Mine eat rabbits, groundhogs, voles, barn rats (well, Kharma eats barn rats, the others just bring them and lay them on the porch for me). I keep an eye out on mine, but since they've been on the EVO there's not been a sign of any type of parasites. The only thing that I can explain that with is they seem to be getting what they need to let their bodies resist that kind of thing successfully. If you think about it, wolves and other wild predators don't seem to have problems with parasites.
You should have seen Shiva with her first groundhog. She wasn't sure how to go about eating it, so she brought it and layed down next to where I was sitting in the yard and proceeded to start on it - head first, with the tongue . . . GACK!