BIOMEDICINE: A View from the Top--Prion Diseases from 10,000 Feet

The transmissible spongiform encephalopathies or prion diseases include scrapie in sheep, mad cow disease, and variant Creutzfeld-Jakob disease in humans. The agent of all of these diseases is thought to be a self-replicating protein or prion. In a report of a recent meeting on prion diseases, Priola, Chesebro, and Caughey discuss the latest developments in this often contentious field of research.