It's a bad one for a facility even though it's not often life threatening, because it doesn't go away. Even with good vaccination regimen, I think it's impossible for a barn to be 100% protected, new horses are always coming in.
I'm amazed at it's ability to live for so long on objects. I had no idea. But the granddaddy of 'em all is Mad Cow Disease. Apparently even fire won't kill it. I read somewhere about them burning the bodies of all the infected cows and saying that even the ASHES were contagious. I'm just glad there's no equine equivalent (that I know of).