The New Mexico Board of Agriculture has imposed a quarantine on the 
movement of livestock in, out and around the state.  Basically, don't 
come in; if you're in, don't leave where you are.
With respect to horses, the disease is a nuisance, but that's about it.  
It's a virus that causes blisters on the tongue and soft tissues of the 
mouth.  The disease is transmitted, for the most part, by biting 
insects.  Incubation is 10 days, the symptoms run for 10-14 days, and the 
horse can be a "carrier" for up to 30 days.
But that's about it.  With all that "stuff" in his mouth, he's not going 
to feel like eating.  The word I've gotten from local vets is that if you 
can just keep them drinking he'll pull through (unless he's really old or 
has other problems).
So -- better safe than sorry.  Much as I hate to say it, don't bring your 
horse here.  We've pretty much written off the summer -- lot's of shows, 
etc., cancelled.  Everyone's holding their breath for the state fair and 
the arabian national show to be held here in Sept.
I don't know what's happening in Arizona.
Best regards,
Mark Thayer
Albuquerque, NM