Creutzfeldt-Jakob Disease (CJD) and Variant CJD (vCJD)
Creutzfeldt-Jakob disease (CJD) is a rare, fatal brain disease caused by abnormal human prions (microscopic protein particles). It is found worldwide, including in the United States (US), and usually affects older persons. CJD belongs to a class of diseases known as transmissible spongiform encephalopathies.
In the US and worldwide, CJD occurs at an annual incidence of approximately one case per million people. During 2004-2008, the US has reported approximately 300 cases of CJD a year. The annual incidence increases with increasing age, and in persons 65 years and older, the annual incidence has averaged approximately 4.8 cases per million people. Rarely, CJD has been reported in persons younger than 40 years old.
In California, approximately 20-30 cases of laboratory-confirmed CJD have been reported annually in recent years.
Variant CJD (vCJD) is a type of CJD first reported in 1995. vCJD was first identified in the United Kingdom following an epidemic of bovine spongiform encephalopathy (BSE) in cattle during the 1980s and 1990s.