Cerebrospinal fluid (CSF) testing for equine protozoal myeloencephalitis (EPM) has been widely regarded as the only definitive way to diagnose the disease. This test can be difficult, expensive, and potentially dangerous, and according to new research from Colorado State University, it might not be necessary.

Researchers found that a blood serum sample can undergo indirect fluorescent antibody testing (IFAT) and reveal not only the presence of antibodies to Sarcocystis neurona (the parasite that most frequently causes EPM), but also quantify the antibody concentration. IFAT gives a more specific result than the currently used Western blot test.

The difficulty of diagnosing EPM is that a horse exposed to S. neurona will have antibodies against that organism whether or not the horse is actually displaying clinical signs of EPM. The study, by Paulo C. Duarte, DVM, MPVM, PhD, et al., appeared in the American Journal of Veterinary Research