EPM: A success story

E-P-M… three letters that no horse owner ever wants to hear–but the diagnosis doesn’t have to be a career-ender. Katie Passerotti tells the story of her horse’s journey to full recovery.

From Katie:

EPM  is a frustrating diagnosis. There is a lot that we do know about this disease, but there is still a lot that we don’t know. If you want some great info, I suggest checking out www.epmhorse.org–it has got a lot of great information about EPM and it’s pretty reader-friendly.


There are lots of EPM stories out, and I think that they are slowly turning to more positive outcomes as owners become more knowledgeable and effective treatments continue to be more readily available. I bought my current horse in May of 2007 as an untouched 3-year-old Thoroughbred–he was going to be my event prospect. In August of 2007, I remember noticing that he was dragging his left hind toe, but I didn’t think anything of it. He was actually a pretty lazy and laid-back guy so I figured he was just being lazy. Little did I know that those little protozoa were weaseling their way into my boy’s body.

Diagnosis & Treatment

In September, a vet diagnosed him as having EPM. He had failed all of his “neurological” testing and there was a definite difference between his right and left hips–the left hip was much lower and there was a lack of muscling on that side as well.

We put him on Marquis but didn’t change anything else. He wasn’t in work yet (I was laid up with my own injury so he was still just chillin’ in the pasture) and he wasn’t off, so he still got nightly turnout and we continued his ground education with grooming, cross-tying, getting used to tack and going for walks. He did have a difference in his stride on his left side, but standing in his stall wasn’t going to fix that, so regular turnout it was and he ran, bucked and played with his herd and was happy.  It never got worse; had it gotten worse I would have nixed his turnout privileges.

He was on the Marquis for a month, just one round. Then we played the waiting game. He made noticeable progress once he started on the drug, but we still had the wonky hip. In the spring we tried to start his training as far as having a rider get on and start walking and trotting, but we never made it past lunging. He wasn’t balanced and even enough through his hind end. Finally in June he started to make some real progress. He was moving more evenly and had figured out how to compensate for his lack of muscle on the left. So we started riding him. After only two months under saddle, I had the unfortunate experience of coming off of him and breaking my hip. I didn’t have the money to keep him in training so he moved from my trainer’s to my parents’ where I had a barn and pasture for him to play in.


He didn’t go back into work until February of 2009. I definitely think that our unintentional hiatus was good for him, not only for helping him regenerate what muscle he could on his own, but it also really helped his training–he had the chance to mature. He has stayed in regular training and work since then. It took the rest of the year, but by the spring of 2010, unless you really looked closely you couldn’t tell that he was a little short-strided on his left side. I bought a pair of weighted hind boots and worked him twice a week with the boot on his left leg–it definitely made a difference. We competed successfully in Training and First level dressage that year, including placing in the top 10 at Regionals. I never had a judge comment on him concerning a lack of balance or a shortness of step. We are currently jumping regularly and getting ready for our first Beginner Novice event this spring.

After every successful ride, every jumping milestone (tonight it was our first 2’9” vertical together!), I remember the uncertainty and fear I felt when the vet said those three little letters. I knew nothing about EPM at the time other than the fact that it was spread by possums and that most cases ended with horse being put down or unsound for work. Google became my best friend–I read every article and story I could find and learned a lot. Our future was so uncertain and somehow, by pure luck, we managed to overcome this disease and be successful.  It took a full two-and-a-half years for him to be ready for full work, but it was worth the wait. Today he pushes off evenly from both hind legs, even though if you stand behind him you’ll still see the permanent muscle atrophy his right and left hips. The bones themselves are even (thank you, chiropractor!) but the muscling is not.

Everyone hears about the unhappy endings. Our story has a happy one, Bastian has made a full recovery, and we’re about to take the eventing world by storm! So if you’re facing EPM, stay strong and be patient. It is very possible for your horse to make a full recovery from this harmful parasite and to go on and have a happy and successful career.

Photo: Used with permission from Casual Creations Photography.

Read more about Katie and her adventures with Bastian at her blog.

Lead photo: Used with permission from WNC Photography.

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