First discovered in diseased hamster brains by Stanley Prusiner, these agents are also responsible for Creutzfeldt-Jakob Disease.  
One of these entities stimulates the production of antizyme, a regulator of polyamines, and they can also be used to rescue doppel-programmed ataxia.  Carleton Gajdusek won the 1976 Nobel Prize in Physiology or Medicine for his study of one disease caused by these agents.  In (*) Gerstmann-Sträussler-Scheinker disease, these infectious agents affect the cerebellum; in Fatal Familial Insomnia, they affect the thalamus region.  An end to ritual cannibalism has largely decreased the prevalence of the aforementioned disease of the Fore of New Guinea.  First discovered in diseased hamster brains by Stanley Prusiner, these agents are also responsible for Creutzfeldt-Jakob Disease.  For 10 points, name these misfolded proteins that cause Bovine Spongeform Encephalopathy, or Mad Cow Disease, and whose name is short for "proteinaceous infectious particle."
One of these entities stimulates the production of antizyme, a regulator of polyamines, and they can also be used to rescue doppel-programmed ataxia.  
{prion}s (3) [DW]