Multiple anthelmintic resistance of nematodes in imported goats
Varady, M.; Praslicka, J.; Corba, J.; Vesely, L.
Veterinary Record 132(15): 387-388
1993
ISSN/ISBN: 0042-4900 PMID: 8080466 Document Number: 408308
A flock of 650 Cashmere and Angora goats was imported into Czechoslovakia from New Zealand in October 1991, placed on 4 farms and kept in quarantine. In an in vitro egg hatch assay using thiabendazole, the observed ED50 values ( micro g/ml) were between 0.27 and 0.36 on the 4 farms, demonstrating the presence of benzimidazole resistant nematodes. Faecal nematode egg count reduction tests 10 days after treatment gave mean arithmetic reductions of 74% with albendazole (Vermitan) at 5 mg/kg, 86% with levamisole (Revlin) at 7.5 mg/kg and 83% with ivermectin (Ivomec) at 0.2 mg/kg. A further simultaneous treatment 9 days later with albendazole (5 mg/kg) and tetramisole (15 mg/kg) was completely effective on 3 farms where only Cashmere goats were kept, while on the 4th farm where the flock was mixed it was effective only in Cashmere goats. In Angora goats the infection persisted and the ED50 value was 1.13 micro g/ml, 4 times higher than that of the original isolate. The resistant nematode genera consisted of 54% Ostertagia spp. and 46% Trichostrongylus spp. Simultaneous treatment of the Angora goats with ivermectin at 0.4 mg/kg injected s.c. and tetramisole at 30 mg/kg and albendazole at 20 mg/kg orally, was completely effective (faecal nematode egg counts were negative at 8 and 21 days after treatment). This is the first report of animals carrying anthelmintic resistant nematodes being moved between countries and the first report of the movement of animals carrying nematodes resistant to all types of broad-spectrum anthelmintics.