Prion diseases, or transmissible spongiform encephalopathies (TSEs), are a group of rare, fatal neurodegenerative disorders leading to motor and cognitive impairments, extensive brain damage, and neuronal degeneration. Besides the infamous widespread of bovine spongiform encephalopathy in cattle, more recently an epidemic is expanding in North America know as chronic wasting disease in cervids. Historically, these diseases have attracted considerable interest for its unusual agent: the prion. Unlike other pathogens, the prion is composed solely of proteins. Here we describe the essential information to understand the scientific events and the various forms of the disease in humans and animals.
