Effect of sub-lethal concentrations of different synthetic pyrethroids on the level of cytochrome P450 monooxygenase of Aedes albopictus (Skuse) larvae from northern part of West Bengal, India.

Development of resistance against synthetic pyrethroids has become a major challenge for the control of Aedes mosquitoes as well as for dengue control in northern part of West Bengal. Metabolic resistance by enhanced levels of cytochrome P₄₅₀ monooxygenases is one of the major mechanisms responsible for pyrethroid resistance and this enzyme can be induced by pyrethroid exposure. Therefore, the present study focused on the concentration dependent and time dependent effect of different synthetic pyrethroids on the monooxygenase enzyme of the larvae of Aedes albopictus which is a highly prevalent dengue vector of northern part of West Bengal. Larvae of wild Ae. albopictus populations were exposed to their respective sublethal concentrations (LC₁₀ and LC₅₀) of deltamethrin, lambda-cyhalothrin and permethrin and monooxygenase levels were recorded after 24, 48 and 72 hours of exposure. Hjghest levels of the enzyme were observed after 24 hours of permethrin exposure (at LC₁₀) and after 72 hours of deltamethrin and lambda-cyhalothrin exposure (at LC₅₀). From this study, it can be concluded that different synthetic pyrethroid compounds can differentially induce the monooxygenase enzyme in the larvae of Ae. albopictus. Development of resistance against synthetic pyrethroids has become a major challenge for the control of Aedes mosquitoes as well as for dengue control in northern part of West Bengal. Metabolic resistance by enhanced levels of cytochrome P₄₅₀ monooxygenases is one of the major mechanisms responsible for pyrethroid resistance and this enzyme can be induced by pyrethroid exposure. Therefore, the present study focused on the concentration dependent and time dependent effect of different synthetic pyrethroids on the monooxygenase enzyme of the larvae of Aedes albopictus which is a highly prevalent dengue vector of northern part of West Bengal. Larvae of wild Ae. albopictus populations were exposed to their respective sublethal concentrations (LC₁₀ and LC₅₀) of deltamethrin, lambda-cyhalothrin and permethrin and monooxygenase levels were recorded after 24, 48 and 72 hours of exposure. Hjghest levels of the enzyme were observed after 24 hours of permethrin exposure (at LC₁₀) and after 72 hours of deltamethrin and lambda-cyhalothrin exposure (at LC₅₀). From this study, it can be concluded that different synthetic pyrethroid compounds can differentially induce the monooxygenase enzyme in the larvae of Ae. albopictus.