Raccoons do not hibernate in winter though they remain in their dens more, only coming out to forage for an hour or so each day. During spells of bitter cold or extremely harsh conditions, raccoons do not venture out of the den at all, burning calories from the extra weight they put on in the fall until the weather becomes more agreeable. The two illnesses most commonly associated with raccoons are distemper and rabies. Rabies, unfortunately, occurs in the eastern U.S., having spread as far west as eastern Missouri. Rabid raccoons are probably not as common as the media reports would have us believe.
Distemper occurs throughout the entire range and is highly contagious.
Both are fatal. Symptoms of both diseases are similar and include difficulty walking, apparent confusion, and stoicism. Do not attempt to make a diagnosis yourself. Call a wildlife rehab professional if you suspect rabies or distemper. Wildlife rehab centers are listed in the yellow pages under 'Animal Rescue Services'.