Tuesday, October 25, 2011

News Alert! - Now I Get to Learn About EPM . . .

Several weeks ago, Pie received a thorough neurological evaluation from our vet/chiropractor - I had her out when he seemed (incorrectly) to be over his repeated colic attacks, in the hopes that she could work on his continued body stiffness and lack of free movement.  I also had mentioned that he seemed to be having trouble when I picked his right hind - he didn't want to keep it up, which probably meant that he didn't want to continue weighting his left hind.  And he had several small interference injuries, where he had stepped on the inside of his left hind with his right hind when moving around the pasture, which meant the left hind wasn't getting out of the way quickly enough. When she did the neurological exam - which was very thorough - she found some anomalies in his cranial nerve responses and and also his spinal nerve reflexes - these tests involved using a pen to press on various points on the face to see his responses/reflexes, and running a pen down both sides from poll to tail to see what responses were triggered.  His backing and the tests involving turning in a small circle were pretty normal, but one of his foot placement tests - where the foot is moved to an unusual position to see if the horse moves it back - was highly abnormal - if she placed his left hind behind his right hind, he would just stand there for a very long time - I had noticed this before and in fact one time he actually caught his left hind behind his right hind and had a lot of difficulty disentangling himself.  She did only a little chiro work on him - to make him feel happy about her visit - since she thought it wasn't a chiro problem and I would just be wasting my money.

She suspected the early stages of EPM - here's a site with a lot of good information about it - and sent blood off for the new, much more accurate ELISA test that's in clinical trials - here's some information about the test and new treatment.  And it came back positive for all three antigen strains that occur in horses, but the positive numbers were only just into the range of likely active infection, and then we were off to U. Wisconsin to deal with Pie's repeated colic attacks.  I decided to wait until his liver enzyme numbers were pretty much back to normal in order to do a retest - one of the clearest signs of active EPM infection is a significant increase in the titer - a doubling or more.

I did a post a while ago about EPM, and the new test and treatment protocol that are in clinical trials.  EPM is a disease which horses get by consuming hay or grass, or drinking water, that are contaminated by the urine or feces of infected opossums.  Horses do not show clinical signs until the organism passes the blood/brain barrier, when it infects the central nervous system.  Some horses are exposed and never become infected.  Until recently, the only definitive test for it has been a spinal tap, and many horses have developed severe symptoms - falling, tripping, severe gait abnormalities, muscle wasting and/or difficulty chewing and swallowing - before being diagnosed.  There are other diseases/conditions that can cause similar neurological symptoms.  The older tests, other than the spinal tap, could not distinguish between exposure and active infection.  Until recently, there were few available treatments, and the most recent approved treatment that was available is very expensive and possibly not effective against all strains of EPM that infect horses.

I had our vet/chiropractor come back about two weeks after Pie's previous test to retest him - his liver enzymes had normalized.  In the interim, he had gotten better about picking up his right hind, but now the right front was a big problem for him - he clearly didn't want to stand with that foot off the ground.  When she evaluated Pie again, his hind foot placement tests were now abnormal for both hinds. And I had asked her to do some chiropractic work on Drifter - he'd started feeling "funky" behind - not off, precisely, but as if the "push" wasn't quite there.  I suspected the left hind based on how it felt and rode.  It was very subtle, but something wasn't quite right.  We observed him trotting at liberty in the paddock, and as I suspected, it was the left hind.  It was so subtle that it didn't even qualify as "off" and certainly not as lame, but it was there - he would bring the left hind forward normally, but then the backwards push was just slightly weak - that's what I'd been feeling.  She did a full neurological exam on him, and everything was normal, except for his backing - he tended to drag his toes behind (in fact he does this sometimes when moving forwards), and his hind foot placement test - he had difficulty correcting incorrect foot placement with both hinds.  We decided to send his blood in for the EPM test - the signs were very subtle but he clearly had no soft tissue issues going - no swelling or heat and the "offness" was extremely subtle - and his recent hock x-rays were completely normal.  As with Pie the last time she visited, she didn't do a full chiro treatment on Drifter as she felt it would have been a waste of time and my money.

Since Dawn was handy, we did a neuro exam on her too, and to quote my vet/chiro, Dawn was "appallingly normal".  So we didn't bother to do a blood test on her.  Opossums are very common in our part of the world - I see them often at night - but so far Dawn seems to have escaped, which is surprising, considering her propensity to strange diseases/conditions.

The results of the blood tests were interesting:  Pie's original results were phenotype SAG1-20, SAG5-20 and SAG6-40.  One, 5 and 6 are the three strains that infect horses.  The SAG6 story is complicated - focus on the SAG1 and 5 results.  Pie's second test - about two weeks later - SAG1-8,  SAG5-40 and SAG6-40.  Drifter's only results:  SAG1- 4, SAG5-40 and SAG6-40.  The cutoff for active infections is 16, and a doubling of a titer between two tests two to four weeks apart is highly indicative of an active infection.

Both Pie and Drifter have active EPM infections with strain 5, and Pie's is accelerating as shown by the doubling of the strain 5 titer.  If Pie was exposed to strain 1 - this may even have happened before I got him - he may have cleared the infection on his own as shown by the reduced titer - this is good news as strain 1 tends to have the worst symptoms.

The good news is that both horses can be treated, using the new trial treatments - which have very low toxicity and have produced good results in almost 200 horses so far - and the results of treatment should be to clear all infection.  I'll be calling the pharmacy tomorrow to confirm the orders our vet/chiro called in today, and we'll be off on our treatment path.  Drifter will get the trial 10-day paste treatment of Oroquin-10 followed by a 90-day feed treatment as a follow-up.  Oroquin-10 is a compound of a higher dose of decoquinate plus an immune stimulant. Because we're concerned that Pie's immune system may already be somewhat compromised as evidenced by his reaction to his vaccinations and the lumps in his abdomen, which may be enlarged lymph nodes, he'll be on only the 90-day treatment - decoquinate without the immune stimulant - where the medicine is added to his feed.

With the benefit of hindsight, some of Pie's other symptoms/behaviors may be related to EPM as well - his constant yawning and moving his jaw from side to side, the odd gulping noises he would make from time to time - effects on chewing and swallowing are common with EPM - his sluggishness and reluctance to move freely, and some recent head shaking and head rubbing that may indicate head discomfort.  We're hoping, perhaps against hope, that his digestive problems and the abdominal lumps may be related to his immune response to EPM and not to something more sinister, but only time will tell with that.

When they're in treatment, I can keep riding both Pie and Drifter provided they don't show dangerous gait or balance abnormalities.  I'm to avoid any steep hills either up or down, and also any cantering - it's a faster gait and there are times when only one foot on the ground, so in a horse with potential limb weakness or balance issues, cantering is inadvisable.  I have to be especially careful at certain periods in their treatment when symptoms may worsen due to the organisms being killed off - days 3 to 5 for Drifter and starting at about day 14 for Pie - and should probably avoid riding them at that time.

Sometimes I feel that my karma is to learn about lots of horse diseases, perhaps as punishment for my not having gone to vet school . . .


31 comments:

  1. Wow - this is quite a lot for you to digest. I'm so glad the prognosis is good, and that it may account for Pie's colic like problems too. Here's hoping. The new tests and trial treatment sound like a God send. Thanks for writing about them.

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  2. Oh geez, at least you know for sure now, right? I'll keep my fingers crossed for your boys that they give EPM the heave-ho and end up as good as new.

    I don't know about the karma about not going to vet school, but I at least know a lot more now about EPM than I did 15 minutes ago.

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  3. Holy cow that's a lot of stuff. I'm glad you have a definitive answer on that stuff. Sure hope it clears up Pie's digestive issues too.

    Prayers for you that the treatments work as hoped.

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  4. Amazing. I would be good if the treatment fixed all of Pie's other issues as well.

    I only knew of one horse with EPM that underwent the older treatment. This new protocol sounds so much more promising.

    Wishing you all the best on this one. I do have to admire your medical detective skills. You simply do not give up when something is wrong with one of your horses. Well done.

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  5. I had no idea about EPM. I am glad that you have discovered what has been bothering Pie and that there is treatment for him and Drifter. Best wishes for a speedy recovery for both of them.

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  6. That's how I've felt with Lilly too... I've learned more about horse diseases and problems since owning her than I ever have before. I also decided not to go to vet school.

    I hope the treatment works well and both horses are free from organisms soon!

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  7. Please consider joining the Yahoo EPM Group. Those women are ON TOP OF IT. They can tell you what works and what doesn't. Sadly, vets are only human and can only look into certain diseases so deeply before they have to specialize. Good luck. This disease is a tough one though the advancements sound wonderful. You can find the link for the list and much more info here: http://www.meadowherbs.com/index.htm. Patti's Moose is a recovered EPM'er.

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  8. Wow...I've never heard of this until reading your posts. This is so scary - it just goes to show how vulnerable our animals are to environmental issues we have not control over. I'm so glad to hear that there is an effective treatment. It will be very interesting to see if Pie's digestive issues clear up. I'm betting they will.

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  9. Kate...your attention to details involving your horses will probably make such a difference in the outcome. You are a great resource for all of us. Thank you for sharing what you have learned. I hope that Pie and Drifter do will with their treatments. I'm sure you will keep us posted.

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  10. Your comment about not going to vet school made me smile. I'm with you on that one. I'm glad there is a promising treatment. I don't know much about the disease -- or didn't until reading your post. It was very interesting. You explain things so well.

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  11. Kate, you are not being punished...although every horse owner feels like that at some point, I swear:) EPM scares the bejesus out of me, but it sounds like you have a great handle on things so far. You know your horses so well. Best of luck. You WILL learn a lot:)

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  12. I too feel that I know way too much about equine illnesses.

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  13. good grief! I hate to say it , because you don't deserve this, but awful glad they are your horses ! they couldn't be in better care!

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  14. It's certainly not the best news, but what a relief it must be to finally have some kind of answers about Pie! And it's treatable, YAY!

    I'll be interested to learn if any other horses at the barn show signs.

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  15. A lot to go through, Kate, but at least you know and it's treatable. As for Pie's digestive problems -- you know, I would say it's like car problems -- coincidences are extremely rare. Usually, if you see two problems happening, they are usually caused by the same underlying problem. I would expect that is most likely the case with Pie too, especially since it all hit at about the same time, but I will keep my fingers crossed for you!

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  16. Sounds like you may have finally found whats wrong with Pie!
    It sounds like your learning heaps and I'm glad you've found the problem.

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  17. Rebecca - thanks for the tip!

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  18. That's a lot for you to deal with Kate, it never rains but it pours! It does seem likely that Pie's other problems are related, so hopefully he'll recover now that you have a treatment plan. I didn't know anything about EPM until now, but I'm with you on knowing far too much about equine diseases and injuries!

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  19. It sounds as if you're on the right road to getting Pie back to normal. And Drifter too. I'm glad you finally found out what was wrong and how to help them. Amazing how fragile they are and how many diseases they can pick up from other animals. Good luck with both horses, I'm sure with their treatments they'll be feeling much better in no time.

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  20. You are certainly are learning a lot about a lot of things, and sharing those lessons with us. I am just sorry that you are learning from issues and discomfort for your horses. Thank you for spreading your knowledge. I bet all your readers will be testing their horses ability to right their hind quarters today.
    Wishing you and yours all the best. Pie and Drifter and lucky to have such a caring human.

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  21. Jeez Kate. You are doing a great job, but it is still a bummer. I had one horse diagnosed with EPM maybe fifteen years ago. As you say, the tests were not accurate then, nor was the treatment all that effective. This same horse was diagnosed elsewhere with a "strained sacroiliac joint." I never knew which diagnosis to believe. I did treat this horse for EPM, but as you say, the treatment at that time wasn't always effective, and it certainly wasn't on him. We still have him, he's been a pasture pet for fifteen years--pain free but moves with some degree of incoordination. I wish I had been able to diagnose and treat him as you are doing for Pie and Drift. Sounds like their prognosis is very promising. But still, a lot for you to deal with. Horses can be very frustrating. Sending you good wishes.

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  22. I am really amazed at this... sounds like a bit of late night possum hunting is in order? You think this would be common - and should have been figured out before now... You are educating us all and I thank you for taking all this time documenting your experience. I truly hope the new treatment is a cure-all.

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  23. WOw so much going on. Its sad to hear that Pie and Drifter are exhibiting EPM, but I am VERY happy to hear that they are treatable. I learned quite a lot (as I always do) from this blog post too. While opposums are not common in my area, its another good awareness to have as it seems I have been hearing a lot of EPM lately. WIshing you and your horses the best.

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  24. Wow! I have heard of EPM before, but I never gave it much thought and really did not know what it is. At least treatment looks more promising now! I hope Pie and Drifter recover completely!

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  25. I am glad to hear that it's so treatable and I hope everyone recovers quickly!

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  26. Oh goodness. It does sound serious, but the treatment sounds hopeful. I think you deserve an honorary DVM degree after this.

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  27. Interesting! Sure makes me glad we dont have Opposums up here.

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  28. Just wanted to say we will be thinking about you and Pie and Drifter. The new treatment sounds promising. I heard about it from my vet and I hope that is all the knowledege I ever need to gain on the subject . . .

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  29. Boy, I don't check on you for a week and things go crazy!

    Seriously though, I'm glad treatments have advanced for EPM. Sounds like a long road, but one with a good chance of success.

    Is there any way to treat water or pastures to prevent reinfections?

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  30. Breathe - theoretically, it would be possible to "vaccinate" opossums by leaving feed out for them with decoquinate in it, but as far as I know no one's tried it.

    Also, the hope is that the immune system stimulant that's in the Oroquin-10 plus the 90-day add on feed treatment will give treated horses long-term resistance to all the strains of EPM - this is not proven yet. But if your horse has only certain strains - like Drifter who appears to have strain 5 but not strain 1 - it would be possible for him to get the other strain at a later time. There's no practical way to avoid exposure to opossums in our part of the world.

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  31. wow..so interesting. I'm wishing you the best of luck in the upcoming days of testing and treating.
    I hear you on learning through experience....I think it's b/c you are so open to seeing signs so many people miss/ignore

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