Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, Republic of South Africa.
TBD International BV, BioScience Center, Wageningen University & Research, Runderweg 6, 8219 PK, Lelystad, The Netherlands.
Parasit Vectors. 2024 Sep 28;17(1):406. doi: 10.1186/s13071-024-06472-6.
Brown dog ticks (Rhipicephalus sanguineus sensu lato) are vectors of pathogens adversely affecting the health of dogs in many regions of the world. The three-host life cycle of R. sanguineus s.l., with all stages feeding on dogs, can lead to an uncontrolled build-up of large tick populations if not controlled by acaricides. However, frequent tick control on dogs using acaricides has led to the emergence of resistance to permethrin and fipronil. Currently, the larval packet test (LPT) is the standard tick resistance test, which is laborious, requires laboratory facilities, and takes at least 6 weeks before larvae derived from engorged female ticks can be tested. Our novel approach is to expose semi-engorged adult ticks to acaricides immediately after removing them from dogs, obtaining results within 24 h.
Adult ticks from three laboratory colonies of R. sanguineus s.l. were tested in RaTexT, a rapid tick exposure test in which ticks were confined to small compartments and exposed to an acaricide-impregnated, specially designed matrix. Resistance was confirmed by testing larvae derived from the same laboratory colonies using the LPT. RaTexT was also used to determine the susceptibility of R. sanguineus acaricides in dog shelters.
RaTexT detected resistance to permethrin in adult R. sanguineus s.l. ticks from two Brazilian laboratory colonies compared to a susceptible laboratory strain originating in Greece. Resistance was confirmed by LPT testing of larvae from the same colonies with resistance factors between 2.2 and 3.1. All laboratory strains were susceptible to fipronil. A suspected case of fipronil resistance at a dog shelter in Caxias do Sul, Brazil, was resolved within 24 h by testing adult ticks in RaTexT and could be attributed to improper treatment.
RaTexT is a valuable tool for monitoring the development of resistance to synthetic pyrethroids or phenylpyrazoles in tick-infested dogs.
褐黄狗蜱（Rhipicephalus sanguineus sensu lato）是世界许多地区影响犬类健康的病原体的传播媒介。R. sanguineus s.l. 的三宿主生命周期，所有阶段都以犬类为食，如果不使用杀蜱剂进行控制，可能会导致大量蜱虫不受控制地滋生。然而，频繁地使用杀蜱剂控制犬类身上的蜱虫已经导致了对氯菊酯和氟虫腈的抗药性。目前，幼虫包被测试（LPT）是标准的蜱虫抗药性测试，该测试繁琐，需要实验室设施，并且至少需要 6 周时间才能对来自饱血雌蜱的幼虫进行测试。我们的新方法是在从犬身上取下半饱血的成年蜱虫后立即将其暴露于杀蜱剂中，在 24 小时内获得结果。
来自 R. sanguineus s.l. 的三个实验室品系的成年蜱虫在 RaTexT 中进行了测试，RaTexT 是一种快速蜱虫暴露测试，其中蜱虫被限制在小隔间中，并暴露于含有杀蜱剂的特制基质中。通过使用 LPT 测试来自同一实验室品系的幼虫来确认抗药性。RaTexT 还用于确定犬舍中 R. sanguineus 杀蜱剂的敏感性。
RaTexT 检测到来自巴西两个实验室品系的成年 R. sanguineus s.l. 蜱虫对氯菊酯的抗药性，而来自希腊的敏感实验室品系则没有。通过对来自同一品系的幼虫进行 LPT 测试，确认了抗药性，抗性系数在 2.2 到 3.1 之间。所有实验室品系对氟虫腈均敏感。巴西卡西亚斯杜苏尔的一个犬舍中疑似对氟虫腈产生抗药性的情况在 24 小时内通过在 RaTexT 中测试成年蜱虫得到解决，这归因于不当的治疗。
RaTexT 是监测受感染犬类对合成拟除虫菊酯或苯基吡唑类药物抗药性发展的有价值的工具。
