Epidemiology of Creutzfeldt-Jakob disease.

Extensive information on the epidemiology of Creutzfeldt-Jakob Disease (CJD) has accumulated since the original transmission of CJD to primates in 1968. One aim of this research was to discover the mechanism of natural transmission of CJD but the epidemiological evidence virtually precludes case to case transmission as a causative mechanism, except in rare iatrogenic cases, and has provided little evidence to suggest an environmental 'source of infection'. An understanding of the few positive epidemiological findings such as the high incidence in Slovakia has depended on major advances in molecular biology rather than on epidemiological evidence. The occurrence of Bovine Spongiform Encephalopathy (BSE) has however reinforced the importance of having established the epidemiological characteristics of CJD and this information is an important background on which to evaluate the findings from basic scientific research.