Yes it is! Heck, a person could even bring it in on their shoes or clothing fergoodnesssake.
Oh, and while we are talking about bad things that can happen, I was talking to a girl who works in another office here who raises quarter horses. She had a mare and foal to both die this past weekend. It seems the mare got that condition we were talking about back when Sharn's mare Sugar was getting ready to foal, where the abdominal wall ruptures.
She said the mare had had 4 foals before with no problems. But the worst part was that the foal died unnecessarily. I don't know if they didn't know that the mare was ready to foal or what, but they had her in a lot with a stallion and when the mother died, the stallion apparently ran the baby nearly to death. The poor little thing got run into the fence and everything else. They said the mare and stallion had been in the same pasture all this time, but still! I didn't want offend her, but it was all I could do to not say "WHAT were you THINKING!!??" The foal was still alive when they found it and the mare. They called the vet and he told him to milk the mare's body to get some colostrum and to start bottle feeding him every 2 hours. They did get some colostrum and gave it to him but he was apparently too stressed and died anyway.
I can't remember what that condition was called, but the vet said that it was nearly always fatal in horses. He said it happened to cows fairly often and they usually get over it, but horses just don't seem to be able to recover.
So sad! So I've been paranoid about that all this week too!
Good grief.