SEARCH STRING: su:bse

ACCESSION NO:  97-98-1717
       TITLE:  Prion Diseases and the BSE Crisis
      AUTHOR:  PRUSINER, STANLEY
     JOURNAL:  Science
    CITATION:  October 10, 1997, 278(5336): 245-251.
        YEAR:  1997
    PUB TYPE:  Article
 IDENTIFIERS:  PUBLIC HEALTH; PRION DISEASES; CENTRAL NERVOUS SYSTEM; GREAT 
               BRITAIN; MAD COW DISEASE; BOVINE SPONGIFORM ENCEPHALOPATHY 
               (BSE); SCRAPIE; DRUG THERAPIES; EPIDEMIC; PROTEIN; 
               CREUTZFELDT-JAKOB DISEASE VARIANT
    ABSTRACT:       Bovine spongiform encephalopathy (BSE) commonly called 
               "Mad Cow" disease, Creutzfeldt-Jakob disease (CJD) in humans, 
               and scrapie in sheep are among the best known disorders 
               caused by prions (posttranslationally modified cellular 
               proteins). These fatal diseases are central nervous system 
               (CNS) degenerative disorders. Prion diseases have come to the 
               forefront because of 20 cases of an atypical variant CJD 
               (vCJD). In this variant, the prion disease may have been 
               transmitted from cows infected with bovine spongiform 
               encephalopathy when tainted beef was consumed. Research has 
               shown that prions can be transmitted between species.
                    The accumulation of a prion is the hallmark of all prion 
               diseases. The normal cellular protein (PrPC) is converted 
               into PrPSc, the abnormal isoform which causes disease. This 
               structural modification changes the properties of the 
               protein. PrPSc is the major, and probably the only, component 
               of the infectious prion particle. A factor, called protein X, 
               binds to PrPC and facilitates PrPSc formation.
                    The greatest risk to human health seems to be the 
               possibility of bovine prions being transmitted to humans 
               through tainted beef. The vCJD cases thought to be related to 
               BSE have all occurred in Great Britain and France. In Great 
               Britain, almost one million cattle are estimated to have been 
               infected with prions, and more than 160,000 cattle have died. 
               Offal from the meat industry was turned back into food for 
               cattle as a high-protein supplement. This may have fed 
               disease-causing prions back into the food chain. Laws have 
               now been made to prevent this type of reinfection. It is 
               important to monitor the frequency of prion disease in cattle 
               since they are slaughtered for human consumption, but no 
               reliable test for prion disease in live animals is available.
                    Because the incubation period is long, even the 
               legislation designed to protect the food supply may not help 
               those already infected. No one knows if there will be a human 
               epidemic to rival BSE. Given the possibilities, therapeutics 
               should be a priority. Therapy options could interfere with 
               the conversion of PrPC, prevent the aid of protein X, or 
               destabilize the structure of PrPSc. Producing domestic 
               animals that are genetically engineered to be prion resistant 
               is another focus.


ACCESSION NO:  97-98-1399
       TITLE:  Bovine Spongiform Encephalopathy (BSE): Causes and 
               Consequences of a Common Source Epidemic
      AUTHOR:  NATHANSON, NEAL; WILESMITH, JOHN; GRIOT, CHRISTIAN
     JOURNAL:  American Journal of Epidemiology
    CITATION:  June 1, 1997, 145(11): 959-969.
        YEAR:  1997
    PUB TYPE:  Article
 IDENTIFIERS:  BOVINE SPONGIFORM ENCEPHALOPATHY (BSE); TRANSMISSIBLE 
               SPONGIFORM ENCEPHALOPATHY (TSE); PRION DISEASES; CATTLE; 
               SHEEP; UNITED KINGDOM; MEAT CONTAMINATION; BONE MEAL; 
               NEUROLOGICAL DISEASES; ANIMAL FEED; CREUTZFELDT-JAKOB DISEASE 
               (CJD)
    ABSTRACT:       Bovine spongiform encephalopathy (BSE) is a 
               transmissible spongiform encephalopathy (TSE) that affects 
               cattle. It was first recognized in 1986 in the U.K., where it 
               produced a common source epidemic that peaked in January 
               1993. BSE has subsided markedly since that time. The epidemic 
               began simultaneously at many geographic locations and was 
               traced to contamination of meat and bone meal (MBM), a 
               dietary supplement prepared from rendering of slaughterhouse 
               offal.
                    Researchers have found that the epidemic was initiated 
               by the presence of the agent of scrapie (a long-standing TSE 
               of sheep) that was first transmitted to cattle, beginning in 
               the early 1980s, when most rendering plants abandoned the use 
               of organic solvents in the preparation of MBM. The epidemic 
               was probably accelerated by the recycling of infected bovine 
               tissues prior to the recognition of BSE.
                    In July 1988 a prohibition on the feeding of ruminant-
               derived protein to ruminants was introduced in the U.K. to 
               terminate the epidemic. The ruminant feed ban accounts for 
               the decline of the epidemic after an interval of about 5 
               years, approximately equivalent to the incubation period of 
               BSE. Relatively few cases of BSE have occurred in cattle born 
               after 1993, and it is predicted that the epidemic will 
               terminate about the year 2000 based on an extrapolation of 
               the present declining curve.
                    Recently, cases of a variant form of Creutzfeldt-Jakob 
               disease (a TSE of humans) have been reported in the U.K. 
               These cases, at least 10 of which had onset in 1994-1995, are 
               distinguished by their occurrence in subjects under age 40 
               years by their clinical presentation, and by their 
               neurohistopathologic picture. The appearance of this novel 
               disease and its concentration in the U.K. have raised the 
               question that it might represent the transmission of BSE to 
               humans.