Texas Equine Veterinary Association

• 22 • DRAFT FOR REVIEW EPM Suspect Case Immunodiagnostics Blood serum (+) ≠ EPM EPM ruled out Differential 3 Differential 2 ? ? CSF (-) CSF (+) Correlates with EPM EPM ruled out Treat Re-evaluate (30 days) ? ? Figure 1: What is a Proper EPM Diagnostic Work-up? If EPM rises to the top of your list of differentials after a thorough physical and neurological exam, antibody testing should be used to further differentiate EPM from other neurological diseases. Intrathecal antibody production is the most accurate way to support an EPM diagnosis, while blood is useful for screening. Blood serum (-) Differential 2 Differential 3 Copyright © 2021 Intervet Inc., d/b/a Merck Animal Health, a subsidiary of Merck & Co., Inc. Figure 1: What is a Proper EPM Diagnostic Work-up? If EPM rises to the top of your list of differentials aer a thorough physical and neurological exam, antibody testing should be used to further differentiate EPM from other neurological diseases. Intrathecal antibody production is the most accurate way to support an EPM diagnosis, while blood is useful for screening. • • • • • ::: Tips for Talking EPM Diagnostics with Clients ::: As practitioners, we oen face the eager client who confidently walks in and says, "Doc, I need this horse tested for EPM," or "I'm pretty sure it's EPM, can you get him started on an EPM treatment?" 1) Remind owners that EPM can be the "master of disguise" and mimic many neurologic diseases. It's important to evaluate all potential causes of the horse's illness before rushing to EPM testing and/or treatment. 2) More than two-thirds of healthy U.S. horses are carrying antibodies to S. neurona – the primary causative organism of EPM – without showing clinical signs. Only a very small percentage (<1%) of horses succumb to clinical disease. 3 3) If the horse does not have EPM, it will not respond to an EPM treatment and you've wasted time and money without getting to the root cause of the issue. is can prolong suffering for the horse. 4) Increase client confidence in your diagnostic work up by explaining the importance of a thorough history on the horse, as well as a physical and neurological examination along with proper antibody testing to rule EPM in (or out). We cannot rely on one without the other. 5) Emphasize the importance of continued vigilance with regular veterinary examinations to ensure treatment success and ongoing care and management of the horse with EPM. 6) Reinforce early veterinary intervention for any horse showing signs of neurological disease. e earlier disease is caught, and treatment begins, the better the outcome.

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