality). Significant elevated activities (P<0.05) of GST, esterase and lower activity of monooxygenase was recorded in permethrin resistant strain compared to susceptible strain of Auyo irrigation sites. Also a significant higher (P<0.05) activities of GST, esterase and monooxygenase was established in Deltamethrin resistant strain of both AR and AI, except for esterase in AR.

Conclusion: The findings of the study established resistance in both residential and irrigation sites, which could be associated to indiscriminate use of insecticides in residential sites against malarial vector and other flying insects as well as agrochemicals in the irrigation sites. Based on this finding it may be concluded that selection pressure that confers resistance to malarial vector is not restricted to agricultural activities alone.