Anthelmintic resistance of bovine gastrointestinal nematodes to macrocyclic lactones in Japan

2009年和2010年，在日本北部青森和北海道的牛场进行了使用伊维菌素浇泼剂的粪便虫卵计数减少试验，以调查胃肠道线虫对驱虫剂的耐药性。在青森的一个农场和北海道的两个农场，在8月伊维菌素处理后，虫卵计数减少低于90%，强烈表明存在驱虫药耐药性。这是日本首次确认牛体内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.