Identification of 12 Piroplasms Infecting Ten Tick Species in China Using Reverse Line Blot Hybridization

Piroplasmosis, a disease of domestic and wild animals, is caused by tick-borne protozoa in the genera of Theileria and Babesia. There is limited information available about the prevalence of piroplasmosis in ticks in China, and to assess the potential threat of piroplasmosis in China, we investigated the infections of ovine and bovine Babesia and Theileria species in ticks collected from cattle, yaks, sheep, horses, and camels in several regions of China where tick-borne diseases have been reported. In total, 652 ticks were collected from the animals in 6 provinces of China. Babesia spp. and Theileria spp. were detected with a PCR-RLB method and identified by sequencing. Overall, 157 ticks (24.1%) were infected with 5 Babesia and 4 Theileria species. Among tested tick samples, 134 (20.6%) were single infections with 1 of 7 piroplasm species, with Theileria annulata (118/652, 18.1%) being dominant. Only 23 (3.5%) tick samples were double or triple infected, Theileria luwenshuni and Theileria sinensis (18/652, 2.8%) were frequently observed in co-infections. Some piroplasm species were carried by ticks that were not previously reported to be vectors.