Susceptibility status of Cx. vishnui subgroup of mosquitoes against different Insecticides and detection of novel mutations in esterase beta gene in Cx. tritaeniorhynchus

Abstract

Japanese encephalitis (JE) is a mosquito-borne viral disease and several species of the Culex genera can transmit JE. The present study was conducted to observe resistance in Cx. vishnui subgroup against organophosphates, widely used in fogging and controlling JE. The study was conducted in 12 localities of Dibrugarh and Tinsukia districts of Assam, endemic for JE. Susceptibility tests performed revealed both Cx. pseudovishnui and Cx. tritaeniorhynchus were found resistant against Organophosphates Malathion (5%) and Fenitrothion (1%). Molecular characterization of genes responsible for resistance depicted two non-synonymous polymorphisms for the primary JE vector Cx. tritaeniorhynchus. To the best of our knowledge, this is the first report on detection of SNP’s in esterase beta (estβ) gene in India for the species Cx. tritaeniorhynchus. As data regarding characterization of genes responsible for resistance in JE vectors is lacking from this country, this study will aid in understanding the characteristics of genes involved in resistance manifestation.