I was filling out the questionnaires for the EPM group on Yahoo, and it was interesting to see a list of the various symptoms Pie, Red and Dawn have had in their bouts with EPM.
Pie's case is most complicated, as he's now had two separate infections, first with antigen strains 5/6 and then with antigen strain 1. Dawn only had strain 1 and Red only had strains 5/6. Strain 1 is purportedly more serious, and Dawn certainly had a serious case in a very short time - she was a bit wobbly both in front and in back - all my other cases only affected the hind legs. Pie's strain 1 case wasn't as bad symptom-wise, but that might be because he'd earlier had an infection with strains 5/6.
Some symptoms were common to all three horses and some were different. All four cases were diagnosed after neurological exams and ELIZA peptide antigen tests. Here's my summary:
Pie, strain 5/6: head shaking, head pressing; tongue lolling, frequent yawning and some "gulping" noises while swallowing; swollen glands in throat; heat intolerance; body soreness; strong reluctance to move forward; gait abnormalities - little impulsion and toe dragging/tripping/catching with left hind; difficulty backing normally; felt off at trot; very difficult to pick feet; chronic resolving colic - he would have severe pain, lie down and groan and then would be OK after about a half hour - this went on for several weeks and was diagnosed at U Wisconsin with abdominal "lumps" that may have been inflamed lymph nodes - they did not suspect EPM. He may have had this for a while before we caught it.
Red, strain 5/6: extreme reluctance to move forward and irregular gait, left hind most affected - toe dragging and short striding; very difficult to pick feet.
Dawn, strain 1: swollen glands in throat; gait and balance abnormalities - tripping, odd steps, little impulsion, foot dragging - particularly left hind; felt wallowing and fronts also affected as well as backs - stopped riding because she was so unsteady.
Pie, strain 1: swollen glands in throat; gait and balance abnormalities - tripping, odd steps, little impulsion, foot dragging behind, difficulty backing, trouble going downhill.
So far, treatment with Oroquin-10 (levamisole plus decoquinate) plus the 90-day decoquinate feed top dressing, seems to have fixed our problems and all horses are currently doing well. Dawn is at about day 30 in her treatment for strain 1 and is doing well, although I have to careful not to overdo as her deficits were pretty extensive after a short period of infection. Pie is on day 6 of treatment for strain one, and is walking under saddle and doing well - we're not ready to trot yet but we'll get there.
I must say this EPM experience has been interesting, although I would have preferred to have avoided it!