Bovine Spongiform Encephalopathy

Bovine spongiform encephalopathy (BSE) was first identified in 1986 and to date more than 184 000 cases have been identified in the UK and more than 5000 in other countries, mainly, but not exclusively, in Europe. BSE was transmitted through contaminated feed and legislative measures to limit exposure to infection have resulted in a decline in the numbers of cases in most countries. It is possible that the introduction and implementation of appropriate control measures will lead to the elimination of this condition. Variant Creutzfeldt–Jakob disease (vCJD) is a zoonosis caused by infection with BSE, probably through high-titer bovine infectivity entering the human diet. The feared epidemic of vCJD has not yet materialized, with the number of deaths declining in the UK and only a small number of cases identified in other countries. However, uncertainties about the prevalence of infection and the probability of secondary transmission of this condition through blood transfusion compromise any accurate predictions on the likely total future burden of disease.