Prions are proteins (PrP) that usually reside in the brain. There are two different forms of prions: normal PrPC and the pathological isoform, PrPSc. The two forms are chemically similar but shaped, or folded differently. PrPC occurs naturally in most mammals but PrPSc seems to bring with it various diseases, or spongiform encephalopathies. Various forms of these diseases have been found in many animal species, including humans. The actual means by which PrPSc propagates itself remains unknown but scientists believe the modified protein alters the normal protein molecules. The diseases may be contracted in a variety of ways. They may be genetically inherited, acquired by contamination, or occur…show more content… Familial CJD (which is inherited) "accounts for about 10-15% of all CJD cases" (Ridley, 3). Other human prion diseases occur only when genetically determined. Gerstmann-Sträussler-Scheinker syndrome (GSS) is one such inherited disease, as is Fatal Familial Insomnia (FFI). Atypical prion disease is also genetically inherited, though it "does not easily fit the various diagnostic criteria for prion disease" (Ridley, 3). Another human prion disease is Kuru, which has been referred to as “the laughing death” (Prusiner). It was an acquired disease (i.e., contracted through contamination) found in the Fore Highlanders of Papua New Guinea. The disease was likely spread by cannibalism, as the Fore honored their dead by eating their brains. However, as this particular ritual stopped, Kuru virtually disappeared (Prusiner).
The Animal Diseases:
Prion diseases are widespread in other animals as well (prionSP). Scrapie, for example, is a rare endemic brain disease that occurs in sheep and goats. Transmissible mink encephalopathy (TME), Bovine spongiform encephalopathy (BSE, more commonly referred to as "mad cow disease"), Feline spongiform encephalopathy (FSE), and spongiform encephalopathy in other species are all believed to be caused by ingesting material contaminated with scrapie and/or BSE. The cause of Chronic wasting 3 disease (CWD), a scrapid-like disease found in mule deer and Rocky Mountain elk,