Furrowed brow over mad cow

Anxieties over the possibility that material from or contact with cows infected with bovine spongiform encephalopathy might cause Creutzfeldt-Jakob disease revolve around three questions. Could it happen? Bovine spongiform encephalopathy in cows, scrapie in sheep and experimental animals, and Creutzfeldt-Jakob disease are all caused by the same class of pathogen and are more accurately called prion diseases.1 Human prion disease is rare, but the public health importance of prion disease far exceeds its rarity for the following reasons. It has been transmitted experimentally to various animal species1 2 (bovine spongiform encephalopathy has been transmitted experimentally in primates), and accidental person to person transmission has occurred.3 In addition, it has been shown that prion disease can be transmitted orally by the ingestion of infected foodstuffs or infected tissues.4 5 The …