Concern about chronic wasting disease is growing in Wisconsin and the Rocky Mountain states. A deer's lip curls, used for browsing or sampling urine in rutting season may spread the disease.

The mule deer doe shown here exhibits advanced signs of the disease.

 

Brain Disease Rises in Deer by Sandra Blakeslee, New York Times, Section F, p 1+

chronic wasting disease mad cow disease
endemic velvet Viagra
aberrant proteins plaques
transmissable spongiform encephalopathies prion
Creutzfeldt-Jakob disease scrapie
rendering plants biopsies
rutting season estrus
Centers for Disease Control and Prevention  

More reading on this subject:

Hearts Heavy, Hunters Stalk Ailing Deer