What is a prion and what does it do to your body?

Prion: Prions are proteins that have changed physical conformation, so that the normal function of the protein inside the cells cannot be accomplished. The prions' abnormal folding also causes other normal proteins to misfold and make more prions, spreading the process. The prions affect many cells in the body, but they particularly harm nerve cells in the brain, causing progressive rapid degeneration.

Prion: Sub viral protein which infects. Cause of jacob-creutzfeld disease, a dementing illness.