ABSTRACT
Prion diseases, or transmissible spongiform encephalopathies (TSEs), are a family of insidious brain-wasting diseases that infect humans and other mammals. Human prion diseases include kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-SträusslerScheinker (GSS) disease, and fatal insomnia (FI). Prion diseases in nonhuman mammals include bovine spongiform encephalopathy (BSE), or “mad cow” disease, in cattle, chronic wasting disease (CWD) in North American members of the deer family, scrapie in sheep and goats, and transmissible mink encephalopathy (TME) in farmed mink. Prion diseases are characterized by a long incubation period (years to decades in humans) during which the infected individual does not display symptoms. Once clinical symptoms manifest, the disease progresses inexorably to death, often within six months. Prion disease symptoms in humans include dementia, memory loss, speech impairment, loss of motor control, personality changes, hallucinations, and
seizures. The brains of infected individuals are characterized by the death of nerve cells, leading to a spongy appearance (hence “spongiform” encephalopathies) and accumulation of an abnormally folded form of the prion protein (PrP).
