Survey of tick species and tick-borne pathogens in pet dogs and cats in mainland China.

Ticks are major vectors of zoonotic diseases, harboring and transmitting various bacteria, viruses and parasites. In mainland China, the rapidly growing population of companion animals has rendered pets important tick hosts and a critical bridge for tick-borne pathogens to infiltrate domestic environments, yet no systematic investigations have been conducted on tick species parasitizing pets and the pathogens they carry.This study was conducted from May 2024 to August 2025. We collected ticks from the body surfaces of outpatient dogs and cats at 231 pet hospitals across 27 Chinese provinces and municipalities. Tick species were identified, and four key tick-borne pathogens (Babesia spp., Anaplasma phagocytophilum, Ehrlichia spp., and Lyme disease spirochetes) were detected via polymerase chain reaction (PCR); positive samples were further sequenced and subjected to phylogenetic analysis.A total of 2158 ticks were collected, 1942 (90.0%) from dogs and 216 (10.0%) from cats, belonging to 16 species of four genera. Haemaphysalis longicornis (40.6%) and Rhipicephalus sanguineus sensu lato (35.5%) were the dominant species. A. phagocytophilum was not detected in any samples. Babesia spp. had the highest infection rate (1.44%), including B. vogeli and B. gibsoni; Ehrlichia spp. and Lyme disease spirochetes were detected at 0.37% and 0.28%, respectively, with multiple species/genotypes identified for both. Pathogen distribution exhibited distinct tick-species specificity and spatial clustering.This is the first systematic survey of the diversity of pet-parasitizing ticks and the prevalence of four key tick-borne pathogens in mainland China, confirming that pets face persistent and diverse threats from tick-borne diseases. Our findings highlight the need for regionally differentiated surveillance, year-round tick control measures, and enhanced prevention and control awareness among veterinarians and pet owners, providing a scientific basis for clinical diagnosis, treatment and public health prevention and control.