Insecticide resistance status of important malaria vectors in a tribal district of Rajasthan

Abstract

Investigations have been carried-out in a malaria prone district of Rajasthan to determine insecticide resistance status of important malaria vector species viz. Anopheles culicifacies, An. annularis and An. stephensi, against insecticides being used under National Malaria Control Programme in two Block Public Health Centres of Banswara district of Rajasthan. An. culicifaies, except one canal irrigated village, where it was found susceptible to DDT, was found either resistant or intermediate resistant. Against Malathion An. culicifacies was found susceptible in one rain-fed irrigation village, whereas in all other villages, it was found either resistant or intermediate resistant. Against synthetic pyrethroids An. culicifacies was found susceptible to both Alpha Cypermethrin and Cyfluthrin, except one rain-fed irrigation village, where against Cyfluthrin, the species exhibited intermediate resistance. This is a first report of synthetic pyrethroid resistance from Rajasthan. An. annularis, was found resistant to DDT in both canal irrigated and rain-fed irrigation villages, however, against Malathion it exhibited resistance in canal irrigated village and intermediate resistance in rain-fed irrigation village, however, against Alpha Cypermethrin and Cyfluthrin the species was found totally susceptible in both the areas. An, stephensi was tested only against Alpha Cypermethrin in a canal irrigated village and found totally susceptible. In the study area An. culicifacies have exhibited triple resistance, showing resistance to DDT, Malathion and intermediate resistance to cyfluthrin, however, An. annularis exhibited double resistance to DDT and Malathion.