Equine theileriosis: Review

Equine theileriosis, caused by the Apicomplexa protozoan Theileria equi , is an intra-erythrocytic parasite disease found in horses, and it is widely distributed throughout the world. Its prevalence and endemicity are linked to the presence of tick vectors and chronic equine carriers. Diagnosis of theileriosis is based on serological methods, including ELISA (Enzyme-Linked Immunosorbent Assay), IFAT (indirect fluorescent antibody), and molecular methods such as PCR (Polymerase Chain Reaction). Theileria has merozoite proteins, (EMA-1, EMA-2, EMA-3 and EMA-6). These antigens play an important role in pathogenesis and provide as host immune response targets against the parasite. EMA-1 and EMA-2 have been identified as immunodominant antigens and they are expressed on the surface of extra-erythrocyte merozoites. EMA-1 protein has been used in commercial testing of immunodiagnostic; however, EMA-2 is a highly conserved immunogenic protein and a promising target. The aim of this study is to contribute to improving the diagnosis and prevention of equine theileriosis.