Anthelmintic Resistance of Gastrointestinal Parasites in Small Ruminants:A Review of the Case of Ethiopia

Abstract

Analysis of 13 published anthelmintic sensitivity studies against gastro-intestinal (GI) nematodes of small ruminants was conducted to describe anthelmintic use trends and resistance problems in Ethiopia. Anthelmentic use surveys in 5 small ruminant rearing areas indicated widespread risky practices including; marketing of unknown formulation drugs, professionally unsupervised prescription and use of drugs, inappropriate calculation of drug doses and exhaustive use of few drugs. Evidence of small ruminant GI nematode resistance to albendazole, levamisole, teramisole and ivermectin was aparent in 15 (32.9%), 5 (41.7%), 4 (25%) and 2 (13.3%) trials, respectively. Resistance to multiple antihelmintic families was recorded in 4 studies conducted at 2 experimental goat farms. The nematode populations implicated in resistance belonged to Haemonchus, Oesophagostomun, Trichostrongylus and Trichuris species. Small ruminant GI nematode resistance to the broad spectrum anthelmintics is a significant livelihood and economic threat in Ethiopia. Strategic effort aimed at halting the emergence and spread of anthelmintic resistance is urgently needed.