The interest in prion diseases, particularly the Creutzfeldt-Jakob type (CJD), rose dramatically in the last years for two reasons. 1) The general public wants to know whether eating beef may cause CJD. Discovering the new variant Creutzfeldt-Jakob disease (nvCJD) and experimental evidence that nvCJD and bovine spongiforme encephalopathy (BSE) are caused by the same prion strain make this idea probable. 2) Infectiologists and Neuroscientists recognise a model disease for a new infectious principle in that the same disease may occur as being inherited as well as transmitted. Additionally, it might allow new insights into the possible aetiologies of neurodegenerative disease.