[CindyDawg]

Yeah. I'm waiting for the vet to open. You might get more than a sick horse if your mare in that pasture:') Seriously, Okie had no contact with the first sick horse. If it's airborne there isn't much you can do I guess. I thought this had about run it's course and over and it was looking like the mares spared. Then it was really windy last week and it's starting up again.

[HairOfTheDog]

It's contageous through even indirect contact... even using the same tack or brushes... or hands.

Epidemiology
Strangles is very contagious, especially with foals, spreading easily from horse to horse and often leading to large outbreaks with many horses affected. It is spread in the discharges (pus) from the nose and burst abscesses. Objects such as water troughs, feed buckets, brushes, reins and other equipment, if contaminated with infected pus, can also spread the disease. Recovered horses can spread the disease for up to eight months, even though they can appear clinically healthy and normal.

Strangles Information Page