A Seroepidemiological Survey of Theileria equi and Babesia caballi in Horses in Mongolia.

Equine piroplasmosis caused by and is an economically important disease with a worldwide distribution. The objective of the present study was to investigate the seroepidemiology of and in horses reared in various Mongolian provinces. Serum samples prepared from blood collected from horses in 19 Mongolian provinces were screened for antibodies specific to and using enzyme-linked immunosorbent assays based on recombinant forms of merozoite antigen-2 and the 48-kDa merozoite rhoptry protein, respectively. Of 1,282 horses analyzed, 423 (33%) and 182 (14.2%) were sero-positive for and , respectively. Additionally, 518 (40.4%) were positive for at least 1 parasite species, of which 87 (16.8%) were co-infected with both parasites. Both and were detected in all surveyed provinces, and on a per province basis the positive rates ranged from 19.0 to 74.2% and 4.5 to 39.8%, respectively. - and -positive rates were comparable between male horses (31.9 and 14.1%, respectively) and female horses (34.5 and 14.3%, respectively). However, the positive rates were higher in the >3-yr-old age group (37.7 and 15.6%, respectively) compared with the 1-3-yr-old age group (19.4 and 10.0%, respectively). These findings confirmed that and infections are widespread among horses all over Mongolia, and that horse age is a risk factor for infection in this country. Our results will be useful for designing appropriate control measures to minimize and infections among Mongolian horses.