Ditto Strangles is more common in younger horses, which is why everyone was shocked my 27 yr old ended up with it. He was a cast iron tough horse, never sick with anything.
Given his good health and that he lived on 40 acres, with my other two horses and the landowner's Black Angus, it was the last thing I expected.
I would imagine a horse getting Strangles at age 27 might be comparable to a human getting a full blown case of the Mumps. Childhood diseases are much more difficult to get thru for an adult
I absolutely had no way to isolate Sonny; amazingly, my other two horses never got Strangles from being exposed to him. One was 25, the other in her early teens.
This happened in 1987 and I am pretty sure I gave Sonny some sort of oral antibiotic. I don't think that is done today if it stays under the jowels. Yes? No?
I also had something medicated to clean him with twice daily.