One of the yearlings came up with a really gunky eye five/six days ago. A mare later that day. Then another yearling a day later. Followed by a few other horses. Half of the herd has it now. It is not typical runny eyes or seasonal gunk. I had just cleaned their eyes when I took the pictures so there isn't much more than the irritated pink rims to see but the gunk is a bright yellow puss. A lot of tearing. Not much swelling. The horses are masked for minimal fly activity but, not at night. Now today two in my quarantine pasture a few hundred feet away have it. They do not share halters, buckets or the like nor can they touch other horses obviously so its clearly transferred by flies or airborne. So far no one has a fever, no other symptoms. But my yearling filly looks awful today and feels sh*tty too. I have been cleaning eyes 2 or 3 times a day and using Terramycin ointment. (Using ointment in a horse eye is a joke)
Finally called my vet today for an opinion since it just isn't going away. He seems to think that horses cannot get pink eye that spreads like cattle and has never heard of a whole here getting conjunctivitis. Not sure if that is true or not as that's what I've "assumed" it was and treated as such. He said he'd just keep doing what I am doing because he has no idea what else to do. I'm curious if anyone else has seen this before, or pink eye, or has any ideas and I'd really like to know how long it will take to run its course or if I should just start giving penicillin now, might try that on the filly and see if there is any chance it helps. Her eyes look the worst and she clearly feels under the weather today. It doesn't make me happy that this hasn't gotten better, only worse, over the course of the week.
Sorry for the book, pictures attached.