Best thing to do when coming back from a show/pet shop is before you even go near your animals change your clothes and take a nice long shower. That should eliminate just about any risk of bringing something unwanted home from the show. While you're at the show make sure that you use hand sanitizer (most vendors worth their crap should have some on their table) anytime you pick up an animal and that will reduce the risk also.
one time i told someone i undressed in the car and ran to the house naked.