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

This study investigates the prevalence of antibodies for Sarcocystis neurona in a group of horses from Chester County, Pennsylvania, and explores the relationship between antibody prevalence and factors such as age, sex and housing conditions. The research highlights the limited value of serologic examination as the sole diagnostic tool for equine protozoal myeloencephalitis.

Objective and Methodology

• The research aimed to identify the prevalence of Sarcocystis neurona-specific antibodies in a sample of horses. Sarcocystis neurona is a parasite associated with equine protozoal myeloencephalitis (EPM), a disease that causes neurological dysfunction in horses.
• The study involved analyzing serum samples from 117 horses, selected from a population of 580 Thoroughbreds in Chester County in Pennsylvania.
• The researchers used a technique known as a western blot for testing the presence of antibodies to Sarcocystis neurona in the horse serum samples.
• Information about the horse’s age, sex, and housing was obtained through questionnaires. The data collected was subsequently analyzed using multivariable logistic regression to understand potential relationships and correlations.

Results

• The study found a seroprevalence of 45.3% – this means that approximately 45% of the horses tested were found to have antibodies against Sarcocystis neurona in their blood.
• The research found no significant correlation between the seroprevalence and the sex of the horses. This indicates that both male and female horses had equally likely chances of having antibodies against the parasite in question.
• A higher seroprevalence was observed in older horses, suggesting that age might play a factor in the immune response against the parasite. However, the researchers noted that the statistical significance of these findings was marginal (P = 0.16).

Conclusions

• Despite the high seroprevalence of antibodies to Sarcocystis neurona, there was a lack of neurologic deficits among the horses sampled. This suggests that many particular horses were exposed to the parasite, but did not develop EPM.
• The researchers concluded that positive results of serologic examination alone have limited value for diagnosing EPM, as the presence of Sarcocystis neurona antibodies does not necessarily mean that the horse has or will develop the disease.
• Instead, clinical signs consistent with the disease, such as neurologic deficits, are considered to be the most important factors in making an accurate diagnosis.