DOI: http://dx.doi.org/ehs2001.02.005 - - - The report by the British government concerning the situation of the cattle epidemic BSE (bovine spongiform encephalopathy or mad cow disease) in October 2000 (http://www.bseinquiry.gov.uk/) once again kindles the discussion which has been pervasive since the outbreak of this epidemic disease at the beginning of the 80s. These types of neurodegenerative diseases and their different manifestations, on the one hand, have already been described for a long time in animals, although similar illnesses have also been previously observed in humans even before the start of the BSE epidemic. Nevertheless, the extent of the BSE epidemic in the British Isles, as well as its spread to the European continent raises the question as to whether BSE can be transmitted to humans or not. Therefore, a historical synopsis of the discovery and the knowledge about the transmissible spongiform encephalopathies is presented and, in this connection, the uniqueness of the infection pathway is highlighted. For the description of this new infection process, the Nobel prize was awarded to C. Gajdusek (1976) and S.B. Prusiner (1997). The unprecedented details of the molecular mechanisms by which this infectious agent exerts its activity were discussed. In the 18th century, scrapie in sheep was mentioned in the UK for the first time. During the last hundred years, further diseases in animal and humans have been described. The autopsy revealed post mortem spongiosis of the brain (sponge-like structures) associated with amyloid-like plaques, astrocytosis and gliosis. The first evidence that it is an infectious process came from the investigations of D.C. Gajdusek, who discovered the phenomenon of kuru in a tribe native to Papua, New Guinea, where he had identified the transmission pathway. Meanwhile, a genetic predisposition for these diseases could be detected, since they demonstrate mutations in a distinct gene-locus: the prion protein. The discovery of the prion protein as the pathogen in BSE as a new biological principle of infection by S.B. Prusiner led to the second Nobel prize related to this field. This contribution describes the history of this disease, the pathogenic principle behind it and the potential risk for human health that nonetheless remains an area of speculation. Nevertheless, scientific evidence exists regarding a connection between BSE and the occurrence of a new variant of the Creutzfeldt-Jakob disease which is usually observed in younger human subjects. |
