Possums have a natural immunity to rabies, same as squirrels and chipmunks, a good place to look is possumrescue.com. I was also told by animal control and veternarians and the doctors at the hospital the same thing. It would take a 100,000 times the virus to give a possum, squirrell or chipmunk the disease that it takes a fox, raccoon or bat. It is very rare that a possum will get rabies in any area. I live in a high rabies area, and the last 3 rabid raccoons were found on my land.