Molecular prevalence of Theileria infections in cattle in Yanbian, north-eastern China.

Bovine Theileria are tick-borne protozoan parasites that invade bovine erythrocytes and lymphocytes. Three main bovine Theileria species have been identified in China: T. orientalis, T. sinensis, and T. annulata. To examine the prevalence of bovine theileriosis in Yanbian, a total of 584 bovine blood samples were collected from five localities from 2017 to 2019 and analyzed by PCR. Six pairs of oligonucleotide primers directed against the 18S rRNA gene of Theileria spp., Tams-1 gene of T. annulata, MPSP gene of T. orientalis, and T. sinensis, were used to detect these parasites. A sequence analysis of the amplified genes confirmed that the Theileria species were T. orientalis and T. sinensis, without T. annulata. The overall prevalence of Theileria in cattle was 42.81% (250/584). Out of the 584 samples, 159 (27.23%) and 157 (26.88%) were positive for T. sinensis and T. orientalis, respectively, and the mixed infection rate was 11.30% (66/584). The total prevalence of bovine Theileria species in Helong, Hunchun, Longjing, Yanji, and Dunhua was 66.28%, 49.68%, 23.81%, 28.15%, and 0%, respectively. These results provide epidemiological data for the prevention and control of bovine Theileria species in Yanbian, China.