Emerging problems in prion disease.

The authors comment on the report by Drs. Chris MacKnight and Kenneth Rockwood (see pages 529 to 536 of this issue) on the implications for Canadian physicians of human prion diseases. They argue that there is reason for concern about the possible crossover of bovine spongiform encephalopathy to humans in the form of a variant of Creutzfeldt-Jakob disease (CJD) recently identified in the United Kingdom. A second emerging issue is the potential for the causative agent of CJD to be transmitted through donated blood and tissue. Although the epidemiologic evidence suggests that this risk is remote, current national and international initiatives to increase surveillance for new cases of CJD are timely.