Boersema J H, Borgsteede F H, Eysker M, Hendrikx W M, Jansen J, Smith-Buys C M
Res Vet Sci. 1987 Jul;43(1):18-21.
A survey was carried out in The Netherlands to determine the prevalence of benzimidazole resistance in sheep nematodes. It was shown that 47 per cent of the 59 investigated flocks harboured trichostrongylid populations with resistance to benzimidazoles, as demonstrated by an LD50 value of 0.12 micrograms ml-1 thiabendazole or higher in an in vitro egg hatch assay. On these farms Haemonchus contortus was found to be the dominant species. In two flocks resistant Ostertagia and, or, Trichostrongylus species populations were found. Farms with resistance were revisited to determine the anthelmintic efficacy in vivo by means of treatment and egg count. In only four of the 19 flocks which showed resistance in vitro was an efficacy of less than 95 per cent in vivo achieved. This means that there is a discrepancy between the in vivo and in vitro results. Resistance was found more frequently on pure sheep farms than on mixed farms. It is suggested that mixed farms offer more refuge for susceptible H contortus populations.
在荷兰开展了一项调查，以确定绵羊线虫对苯并咪唑的耐药性流行情况。结果显示，在59个被调查的羊群中，有47%的羊群寄生有对苯并咪唑耐药的毛圆科线虫种群，这在体外虫卵孵化试验中表现为噻苯达唑的半数致死剂量（LD50）值达到0.12微克/毫升或更高。在这些农场中，捻转血矛线虫是优势种。在两个羊群中发现了对苯并咪唑耐药的奥斯特线虫和/或毛圆线虫种群。对存在耐药性的农场进行了回访，通过治疗和虫卵计数来确定体内驱虫效果。在19个体外显示有耐药性的羊群中，只有4个羊群的体内驱虫效果低于95%。这意味着体内和体外结果之间存在差异。在纯养绵羊的农场中比在混养农场中更频繁地发现耐药性。有人认为，混养农场为易感的捻转血矛线虫种群提供了更多庇护所。
