RESUMEN
Approximately 50% of buffalo herds in Brazil are located in Pará state in northern Brazil. There are several properties where cattle and buffalo live and graze together, and thus, buffalo pathogens may threaten the health of cattle and vice versa. Therefore, knowledge of infectious agents of buffalo is essential for maintaining healthy livestock. Clinical disease caused by Theileria and Babesia parasites in the Asian water buffalo is not common, although these animals may act as reservoir hosts, and the detection of these hemoparasites in buffaloes is as important as it is in cattle. Studies of the infection of buffaloes by hemoparasites in Brazil are scarce. The objective of the present study was to investigate the occurrence of Piroplasmida parasites in Asian water buffaloes in the state of Pará in the Amazon region of Brazil using nested PCR assays and phylogenetic analysis. The 18S rRNA gene and ITS complete region were amplified from DNA extracted from blood samples collected from 308 apparently healthy buffaloes bred on six properties in the state of Pará, Brazil. The prevalence of positive buffalo samples was 4.2% (13/308) for Theileria spp., 3.6% (11/308) for Babesia bovis and 1% (3/308) for Babesia bigemina. Animals infected with Theileria were detected in 50% (3/6) of the assessed properties. Phylogenetic analyses indicated that the Theileria species detected in this study were closely related to Theileria buffeli, Theileria orientalis and Theileria sinensis. To our knowledge, this is the first report of Theileria in Asian water buffaloes in the Americas. The majority of Theileria-positive buffaloes (11/13) belong to a property that has a history of animals presenting lymphoproliferative disease of unknown etiology. Therefore, the present research suggests that this disorder can be associated with Theileria infection in this property. Our results provide new insights on the distribution and biological aspects of hemoparasites transmissible from buffaloes to cattle.