29 March 1996

Still no scientific proof of transmission to man

By Rebecca Austin

THERE is still no scientific proof that BSE can be transmitted to humans, emphasises Colin Maclean, the Meat and Livestock Comm-issions director general.

Scientists concluded the 10 new Creutzfeldt-Jakob disease cases were clinically and pathologically different to anything seen before.

But Mr Maclean has been led to understand they are not clinically different from young cases elsewhere in the world. And this has not been made clear, he stresses.

"Scientists specified the length of the clinical course (averaging 13 months) was different from other sporadic CJD cases. That is true, but it is not different from the cases recorded in France, America or Canada, I believe."

Mr Maclean acknowledges that ataxia (wobbliness), one of the earlier clinical symptoms in these young cases, is different from sporadic CJD, where dementia appears first. But he says the latest cases are not different from other young cases abroad, where ataxia was the predominant symptom. So the difference is the pathology, concludes Mr Maclean. Brain lesions are the same in type and material but there are more of them in these latest cases and they are in the forebrain. Some of the other CJD cases tend to be in the base of the brain and in the cerebellum. "The sites in young people are different from the site in cattle with BSE," he says.

Mr Maclean concedes that although the population is protected now by all of the controls in place, it was exposed between 1986 and 1989 to some infected material, albeit in very low numbers.

Colin Maclean… No proof.