Seroprevalence of antibodies to Sarcocystis neurona in horses residing in a county of southeastern Pennsylvania.

OBJECTIVE

To determine seroprevalence of Sarcocystis neurona-specific antibodies in a population of horses residing in Chester County, Pa.

DESIGN

Prevalence survey.

SAMPLE POPULATION

117 serum samples from selected members of a population of 580 Thoroughbred horses.

PROCEDURE

Serum was analyzed for antibodies to Sarcocystic neurona, using a western blot. Information regarding age, sex, and housing of horse was obtained by questionnaire. Data were analyzed, using multivariable logistic regression.

RESULTS

Seroprevalence was 45.3% (95% CI, 36.3 to 54.3%). A relationship was not found between seroprevalence and sex of horse. Seroprevalence was greater in older horses (logistic regression; P = 0.16).

CLINICAL IMPLICATIONS

High seroprevalence of antibodies to S neurona and the lack of neurologic deficits among horses sampled indicate that positive results of serologic examination alone are of limited value for diagnosis of equine protozoal myeloencephalitis. Clinical signs consistent with the disease are the most important consideration in accurate diagnosis.