Persistence of serum antibodies to Sarcocystis neurona in horses moved from North America to India.

The study investigates if antibodies to Sarcocystis neurona, a parasite causing neurological disorders in horses, persist in horses of North American origin after being relocated to India, outside of endemic areas for the parasite. The research found that such antibodies can be detected for many years.

Research Objective and Methodology

The research aimed to detect the persistence of antibodies to the parasite Sarcocystis neurona in horses originating from North America but living in India for at least a year. This analysis serves two purposes:

• Determine the longevity of these antibodies.
• Investigate the indication of a chronic infection.

For this study, a total of 228 Thoroughbred horses were sampled. These comprised 86 North American horses living in India for between 1 and 13 years, 124 Indian-born horses, 8 horses each from Ireland and England, and 2 from France. The presence of antibodies in horses’ serum was tested using an established scientific technique called western blot analysis.

Research Results

From the sampled population, the study observed striking variations in the test results among horses from different origins:

• Only 0.8% of Indian-born horses were test positive for S. neurona antibodies.
• About 42% of relocated North American horses were test positive.
• All English and Irish horses were test negative, suggesting a lack of exposure to the parasite or different immune responses.
• All French horses were test positive.

Research Conclusions

The data suggested the antibodies against S. neurona could be detected several years after horses were removed from an endemic area like North America. The persistence of these antibodies could be attributed to the long half-life of antibodies or due to a chronic infection that continually induces antibody production. However, the study does not conclude definitively and suggests both possibilities.

This research is significant because it enhances our understanding of S. neurona infection and antibody responses, beneficial for managing equine neurological disorders related to this parasite, particularly in relocating horses across geographical boundaries.