Seroprevalence of antibodies to Sarcocystis neurona in equids residing in Oklahoma.

A sampling of equids from the state of Oklahoma produced an estimate of seroprevalence of antibody to Sarcocystis neurona to be about 89.2%. This figure represents the highest currently reported regional seroprevalence of antibody to this organism. Regional differences in seroprevalence were found in the western quadrants of the state relative to the eastern quadrants of the state, with a significantly higher seroprevalence in the eastern regions. Thoroughbreds were found to exhibit a statistically significant lower seroprevalence as a breed group when compared with other breeds sampled.