The seroprevalence of antibodies to Sarcocystis neurona in Michigan equids.

The research article investigates the prevalence of antibodies to Sarcocystis neurona, which is the cause of equine protozoal myeloencephalitis, in horses in Michigan and tries to identify risk factors for the presence of these antibodies.

Research Methodology

The researchers conducted a cross-sectional study on horses from Michigan. A weighted random sample of horse farms across Michigan was selected for the study with stratification based on the local opossum population in the area and the number of horses on each farm. This selection considered opossum population because opossums are known to carry Sarcocystis neurona. The research was conducted from late March to October of 1997 with 98 horse operation owners agreeing to participate.

• Data was collected on the feeding and management practices of these farms.
• Descriptive data about each of the 1,121 individual horses was also gathered.

Serum samples were tested for antibodies against S. neurona using the Western blot test.

Findings

The research estimated that the true seroprevalence of antibodies specific to S. neurona was approximately 60% in the population.

• Chi-square analysis showed that the presence of antibodies was lowest in the colder regions of the state, which also had fewer opossums. This suggest a possible correlation between opossums and the prevalence of S. neurona.
• The study identified several risk factors for seropositivity (the presence of antibodies). The age of the horse and exposure to pasture were associated with increased chances of testing positive.
• Feeding horses with sweet feed resulted in lower chances of testing positive for S. neurona antibodies.
• No association was found between the size of the farm or the horse’s gender and the chances of testing positive for S. neurona antibodies.
• Moreover, the type of hay fed, the type of housing provided to the horses, and exposure to natural surface water did not appear to influence the presence of these antibodies.

Overall, the research suggests that certain factors, such as location, age and exposure to pasture, can influence the prevalence of S. neurona, but further investigation is needed to uncover the extent and nature of these associations.