Transplacental transmission of Theileria equi in mules: Should we worry?

Equine piroplasmosis, disease globally responsible for significant economic losses, is caused by the transmission of the hemoprotozoa Theileria equi and Babesia caballi by ticks. Transplacental transmission has been reported previously in horses, which is not the case for mules´ foals. The present study investigated, by Real Time-PCR (RT-PCR), the presence of both Theileria equi and Babesia caballi in newborn mules before the ingestion of colostrum. Blood samples of 18 mares and their respective mules´ foals were collected and analyzed by RT-PCR. Only one mare was positive for B. caballi. In contrast, 13 mares were positive for T. equi, with two foals (11.1%) positive for the same protozoon, both of affected mares. We may conclude that transplacental transmission of Theileria equi also occurs in mules which may be an important concern while breeding such animals.