Assessment of deltamethrin resistance in Haemaphysalis spp. on goats in Kerala by larval packet test

Abstract

Tick- and tick-borne infections contribute to huge economic loss in livestock sector. The most practical strategy for tick control is chemotherapy, the efficacy of which has been challenged by the emergence of drug resistance. Acaricide resistance has been well studied in cattle ticks, but not in goat ticks. The status of deltamethrin resistance in Haemaphysalis spp. infesting goats of Thrissur and Palakkad districts was assessed by larval packet test using different concentrations of technical grade deltamethrin. In the present study, Ottapilavu, Mundupalam and Poomala isolates were found susceptible, while Vadakkanchery isolate was resistant. Log probit analysis was done to derive the LC50 and LC90 of resistant and susceptible isolates. Haemaphysalis spp. on goats are developing resistance to deltamethrin. Future investigations are to be conducted on molecular characterisation of resistance in these species of ticks and to detect the status of resistance to different group of acaricides throughout the state.