<div>Prion diseases are a group of rapidly progressive, fatal and infectious neurodegenerative disorders affecting both humans and animals: Bovine Spongiform Encephalopathy (BSE) or 'mad cow' disease is one of the most famous since in 1996 scientists found that the agent responsible for the disease in cows, is the same agent responsible for the so-called variant Creutzfeldt-Jakob Disease (vCJD), a disease affecting humans.</div>