Here we are back at the story of our little horse that was vigorous and strong only 3 weeks ago and now looks like it has lost 300 lbs, has a severe anemia in which the owner has given one blood transfusion, and has a fever that is on again and off again and has spiked now to 109.5! That is not a typo – the horse’s temperature was at 109.5 degrees during the day when the outside temp was near 90. Bathing the horse and putting it under fans and giving some Banamine reduced the fever, but that was very scary!
So what happened next. Well my friend who owns this horse being a small animal veterinarain asked me a simple question, can the horse still have immune mediated anemia and have a negative Coombs test. Well I’ll be – a question I did not know the answer to – LOL. So he asked a clinical pathologist, a doctor who specializes in reading blood results and other laboratory tests. He’s the doctor we get on the phone with when all the blood results look screwy and we have no idea what way the blood is directing us. He is the guy that makes sense of it all. So the answer came as a startling yes. The horse can have immune mediated disease and still have a negative Coombs test. OK well then what now?
The clinical pathologist then asked the most important question of them all, the one that solved this mystery. When was the horse last vaccinated and with what? Did it have a strangles vaccine recently? YES, it did have a strangles vaccine at the same time the Coggins test was pulled. Well looking at the results of the blood tests and the signs and symptoms of your horse, he believes the horse has vaccine induced immune mediated anemia. Otherwise known as Streptococcus myositis caused by a reaction to the Strangles vaccine. It is much more prevalent in Quarter Horses but can happen in any breed. The theory is if the horse already has a high titer to Strangles and the vaccine is given anyway it sends the immune system into overdrive and causes purpura hemorrhagica and results in a immune mediated myositis (muscle inflammation and deterioration).
So that is what I was seeing not a trauma induced bloddy nose but rather purpura hemorrhagica. Also the horse was tying up but the cause was not because of being cast but rather an immune mediated myositis. Here is a picture of what I saw – The picture is from the Merck Veterinary Manual Website -
Notice the nose looking like it was hit with something.
The horse seems to be doing better, however, we are not out of the woods quite yet. He still needs some TLC to get better and as I said before the Rapid Response is helping this horse tremendously. I will keep you posted on the events with this horse, but hopefully this story will help you realize as to how important it is to be informed on your decisions to vaccinate with what and when. It may be more important to not vaccinate for certain diseases as is my opinion with strangles. If you are not in a high risk environment (meaning stabled with a bunch of 2 year old show horses that come and go every weekend) then it is more important to pass on this vaccine. Your horse’s life may depend on not being vaccinated!
