Abstract

Creutzfeldt-Jakob disease (CJD) is the most common of the human prion diseases (also known as transmissible spongiform encephalopathies), which, according to the leading hypothesis, are caused by an abnormal protein (i.e., prion) that is able to induce abnormal folding of normal cellular prion proteins. Annual worldwide incidence of these always fatal neurodegenerative diseases is estimated at 0.5-2.0 cases per million population. CJD can occur sporadically, or as a genetic disease, or can be transmitted iatrogenically. In 1996, a new human prion disease, variant CJD (vCJD), was first described in the United Kingdom. This disease was believed to have resulted from human consumption of cattle products contaminated with the prions responsible for bovine spongiform encephalopathy (BSE, commonly known as mad cow disease). That year, in part to check for possible vCJD cases, a national survey was conducted in Japan; 821 CJD cases were identified, including 43 cases associated with receipt of cadaveric dura mater grafts. A single brand of dural graft (Lyodura) produced by a German manufacturer before May 1987 was identified as the most likely vehicle of transmission in all but one case. By 2003, continued surveillance in Japan had identified a total of 97 such cases. Since then, an additional 35 cases have been identified. This report updates previous reports and summarizes the investigation of all 132 cases to date linked to dural grafts. The results suggest that, because of the long incubation period between graft receipt and symptom onset (possibly >24.8 years), continued surveillance in Japan might identify additional CJD cases associated with dural grafts.