Human mad cow disease estimates in UK may be higher

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Human mad cow disease estimates in UK may be higher

2004-05-21 10:32:24

 

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By Patricia Reaney

 

LONDON (Reuters) - Just as concerns were abating, the results of a

new report suggest that the human form of mad cow disease in Britain

could be more widespread than thought.

 

Scientists have estimated that 3,800 people in Britain could be

carrying the prion protein responsible for variant Creutzfeldt-Jakob

disease (vCJD), a fatal brain-wasting condition.

 

" Our findings need to be interpreted with caution, but cannot be

discounted, " said David Hilton, of Derriford Hospital in Plymouth,

and lead author of the report published in The Journal of Pathology.

 

Hilton and scientists from the CJD Surveillance Unit in Edinburgh,

Scotland and Imperial College in London studied 12,674 stored

appendix and tonsil samples removed during routine operations in the

late 1990s from people in their 20s. Three showed evidence of prion

protein accumulation associated with vCJD.

 

Based on their findings, they came up with the 3,800 figure.

 

" There is still much to learn about vCJD and the presence of the

protein in these tissue samples does not necessarily mean that those

affected will go on to develop vCJD, " Hilton added.

 

The scientists stressed that only one of the three positive samples

showed a pattern of the prion accumulation similar to that seen in

known vCJD cases. The other two were different, so their

significance is uncertain.

 

Sir Leszek Borysiewicz, of Imperial College in London, said the

figures are not alarming, but warrant further investigation to get

to more accurate answers.

 

" They scream out at me that we still need better diagnostic tests, "

he said in an interview.

 

" It is a relatively unusual condition but every case is one more

than you would want, " he added.

 

Since vCJD was first detected and linked to eating meat contaminated

with mad cow disease, or bovine spongiform encephalopathy (BSE), in

the mid-1990s, 141 people have died of the illness, which is caused

by prion infection in the brain.

 

It is difficult for scientists to predict how may people may get the

illness or when it will peak because of the long incubation period,

which experts say can be from 10-20 years or longer, and genetic

factors that could influence susceptibility to the illness.

 

Previous estimates have ranged from less than 100 to up to 50,000.

 

" Although the numbers of cases are currently in decline, the

possibility of further rises cannot be excluded, " the researchers

said in the report.

 

They added that the findings reinforce the importance of safety

measures to reduce the spread of vCJD through blood transfusions or

surgical equipment.

 

Britain banned people who have had transfusions in the past two

decades from donating blood after a report of what is thought to

have been the world's first case of vCJD caused by a blood

transfusion.

 

 

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