Iatrogenic Creutzfeldt-Jakob disease: the waning of an era.

The outbreaks of iatrogenic Creutzfeldt-Jakob disease (CJD) from cadaveric human growth hormone and dura mater are winding down and, like the only other environmentally acquired form of CJD (variant CJD due to infection with the agent of bovine spongiform encephalopathy), iatrogenic disease seems to have reached its high water mark during the 1990s. The total number of cases has reached 405, and the diminishing number of new cases is due to extremely long incubation periods from infections acquired before 1985 (up to 23 years for dura mater and 36 years for growth hormone). Although no cases associated with surgical or other invasive procedures have been identified during the past several decades, the recent discovery of three transfusion-associated variant CJD infections has provoked new concerns about the possibility of further secondary transmissions from operative procedures as well as blood and tissue donations. Therefore, at least in those countries in which variant CJD has occurred, precautionary measures must continue for the indefinite future.