Brown dog tick, Rhipicephalus sanguineus sensu lato, an important ectoparasite transmitting several pathogens, is the most common tick species infesting dogs. Control of ticks being central to the control of fatal tick-borne diseases, this study attempted to assess the susceptibility/resistance of brown dog ticks to synthetic pyrethroids, the commonly used acaricides against ticks. Larval packet assay revealed 60% of isolates tested to be resistant and tolerant to deltamethrin as per the resistance factor that ranged from 1 to 53.7. Sequence analysis of the PCR amplified product of domain II S4-5 linker of sodium channel gene in R. sanguineus revealed novel polymorphisms, viz., C190A, G215T and T270C. In domain III S6 region of the gene, a T2134C mutation was observed. Genotyping with allele-specific PCR targeting domain II S4-5 linker region using single larvae revealed that most R. sanguineus larvae in the study population were homozygous resistant (RR) genotypes, followed by heterozygous (RS) and homozygous susceptible (SS) genotypes. A higher proportion of RS genotypes was also observed in domain III S6 region. This first report of genotyping of Indian R. sanguineus to analyse synthetic pyrethroid resistance highlights the need to devise alternate control strategies to reduce the brown dog tick population.

棕色狗蜱，Rhipicephalus sanguineus sensu lato 是一种重要的外寄生虫，可传播多种病原体，是感染狗的最常见蜱种。蜱的控制是控制致命的蜱传疾病的核心，本研究试图评估棕色狗蜱对合成拟除虫菊酯的敏感性/抗性，合成拟除虫菊酯是常用的杀螨剂。幼虫包检测显示 60% 的分离株经测试对溴氰菊酯具有抗性和耐受性，抗性因子范围为 1 至 53.7。血红藻钠通道基因结构域II S4-5接头PCR扩增产物序列分析揭示了新的多态性，即 C190A、G215T 和 T270C。在该基因的域 III S6 区域，观察到 T2134C 突变。使用单个幼虫对等位基因特异性 PCR 靶向域 II S4-5 接头区域进行基因分型显示，研究群体中的大多数血红罗非鱼幼虫是纯合抗性 (RR) 基因型，其次是杂合 (RS) 和纯合易感 (SS) 基因型。在域 III S6 区域中也观察到更高比例的 RS 基因型。第一份对印度血红蜱进行基因分型以分析合成拟除虫菊酯抗性的报告凸显了设计替代控制策略以减少棕狗蜱种群的必要性。