Doramectin and albendazole resistance in sheep in The Netherlands.
A faecal egg count reduction test was conducted on a sheep farm with suspected avermectin resistance. Five groups of 10 sheep were formed. Group 1 was the untreated control group. Groups 2-5 were treated according to weight with the recommended dose of, respectively, levamisole, doramectin, moxidectin or albendazole. Resistance was found in the sheep treated with doramectin (15% efficacy) and albendazole (87% efficacy). Levamisole and moxidectin were 100 and 99% effective, respectively. Larval identification of the faecal cultures of the doramectin-treated sheep revealed 100% Haemonchus contortus larvae. After albendazole treatment, 77% of the cultured larvae were H. contortus and 23% Teladorsagia/Trichostrongylus. Because there is a lot of trade in sheep on the farm, it is probable that the resistant worms were introduced with livestock from other farms than being selected on the farm.
Borgsteede
Fred H M
FH
Animal Sciences Group WUR, Division Infectious Disease, P.O. Box 65, 8200 AB Lelystad, The Netherlands. fred.borgsteede@wur.nl
Dercksen
Daan D
DD
Huijbers
René
R
D015766:Albendazole / Q000627:therapeutic use; D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance; D005243:Feces / Q000469:parasitology; D006374:Helminthiasis, Animal / Q000188:drug therapy*; D007559:Ivermectin / Q000031:analogs & derivatives / Q000627:therapeutic use; D009426:Netherlands / Q000453:epidemiology; D010270:Parasite Egg Count / Q000662:veterinary; D021261:Parasitic Sensitivity Tests / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy*; D016896:Treatment Outcome
D000871:Anthelmintics; D007559:Ivermectin; D015766:Albendazole; C084101:doramectin