Anthelmintic resistance of bovine gastrointestinal nematodes to macrocyclic lactones in Japan

2009年和2010年，在日本北部青森县和北海道的养牛场进行了使用伊维菌素制剂的粪卵计数减少试验，以调查胃肠线虫对驱虫剂的耐药性。主要感染线虫虫卵数减少。8月，青森县1个养殖场和北海道2个养殖场经伊维菌素治疗后，感染率低于90%。卵数下降到90%以下强烈表明存在抗虫性。这是日本首次确认牛中存在伊维菌素耐药线虫。

Fecal egg count reduction tests using ivermectinpour-onformulation were conducted to investigate the prevalence of anthelmintic resistance in gastrointestinal nematodes on cattle farms in Aomori and Hokkaido, northernJapan, in 2009 and 2010.The egg count reductionsof predominant infecting nematodes, Cooperiaspp., were lower than90% on one farm in Aomori and two farms in Hokkaido after ivermectin treatment on August. The egg count reductions below 90% strongly suggest the presence of anthelmintic resistance. This is the first confirmation of ivermectin-resistantnematodes in cattle in Japan.