Although the infective agent responsible for the fatal degeneration of the brain is still not known, veterinary scientists believe it entered the cattle population from feed made from the remains of sheep infected with scrapie, a similar neurological disease.
The Government banned this form of animal feed in July 1988 and believes the move was largely responsible for the steady decline in the number of confirmed cases of BSE, which takes several years to incubate, seen over the past year or so.
'The peak of the epidemic has been reached. We are over it,' Kevin Taylor, assistant chief veterinary officer at the Ministry of Agriculture, Fisheries and Food, said.
Animals showing symptoms of BSE, such as an unsteady gait and unpredictable behaviour, and suspected as having the disease are destroyed and incinerated.
As an additional precaution to the human food chain, bovine offal - brain, spinal cord, spleen, thymus, tonsils and intestines - from healthy cattle over six months of age is removed before carcasses are deemed fit for human consumption.
Mr Taylor and other Government scientists believe these measures are adequate to protect human health.
But German scientists argue that the only way to eliminate the risk of BSE jumping the 'species barrier' and causing a similar brain disorder in humans, notably Creutzfeld Jacob's disease, is to ban the export of British beef.
Mr Taylor said the Germans were alone in believing there was any realistic risk to humans. 'It's not us against the Germans, it's the Germans against everyone else . . . They have not produced any evidence themselves.'
Laboratory experiments have failed to transmit BSE from beef muscle into mice that are susceptible to the disease, he said. However, the Germans argue that the agent has already infected certain members of the cat family that have eaten contaminated meat.
British scientists are conducting a series of other experiments to determine whether BSE can pass from cow to offspring or between one member of a herd and another. They are confident that even if such routes of infection are possible, the evidence points to them not being a sufficiently easy form of transmission to sustain the current epidemic, which they hope will begin to peter out by the end of the decade.
Exports of British beef to Germany are worth about pounds 8m out of total beef exports of pounds 400m.
France and Switzerland are the only other countries known to have their endemic BSE, but both have less than 100 cases as a result of importing British cattle.Reuse content