Seroprevalence and risk factors associated with Babesia caballi and Theileria equi infections in donkeys from Southern Italy

•This is the first study to estimate the occurrence of donkey piroplasmosis in the Campania region of Southern Italy.•Of 203 serum samples tested, 72 (35.5%) were found to be positive for B. caballi and 90 (44.3%) were positive for T. equi. The overall seroprevalence of EP was 57.1% (116/203) and a proportion of the donkeys were co-infected by both protozoa (46/203–22.6%).•Clinical examination of the most seropositive animals failed to show any evidence of abnormalities. Only one male donkey, with a titre of 1:640 against T. equi, showed the acute symptoms of disease.•Our findings showed that EP is widespread in donkeys living in this area of Southern Italy and therefore the establishment of an appropriate and effective control program is of great importance for these equids.•Donkeys could be chronic carriers and a potential continuous source for maintaining and disseminating the piroplasms in the rural environment. Equine piroplasmosis (EP) has been frequently described in donkeys in subtropical and tropical regions, but published data reflecting large scale surveys are very limited in Europe. The seroprevalence of Babesia caballi and Theileria equi was determined in a donkey population from Campania Region in Southern Italy using a commercial indirect fluorescent antibody test (IFAT), and the risk factors associated with the occurrence of the infection were assessed. Of 203 samples, the overall seroprevalence for EP was 57.1% (116/203), with 35.5% (72/203) for B. caballi and 44.3% (90/203) for T. equi. Co-infection was detected in 46 donkeys (22.6%). The distribution of IFAT antibody titres to B. caballi was: 1:80 (n = 67), 1:160 (n = 2), 1:320 (n = 3); while the distribution of IFAT antibody titres to T. equi was: 1:80 (n = 25), 1:160 (n = 42), 1:320 (n = 12), 1:640 (n = 8), 1:1280 (n = 3). All examined donkeys were asymptomatic, except one adult male (with a titre of 1:640 against T. equi) that showed clinical signs corresponding to the acute stage of EP, reported for the first time in Italy. The unique risk factor associated with a higher B. caballi seroprevalence was the presence of horses in the farms, while risk factors associated with a higher T. equi seroprevalence were poor body condition, presence of ruminants in the farms and milk production. The results indicate a high level of exposure in donkeys living in Southern Italy and suggest that donkeys may be an important reservoir of EP.