albiventris, Didelphis aurita, Didelphis marsupialis, and Didelphis imperfecta ( 6). While only one species of Didelphis is found in North America, four species of this genus are found in Brazil: D. neurona in North America ( 3, 4), whereas Didelphis albiventris was identified as definitive host of S. The opossum Didelphis virginiana serves as definitive host of S. The coccidian parasite Sarcocystis neurona is the major cause of equine protozoal myeloencephalitis (EPM), a debilitating neurological disease that affects horses in the Americas ( 1, 2). Exposure of the tested horses to other Sarcocystis species, such as Sarcocystis lindsayi, Sarcocystis speeri, and Sarcocystis fayeri, or Sarcocystis bertrami cannot be excluded in the current study. Antigens in the range of 16 and 30 kDa are probably homologous in the two parasites. We concluded that Brazilian horses are exposed to distinct Sarcocystis species that generate different serological responses in exposed animals. Proteins in the range of 16 and 30 kDa were recognized by part of IFAT-positive sera using both antigen preparations. neurona by IFAT, two sera that tested negative to both parasites by IFAT, and a negative control horse serum from New Zealand. falcatula–like by IFAT, six sera positive to S. Horse sera evaluated by WB consisted of four sera reactive to S. A poor agreement was observed between the two employed IFATs (κ = 0.364), indicating that horses were exposed to more than one Sarcocystis species. neurona antigen sera from 25 animals (6.1%) were positive for both parasites by IFAT. falcatula–like and 70 of 409 (17.1%) were reactive to S. Sera from 43/409 (10.5%) horses were reactive to S. Samples were examined by immunofluorescent antibody tests (IFATs) at start dilutions of 1:20, and a selected number of samples was tested by Western blot (WB).

falcatula–like (Sarco-BA1) and from a North American strain of S. The aim of this study was to test the sera reactivity of 409 horses in Brazil using antigens derived from a Brazilian strain of S. neurona–seropositive horses in Brazil are also derived from exposure of horses to S. Four Didelphis species are found in Brazil, and in most reports in this country, Sarcocystis species shed by opossums have been classified as S. The opossum Didelphis virginiana is the definitive host of these parasites in North America. The former is the major cause of equine protozoal myeloencephalitis, and the latter is associated with pulmonary sarcocystosis in birds. Sarcocystis neurona and Sarcocystis falcatula are protozoan parasites endemic to the Americas. Department of Anatomy, Pathology and Veterinary Clinics, School of Veterinary Medicine and Animal Science, Federal University of Bahia, Salvador, Brazil.

Western blot results epm