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9 December 2002
They drive us Mad with False Fears about Mad Cows
Magnus Linklater, The Times, 5th December, 2002
http://www.timesonline.co.uk/article/0,,3284-503184,00.html
It is time to call a halt to the series of unprincipled
scare stories that are being peddled about BSE and new variant CJD.
The latest, which comes directly from the Nobel Prize-winning scientist,
Stanley Prusiner, is the most outrageous of them all. Last weekend
he gave warning that people who had eaten beef or lamb in Britain
were still at risk from vCJD, a disease for which there is no known
cure. He called for nationwide tests to determine how many of us
had been exposed to the infectious prion proteins he believes to
be the cause of the disease. His latest experiments, he said, suggested
that the prions might be lurking, not just in the brains and spinal
columns of cattle and sheep, but in the muscles as well. A
million cattle infected with BSE entered the British food chain,
so almost everyone in the country will have been exposed. . .
he said.
It would be hard to exaggerate the sheer folly
and irresponsibility of this comment. If taken seriously, it would
cripple the farming industry and demand a massive testing programme,
spreading alarm throughout the population. One estimate suggests
that for every real case of infection exposed by Prusiners
testing programme, there would be at least nine false positives,
that is, people who appear to be incubating the disease but have
not in fact contracted it. Their jobs, insurance and life prospects
would be blighted. And, since there is no cure, the real victims
would gain nothing save the knowledge that they face a painful and
lingering death.
So what on earth was the point? It seems to be
that Prusiners thesis about the link between BSE and vCJD
is running out of steam. It is now five years since he won his Nobel
Prize for claiming that degenerative diseases such as CJD are caused
by prions cell membrane proteins that are found in high concentration
in the brain or spine. With the acceptance of his thesis, the scientific
establishment threw its weight behind it. Warnings about a possible
vCJD epidemic began to proliferate, with the CJD surveillance unit
in Edinburgh regularly adding to the grim scenario. Estimates of
a death toll of more than 100,000 in Britain were predicted.Yet
what is the reality? The latest figures from the Edinburgh unit
show that there have been 15 cases this year, down from 20 last
year, and 28 the year before. That is approximately one in three
million. The numbers are, in fact, falling, not rising. Closer scrutiny
reveals other curious statistics. An article in The Lancet reported
that the geographical distribution of vCJD and BSE did not tally.
The highest concentration of BSE-affected cattle was in the South
and West of England, while most cases of vCJD were in Scotland.
A damning article in the British Medical Journal, written by George
Venters, a consultant in public health medicine at the Lothian Health
Board, argued that the disease was neither new nor caused by prions.
Headlined New variant CJD: the epidemic that never was,
it drew a furious response from prion supporters. But nothing has
caused Venters to change his mind.
There is, of course, money to be lost and reputations
to be damaged if the bottom drops out of the prion creed. Now, however,
the whole issue is about to become political. Later this month Margaret
Beckett, the Environment Secretary, will be asked to approve a new
research grant for Professor Alan Ebringer of Kings College
London, a distinguished scientist who has identified a microbe which
he believes was responsible for BSE and which may also hold the
clue to multiple sclerosis. His thesis is radical, like all the
best scientific advances, but at least it is statistically consistent.
So far it has been opposed by SEAC, the government committee which
approves research projects. That is hardly surprising: six out of
the 12 SEAC members are involved in prion research.
The time has come, therefore, to explore the alternatives.
Mrs Beckett should have the courage to challenge the Prusiner orthodoxy
and break new ground. Anything must be better, surely, than what
Venters calls terrifying a population to keep interest going
in a rare disease.
Magnus Linklater
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