Prions, mad cow disease, and preventive measures: a critical appraisal.

Abstract

In 1996 the first key epidemiological study on bovine spongiform encephalitis (BSE) appeared in the renowned journal Nature [1]. In that article it was estimated that by the year 1996, some 750,000 cows with BSE had entered the food chain in Great Britain. Accordingly, millions of people in GB must have consumed contaminated meat. That same year the first report on a new form of Creutzfeldt-Jakob disease [variant (v) CJD] manifesting in young patients appeared [26]. A connection between this disease and BSE was assumed. In view of the suspicion that the use of meat and bone meal (MBM) had led to the outbreak of BSE, feeding with MBM was banned in the year 1988. The number of new BSE infections in Great Britain peaked in 1991/ 1992 and has been steadily declining since. The epidemic will probably end within the next few years. In November 2000, the first BSE cases were diagnosed in Germany. The total number of animals that have tested BSE positive is currently about 200 in this country. The discovery triggered a panic reaction involving measures of gigantic proportions. These ranged from culling a hundred thousand clinically healthy animals to the statutory introduction of BSE tests for cattle, up to tendering for expensive special programmes to research into BSE and prion diseases. The costs incurred by the BSE crisis have long exceeded the billion Euro level in Germany alone. They contribute significantly to the burden on Europe's economy. No end to the measures is in sight since considerable uncertainty remains, not only in society and among politicians, but also among physicians. Because politicians, society, and scientists themselves have incurred this situation, we should take time out to reflect on the sense and nonsense of our actions.