Susceptibility Status of Rat Flea, Xenopsylla Cheopis (Siphonaptera: Pulicidae) Vector of Human Plague against Organochlorine, Organophosphate and Synthetic Pyrethroids in Beed District, Maharashtra, India

Susceptibility status of Xenopsylla cheopis, rat flea against DDT-4.0 percent, malathion-5.0 percent, deltamethrin-0.05 percent, permethrin-0.75 percent, cyfluthrin-0.15 percent and lamdacyhalothrin-0.05 percent was studied following standard WHO procedures at enzootic foci of plague in Beed district from 2003 to 2009. The study was conducted to ascertain the appropriate use of insecticides for residual indoor spray and insufflations to obtain cent percent mortality of the target population particularly Xenopsylla cheopis (Rothschild), which are usually found to be the ectoparasite on susceptible rodent population to Yersinia pestis infection. Susceptibility test results revealed that Xenopsylla cheopis developed resistance for 1 hour exposure period to DDT-4.0% (Mean mortality-36.8%), Malathion-5% (Mean mortality-48.7%), and Deltamethrin 0.05% (Mean mortality-48.2%), but mortality against Permethrin 0.75%, Cyfluthrin 0.155% and Lamdacyhalothrin 0.05% were 61.9, 72.5 and 79.5 percent respectively. It is suggested that some more studies are required before switching over to new insecticides for flea control. Inter sectoral co-ordination between public health and agricultural sectors for the appropriate use of insecticides/ pesticides is necessary to avoid precipitated tolerant/ resistant of vectors of medical importance.