Mad cow? Yikes! Guys, blue tongue is EHD. Epizooic hemorragic disease. The black fly or midge, like drstalker said, spreads it. Deer eventually have ruptured tubercles in their lungs, and bleeding from the rectum before death. They also have swollen inflamed mucus membranes, like a swollen mouth and tongue, thus the term blue tongue. They usually are found dead or dying near a water source, unable to drink. In captivity some cases have been known to be reversed, and many guys I know are actually trying to breed deer which have developed a resistance to it with northern deer that havent.

Yes, you could see an outbreak in Illinois. Ohio had some cases a couple years ago, as I recall. It isnt spread by anything you as a hunter does, or by any deer farms. Its all in those flies!