STEVE: Strangles infection is caused by a bacteria known as Streptococcus equi. What it normally does in the typical case is that it is taken into the oral mucosa or inspired in, but typically it’s most likely taken in the oral mucosa due to being exposed to the contaminant, usually water, feed tubs, inanimate objects.

This particular bacteria sets up housekeeping in the retropharyngeal lymph nodes in the back of the throat of the horse. Typically, you see signs where these retropharyngeal lymph nodes will go ahead and enlarge and finally will rupture, and they look almost like a chipmunk, almost like they have swelling right below their jaw line, and they’ll go ahead and abscess out there.

If they do not abscess out through the skin there, which they typically don’t always do, you’ll see drainage, where they’ll drain internally in the upper airway, and you’ll see discharge out their nose. This will usually occur somewhere on the order of about four or five days after exposure to an infected case, and you’ll go through this episode for roughly, oh, four or five days until the horse essentially builds up enough of their own immunity. They’ll have a high fever, they’ll have discharge, and they’ll have basically discomfort for a number of days.

What I normally do is we just put them on Bute, and I don’t put them on antibiotics because that can essentially create a bigger problem for you, where it will encapsulate this Streptococcus, create a systemic infection or septicemia, where it disseminates through a lot of other lymphoid tissue throughout the body and creates abscesses that will go ahead and open and drain in the inguinal area, upward of the hips, and down in the chest region, this sort of thing, which is known as bastard strangles. And the reason that term is used is because it has the ability to disseminate and rupture out in other areas that wouldn’t normally cause abscesses.

As a rule, it just is bit of an inconvenience, and it can be extremely contagious to other animals. So what we try to do is we try to isolate that animal and stop it from exposing inanimate objects, to feed tubs, whatnot, water, that that horse would be exposed to in order to keep the infection in check.

What we do have the luxury of, as a combatant to it now, is we do PCR or DNA testing from the discharge in the upper airway, and we’ll go ahead and flush the guttural pouches, which we found that the retropharyngeal lymph nodes tend to be attached right to, and this particular bacteria sets up housekeeping in, and we’ll go ahead and flush that area with a penicillin derivative or gel that stays in there in long term. Then we’ll go ahead and keep flushing it until we do have a clean PCR or that we know that there’s no more DNA from that particular bacteria in the horse. Once we do that, we’d go ahead and expose that horse to other horses again, and it’s no longer a problem.

We used to believe it was in the soil and things of this nature. Now we know that the guttural pouches of the horse, which are analogous to the Eustachian tubes, that’s a big dilation in the upper airway, the horse back in the recesses of their airway. It’s a big pouch that has the capacity of about half a liter in each one of these pouches, to where this bacteria gets in there and sets up housekeeping. Essentially, unless you flush it and get rid of it, it’s going to be there, and it can potentially be a carrier and expose other horses to it for a long time until you address it.

ALEX: How important is it for somebody, if they have more than a few horses, to take a horse like that and get him isolated from the other horses?

STEVE: Oh, it’s paramount. You have to isolate him as soon as you identify one horse, and the biggest problem is, by the time that you’ve recognized it, usually you’ve exposed all of them anyway, as a rule, or you’ve exposed quite a few of them, the horses next to him, because horses tend to be very social, and they’ll touch each other, breathe on each other.

So as soon as you realize that you have one, that horse needs to be isolated as soon as possible to try to minimize infection. Typically, you need to set up typical isolation protocol meaning that that’s the last horse touched or exposed to the people that are working in the barn, and every time you’re around that horse, when you’re done, you need to get out of the way from all the other horses and not touch them or be exposed to them again and clean all your clothes, hands, gloves, jackets, and whatnot in order to stop contamination. That includes your boots and/or clothing or anything that could’ve been exposed to the horse.