A review of acaricide resistance of the Rhipicephalus sanguineus group worldwide.

The brown dog tick Rhipicephalus sanguineus (included in the R. sanguineus group) is the most widespread Rhipicephalus species globally. This tick species is a vector of pathogens of veterinary and public health importance. The improper and frequent use of acaricides might have led to the development of acaricide resistance in this tick group. This review presents the status of R. sanguineus group resistance to various acaricides worldwide. Fifty studies published from 2001 to 2025 were included. Resistance is documented in multiple species, including R. sanguineus sensu lato and sensu stricto (worldwide), as well as morphologically related species such as R. rutilus (Italy) and R. linnaei (Thailand). Resistance in the R. sanguineus group to synthetic pyrethroid (SPs: permethrin, deltamethrin, cypermethrin, and etofenprox) is reported from America, Europe, Africa, and Asia. Organophosphate (coumaphos) resistance has only been reported in Brazil and Panama, as well as chlorpyriphos-methyl in Turkey. Likewise, resistance to macrocyclic lactones (ivermectin) has been reported in Argentina, Brazil, Mexico, Italy, India, and Thailand. Fipronil resistance has been reported in seven countries, while amidine (amitraz) resistance has been reported in five countries, and carbamate (propoxur) in only one country. Different mutations in the voltage-gated sodium channel have been identified and associated with synthetic pyrethroid resistance. Metabolic resistance mechanisms, involving oxidase, esterase, and glutathione S-transferase activity, have been documented in multiple populations. ATP-binding cassette (ABC) transporters were involved in fipronil and ivermectin detoxification of R. sanguineus sensu lato.