Bovine spongiform encephalopathy--the beginning of the end?

The incidence of bovine spongiform encephalopathy (BSE) in the United Kingdom is now declining at a significant rate, indicating that the 1988 ban on feeding ruminant-derived meat and bone meal to cattle is having the anticipated effect. The question now is whether or not BSE can be completely eradicated. At present there is no evidence of lateral or maternal transmission, the occurrence of which would complicate the eradication process. Eradication therefore seems to be achievable, especially now that meat and bone meal has been recently banned from the diets of all farmed animals in the UK. In this review the aetiological role of meat and bone meal in the causation of BSE is discussed together with the epidemiological data and the results of studies on genetic susceptibility. The controversial theories relating to the nature of the causal agent, and strain-typing studies on BSE agent, are described. Current information on pathogenesis and diagnosis is presented. The occurrence of BSE in cattle outside the United Kingdom, and BSE-related disease in species other than cattle is also discussed.