Death of man aged 74 raises new CJD fears

BSE infection: Scientists must revise predictions of eventual death toll from illness linked to 'mad cow disease' after oldest victim succumbs

A man of 74 has died of the human form of "mad cow" disease - the oldest victim so far - which has led scientists to reappraise their predictions of how many people could eventually die of variant Creutzfeldt-Jakob disease (vCJD).

A man of 74 has died of the human form of "mad cow" disease - the oldest victim so far - which has led scientists to reappraise their predictions of how many people could eventually die of variant Creutzfeldt-Jakob disease (vCJD).

Until now it was assumed that older people were not susceptible to vCJD, but the man's death has shown that a far wider segment of society was vulnerable to infection when the agent responsible for bovine spongiform encephalopathy (BSE) in cattle was contaminating the human food chain.

Doctors from the National CJD Surveillance Unit in Edinburgh have confirmed that the man has died of the debilitating brain disorder. He was 20 years older than the previous oldest victim, the Department of Health said yesterday.

Most of the 85 people who have had the disease are under 30. The youngest was 12 when she contracted the disease.Computer predictions this year assumed the majority of the elderly were never at risk.

Professor Roy Anderson, a member of the Government's Spongiform Encephalopathy Advisory Committee and an eminent epidemiologist at Imperial College, London, said the appearance of vCJD in an older person had caused a review of the latest assessment of the epidemic's future course.

"We're trying to redo the analysis at the moment because we'd been somewhat guided by the considerable clustering of the cases in the younger age groups," Professor Anderson said. "This one case somewhat changes that view so We are in the process of taking into account the rise of the numbers in the light of a considerably broader age range.

"These are quite messy calculations to do and one has to do millions of them. There are great uncertainties about the incubation period so you have to span across the whole range of possibilities," he said.

Younger people were considered to be more susceptible because they may have been exposed to more BSE in "junk" food. Another explanation is that they have more active immune systems which could have aided the uptake of the infectious agent.

Computer predictions by Professor Anderson's team published in August ruled out a large-scale epidemic of vCJD involving hundreds of thousands of people. The model suggested the most likely scenario was that fewer than about 6,000 people were infected as a result of about 750,000 infected cattle entering the human food chain between 1980 and 1996.

However, such are the uncertainties, notably the length of the incubation period, that scientists suggested the true figure could be as high as 136,000 victims, if the disease takes up to 60 years to incubate.

Although it is believed that millions of Britons may have been exposed to BSE at the height of the epidemic, before health controls were properly enforced, some scientists believe the relatively low number of cases so far could mean a large epidemic is now unlikely.

But Professor Anderson warned that next year would be crucial in determining whether this will turn out to be true. "We'll know a lot more after the year 2001. By then, if the incubation period is short, one should start to see a downturn in the cases," he said.