Potential role of dogs as sentinels and reservoirs for piroplasms infecting equine and cattle in Riyadh City, Saudi Arabia.

Canine tick-borne diseases have been considered emerging and re-emerging threats, given their increasing global prevalence. In this molecular survey, we aimed to detect and identify common tick-borne pathogens in dogs from Riyadh city in Saudi Arabia. Initially, the study included 36 dogs visiting private veterinary clinics. PCRs targeting the 18S ribosomal RNA gene (rDNA) of haemoparasites (Babesia, Theileria and Hepatozoon) and the 16S rDNA of Anaplasmataceae were performed. The results showed that 26 (72.2%) dogs were infected by some of the haemoparasites under investigation. The sequencing analysis of the amplicons confirmed the infections due to two parasite species Theileria equi and Theileria velifera. Further examination of guard dogs kept in the horse stables of the Riyadh Municipality revealed that the majority of the tested dogs (65.2%: 30 out of 46) were infected with either of the parasites. In addition, the genotypes of all the parasites in these dogs were identical to those of the parasites in the dogs from the veterinary clinics. Thus, it can be concluded that dogs are infected with these haemoparasites and serve as a reservoir for both T. equi and T. velifera in the study area; however, the clinical implication of this finding is to be studied.