Is there a way to prevent your horse from being infected? I'm guessing no, but this kinda scares me!
It is extremely contagious. If a horse comes into contact with an infected horse, or with a bodily fluid (snot, spit, etc) then they can get infected.
Especially if you transport your horse, or have your horses around others who travel, you need to take precautions. The AQHA has some good ideas on their websites. I am lucky enough to live in an area where it is not reported, but if it was, there are a few things I would do.
1. Talk to the local vet about outbreaks and treatment/prevention.
2. Wash ALL of my horse stuff and disinfect it.
3. Always be careful when around other horses, and wash your clothes, hands, and disinfect yourself before interacting with your horse (this especially if they live on separate farms. So if you go ride a friends horse, wash yourself before going back to your farm.)
4. DON'T SHARE TACK OR SUPPLIES!!! It is just not worth it.
5. Put any new horses on the property in solitary confinement for a few weeks to make sure they are not infected, and thus don't spread it.
6. Designate certain tack/supplies for one horse (feed buckets/brushes/stalls), and keep them separate (label them if necessary). That way if one horse gets infected, at least you didn't use the same stuff on the other ones.
7. Know the signs. If any symptoms show up, IMMEDIATELY (this very moment) call the vet.
8. Hold off on shows/community trail rides. Unless, of course, you need to show or that's what you do (higher up competition). But I would be super careful, as the major outbreaks were the result of a show in Utah.