Efficacy of levamisole and oxyclozanide treatment on gastrointestinal nematodes of ungulates at the Central Zoo, Nepal

Abstract

The efficacy evaluation of levamisole and oxyclozanide treatment on the gastrointestinal nematodes of ungulates at the central zoo, Nepal was carried out from June—August 2021. A total of 40 fecal samples were collected from 10 species of ungulates from the central zoo for determining the efficacy of the anthelmintic given at day 0 of pretreatment and post-treatment analysis on day 07 and day 14. The concentration method (floatation concentration) was used for the microscopic examination of eggs, and quantitative examination (EPG) of nematode eggs was carried out with the help of modified McMaster slides. The identification was done using an optic micrometer and fecal egg culture. Anthelmintic resistance status was evaluated by the Fecal Egg Count Reduction Technique (FECRT) based on the method described by the World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines and with the Bayesian hierarchical model. Out of 40 samples, nematode prevalence was found to be 68%, in which single infection was detected in 48% and double infection in 52%. The efficacy of Zanide L forte (levamisole-0.75 g and oxyclozanide-1.00 g) was found to be 85% (UI 80-89) at day 07 and 89% (UI 85-92) at day 14 by using Hierarchical Modelling of Fecal Egg count based on ‘eggCounts-2.3 on R version 3.6.1 and 86% (CI 61.51–95%) at day 07 and 90% (CI 74.18–95%) at day 14 by WAAVP guidelines. This study represents the first documented case of ineffectiveness of anthelmintic treatment resulting in anthelmintic resistance in the central zoo. Thus, there is a requirement for a suitable and efficacious anthelmintic program.