Laboratory of Veterinary Clinical Parasitology, Department of Veterinary Medicine, Federal University of Parana, UFPR, Rua Dos Funcionários 1540, CEP: 80.035-050, Curitiba, PR, Brazil.
Laboratory of Veterinary Clinical Parasitology, Department of Veterinary Medicine, Federal University of Parana, UFPR, Rua Dos Funcionários 1540, CEP: 80.035-050, Curitiba, PR, Brazil.
Exp Parasitol. 2024 Oct;265:108812. doi: 10.1016/j.exppara.2024.108812. Epub 2024 Aug 8.
Infections caused by the ectoparasite Rhipicephalus microplus can cause major health problems in cattle, including death. Tick control is regularly made using a range of acaricide products. As a consequence, tick populations have been heavily selected for drug resistance. The objective of this work was to determine the in vitro efficacy of copper chloride and sulfate (CuCl and CuSO) solutions against R. microplus. The adult immersion test (AIT), which measures the egg-laying and egg-hatch effects, was used for the Cu-II solutions at 30, 60, 120, 240, 480, and 1000 mM, in triplicates. Distilled water and the combination of cypermethrin 20% and chlorpyrifos 50% were used as controls. Histological sections were performed from the ovaries of adult engorged female ticks treated with 240, 480, and 1000 mM of CuCl and CuSO. We have established a histological index of the damage caused by the solutions to the tick oocytes. The overall efficacy (egg laying & egg hatch) for CuCl and CuSO was 81.3, 82.5, 89.8, 84.5, 100.0, and 100%, and 61.7, 43.4, 62.5, 93.1, 100.0, and 98.5% respectively. Smaller oocytes were found in the Cu-II groups compared to the negative control. The histological data showed a concentration-dependent degenerative lesion of oocytes, described as cytoplasmic vacuolation and nuclear disorganization. The combination of cypermethrin and chlorpyriphos showed 100% efficacy. Cu-II solutions showed in vitro efficacy against adult engorged ticks being particularly harmful to oocytes. Thus, bioactive metals could be a complementary biofriendly treatment to control R. microplus and these injuries could be responsible for preventing egg hatch, and reducing pasture contamination. Safety studies are underway demonstrating the Cu-II potential in naturally infected cattle and their persistence in the environment.
硬蜱属外寄生虫引起的感染会给牛造成严重的健康问题，包括死亡。通常使用一系列杀蜱剂产品来控制蜱虫。因此，蜱虫种群已经对药物产生了强烈的耐药性选择。本工作的目的是确定氯化铜和硫酸铜 (CuCl 和 CuSO) 溶液对 R. microplus 的体外功效。使用成年浸浴试验 (AIT) 来测量产卵和孵化效果，Cu-II 溶液浓度为 30、60、120、240、480 和 1000 mM，重复 3 次。使用蒸馏水和氯菊酯 20%和毒死蜱 50%的混合物作为对照。对用 240、480 和 1000 mM CuCl 和 CuSO 处理过的饱血成年雌蜱的卵巢进行组织学切片。我们建立了一种组织学指数，用于评估溶液对蜱卵母细胞的损伤程度。CuCl 和 CuSO 的总体功效（产卵和孵化）分别为 81.3%、82.5%、89.8%、84.5%、100.0%和 100.0%，61.7%、43.4%、62.5%、93.1%、100.0%和 98.5%。与阴性对照相比，Cu-II 组的卵母细胞较小。组织学数据显示，卵母细胞出现了浓度依赖性的退行性病变，表现为细胞质空泡化和核结构紊乱。氯菊酯和毒死蜱的混合物表现出 100.0%的功效。Cu-II 溶液对饱血成年蜱具有体外功效，对卵母细胞特别有害。因此，生物活性金属可能是控制 R. microplus 的一种补充性生物友好型治疗方法，这些损伤可能是防止卵孵化和减少牧场污染的原因。正在进行安全性研究，以证明 Cu-II 在自然感染的牛中的潜力及其在环境中的持久性。
