Drudge J H, Lyons E T, Tolliver S C
Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington 40546-0099.
Am J Vet Res. 1991 Aug;52(8):1308-12.
Critical tests were completed on foals (n = 15) naturally infected with benzimidazole (BZ)-resistant population-B strongyles during the period between 1981 and 1987. Thiabendazole at a dosage of 44 mg/kg was tested in 8 foals, oxfendazole at 10 mg/kg was tested in 4 foals, and phenothiazine at 55 mg/kg, cambendazole at 20 mg/kg, and fenbendazole at 5 mg/kg were tested in 1 foal each. Efficacies of thiabendazole, cambendazole, and fenbendazole against the 5 species of BZ-resistant small strongyles (Cyathostomum catinatum, Cyathostomum coronatum, Cylicocylus nassatus, Cylicostephanus goldi, and Cylicostephanus longibursatus) were partial. Removals in the aggregate averaged 48%, 52%, and 68%, respectively, indicating continued resistance of the 5 species of small strongyles to thiabendazole, cambendazole, and fenbendazole. In contrast, oxfendazole was efficacious, removing an aggregate average of 95% of the 5 BZ-resistant species of small strongyles in the 4 foals. This apparent reversion to susceptibility to oxfendazole may be attributable to paucity of reference data (1 test foal) done in 1976. All 5 species of the BZ-resistant small strongyles had cross resistance to phenothiazine (38% aggregate removal), whereas 9 of the BZ-susceptible species were effectively (99%) removed. This suggests a similar mode of action between phenothiaznie and the BZ compounds.
1981年至1987年期间，对15匹自然感染苯并咪唑（BZ）耐药种群B类圆线虫的马驹进行了关键试验。对8匹马驹测试了44毫克/千克剂量的噻苯达唑，对4匹马驹测试了10毫克/千克剂量的奥芬达唑，对1匹马驹分别测试了55毫克/千克剂量的吩噻嗪、20毫克/千克剂量的坎苯达唑和5毫克/千克剂量的芬苯达唑。噻苯达唑、坎苯达唑和芬苯达唑对5种BZ耐药小型圆线虫（卡氏杯冠线虫、冠状杯冠线虫、鼻状环行线虫、戈氏环盘线虫和长囊环盘线虫）的疗效是部分有效的。总体清除率分别平均为48%、52%和68%，表明这5种小型圆线虫对噻苯达唑、坎苯达唑和芬苯达唑仍具有耐药性。相比之下，奥芬达唑是有效的，在4匹马驹中平均总体清除了95%的5种BZ耐药小型圆线虫。这种对奥芬达唑敏感性的明显恢复可能归因于1976年进行的参考数据较少（仅1匹试验马驹）。所有5种BZ耐药小型圆线虫对吩噻嗪都有交叉耐药性（总体清除率为38%），而9种BZ敏感型圆线虫被有效清除（99%）。这表明吩噻嗪与BZ类化合物之间存在相似的作用模式。
