Submitted to: Journal of the American Veterinary Medical Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 22, 1999
Publication Date: N/A
Interpretive Summary: Equine protozoal myeloencephalitis (EPM) is a neurologic disease of horses in Americas. It is caused by the single celled parasite, Sarcocystis neurona. In the U.S. approximately 40 percent of horses were found to have antibodies to S. neurona. Prevalence of S. neurona in Central and South America is unknown. Scientists at the Beltsville Agricultural Research Center and the Sao Paulo Jockey Club found antibodies to S. neurona in 36 of 101 Thoroughbred horses from Brazil. Results will be of interest to veterinarians, horse comers and parasitologists.
Objective - To determine serologic prevalence of Sarcocystis neurona, Toxoplasma gondii and Neospora caninum in horses from Brazil. Design - Prevalence survey. Animals - 101 Thoroughbreds from S o Paulo Jockey Club, Brazil. Procedure - Serum samples were obtained from horses in September, 1998 and tested for antibodies to Sarcocystis neurona by immunoblot using culture derived S neurona merozoites as antigen, for Toxoplasma gondii and Neospora caninum by the use of modified agglutination tests incorporating whole formalin-preserved tachyzoites (T gondii or N caninum) and mercaptoethanol. Results - Antibodies to S neurona and T gondii were detected in 36 and 16 of 101 horses, respectively. There was no cross- reactivity between T gondii and S neurona. Antibodies to N caninum were not found in any of the horses. Clinical Implications - The high prevalence of antibodies to S neurona found in clinically normal horses emphasizes the importance of examining CSF for S neurona-specific antibodies when establishing a diagnosis of equine protozoal myeloencephalitis.