Faculdade de Medicina Veterinária e Zootecnia, Universidade Federal do Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brazil.
Fazenda Primavera, Bodoquena, Mato Grosso do Sul, Brazil.
Vet Parasitol. 2021 Jan;289:109335. doi: 10.1016/j.vetpar.2020.109335. Epub 2020 Dec 11.
The objective of this study was to evaluate the therapeutic efficacy of 1 % injectable doramectin to control Dermatobia hominis in naturally infested beef cattle in a farm with history of clinical parasitism after avermectin use. The study was conducted in a commercial beef cattle farm in Brazil. Twenty crossbred cattle (Nellore x Angus) were selected based on the minimum number of 10 live larvae. Assessment of infestation was performed based on tactile-visual inspection of the entire body of the animals. The animals were allocated to two experimental groups of ten animals each: treated group - dosed with doramectin 200 μg/kg live weight (LW), and control group - dosed with saline solution 1 mL/50 kg LW. Both treatments were administered subcutaneously in a single dose. After treatment, larval counts were performed at 1, 3, 7 and 14 days post-treatment (DPT). For the treatment to be considered efficient, it should reach an efficacy greater than or equal to 90 % by the 10th DPT and the average larval count in the treated animals should be statistically lower than the average larval count in the control group. The geometric means of larval counts at the beginning of the study were 27.2 and 26.3 for the control and treated groups, respectively. After 72 h of treatment, there was a significant reduction (p < 0.01) in the larvae counts of the treated group, extending to the 14th DPT, at which point maximum efficacy for doramectin (86.3 %) was obtained. After treatment, 90 % of the animals remained parasitized with live larvae on the 7th DPT and 70 % on the 14th DPT, while in the control group, all animals were infested on all dates. The administration of injectable doramectin was not effective in controlling D. hominis in naturally infested cattle.
本研究的目的是评估 1%伊维菌素注射液对既往使用阿维菌素后出现临床寄生虫病史的农场中自然感染双翅目皮蝇蛆的治疗效果。该研究在巴西的一个商业肉牛场进行。根据至少 10 条活幼虫的数量，选择了 20 头杂交牛（尼洛拉牛×安格斯牛）。感染评估是基于对动物全身的触觉-视觉检查进行的。将动物分为两组，每组 10 头：治疗组 - 以 200μg/kg 活重（LW）剂量给药，对照组 - 以 1mL/50kg LW 剂量给药。两种治疗均以单剂量皮下给药。治疗后，在治疗后 1、3、7 和 14 天（DPT）进行幼虫计数。为了使治疗有效，它应该在第 10 DPT 时达到 90%以上的疗效，并且治疗动物的平均幼虫计数应低于对照组的平均幼虫计数。研究开始时幼虫计数的几何平均值分别为对照组和治疗组的 27.2 和 26.3。治疗后 72 小时，治疗组幼虫计数显著减少（p<0.01），直至第 14 天 DPT，此时伊维菌素的最大疗效（86.3%）得到。治疗后，第 7 天 DPT 时 90%的动物仍有活幼虫寄生，第 14 天 DPT 时 70%的动物仍有活幼虫寄生，而对照组所有动物在所有日期均有寄生虫感染。在自然感染的牛中，注射用伊维菌素对控制双翅目皮蝇蛆无效。
