First Molecular Detection of Babesia gibsoni in Stray Dogs from Thailand.

In southern Thailand, the increasingly growing population of stray dogs is a concern to public health and environmental safety because of the lack of medical attention and control. More importantly, these animals are considered reservoirs for many zoonotic pathogens. The objective of this study was to molecularly detect canine vector-borne pathogens, and to perform genetic characterization of Babesia gibsoni present in stray dogs from southern Thailand. Blood samples were collected from 174 stray dogs in two provinces (Songkhla and Narathiwat) in southern Thailand. PCR analyses were executed using specific primers based on the Babesia spp. 18S rRNA gene, Babesia gibsoni Internal transcribed spacer 1 (ITS1) region, Ehrlichia canis citrate synthase (gltA) gene, Hepatozoon spp. 18S rRNA gene and Anaplasma platys heat shock protein (groEL) gene. The most common canine vector-borne pathogen found infecting stray dogs in this study was Hepatozoon canis (24.7%) followed by A. platys (14.9%), Babesia vogeli (8.0%), B. gibsoni (6.3%), and E. canis (1.72%). Concurrent infection with more than one pathogen occurred in 72 cases. Phylogenetic analysis based on the ITS1 region and 18S rRNA gene revealed that the B. gibsoni isolates from this study shared a large proportion of their identities with each other and with other reported B. gibsoni genotypes from Asia. This study highlights the molecular detection of B. gibsoni in dogs in Thailand for the first time and presents the genetic characterization by sequencing the ITS1 region and 18S rRNA gene of B. gibsoni from Thailand. Follow-up studies are needed to elucidate the origin, distribution, and vectors of B. gibsoni parasites circulating in dogs in Thailand, as well as to determine to what extent dogs are important reservoir hosts for zoonotic canine vector-borne disease infection in the studied area.