Centro de Enseñanza, Investigación y Extensión en Ganadería Tropical, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Martínez de la Torre, Veracruz, Mexico.
Vet Parasitol. 2012 Feb 10;183(3-4):338-42. doi: 10.1016/j.vetpar.2011.07.028. Epub 2011 Jul 23.
We document the presence of a Rhipicephalus microplus tick population resistant to acaricides (organophosphates (OP), synthetic pyrethroids (SP), amitraz) and macrocyclic lactones (ML) (ivermectin). Engorged females of R. microplus were collected from a cattle farm in Veracruz, Mexico, to evaluate acaricide and ivermectin resistance. The modified larval packet test (LPT) was used to detect OP (chlorpiriphos and diazinon) and SP (flumethrin, deltamethrin and cypermethrin) resistance and the larval immersion test (LIT) to detect resistance to amitraz and ivermectin. Both, LPT and LIT were performed twice at different times with different collected samples. Mortality data with ivermectin were subjected to probit analysis to obtain lethal concentrations and resistance ratios (RR) using an ivermectin-susceptible strain (Deutch) as a reference. The R. microplus population showed resistance to all acaricides tested, with different mortalities at the discriminate dose: chlorpiriphos (1%), diazinon (24.2%), flumethrin (92.8%), deltamethrin (94.2%), cypermethrin (98.0%) and amitraz (1.5%). The studied tick population also showed resistance to ivermectin with a resistance ratio at 99% of 9.58 and 6.52 in the first and second evaluation, respectively. We report for the first time a R. microplus population in Mexico with different levels of resistance to OP, SP, amidines (Am) and ivermectin. The uncontrolled use of these products in the study area may promote the complete failure of tick control within a short period of time.
我们记录了一种对杀蜱剂（有机磷化合物（OP）、合成拟除虫菊酯（SP）、阿莫曲坦）和大环内酯类（伊维菌素）具有抗性的璃眼蜱（Rhipicephalus microplus）种群的存在。从墨西哥韦拉克鲁斯的一个奶牛场收集了已饱血的璃眼蜱雌性成虫，以评估杀蜱剂和伊维菌素的抗性。改良的幼虫包被测试（LPT）用于检测 OP（毒死蜱和二嗪磷）和 SP（氟氯氰菊酯、溴氰菊酯和氯氰菊酯）抗性，幼虫浸渍测试（LIT）用于检测阿莫曲坦和伊维菌素抗性。LPT 和 LIT 均在不同时间使用不同收集的样本进行了两次。用伊维菌素进行死亡率数据的概率分析，以获得致死浓度和抗性比（RR），使用伊维菌素敏感株（Deutch）作为参考。璃眼蜱种群对所有测试的杀蜱剂均表现出抗性，在鉴别剂量下死亡率不同：毒死蜱（1%）、二嗪磷（24.2%）、氟氯氰菊酯（92.8%）、溴氰菊酯（94.2%）、氯氰菊酯（98.0%）和阿莫曲坦（1.5%）。研究中的蜱种群对伊维菌素也表现出抗性，在第一次和第二次评估中，抗性比分别为 99%时的 9.58 和 6.52。我们首次报告了墨西哥的一种璃眼蜱种群对 OP、SP、脒类（Am）和伊维菌素具有不同程度的抗性。在研究区域内无控制地使用这些产品可能会在短时间内导致蜱的控制完全失效。
