Leading the Way in EPM Testing

***Horse Report coverage of this story***

Equine protozoal myeloencephalitis (EPM) remains a significant disease for equine veterinarians and researchers to study. Caused by protozoa that are present in the feces of the opossum, EPM is a debilitating neurologic disorder in horses that can ultimately be fatal. Thanks to support from donations to the Center for Equine Health, a group of UC Davis scientists, led by Dr. Nicola Pusterla, are learning more about the disease every year.

Due to the difficulty in diagnosing the disease, veterinarians rely on experience in recognizing signs, but ultimately the only definitive diagnosis of EPM comes from tests of the horse’s serum or cerebrospinal fluid to determine the presence of antibodies to the protozoa.

Historically, the Western immunoblot test was used to diagnose EPM, but Pusterla’s team sought an improved diagnostic tool. To that end, they developed and successfully validated the SarcoFluor™ and NeoFluor™ tests – immunofluorescent antibody tests for both of the known causative agents of EPM (Sarcocystis neurona and Neospora hughesi). These provide a quantitative indication of EPM infection and provide greater sensitivity and specificity than the Western immunoblot test on serum samples. The new methods also reduce the necessity to obtain cerebrospinal fluid in order to screen for antibodies against the two protozoal agents.

The school offers the only commercial platform that tests for both S. neurona and N. hughesi antibodies, ensuring more cost effective and complete screening from a single sample.

UC Davis clinicians also created an EPM website with several pages of pertinent information, including a diagnostic flow chart that veterinarians can follow to determine if laboratory testing to confirm EPM is necessary. It can be found at: www.vetmed.ucdavis.edu/go/epm.

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