Genetic characterization of Babesia and Theileria parasites in water buffaloes in Sri Lanka.

Water buffaloes are thought to be the reservoir hosts for several hemoprotozoan parasites that infect cattle. In the present study, we surveyed Sri Lankan bred water buffaloes for infections with Babesia bovis, Babesia bigemina, Theileria annulata, and Theileria orientalis using parasite-specific PCR assays. When 320 blood-derived DNA samples from water buffaloes reared in three different districts (Polonnaruwa, Mannar, and Mullaitivu) of Sri Lanka were PCR screened, B. bovis, B. bigemina, and T. orientalis were detected. While T. orientalis was the predominant parasite (82.5%), low PCR-positive rates were observed for B. bovis (1.9%) and B. bigemina (1.6%). Amplicons of the gene sequences of the Rhoptry Associated Protein-1 (RAP-1) of B. bovis, the Apical Membrane Antigen-1 (AMA-1) of B. bigemina, and the Major Piroplasm Surface Protein (MPSP) of T. orientalis were compared with those characterized previously in Sri Lankan cattle. While the B. bigemina AMA-1 sequences from water buffaloes shared high identity values with those from cattle, B. bovis RAP-1 sequences from water buffaloes diverged genetically from those of cattle. For T. orientalis, none of the MPSP sequence types reported previously in Sri Lankan cattle (types 1, 3, 5, and 7) were detected in the water buffaloes, and the MPSP sequences analyzed in the present study belonged to types N1 or N2. In summary, in addition to reporting the first PCR-based survey of Babesia and Theileria parasites in water buffaloes in Sri Lanka, the present study found that the predominant variants of water buffalo-derived B. bovis RAP-1 and T. orientalis MPSP sequences were different from those previously described from cattle in this country.