PCR detection and genetic characterization of piroplasms from dogs in Myanmar, and a possible role of dogs as reservoirs for Theileria parasites infecting cattle, water buffaloes, and goats

Canine vector-borne pathogens can act as zoonotic agents in humans; however, it poorly understood whether dogs play a role as reservoirs of vector-borne parasites in livestock animals. Here, we report the unexpected detection of 18S rRNA gene (rDNA) sequences of five ruminant Theileria species from the peripheral blood of dogs in Myanmar, in addition to those of two canine Babesia species. Using novel BTH primers capable of amplifying the 18S rDNA of Babesia, Theileria, and Hepatozoon spp., approximately 1,500 bp nested PCR products were detected in 19% (17/91) of local or imported dog breeds in different regions of Myanmar. Among the sequences of the 17 PCR products, ten were determined as Theileria 18S rDNA, including three as Theileria orientalis, three as Theileria buffeli, two as Theileria cf. velifera, one as Theileria luwenshuni, and one as Theileria sp. Most of these sequences showed higher identities with Theileria sequences determined in previous studies of cattle, water buffaloes, and goats in Myanmar. Six PCR products were identified as Babesia vogeli and one sample was determined as Babesia gibsoni. Furthermore, we obtained approximately 900 bp thrombospondin-related adhesive protein (TRAP) gene fragments from three dog blood DNA samples. Phylogenetic analysis of the TRAP gene showed that B. gibsoni parasites in Myanmar were considerably related to isolates from China, Korea, Japan, and Taiwan, but clearly separated from those from Bangladesh and India. These results provide new insights into a possible role of dogs in maintaining and spreading tick-borne pathogens among livestock and canine populations in Myanmar.