Involvement of metabolic resistance and F1534C kdr mutation in the pyrethroid resistance mechanisms of Aedes aegypti in India

• Published in: Acta tropica 2015-08, Vol.148, p.137-141
• Main Authors: Muthusamy, R., Shivakumar, M.S.
• Format: Article
• Language: English
• Subjects: Aedes - enzymology; Aedes - genetics; Aedes aegypti; Animals; Carboxylesterase - metabolism; Cytochrome P-450 Enzyme System - metabolism; Detoxification enzymes; Gene Frequency; Glutathione Transferase - metabolism; India; Insecticide Resistance - genetics; Insecticide Resistance - physiology; Insecticides; Mosquito Control; Mutation; Permethrin; Permethrin resistance; Pyrethrins; Synergist; Target site insensitivity; Voltage-Gated Sodium Channels - genetics
• ISSN: 0001-706X; 1873-6254
• DOI: 10.1016/j.actatropica.2015.04.026

•Resistance ratio was high in field mosquitoes compared to susceptible population.•High PBO synergism was found in field population than susceptible population.•Esterase and GST activity was elevated in field populations.•High frequency of Phe1534Cys kdr mutation was found in field population. Pesticide resistance poses a serious problem for worldwide mosquito control programs. Resistance to insecticides can be caused by an increased metabolic detoxification of the insecticide and/or by target site insensitivity. In the present study, we estimated the tolerance of Indian Aedes aegypti populations using adult bioassays that revealed high resistance levels of the field populations to permethrin (RR-6, 5.8 and 5.1 folds) compared to our susceptible population. Enzymatic assays revealed increased activities of glutathione S-transferase and carboxylesterase enzymes in the field populations comparatively to the susceptible population. PBO synergist assays did not confirm that cytochrome P450 monooxygenase metabolic detoxification acted as a major cause of resistance. Hence the role of target site resistance was therefore investigated. A single substitution Phe1534Cys in the voltage gated sodium channel was found in domain III, segment 6 (III-S6) of the resistance populations (allele frequency=0.59, 0.51 and 0.47) suggesting its potential role in permethrin resistance in A. aegypti.