Background: Prospective epidemiological studies are being employed to determine the incidence and possible risk factors of Creutzfeldt-Jakob disease (CJD) in five European countries in which bovine spongiform encephalopathy (BSE) occurs at different rates of incidence.
Patients and methods: Using a voluntary reporting system throughout the Federal Republic of Germany, suspected cases of CJD were investigated and the incidence calculated. Possible risk factors in patients and control groups were obtained by questionnaire. Serum and cerebrospinal fluid samples served to delineate genetic forms and distinguish the disease from other major dementias.
Results: A total of 544 patients with suspected CJD, reported in Germany between 1993 and 1997, were examined. 232 (plus 27 investigated only neuropathologically) were confirmed as definite or probable, an annual incidence per million population of between 0.76 (for 1994) and 0.98 (for 1995), similar to figures from other European countries. In Great Britain, the cases of "new variant" CJD, not yet observed in Germany, were excluded from the calculation of incidence. So far, dementia in the family and handling of horn shavings have been identified as risk factors. A rise in the concentrations of neurone-specific enolase and of S100 protein as well as the demonstration of certain proteins in cerebrospinal fluid (p130/ 131 and 14-3-3, respectively) have been shown as being diagnostically superior to EEG changes.
Interpretation: There has so far been no increase in the incidence of CJD within Europe. However, the occurrence of the new variant in Great Britain requires long-term monitoring. The diagnostic criteria used for this can be improved by biochemical methods.