Anthelmintic resistance of nematode parasites of small ruminants in eastern Ethiopia: exploitation of refugia to restore anthelmintic efficacy.
Faecal egg count reduction tests (FECRT) were conducted in May 2003 to determine the efficacy of anthelmintics used for treatment against nematode parasites in separately managed sheep and goat flocks at Alemaya University in eastern Ethiopia. These tests revealed high levels of anthelmintic resistance to albendazole, tetramisole, the combination of these two drugs, and to ivermectin in the goat flock (predominantly infected by Haemonchus contortus and Trichostrongylus spp.), whereas all drugs were highly efficacious in the sheep flock. A second FECRT confirmed these observations. Following this, a new management system was implemented on the goat flock for a period of 9 months (January-September 2004) in an attempt to restore the anthelmintic efficacy. This involved a combination of measures: eliminating the existing parasite infections in the goats, exclusion from the traditional goat pastures, and introducing communal grazing of the goats with the university sheep flock and livestock owned by neighbouring small-holder farmers. A second series of FECRTs (Tests 3 and 4) conducted 7 months after this change in management, showed high levels of efficacy to all three drugs (albendazole, tetramisole and ivermectin) in the goat flock. This is the first field study to demonstrate that anthelmintic efficacy in the control of nematode parasites of small ruminants can be restored by exploiting refugia.
Sissay
Menkir M
MM
Department of Parasitology (SWEPAR), National Veterinary Institute and Swedish University of Agricultural Sciences, SE-751 89 Uppsala, Sweden.
Asefa
Asmare
A
Uggla
Arvid
A
Waller
Peter J
PJ
D015766:Albendazole / Q000494:pharmacology / Q000627:therapeutic use; D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology* / Q000627:therapeutic use; D004351:Drug Resistance; D004359:Drug Therapy, Combination; D005002:Ethiopia; D015511:Goat Diseases / Q000188:drug therapy* / Q000469:parasitology; D006041:Goats; D006189:Haemonchus / Q000187:drug effects; D007559:Ivermectin / Q000494:pharmacology / Q000627:therapeutic use; D009349:Nematode Infections / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D021261:Parasitic Sensitivity Tests / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy* / Q000469:parasitology; D013773:Tetramisole / Q000494:pharmacology / Q000627:therapeutic use; D016896:Treatment Outcome; D014254:Trichostrongylus / Q000187:drug effects
D000871:Anthelmintics; D007559:Ivermectin; D013773:Tetramisole; D015766:Albendazole