Rodriguez-Vivas R I, Ojeda-Chi M M, Trinidad-Martinez I, Bolio-González M E
Departamento de Salud Animal y Medicina Preventiva, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico.
Med Vet Entomol. 2017 Mar;31(1):72-77. doi: 10.1111/mve.12207. Epub 2016 Nov 11.
Engorged female Rhipicephalus sanguineus sensu lato (Ixodida: Ixodidae) were collected from dogs in the state of Yucatán, Mexico. Fourteen tick populations were collected from dogs at seven veterinary clinics, four residential homes and three cattle farms. The larval immersion test was used in the progeny of collected adult females to test susceptibility to amitraz and cypermethrin. Dose-mortality regressions, 50% lethal concentrations (LC ), confidence intervals and slope were estimated by probit analysis. For amitraz, 12 tick populations (85.7%) were classified as resistant and low inter-population variation in the phenotypic level of resistance was evident [resistance ratios (RRs) at LC : 1.0-13.0]. For cypermethrin, 12 tick populations (85.7%) were classified as resistant and substantial inter-population variation in the phenotypic level of resistance was evident (RRs at LC : 1.0-104.0). Thus, amitraz resistance in R. sanguineus s.l. is common, but generally occurs at low levels; however, alarmingly high levels of cypermethrin resistance are present in R. sanguineus s.l. populations in dogs in Yucatán, Mexico. The intensive use of both acaricides to control ectoparasites on dogs is likely to lead to more serious resistance problems that may cause high levels of control failure in the future.
饱血的雌性广义血红扇头蜱（硬蜱目：硬蜱科）采自墨西哥尤卡坦州的犬只。从7家兽医诊所、4处居民住宅和3个养牛场的犬只身上采集了14个蜱虫种群。对采集的成年雌性蜱虫的后代进行幼虫浸泡试验，以测试其对双甲脒和氯氰菊酯的敏感性。通过概率分析估计剂量-死亡率回归、50%致死浓度（LC）、置信区间和斜率。对于双甲脒，12个蜱虫种群（85.7%）被归类为抗性，且在抗性表型水平上种群间变异较低[LC时的抗性比率（RRs）：1.0 - 13.0]。对于氯氰菊酯，12个蜱虫种群（85.7%）被归类为抗性，且在抗性表型水平上种群间变异显著（LC时的RRs：1.0 - 104.0）。因此，广义血红扇头蜱对双甲脒的抗性很常见，但通常处于低水平；然而，令人担忧的是，墨西哥尤卡坦州犬只身上的广义血红扇头蜱种群对氯氰菊酯具有极高水平的抗性。在犬只身上大量使用这两种杀螨剂来控制体表寄生虫可能会导致更严重的抗性问题，未来可能会导致高度的防治失败。
