Drug Efficacy of Ivermectin Against Parasites After 10 years use

This is an interesting article, not so much for its example of once yearly deworming, but because it gives support of using a rotational program that is based on a different product each rotation. The goal is to avoid more than once yearly exposure to any one product. This is consistent with our own schedules. Access the schedule article in the breadcrumb above. We have just updated the Deworming Schedule article so if it has been awhile it would be a good time to review.
DrO

Helminthologia. 2020 Jan 25;57(1):57-62.
Drug Efficacy of Ivermectin Against Primary Nematodes Parasitizing Captive Przewalski’s Horse (Equus Ferus Przewalskii) after Ten Years of Annually Treatment.
Tang L1, Xiu Y1, Yan L1, Cui Y1, Ma X2, Ente M2, Zhang Y2, Li K1, Zhang D1.

Author information:
1. Laboratory of Non-invasive Research Technology for Endangered Species, School of Nature Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China.
2. Xinjiang Uygur Autonomous Region Wild Horse Breeding Research Center, Urumqi, Xinjiang 831704, China.
Abstract

Reintroduction of endangered species to natural habitat is considered as an important tool for conservation. The effect of drug management on captive population of reintroduced species is largely neglected. Decreased drug efficacy could pose a substantial threat to health of animals. More importantly, captive population without proper drug administration could act as transmission medium of resistance nematodes to wild population, making it important to delay the occurrence of drug resistance in captive population. Ivermectin have been used in captive Przewalski’s horse (Equus ferus przewalskii) to eradicate intestinal parasitic nematodes annually, while no available studies describing the drug efficacy in the recent ten years. Here, fecal egg counts pre- and post-treatment were performed with ivermectin through individual trace. Both large and small strongyles were identifi ed by larval culture. The fecal egg count reduction was almost 100% based on egg counting data of 448 samples from 13 Przewalski’s horses. Feces of two Przewalski’s horses were sampled for successive 20 days. Eggs per gram feces usually increased dramatically at the period of 1 – 2 post-treatment days and declined persistently to 0.0 within 15 days. A sustained high ivermectin efficacy against neither Parascaris equorum nor strongyles was indicated, which can be partly explained by the low deworm frequency.