The best way not to contact it is to keep proper hygiene when handling them and their enclosures. I have had herps for 20+ yrs and NEVER gotten sick from any of my herps b/c I keep them very clean and always wash my hands before and after handling any of them.
If you want check out this link : http://www.petstation.com/repsalmo.html
Very good info on how to prevent getting it.