The incidence of bovine spongiform encephalopathy (BSE) in the United
Kingdom is now declining at a significant rate, indicating that the 19
88 ban on feeding ruminant-derived meat and bone meal to cattle is hav
ing 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, es
pecially now that meat and bone meal has been recently banned from the
diets of all farmed animals in the UK. In this review the aetiologica
l role of meat and bone meal in the causation of BSE is discussed toge
ther with the epidemiological data and the results of studies on genet
ic susceptibility. The controversial theories relating to the nature o
f the causal agent, and strain-typing studies on BSE agent, are descri
bed. Current information on pathogenesis and diagnosis is presented. T
he occurrence of BSE in cattle outside the United Kingdom, and BSE-rel
ated disease in species other than cattle is also discussed.