Prevalence of agglutinating antibodies to Sarcocystis neurona in raccoons,Procyon lotor, from the United States

Equine protozoal myeloencephalitis (EPM) is the most important protozoal di sease of horses in North America and it is caused by Sarcocystis neurona. N atural cases of encephalitis due to S. neurona have been reported in raccoo ns, Procyon lotor. We examined 99 raccoons for agglutinating antibodies to S. neurona using the S. neurona agglutination test (SAT) employing formalin -fixed merozoites as antigen. Raccoons originated in Florida (N = 24, colle cted in 1996), New Jersey (N = 25, collected in 1993), Pennsylvania (N = 25 , collected in 1999), and Massachusetts (N = 25, collected in 1993 and 1994 ). We found that 58 (58.6%) of the 99 raccoons were positive for antibodies to S. neurona using the SAT; 44 of 99 raccoons (44%) had titers of greater than or equal to 1:500. This prevalence is similar to the reported seropre valence of 33-60% for S. neurona antibodies in horses from the United State s using the Western blot test. (C) 2001 Elsevier Science B.V. All rights re served.