ANTIHELMINTHIC EFFICACY OF IVERMECTIN IN HORSES: COPROPARASITOLOGICAL AND HEMATOLOGICAL EXAMS

Abstract The aim of the present study was to evaluate the efficacy of ivermectin at 2% in horses, through coproparasitological and hematological exams. The experiment was performed at a farm in the city of Uberlândia, Minas Gerais State. Twenty-four horses were used, ranging from 3 to 8 years of age, divided into 2 groups according to EPG values. EPG counts and coprocultures were performed on days D0, D+7 and D+14. The animals were treated with the ivermectin 2%-based paste formulation at a dose of 200 mcg/kg, orally. Blood samples were collected on days D0, D+7 and D+14 for evaluation of haematological parameters. The presence of eggs that are characteristic of the Strongylidae family and the identification of larvae that are characteristic of cyathostomins demonstrated the parasitism of the animals by small strongyles. At D+7 and D+14 there was a significant reduction of EPG in the treated group with an efficacy of 99.5 and 99.7%, respectively. A tendency of the erythrocyte framework to remain close to the lower limits was observed, besides a slight leukocytosis, with neutrophils close to the highest values. It can be inferred that ivermectin is effective against cyastostomines, and no significant haematological changes were observed.

摘要 本研究旨在通过粪便寄生虫学（coproparasitological）与血液学（hematological）检查，评估2%伊维菌素（ivermectin）对马匹的驱虫效果。实验于巴西米纳斯吉拉斯州乌贝兰迪亚市的一处农场开展。本研究选用24匹年龄介于3至8岁的马匹，依据每克粪便虫卵数（Eggs Per Gram, EPG）将其分为2组。分别于D0、D+7及D+14日开展虫卵计数（EPG counts）与粪便培养（coprocultures）。受试动物经口给予2%伊维菌素膏剂制剂，剂量为200 mcg/kg。分别于D0、D+7及D+14日采集血液样本，用于评估血液学参数。研究检测到圆形线虫科（Strongylidae）特征性虫卵，并鉴定出杯环线虫（cyathostomins）特征性幼虫，证实受试动物感染了小型圆形线虫。给药后D+7与D+14日，给药组的EPG值均出现显著降低，驱虫效率分别达99.5%与99.7%。观察到红细胞参数有维持在参考下限附近的趋势，同时出现轻度白细胞增多，中性粒细胞数值接近参考上限。由此可推断，伊维菌素对杯环线虫具有良好的驱虫效果，且未观察到显著的血液学变化。