Surveillance for Creutzfeldt-Jakob disease--United States.

Creutzfeldt-Jakob disease (CJD) in humans and bovine spongiform encephalopathy (BSE) in cattle are subacute degenerative diseases of the brain classified as transmissible spongiform encephalopathies. BSE was first identified in 1986 in the United Kingdom (UK), where an epizootic involving > 155,000 cattle appeared to have been greatly amplified by exposure of calves to contaminated rendered cattle carcasses in the form of meat and bone meal nutritional supplements. On March 20, 1996, and expert advisory committee to the government of the UK (1995 estimated population: 58.3 million) announced its conclusion that the agent responsible for BSE might have spread to humans, based on recognition of 10 persons with onset of a reportedly new variant form of CJD during February 1994-October 1995. The 10 persons ranged in age from 16 to 39 years (median age at illness onset: 28 years); of the eight persons who had died, five were aged <30 years. In comparison, in the United States, deaths associated with CJD among persons aged <30 years have been extremely rare (median age at death: 68 years). As a result of the newly recognized variant of CJD described in the UK, CDC updated its previous review of national CJD mortality and began conducting active CJD surveillance in five sites in the United States. These reviews did not detect evidence of the occurrence of the newly described variant form of CJD in the United States.