EPM
May 7, 2009
Equine protozoal myeloencephalitis is a heartbreaking disease.
EPM left a hand sized dip in this successful barrel racer's face.
By Becky Newell in America’s Horse
Equine protozoal myeloencephalitis is a neurological disease caused by a tiny parasite. Opossums carry the parasite, and horses contract the disease by eating feed or drinking water contaminated by opossum feces.
EPM is characterized by the three A’s: Asymmetrical ataxia (incoordination) with or without muscle atrophy (degeneration).
Signs of EPM
- Incoordination (ataxia): stiff, stilted movements (spasticity); abnormal gait or lameness.
- Incoordination and weakness that worsens when going up or down slopes or when the head is elevated.
- Muscle atrophy, most noticeable along the topline or in the large muscles of the hindquarters, but sometimes involving the muscles of the face or front limbs.
Since approximately 50 percent of U.S. horses have been exposed to the organism responsible for EPM, it is extremely important to know the signs of infection. Early detection and treatment are key to recovery. Download The Racing Journal’s FREE EPM report to start protecting your horse.
- Paralysis of muscles of the eyes, face or front limbs.
- Difficulty swallowing.
- Seizures or collapse.
- Abnormal sweating.
- Loss of sensation along the face, neck or body.
- Head tilt with poor balance; horse may assume a splay-footed stance or lean against stall walls for support.
Preventing EPM
- Keep feed rooms and feed containers closed and sealed.
- Use feeders that minimize spillage and are difficult for wild animals to get into.
- Clean up any dropped grain immediately to discourage birds and other scavengers.
- Feed heat-treated cereal grains and extruded feeds.
- Keep water tanks clean and filled with clean, fresh water.
- Maximize your horse’s health and fitness through proper nutrition, regular exercise and routine deworming and immunizations.
- Schedule regular appointments with your equine veterinarian.
To reduce your horse’s risk of contracting this disease, you must take preventative measures. Download The Racing Journal’s FREE EPM report for more important tips to prevent exposure to the organism that causes equine protozoal myeloencephalitis.
Treating EPM
In July 2001, the U.S. Food and Drug Administration approved Marquis, an oral paste that was the first medication developed specifically for the treatment of EPM in the United States. Marquis is manufactured by AQHA Corporate Partner Bayer Animal Health and is an FDA-approved EPM treatment.
Marquis is given to a horse once a day for 28 days. Although most horses respond favorably, drug treatment is not a guarantee for 100 percent improvement. The parasite behind EPM causes damage to the brain and/or spinal cord, so even though it may be out of the horse’s body, some of the damage done may be permanent.
It’s also possible that horses can experience relapses of the disease and even be reinfected. Unless the horse’s environment is drastically changed, there will be continued exposure to the parasite. The sooner you treat a horse that’s showing signs of EPM, the better the chances of a positive outcome.
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6 Comments on “EPM”
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May 15th, 2009 at 6:38 pm
Hi just thought I would like to say, that I have a 9 year old quarter horse that had EPM last October, and was treated with Marquis and another drug after that. He has made a full recovery. I have just started riding him. I’ve owned him for two years now, and he has never rode so good. The vet figures he had the parasite when I bought him. We moved last spring, and the stress of the move likely brought it on. The more information that can put published the better. A lot of horse people have never heard of the disease.
Tammy Clayton, Ontario
October 31st, 2009 at 8:24 pm
Tammy, I’d heard of it, but I didn’t know much about it until
my 5 year old gelding was diagnosed(tentatively) with it last week.
We’re still waiting for the the blood work to come back from Kentucky.
I’m praying it’s not EPM, but he has the clinical signs. Drags his hind end, toes dragging and part of the hoof wall (outer skin)
is peeling off. So far no signs in the face or neck. I should get results back this week.
November 8th, 2009 at 11:17 am
I have a 9 year old gelding that I used for barrel racing, and he started showing lameness early this year, so the vet injected his hocks and stifles, may 22, when he wasnt fully recovered , I took him back jule 8, when it was suggested a epm blood test . the test was neg, and only 1.20 on exposure, so we turned him out.At that time no active disease was present so I did,t go thru the expense of medication. It was suggested but not strongly recommended.
3rd week of Oct , another vet gave him dex for inflammation in his stifles, and within 5 days he has paralisis on his right side of his face,lip and ear hanging. and eye drooping. I took him off the dex, and his lameness is gone, the eye looks better but the ear and lip, and a little cloudiness in right eye is present. Is it too late for him to get marquis? Is the damage done? He’s eating well and drinking on the left side, and is interested in the mares again, he’s always thought he had a “loaded gun!”
My insurance co, Markel, says I was negligent in NOT treating him back in late July,and if he declines won’t cover the loss… and at this time he’s actually feeling good. Any ideas on whats happening and a course of action?
January 7th, 2010 at 10:18 am
My 7 year old Paint horse, that I own for 1 year now, was diagnosed with EPM 4 weeks ago. Right after I found out, I ordered the Treatment Marquis and started to give it to him right away, now we have one week left of the treatment. On the first week, I saw immediate change with him, he stopped dragging his rear feet and toes, and was eating much better. In the second week he started to run with normal gait, finally. I’am very positive he will do a good recovery. We caught him in stage 1 of the desease. It was pretty hard to figure it out that he had that, because he showed intermittent symptoms. but in my training, I knew something was wrong because he was not improving at all in his work. He had a lot of difficulty with his leads, and it was like he did not know where his hind legs where, and I was asking pretty easy stuff for him to do. Anyway, it was a pretty weird feeling on the horse, it was like he did not have much balance. I tryed to do barrels with him, when I did not know he had the EPM, When I was letting him go at his own speed it was fine, when I started to ask more pressure, everything fell apart. I have not restarted the training, since i’am waiting for the treatment to be over and to give him time to recover afterthat. He his now at rest and goes outside with an old mare, to make sure he has less stress as possible.
January 20th, 2010 at 10:27 pm
In the summer of 2008, my horse, Steele was positive for EPM. We treated him with Navigator for 4 weeks, but he still showed neurologic signs of EPM. We then put him on Marquis for 4 weeks. He made great improvement, and by the end of his dosage of Marquis he seemed to have made great recovery with minimal deficits. The past month (January 2010) we started noticing Steele seemed “off” in his hind end. He is a very sweet dispositioned horse. He started laying his ears back when we put the saddle on him! Then he started stumbling. We took xrays thinking Navicular. I walked out of the tack room to see him standing on the cross-ties with his butt wedged up against a stall door. He was pressing his weight against it so hard I thought he would break it down! The old signs of EPM returned to my mind!!! My vet was still at the barn, so I had her do a blood test for it (they now can test for EPM through a simple blood test – I am told you don’t need the spinal tap like I had to do the first time). The labs compared his reports with his old EPM reports. My vet reviewed the results with the Doctor that treated Steele at our Equine Center; and sure enough, he has EPM again! To my surprise, upon further research today, I have found that 25% of horses infected with EPM can relapse, usually within 18 months. I will be treating Steele again with another round of Marquis. He is only 5 years old; he is beautiful both in disposition and in his looks; and most importantly he is my BABY! We bought him when he was 2 and only halter broke. With LOTS of help, we broke him after his first bout of EPM when he was almost 4. I love him so much, if anyone has more information they can offer to help Steele with a full recovery of this dibilitating disease, I’m open for suggestions!
January 25th, 2010 at 1:45 pm
I have a horse with EPM as well. A very nice barrel horse. He started his treatment and its now been 4 months and we have been getting him legged back up for a couple of weeks. He is doing great. We did a different approach and went with the silverlining herbs. Good luck to us all