Prevalence and diagnosis of Babesia and Theileria infections in horses in Italy: a preliminary study.

Babesia caballi and Theileria equi are the causative agents of equine piroplasmosis. In this preliminary epidemiological study, 412 horses reared in central and northern Italy were sampled and three diagnostic methods compared, namely, the microscopy, the indirect fluorescent antibody test (IFAT) and a PCR. Possible risk factors (such as area, season, breed, activity, sex, age, and grazing) associated with serological positivity were evaluated. A seroprevalence of 68.4% was found: 12.4% of the animals had anti-T. equi antibodies, 17.9% anti-B. caballi antibodies and 38.1% had antibodies against both species. Of the seropositive samples, 3.1% and 9.4% were positive to microscopy and PCR, respectively; 31.5% of the horses were IFAT-negative but 1.4% and 2.4% of the corresponding blood samples were positive to microscopy and PCR, respectively. Molecular techniques revealed that the species present were closely related to T. equi, Theileria sergenti, Theileria buffeli and the Babesia microti-like piroplasm provisionally named Theileria annae. Grazing was found to be a pronounced risk factor for equine piroplasmosis.