Hidden But Deadly, The New 'Mad Cow' Disease Trigger

Belgium finds third mad cow case, destroys herd

LONDON (March 30, 1998 11:19 a.m. EST http://www.nando.net) -- Future generations of British cattle could carry the deadly agent that causes "mad cow" disease without ever showing symptoms during their lifetimes.

Dairy herds would continue to act as reservoirs of BSE infections and of its human counterpart, Creutzfeldt-Jakob Disease (CJD).

At the same time, official numbers of notified cases would continue to drop, lulling government officials, doctors and the public into a false sense of security.

This grim prospect was outlined at the latest meeting of the committee that is advising the British government on BSE.

Horrified members called for an urgent research program to be set up to speed up the development of tests for pinpointing infected calves.

Members of the Spongiform Encephalopathies Advisory Committee were told that experiments using mice had shown the agent causing BSE and CJD could persist in the animal without ever leading to the clinical disease.

Researchers found that laboratory mice that were allowed to die of old age had high concentrations of the agent in their bodies, even though they had never displayed a symptom during their lives.

"This raises the possibility that if the same thing is happening in cattle, we would be confronted with apparently healthy animals full of infection," a committee member said.

The British government claims the removal of parts of the bodies of cattle that are known to carry high levels of infection already acts as a protection for the public.

But if the BSE agent were to linger in some cattle without them developing symptoms of mad cow disease, this would clearly be a major blow to the meat industry. The industry's present claims to be able to guarantee that animals are BSE-free would be no longer valid.

"If a reliable field test on live animals could be produced, then this would provide a safeguard against the obvious risks, but so far such a test has not been devised and still seems some way off," said the same committee member.

A Ministry of Agriculture spokesman said all recommendations of the BSE advisory committee were acted upon and dealt with as a matter of urgency.

By ALAN WATKINS, London Observer Service