Field evaluation of deltamethrin against resistant Anopheles culicifacies in Distt. Ghaziabad (U.P.) India

Abstract

A field study to evaluate the impact of deltamethrin spraying on DDT and HCH resistant A. culicifacies population was carried out in Razapur primary health centre (PHC), Distt. Ghaziabad (U.P.) India. The PHC comprising of about 0.14 million population was divided into 3 sections of equal size and sprayed with (i) 3 rounds at 12.5 mg/sq m at 6 weeks interval, and (ii) 2 rounds each at 20 mg/sq m and 25 mg/sq m at 8 weeks interval. One section in Dadri PHC located at a distance of about 22 kms was held as control. In this area 3 rounds of HCH were sprayed by the NMEP as was done to control malaria in this district. Deltamethrin spraying was carried out for 3 years. Results revealed that spraying at 12.5, 20 and 25 mg/sq m resulted in drastic reduction of DDT and HCH resistant A. culicifacies population and in the interruption of malaria transmission. In control area high vector densities and malaria transmission was encountered throughout the period of study. Spraying of deltamethrin resulted in build-up of Culex quinquefasciatus population due to resistance.