Two horses grazing in a green grassy field. Darker horse in the forground. And a lighter colored brown horse in the background.


Hello everyone! I hope y’all are havin’ a nice week, and if not, well, I hope it gets better!

We’re going to continue on our medical discourse today, because I’m off on a tangent now, and there’s nothing worse than Katie off on a tangent. What now, you ask? Equine infectious anemia. A little easier to pronounce than last week’s disease, but we’ll settle for EIA, because it’s kind of difficult to type.

Equine infectious anemia can also be called swamp fever, or, the most well-known title, strangles. This stuff is nasty, moreso than EPM, in my humble opinion, because it’s highly contagious. Blood, saliva, milk, and waste can pass this disease on to other horses, and we’ll talk about how to — hopefully — minimize the spread of it later on. For now, I want to talk about what it does, and what it looks like when your horse has it.

Strangles is basically the HIV of the horse world, and has several stages: acute, which means the very sudden onset of symptoms, and sudden death, subacute, which is a much slower progression, and chronic, which means that the horse has exhibited symptoms in the past, but is seemingly “cured’ at present. The horse then may relapse into acute or subacute forms years after the disease initially presented itself. Symptoms of EIA are as follows:


– High fever

– Anemia, or the breakdown of red blood cells

– General weakness

– Swelling of lower abdomen and legs

– Weak pulse

– Irregular heartbeat

– Sudden death


– Recurrent fever

– Weight loss

– Enlarged spleen (can be determined through a rectal exam by your vet)

– Anemia

– Swelling of lower chest

– Swelling of abdominal wall,

– Swelling of legs

Strangles was the entire reason that the Coggins test was developed by Dr. Leroy Coggins in the 1970’s, and it’s still very effective to this day. So get your horses tested on an annual basis, guys!

The reason I say that is because the disease is transmitted by biting flies, like horse flies and deer flies. It’s also for this reason that it’s very preventable — the incidence of strangles outbreaks in the US has been very low –, so you should remember to spray your horses daily for flies during the seasons where they’re out in force in your area.

As the rules stand, the lab that tests your horse for EIA is required by law to report infected horses to federal authorities, because once the horse has it, it has it for life — see? HIV of the horse world. If your horse tests positive for strangles, there aren’t many options:

Quarantining the horse away from others for the rest of its life, sending it to a research facility, or euthanizing it. Personally, I would rather put the animal to sleep than see it suffer from recurrent symptoms or a painful death, but it is a personal decision for each owner.

Because the risk of getting this disease is so low if the correct prevention and sanitation procedures are followed, hopefully none of you lovely horse owners will have to face any of that horribleness.

Remember to spend time with your horses every day if you can, and kiss them on the nose, but remember foremost to observe them, and learn how they interact, because only when you understand the way horses think will you be able to understand how to truly work with them.

See you next week, readers!

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