Public health and the BSE epidemic.

Bovine Spongiform Encephalopathy was discovered in 1986 in the United Kingdom and relatively rapidly spread into its trading partners in Europe via contaminated cattle feed supplements. The practice of using the discarded bovine carcass as cattle feed supplements led to the recycling of the prion agent and the consequent generation of new point source epidemics in the recipient countries. The advent of rapid diagnostic tests and more widespread testing has led to the identification of BSE in countries not previously reporting cases and the recognition of larger numbers of infections in countries previously only reporting clinical cases. The recognition of the wider spread of BSE and the 1996 recognition of vCJD as a human disease caused by consumption of BSE agent led to international concerns regarding the threat to human health and the demand for stricter controls on human food derived from cattle. Major shifts in food safety policy have occurred as a direct result. The recommendation that risk assessments for BSE infectivity and human exposure pathways be conducted rather than reliance upon rates and simple enumeration of BSE cases is one of the most prominent changes in the basis of policy regarding human health. The movement of BSE into human populations has a wider impact than seen in food safety--surgical procedures, blood, cells, tissues and organ donation programs are all affected. The World Health Organization has recommended that 'the eradication of BSE must remain the principle public health objective of national and international animal health control authorities'. The opinions expressed in this chapter are those of the author and do not necessarily reflect the views of Health Canada. This review was written while the author was employed at the WHO.