A Medical Heads Up – Strangles Vaccine Complication

This particular “heads up” is not specific to Morgans and, in fact, happened to an old TB that I was recently given. It is, however, pertinent to all horses so I thought I would pass it along.

The old TB mare in question is one that I sold to a family as a starter Hunter-over-Fences horse. She served her purpose well and, per terms of her sale, was given back to me when she needed to retire. She came home about 1 week after I returned home from OKC and has been doing well, at least until this last week.

Because she had been with a group of horses that were traveling to shows throughout the year, she and the others at her previous barn were vaccinated on October 1 with the regular vaccines, including the intranasal Strangles vaccine. When she came to my farm she quickly acclimated and was eating/drinking well; she was full of life. Last week the old owners stopped by to see the mare. I received a phone message later that day from the old trainer saying that the old owners had noticed a large lump about half way down her neck under her mane, and to call her back if it was there. Thinking they were crazy, I went and checked. Sure enough there was a hard bump. Because I don’t regularly groom the horses at home (they just go in and out of the barn, get their nighttime sheets and blankets on…) I hadn’t noticed it.

I called the trainer back to find out what information she had and was blown away by what she told me. Approximately 2 weeks after the vaccinations, 4 of the horses vaccinated that day developed lumps on their necks. At first the trainer and her vet thought is was an allergic reaction to newly purchased feed. When the lumps didn’t go away blood was drawn and sent for analysis. Surprisingly the tests all came back normal. Another vet clinic from the area was called and ultrasounds revealed that the lumps were large abscesses. The abscesses were drained and when the cultures were tested they all came back positive for Strep. Equi, the Strangles bacteria. Her horses were put on antibiotics and are all fine. None of them developed any other sign or symptom of Strangles.

Strangely enough, the morning following my discussion with the old trainer my mare began showing some signs of illness. She was still eating/drinking fine, but she was more lethargic than usual. She just looked like she didn’t feel well. The vet was able to come out to ultrasound her lump, found it to be an abscess and lanced it. The culture also came back as Strep. Equi. My mare is on bute and a massive dose of penicillin but she still feels like crap. Today, however, she does look a little better. Luckily she or the other horses in my barn have not developed any of the typical symptoms of Strangles (salivary gland enlargement/rupture, runny nose, coughing…). I am now using tons of Purell, and changing my clothes and shoes all the times in order to keep it that way.

Many of you who are familiar with the intranasal Strangles vaccine might think this was an error on the part of the Vet administering the vaccines. My vet and I assumed that the vaccinating Vet must have administered IM vaccinations at the same time as the intranasal Strangles vaccines. The Strangles vaccine, although given in the nose, can be spread by the horse’s sneezing the live bacterial vaccine strain onto other surfaces. If the bacterium lands on a surface where an IM vaccine is given (like the horses neck or syringe needle) the Strangles bacteria is introduced into the muscle of the horses. A very nasty abscess then forms (VERY, VERY NASTY!!!!). As it turns out, the vet did not perform IM vaccinations at the same time, ruling out the contamination theory. Somehow the bacteria, which were introduced into the nasal mucosa, likely traveled through the horses’ systems to form the abscesses in their necks.

So I suppose my point is this…Please save yourselves tons of trouble and your horses’ possible pain by being very, very, very careful when getting Strangles vaccines. Although you and your Vet may follow all the precautions, watch for any signs of lumps on your horse’s body and watch for several weeks. The first any of these horses showed any signs was at least one week following the vaccination and my mare did show any signs for at least 3 weeks.

(I guess this is my “Public Service Announcement” for this week!!)

Leave a Reply