Abstract

Transmissible spongiform encephalopathies affect a variety of vertebrates, including humans. While scrapie has been enzootic in sheep for centuries, bovine spongiform encephalopathy (BSE) appeared only some 12 years ago but rapidly became epizootic. It is not clear whether BSE originated in cattle as a rare spontaneous event or whether it stems from sheep, but its spread is clearly due to feeding of cattle-derived contaminated bone and meat meal. Recent evidence links the appearance of new variant Creutzfeldt-Jakob disease in humans to consumption of BSE-contaminated cattle-derived products.