Present-day knowledge of BSE and Creutzfeldt-Jakob disease

Prion diseases are infectious and neurodegenerative disorders in humans and in animals. The infection is transmissible within a species and, with restrictions, between species. The most important prion diseases are Creutzfeldt-Jakob disease (CJD) of man, scrapie of sheep, and the bovine spongiform encephalopathy (BSE) of cattle. The causative agent (prion) is devoid of nucleic acid and consists mainly, if not entirely, of protein. This results in a highly unusual resistance of prions to inactivation procedures. BSE has found access to the human population in form of the new variant of CJD (vCJD). At present, more than 140 vCJD victims are known. The development of future numbers is presently not predictable. Since in vCJD prions are present in the lymphatic system, there is the risk of human to human transmission. At present, there are no means for pre-clinical diagnosis or for therapy in human prion diseases. New developments in 2002 are. the obvious spread of prion disease of deer (CWD) in Northern America and the significant increase of CJD in Switzerland.