Prevalence of Ehrlichia spp. in Dogs and Ticks in Hainan Province, China

Background: Ehrlichia spp. are a group of intracellular parasitic bacteria primarily transmitted by ticks and exhibit a wide global distribution. Their ability to infect a diverse range of mammals, including humans, underscores their immense public health significance. Methods: We collected tick and dog blood samples in different areas of Hainan Province. The species of ticks were identified by standard PCR of the tick 16S rRNA gene. Detection of Ehrlichia infection in ticks and dogs using nested PCR of the 16S rRNA gene of Ehrlichia spp.. The obtained sequences were subjected to comparison with other sequences cataloged in GenBank. Subsequently, risk factors affecting Ehrlichia infection were statistically analysed. Results: All 631 ticks belonged to the Rhipicephalus linnaei ; 63 (9.98%) out of 631 ticks tested positive for Ehrlichia canis , while 140 (11.08%) out of 1264 dog blood samples were positive for E. canis . Notably, Ehrlichia ewingii and Ehrlichia chaffeensis were not detected. The prevalence of Ehrlichia infection in dogs is correlated with factors such as age, breed, dewormer use, tick infestation, and living environment, while displaying no association with the gender of the dog. Conclusions : In Hainan Province, Rhipicephalus linnaei is the dominant tick species infecting dogs. Dogs are vulnerable to Ehrlichia infection, particularly rural and stray dogs.