V. Prion Diseases (Transmissible Spongiform Encephalopathies-TSE)
A. Introductory concepts:
Human prion diseases (transmissible spongiform encephalopathies, including Creutzfeldt-Jakob disease (CJD) are all associated with abnormal forms of a specific protein, called prion protein (PrP); the diseases may be sporadic, inherited, and/or infectious. Several of these diseases have been transmitted to primates and to other animals through injections of infected brain tissue. The first prion disease to be transmitted to animals in this way was kuru, which was transmitted in the human population of the Fore tribe in New Guinea through cannibalism rituals. Prion diseases also occur in several mammalian species.
Scrapie has existed for hundreds of years in sheep. Bovine spongiform encephalopathy ("mad cow" disease identified in Great Britain and Europe) occurs in cattle, and is thought to be the source of infection causing the 'new variant' form of CJD (nvCJD or vCJD) identified recently in young adults in Great Britain. Genetically transmitted human prion diseases include Gerstmann-Straussler- Schenker syndrome, fatal familial insomnia, and a small percentage of CJD cases.