Before we get to why I feel like I may have been an idiot, some very good news about Dawn and Pie. They both recently had EPM follow-up blood tests after completion of their 100 days of treatment. Both horses have been completely symptom free for a long time, so I wasn't expecting anything but good news, and that's what we got. Both horses had essentially zero titers to all three strains of EPM (1, 5 and 6) that affect horses, meaning that the treatment was effective and they have cleared the EPM organisms, with no residual effects. (But note that some symptomatic horses can apparently have low titers if their immune systems aren't responding normally - this isn't the case with Pie and Dawn because they are not symptomatic.) The hope is that the treatment they received - the one that's in clinical trials - will also cause them to have residual immunity to the strains they were infected with - here's hoping. See the EPM page for all the details of the illnesses, symptoms and treatments.
But now on to why I feel like I may have been an idiot . . .
Here's the timeline - Red had EPM at the old barn (one strain), and was treated and made a prompt and full recovery. (See the EPM page for all the details.) Dawn and Pie moved to the new barn - not at the same time - and both promptly, within weeks, developed EPM - Dawn for the first time and Pie for the second - different strain than he had at the old barn. Both were treated and made full recoveries, which was just confirmed by their blood tests. Red stayed longer up in Wisconsin - he moved to the new barn on June 8, although I'd been feeding the new barn's hay since about June 1 during the clinic. He started low-dose treatment with the same feed top-dressing used as part of the EPM treatment, in order to try to stave off an EPM infection on his move. On June 21, Red took a very bad step with the left hind while cantering on the right lead, and almost fell with me, and showed significant lameness in the left hind after that. This is almost exactly the timing for Dawn and Pie to develop their EPM cases - three weeks after being exposed to the new barn's hay and pastures. A couple of days after his almost fall, Red got kicked in the hock - huge swelling and cellulitis, although oddly enough not any lamer. He had about two months off, and seemed to be getting better - when he wasn't - the lameness in the left hind has been coming and going, although there's been no heat, swelling or tenderness anywhere in the leg. Red finished his 90 days of low-dose feed top dressing at the end of August.
Two days ago, I took him to the outdoor arena for a ride - he had real trouble navigating the steep hill down and was dragging his left hind, and was struggling with the somewhat deep footing in the outdoor. Hmm . . . And his left hind seems to be easily fatigued in general, and after I ride, he drags the left hind toe. Hmm . . . My regular vet was very distracted by the kick injury and was sure there was hock damage. I was thinking hock arthritis because of the lack of any signs of continuing soft tissue injury. My vet/chiro (who is also an expert on EPM and the new test/treatment protocol, having diagnosed and treated many horses with EPM, both using the old treatments and the new test and treatment that are in clinical trials) was sure he had strained his Achilles tendon and also possibly his sesamoid ligament in the left hind. These things may have been part of what was going on, but none of us were thinking about EPM, since Red had been on the low-dose medicine against EPM.
Today, I thought about EPM in connection with Red's on again off again lameness and the toe dragging, which seems to be getting worse. There is some evidence that the low-dose treatment may not be enough to fully treat some horses for EPM (some people have tried this to save money rather than using the 10-day paste treatment followed by the 90 day feed top dressing). It's possible that it may not have been enough to prevent Red from getting infected. So I did some neuro checks yesterday on Red - remember I am not a vet, I'm just an informed amateur. Bingo! Extremely abnormal left hind foot placement test - I could put it wherever I wanted, even behind the right hind, and he would just leave it there - it was pretty clear he had no idea where it was. It's no wonder the poor guy tripped and almost fell, and has had trouble coming back from his (supposed and actual) hind leg injury - EPM horses often injure themselves repeatedly because they don't know where a leg or legs are. He's also been having trouble picking up the left front for hoof picking - trouble or reluctance to pick up a leg on hoof picking is one symptom I've seen in all my horses, and often it's a different leg from the one most affected - it seems to be a balance issue. On the turning test, he did cross over properly in both directions, but the left hind wasn't as active and didn't cross nearly as far. On backing, the left hind wasn't lifting as well and the toe tended to catch. He was just slightly dragging the left hind toe when walking.
My vet/chiro is coming on Saturday morning to do a full neuro test on Red and draw blood for both an EPM and Lyme blood test. Based on the neuro results I had today, I'd be surprised if the blood tests don't show something. If it isn't either of those, then we can deal with it as a mechanical lameness issue, but I have a suspicion that there's something else going on. I feel like an idiot - but at least one who listens to her horse (eventually - sometimes I'm slow on the uptake) . . .