Prion diseases are a group of rare, invariably fatal brain diseases that occur both in humans and animals.
In humans, the best known prion disease is Creutzfeldt-Jakob Disease (CJD), first documented in 1920 by two German doctors, Hans Gerhard Creutzfeldt (1885-1964) and Alfons Maria Jakob (1884-1931). CJD reportedly affects approximately one person per million per population each year worldwide. In the United States, this translates to approximately 300 new cases annually.
The main indications leading to a possible diagnosis of CJD are rapid dementia and one or many of a range of neurological symptoms including unsteady gait, hallucinations and sudden jerking movements.