A study on insecticide resistance in Anopheles fluviatilis and anopheles culicifacies to HCH and DDT in the Malkangiri district of Orissa.

The susceptibility status of malaria vectors to HCH and DDT was studied in Malkangiri district which has been highly endemic for malaria since many decades. An. fluviatilis is the major malaria vector and An. culicifacies is a secondary vector in the area. HCH is being used in malaria control programme from 1972 onwards. Before to that, DDT was used. This study reports that An. fluviatilis has developed resistance to HCH and is susceptible to DDT. This is the first confirmed report of resistance of this species to HCH in Malkangiri district of Orissa. An. culicifacies was found to be resistant to both the insecticides. Extensive use of pesticides in agriculture and indoor residual spraying of HCH for malaria control might have led to the development of resistance in these malaria vectors.