Efficacy of 5% neem seed kernel extract against ectoparasites in six captive wildlife species at Rajiv Gandhi Zoological Park, India

Abstract

This wildlife study aimed to assess the prevalence of ectoparasites and evaluate the in vivo efficacy of a 5% Neem Seed Kernel Extract (NSKE) insecticide in captive wildlife species at Rajiv Gandhi Zoological Park and Wildlife Research Centre (RGZPWRC), Katraj, Pune, Maharashtra, India. Ectoparasites were collected non-invasively from six wildlife species, namely, Black Buck Antelope cervicapra, Spotted Deer Axis axis, Leopard Panthera pardus, Tiger Panthera tigris, Elephant Elephas maximus, and Sloth Bear Melursus ursinus using insect traps in animal shelters and night houses, alongside combing and visual inspection. A total of 865 ectoparasites were documented in the entire study duration of 19 days, of which, 662 ectoparasites were documented before and 203 after the application of 5% NSKE, each over a nine-day period. Flies comprised 93.99% of the total ectoparasites found (865) during the entire study, followed by lice at 5.55% and fleas at 0.46%. The overall relative prevalence was 76.53% pre-treatment and 23.47% post-treatment. By species, Black Buck showed the lowest relative prevalence at 6.24%, and Elephants the highest at 21.73%, with an average relative prevalence of 16.67%. Leopards, Tigers, and Elephants had values of 21.62%, 19.66%, and 21.73%, respectively. Taxonomically, flies represented 96.30% in Black Buck, 63.91% in Spotted Deer, 98.93% in Leopards, and 100% in both Elephants and Sloth Bears. The estimated prevalence exceeded 100% in some species due to multiple parasites per host based on average parasitic load calculations. During treatment, shelters and night houses were washed and sprayed with 5% NSKE. Re-sampling after nine days showed a marked reduction in ectoparasite counts. Efficacy of 5% NSKE against flies, fleas, and lice was 69.29%, 100%, and 66.67%, respectively, with an overall efficacy of 69.33% (P < 0.001) with a 95% confidence interval ranging from 65.70% to 72.90%. The highest efficacy was observed in Elephants at 81.76%. Use of 5% NSKE is hence strongly recommended as an insecticide or repellent in captive wild animal housing systems. These findings support the integration of botanical insecticides into integrated pest management programs for captive wildlife.