National Veterinary Institute, Department of Virology, Immunobiology and Parasitology, Section for Parasitological Diagnostics, SE-751 89 Uppsala, Sweden.
Acta Vet Scand. 2009 Nov 22;51(1):45. doi: 10.1186/1751-0147-51-45.
In the last few years stud farms have experienced increasing problems with Parascaris equorum infections in foals despite intensive deworming programs. This has led to the question as to whether the anthelmintic drugs used against this parasite are failing. This study aimed to investigate the efficacy of ivermectin, fenbendazole and pyrantel on the faecal output of ascarid eggs of foals.
A Faecal Egg Count Reduction Test (FECRT) was performed on nine large studs in Sweden. Anthelmintic drugs were given orally and faecal samples were examined for ascarid eggs on the day of deworming and 14 days later. Faecal Egg Count Reductions (FECRs) were calculated on arithmetic means of transformed individual FECRs and on arithmetic means of individual FECRs.
Seventy-nine (48%) out of a total of 165 foals sampled were positive for P. equorum eggs before deworming and 66 of these met the criteria for being used in the efficacy assessment. It was shown that there was no, or very low activity of ivermectin on the output of ascarid eggs in the majority of the foals, whereas for fenbendazole and pyrantel it was >90%.
Ivermectin resistance was shown in 5 out of 6 farms. Therefore, ivermectin should not be the drug of choice in the control of P. equorum infections in foals. According to the results of this study, fenbendazole or pyrantel are still effective and should be used against this parasite.
尽管进行了密集的驱虫计划，过去几年来种马场在小马驹中越来越多地出现旋毛虫感染问题。这导致了一个问题，即是否用于治疗这种寄生虫的驱虫药物正在失效。本研究旨在调查伊维菌素、芬苯达唑和哌嗪对小马驹粪便中蛔虫卵排出量的效果。
在瑞典的 9 个大型种马场进行了粪便卵计数减少试验（FECRT）。驱虫药物口服给予，在驱虫当天和 14 天后检查粪便样本中是否有蛔虫卵。根据转化后的个体 FECR 算术平均值和个体 FECR 算术平均值计算粪便卵计数减少率（FECR）。
在总共 165 匹被采样的小马驹中，有 79 匹（48%）在驱虫前对旋毛虫卵呈阳性，其中 66 匹符合进行疗效评估的标准。结果表明，在大多数小马驹中，伊维菌素对蛔虫卵的排出几乎没有或很少有活性，而芬苯达唑和哌嗪的活性则大于 90%。
在 6 个农场中的 5 个中显示出伊维菌素耐药性。因此，伊维菌素不应成为控制小马驹旋毛虫感染的首选药物。根据这项研究的结果，芬苯达唑或哌嗪仍然有效，应针对这种寄生虫使用。
