Monday, April 30, 2012

Dawn and I Progress, and Oppressed by Opossums (Redux)

This time last year I had ridden 38 times - this year I've ridden 84 times, even with having Pie and Drifter gone for training where I only rode them two times a week at most  - what a difference having an indoor makes.  Last year this time I'd ridden Pie 14 times, Dawn 9 times, and Red (formerly Drifter) 15 times.  This year so far I've ridden Pie 26 times, Dawn 47 times and Red 11 times.  Pie and Dawn are both now at the new barn, so I can ride them any time I want.  Red is still at the trainer's, so my ride count is still low, but he's been worked by Heather 4 days a week as well.  I feel like I'm finally in a position to make some good progress with my horses.

Dawn and I had another good session today.  We worked on solidifying our walk work, where I was looking to follow her head and then give her a mental release when she was soft.  We quickly worked up to 11 steps in each direction, with lots of rest breaks on a loose rein.  Then we moved up to trot - it took a while for her to find what I wanted, but then we worked in both directions until we got 7 soft steps with my mental release in each direction - it was very good and she felt great.

Pie has been feeling a bit funny lately - the last 10 days or so.  A few stumbles behind, and some abnormal foot placements/leaning when foot picking behind, particularly with the left hind.  But he's feeling good and eating well, and his backing and turning have been pretty good, although he's started "feeling" with his left hind when backing lately - he's searching for where it is.  I recognized some of the symptoms - it looked like it might be EPM (again). He's also been vaccinated lately - 4 way (eastern and western encephalitis, tetanus and flu/rhino), so it's possible he's experiencing some inflammation in reaction to the vaccination - his neck glands were slightly swollen although he never ran a fever or seemed depressed or mopey - this is apparently a not uncommon thing for horses who've had EPM.  So we decided to retest him for EPM, and sure enough he tested pretty strongly positive for strain one - the strain Dawn had - he's had strains 5 and 6 previously.  He's nowhere near as badly off as he was last fall with the other infection, and he isn't feeling as bad as Dawn did with her strain one infection, and he doesn't seem to be getting any worse - I do neuro tests with him (backing, turning and foot placement) before every riding session.  His results on the blood tests were as follows (see the EPM page for details as what this all means):

SAG 1 - 32
SAG 5 - 16
SAG 6 - 4

He's clearly mounting an immune response to strain one, and the strain 5 reaction may be cross-reactivity although we really don't know. Now we're evaluating with the clinician who's conducting the clinical trials (Dr. Ellison) what the best course of action is - it may be that he can mount an effective immune response by himself, or it may be that he needs the help of medication to clear the infection.  We may decide to retest his blood one week after the original test to see if the titers are changing, and in what direction.  All of this is complicated by the fact that I'd really like to take him to the Mark Rashid clinic on June 1, since we missed the clinic last year due to his attack of laminitis . . .

14 comments:

  1. Poor Pie! I hope this bout is mild and brief.

    I'm fighting the opossum battle here too. They are visiting Val's mash pan overnight. I see the tracks every morning.

    I've been washing the pan daily. I always clean the mats. Now I'm doing an evening barn check and removing the pan from the barn. Maybe after a few visits leaving empty handed, they'll move on.

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  2. How frustrating. Hope Pie is developing his own immunity.

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  3. Oh no! I don't suppose there is any way to get away from the oppossums?

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    1. No, they're everywhere. Pie and Dawn have shared no facilities at the new barn - not even water troughs - so we suspect the EPM organism is getting to them through the hay supply - this may have been the case at the old barn too - but different opossums!

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  4. Wow - Kate, you can't seem to catch a break. I sure hope this bout is very mild and easily treated.

    Is this something he will be reactive to with vaccines for the rest of his life?

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    1. Jeni - apparently horses that have had EPM can be more sensitive to vaccinations - even if they are not currently infected with the EPM organism. Vaccination can trigger an inflamatory response - but that would not cause a positive titer for EPM on the peptide antigen test. Our vet's recommendation is to spread out vaccinations as far apart as possible for any horse who's had EPM - that is, don't use the 7-way or even the 5-way - do smaller sets of vaccinations spread apart by a number of weeks. See my reply to your next comment on Pie . . .

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  5. That came out wrong. I know it's not the vacc's that caused the symptoms - it's the compromised immune system from getting the vaccs.

    So does that mean when every his immune system is weakened he will have another reoccurance? Or is this a reinfestation of the organisms?

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    1. Jeni - in Pie's case, he had been infected with the EPM organism - but strain one this time instead of the strains 5 and 6 infections he'd had previously. When he was vaccinated, the stress that put his immune system under caused the infection to "pop" - and he developed real symptoms and a strongly positive titer for strain one. So it's as if he's never had it before as it's a different strain - Dr. Ellison (the researcher) suspects that he may have some partial immunity to strain one as a result of his prior infection with and recovery from strains five and six, as they are after all the same species of organism. That may explain why his symptoms are milder (so far) than what he had last time, and much milder than Dawn's - she was getting worse fast and was significantly uncoordinated - even though strain one is usually more seriously symptomatic that strains five/six.

      Hope that all makes sense.

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  6. Ann... from THE OUTER BANKS of NC....Hope Pie gets to feeling better soon..Prayers for all of you...Just by reading this >Pie knows she is loved

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  7. Hey kate, just catching up. hope pie gets sorted out before your clinic. good luck!

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    1. Jill - I hope he will be - he's starting treatment (again!) tomorrow.

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  8. Thanks Kate! That was a great explanation and makes perfect sense.

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  9. I'm so sorry to hear this. I read all the comments, and I'm still puzzled. It amazes me how all horses don't get this. What is the solution... shoot all the opossums?

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    1. Margaret - it's a disease where a lot of work is still going on to understand it. I've been corresponding with Dr. Ellison, the researcher who developed the new test and treatment, about this issue. It's interesting that Dawn, who developed strain 1 at the new barn, never developed strains 5/6 at the old barn - she may have had a mild case previously and developed immunity. Pie and Red moved to that barn from Montana/Central Minnesota and northwestern Wisconsin, where possums are absent or far less common - and they both developed strain 5/6 after moving to the old barn - they had no immunity. Then Dawn and PIe moved to the new barn and both developed strain 1 - it appears that neither had immunity to that strain.

      There are many, many horses out there who do have EPM who are treated as lazy/unwilling, or diagnosed with lameness or stifle problems. Some horses seem to recover on their own and some progress to disabling (falling down) stages of the disease. Frankly, many people can't tell a lame horse - even a seriously lame horse - if it hits them in the face - until it falls down and then maybe they notice. All the abnormalities my horses developed were relatively minor, but I noticed, and the blood titers showed active EPM infections that were subsequently resolved.

      Possums are widespread, so no hope of eradication. They could be vaccinated with bait, but there's no money to make this happen.

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