Daniele Martín R, Dadé Martín M, Álvarez José D, Reynaldi Francisco J, Errecalde Jorge O, Rodríguez-Vivas Roger I
Universidad Nacional de Río Negro, Sede Alto Valle y Valle Medio, Escuela de Veterinaria y Producción Agroindustrial, Choele Choel, Rio Negro 8360, Argentina; Cátedra de Farmacología Especial y Toxicología, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, 60 y 118s/n, CC 296, La Plata 1900, Argentina; Cátedra de Enfermedades Parasitarias, Facultad de Ciencias Veterinarias, Universidad Nacional del Nordeste, Sargento Cabral 2139, Corrientes 3400, Argentina.
Universidad Nacional de Río Negro, Sede Alto Valle y Valle Medio, Escuela de Veterinaria y Producción Agroindustrial, Choele Choel, Rio Negro 8360, Argentina; Cátedra de Farmacología Especial y Toxicología, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, 60 y 118s/n, CC 296, La Plata 1900, Argentina; Cátedra de Farmacología Básica, Facultad de Ciencias Médicas de la Universidad Nacional de La Plata, Laboratorio de Artrópodos y Vectores (LabArVec), 60 y 120 s/n, La Plata 1900, Argentina.
Vet Parasitol Reg Stud Reports. 2021 Dec;26:100624. doi: 10.1016/j.vprsr.2021.100624. Epub 2021 Aug 28.
Intensive use of macrocyclic lactones for parasite control exerts strong selective pressure for arthropods such as ticks to become resistant to them. Rhipicephalus sanguineus sensu stricto is a tick and disease vector of significant public health and veterinary importance worldwide. We assessed the toxicological response to the macrocyclic lactone ivermectin (IVM) in R. sanguineus s.s. infesting dogs in Argentina. Samples of nine tick populations were obtained by inspecting dogs at veterinary clinics, hospitals, or rural areas in the provinces of San Luis, Rio Negro, and Buenos Aires. Pet owners were interviewed to gather data on the history of dog treatment with ectoparasiticides. The larval immersion test was used to assess the toxicological response of R. sanguineus s.s. to IVM. Dose-response mortality regressions, lethal concentrations (LC), and slope were calculated by probit analysis. The lowest LC concentrations were used to designate the reference susceptible population because a laboratory reference strain of R. sanguineus s.s. does not exist in Argentina. Compared with the most susceptible tick population in this study, six populations (66.66%) were classified as resistant to IVM. A clear interpopulation variation in the level of IVM resistance was present (resistance ratios at LC ranged from 1.0 to 18.33 and at LC ranged from 1.0 to 8.96). In San Luis Province, all tick populations were classified as resistant. The highest level of IVM resistance (resistance ratio at LC:18.83 and LC:8.96) was found in a population of R. sanguineus s.s. from a rural area in the province of Buenos Aires. It is concluded that populations of R. sanguineus s.s. from dogs in three provinces of Argentina were resistant to IVM. Clear interpopulation variation in the level of IVM resistance was present.
大量使用大环内酯类药物控制寄生虫会对蜱虫等节肢动物产生强大的选择压力，使其对这类药物产生抗性。狭义血红扇头蜱是一种蜱虫，在全球范围内对公共卫生和兽医领域具有重大意义，是疾病传播媒介。我们评估了阿根廷感染犬类的狭义血红扇头蜱对大环内酯类药物伊维菌素（IVM）的毒理学反应。通过在圣路易斯省、里奥内格罗省和布宜诺斯艾利斯省的兽医诊所、医院或农村地区检查犬只，获取了九个蜱虫种群的样本。对宠物主人进行了访谈，以收集犬只使用杀外寄生虫剂治疗史的数据。采用幼虫浸泡试验评估狭义血红扇头蜱对IVM的毒理学反应。通过概率分析计算剂量 - 反应死亡率回归、致死浓度（LC）和斜率。由于阿根廷不存在狭义血红扇头蜱的实验室参考菌株，因此使用最低的LC浓度来指定参考易感种群。与本研究中最易感的蜱虫种群相比，六个种群（66.66%）被归类为对IVM具有抗性。IVM抗性水平存在明显的种群间差异（LC的抗性比值范围为1.0至18.33，LC的抗性比值范围为1.0至8.96）。在圣路易斯省，所有蜱虫种群都被归类为抗性。在布宜诺斯艾利斯省一个农村地区的狭义血红扇头蜱种群中发现了最高水平的IVM抗性（LC的抗性比值为18.83，LC的抗性比值为8.96）。得出的结论是，阿根廷三个省份感染犬类的狭义血红扇头蜱种群对IVM具有抗性，IVM抗性水平存在明显的种群间差异。
