Effects of Deltamethrin Exposure on the Cytochrome P450 Monooxygenases of Aedes Albopictus (Skuse) Larvae from a Dengue Endemic Region of Northern Part of West Bengal, India

Aedes albopictus is highly prevalent in the northern part of West Bengal and is considered to be responsible for the recent dengue outbreaks in this region. Control of this vector is largely relied on the use of synthetic pyrethroids which can lead to the development of resistance. In the present study, larvae of three wild Ae. albopictus populations from the dengue endemic regions were screened for deltamethrin resistance and the role of cytochrome P450 monooxygenases (CYPs) was investigated in deltamethrin exposed and unexposed larvae for resistance development. All the populations were either incipient resistant or complete resistant against deltamethrin. Monooxygenase titration assay revealed involvement of CYPs in deltamethrin resistance along with an induction effect of deltamethrin exposure. Gene expression studies revealed differential expression of five CYP6 family genes: CYP6A8, CYP6P12, CYP6A14, CYP6N3 and CYP6N6 with high constitutive expression of CYP6A8 and CYP6P12 in all the populations before and after deltamethrin exposure. From these findings, it was evident that CYPs play an important role in development of deltamethrin resistance in the Ae. albopictus populations in this region.