Researchers Declare War On EPM

According to a number of researchers across the country, anything less than an all-out scientific assault on several fronts will not result in a victory in the battle to conquer equine protozoal myeloencephalitis (EPM). Veterinary schools, equine research centers, private practitioners, and pharmaceutical companies have joined the battle against this devastating and costly disease.

Like other facilities, the strategy of the Center for Equine Health (CEH) at the University of California, Davis, is to study different aspects of the disease over a number of years. The CEH team will investigate new and hopefully more accurate methods of testing for infection, and at the same time take an in-depth look at the infectious process itself -- when and how it occurs.

"Our research activities are motivated by two basic precepts," says Greg Ferraro, DVM, director of the CEH. "First, too little is known about the infectious agents and how they actually produce disease, and second, prevention of infection and/or development of disease should be the primary goal of our EPM research." Treatment after the appearance of central nervous system signs, even if it is successful, often leaves the patient with an impaired ability to perform.

The current Western blot system tests for the presence of antibodies against the parasite in blood and spinal fluid. Because interpretation of test results can be frustrating to veterinarian and owner alike, the group at CEH has embarked on a mission to develop a "gold standard" test for the disease-causing protozoa. Several different testing applications currently are being explored in an effort to find one that can accurately predict clinical disease. Other places working on diagnostic testing include the University of Kentucky and Michigan State University.

Understanding the life cycle of the organism that causes EPM will play a large role in unraveling this complicated disease. Locations hard at work on this aspect include the University of Florida, The Ohio State University, the University of Missouri, Colorado State University, Texas A&M University, and the CEH at UC Davis.

The CEH team plans to undertake an epidemiological study with the cooperation of several large horse breeding farms in California. They will follow a group of producing mares and their offspring from birth to four years of age in an attempt to determine when infection by the parasite actually occurs, and how long after infection it takes for disease to develop. Another aspect of the study will investigate whether infection necessarily results in disease, or whether some individuals have the ability to "throw off" the parasite and why.

Interested horse owners can help their horses fight this battle by becoming better educated about this disease process and its risk factors, changing management procedures in high-risk areas, and consulting their veterinarians immediately if a horse is suspected of having neurologic signs consistent with EPM.

About the Author

Lydia Gray, DVM, MA

Lydia Gray, DVM, is Medical Director and Staff Veterinarian for SmartPak Equine. She was previously the executive director of the Hooved Animal Humane Society in Woodstock, IL, and an Owner Education Director for the American Association of Equine Practitioners.

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