Serologic prevalence of Sarcocystis neurona, Toxoplasma gondii, and Neospora caninum in horses in Brazil

Abstract

Objective To determine serologic prevalence of Sarcocystis neurona , Toxoplasma gondii , and Neospora caninum in horses in Brazil. Design Prevalence survey. Animals 101 Thoroughbreds in Brazil. Procedure Blood samples were obtained from horses and tested for serum antibodies against S neurona by use of an immunoblot procedure with culture-derived S neurona merozoites as antigen, and for serum antibodies against T gondii and N caninum by use of a modified agglutination test with formalinpreserved tachyzoites and mercaptoethanol. Results Antibodies against S neurona and T gondii were detected in 36 and 16 of 101 horses, respectively. Cross-reactivity between antibodies against T gondii and S neurona was not detected. Antibodies against N caninum were not detected in any samples. Conclusions and Clinical Relevance The high prevalence of antibodies against S neurona detected in clinically normal horses emphasizes the importance of examining CSF for antibodies when establishing a diagnosis of equine protozoal myeloencephalitis. ( J Am Vet Med Assoc 1999;215:970–972)