I lost my mare to EPM + Herpes V last fall. In the course of trying to diagnose and treat her and about a dozen horses other horses with roughly similar symptoms in the same equine practice, my vet (and hence I) learned that current abilities to diagnose EPM accurately are so limited as to render meaningful comparisons of different treatments well nigh impossible. IOW, based on the results of necropsy compared to the various diagnostic test administered in the course of treatment, necropsy is at present the only means of establishing with certainty that a horse was in fact afflicted by EPM. Horses with high levels of exposure/titres in their blood or spinal fluid were found to have been neurologically disabled by entirely different diseases, and vice-versa: horses whose tests indicated relatively low levels of exposure were nonetheless found upon necropsy to have severely damaged brains caused by protozoal invasion. This is, I learned (here on COTH), probably the biggest reason why researchers have been unable to produce a credible vaccine. How can scientists adequately test a vaccine if they canāt even reliably produce the disease in test horses? And how can anyone evaluate one course of treatment vs. others if we cannot even reach reliable differential diagnoses until after the horses are dead?
I mention all this here because I remember so well the decision to treat for EPM (with Marquis, because itās FDA approved-- although I now wonder why). The idea was that we could hope my mare had EPM despite her low titres because if she did, the treatment should work-- as it supposedly had for many other EPM cases. As it turned out, my mare DID have EPM despite her low titres (as did another horse that was necropsied), and Marquis did not help her at all (or one other necropsied horse with EPM). Hence, in retrospect, my vet (and I) have come to suspect that many, if not all, the horses said to have recovered from EPM, never had it all. My vetās response has been to go back to school and start researching EPM, from present diagnostic procedures on up (or wherever) because she was so floored by the inadequacy of present knowledge to address this disease. For my own part, I wish the diagnosis were not tossed out with the frequency it has been since the organism and vector were recognized decades ago because the symptoms are so varied, and so difficult (almost impossible) to differentiate from other neurological conditions. In this context, I must say that I find the glossy ads for Marquis hard to take, and the overall tendency of discussion misleading.
Meantime-- I am very, very glad that so many whose horses show terrifying neurological symptoms do recover under various forms of treatment, but, also I want to urge every horse owner who loses this dreadful battle to have a necropsy done and shared with as many people as possible in an ongoing effort to improve, our knowledge of when we are in fact ādealing w/ EPM,ā vs. other conditions with which it can share symptoms.
