Streptococcus equi

By Patty Wilber

A while back, I sent a horse home with lethargy, a snotty nose, and swollen lymph nodes.  Some of those nodes eventually burst and drained (gross), and that is typical of the disease, strangles.  Strangles killed the red pony in a novel of the same name by John Steinbeck. Fortunately, most horses have much milder cases and recover completely.

Lymph nodes that are draining. Ew. Reminds me of dryland distemper, also known as pigeon fever where the muscles of the chest develop large pus-filled abscesses that burst…

In severe cases,  the swollen lymph nodes can impair breathing or even worse, in bastard strangles, abscesses form inside the body, which can be fatal. Another rare complication is purpura hemorrhagica. “This condition causes bleeding from the capillaries and fluid accumulation (oedema) in and around the limbs and the head.”

Strangles is caused by a bacterial speciesStreptococcus equi.  In humans, strep throat is caused by a related species, Streptococcus pyogenes. Luckily humans rarely get Streptococcus equi!

Antibiotics are generally prescribed for strep throat in humans, but unless a horse is really really ill, antibiotics are not given for strangles in horses. In fact, giving antibiotics is a bit controversial because it is said that antibiotics could drive the strangles to move into the body (bastard strangles), forming dangerous internal abscesses. Bastard strangles occurs in about 1% of cases. Antibiotics can also prevent development of immunity, so horses that were given antibiotics may be susceptible to reinfection.  About 75% of animals that recover naturally have immunity for up to 5 years. That will be nice.

The disease is quite contagious and can persist in water and soil for up to four weeks.  Even though I removed the first infected horse from the premises, isolated future infected horses, did not share bridles, and bleached all my water tanks, it was too late, it seemed to have gotten into the soil and thus moved through the herd. There is a vaccine for the disease, but this is the first time I’ve had it here, and now we will have up to five years of immunity, so I will be skipping the vaccine.

The symptoms of strangles:

  • Thick nasal discharge, from both nostrils.
  • Swollen lymph nodes around the horse’s head.
  • Abscesses on lymph nodes.
  • Trouble swallowing and loss of appetite.
  • Difficulty breathing (hence the name ‘strangles’)
  • A cough.
  • Dullness and depression associated with fever.

Luna was the next victim.  The ONLY symptom she had was dullness and depression associated with fever.  She felt lousy and did not want to eat for about five days.  We did put her on antibiotics on the advice of our vet.

The Daytona had a snotty nose and fever, and that’s all.  She also went home, where the fever lasted one day and the snotty nose three days. She seemed to feel fine. No swollen glands.  No cough.

LT showed symptoms a day after Daytona.  Snotty nose and a bit of lethargy for a few days.  No swollen glands. No cough.

Gino had a snotty nose for about two days, and perhaps a bit of a swollen gland in his neck a week later, except he also seemed to have been bitten there, so the cause of the neck thing is unclear.  It did not affect his mood and did not last long.

Then we had a break for a few days, and I thought the remaining three had evaded it, but Gette’s neck swelled up on one side.  There was no snot or cough, and the neck swelling went away.  I figured she’d gotten air in her guttural pouch somehow, but no.  On came the snot for two days, but there was far more out of the nostril on the side where the swelling had been and it’s supposed to be bilaterally snotty.  No cough.

The most recent was Cometa, who is usually more prone to respiratory infections than any of my other horses.  A snotty nose is all he got.

Penny lives with Cometa, and since my previous tries at preventing spread were clearly ineffective, I figure she is going to get it no matter what.  Or maybe she already had a case so mild it was unnoticeable. Or maybe she has immunity.  At any rate, we are nearly through, and should all be fine, just in time for hunt camp!


Cancer Treatment Update. No new symptoms from the shot, and  I feel a lot stronger than I did mid-summer!

Happy Friday!


About BlogPatty

Here's the skinny: I have a thing for horses. They make sense to me. I have a small horse training business (it's a "boutique" training business, not because it's super fancy, but because the horses get a lot of personal attention). I also go by Dr. Wilber, and teach biology full-time at a Central New Mexico Community college.
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6 Responses to Streptococcus equi

  1. Colleen says:

    Wow Patty, what a rough way to keep learning about microbiology. . Glad everyone is fine and you too.

  2. Doranna says:

    May I just say… Ewww…

  3. Sharon Eastman says:

    I am surprised to learn that it is not common practice anymore to inoculate against strangles – we always did, and never had a case in sixty years, even when we had five equines. (Usually had a mule for the mountains.) I have seen cases, and pigeon fever as well – nasty!

    • Patricia G. Wilber says:

      I had one case of pigeon fever in one horse a long time ago. Yes, that is gross, too. I actually have not been offered a strangles vaccine for my equines, but I hadn’t asked for it either, in years…Guess I am sorry now!

  4. Deb Benenson says:

    Patty! Lordy…so very sorry you have been going through this!!!

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