What can we learn from BSE?

Bovine Spongiform Encephalopathy was first identified in the United Kingdom in 1986 as a result of the routine surveillance of animal diseases by the State Veterinary Services (Wells and others 1988). Epidemiological studies were initiated in May 1987. These had a number of objectives: (i) To obtain more detailed descriptions of the clinical signs to improve the ascertainment of suspect cases; (ii) to determine whether BSE was a new disease or not; (iii) to obtain sound descriptive epidemiological data and (iv) to investigate aetiological hypotheses. With respect to the last of these, hypotheses were not restricted to BSE being a member of the Transmissible Spongiform Encephalopathies (TSEs). They can be summarised as BSE being the result of infection with a scrapie-like agent, the result of an-intoxication or a purely genetic disease. For the first of these the possible sources or vehicles of infection were investigated as far as was possible. These were imported cattle, contact with sheep, contact with wildlife and contaminated biological products, including feedstuffs.