Posted 10-20-2003 at 11:36:08
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Have the vets check the horse Pigeon Fever, aka Dryland Distemper. We're currently in an outbreak of it in our area. Friends who ranch in New Mexico say it is common in their state, although this is the first time I've run into it. Our vet has seen it in years past in this area though.
My 23 year old gelding has had it for months now. The disease has nothing to do with pigeons. Rather, the swollen appearance of the horse's chest suggests the normal appearance of a pigeon's chest, hence the name.
The infection follows the pathways of the lymphatic system in the horse and results in deep abscesses. Although the swelling is most commonly seen in the chest, it can also be in the legs or other parts of the body. Antibiotics seem to prolong the progress of the disease, although we chose to try them. If I had it to do over again, I wouldn't have tried the antibiotics.
Lancing the abscesses if and when they are ready to be lanced, can help get the horse over the disease, but good old tincture of time is really about all that can be done.
The disease is thought to be spread by flies and possibly other flying insects, but that is not known for sure. The drainage from the abscesses is extremely contagious, thus we isolated our horse from the rest of our horses, in case his abscess broke. The catch 22 is that if flies spread the disease, then they could have flown from our horse to where our other horses reside. Friends who have had this disease have had it spread to all of their horses when they didn't isolate the infected horse. So far, my older horse is the only one with it, and he has lived for the summer in a portable pen up closer to the house. The exudate from the abscesses is extremely smelly, too, which gives a clue as to what's going on. It is recommended that when an abscess is lanced that a bucket be used to catch and dispose of the drainage.
The bacterium lives in the soil and the infections seem to show up more in dry, droughty years.
Most cases are of the external variety, although occasionally the disease does show up internally. When that happens the prognosis isn't as good.
The large amount of swelling in my horse tends to come and go now. The vet said the horse could still have abscesses in his chest, but he could also just have a temporary blockage of the lymphatic system. He said although one would think the lymphatic system would drain downward toward the heart, in a horse it actually drains upward toward the heart in the chest area and can easily become blocked from swelling.
Here's an excerpt from an article found during a google search for pigeon fever:
"One of the most commonly diagnosed bacterial problems in California (and several other western states) is dryland distemper, otherwise known as pigeon fever.
This disease is caused by Corynebacterium pseudotuberculosis and is seen worldwide. It usually is associated with very deep abscesses and multiple sores along the chest and midline."
Fortunately, my horse is doing very well, even though he still has swelling. He's out on a leased pasture with our cows and happy as a clam.
I hope this helps.