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- The revelation that BSE and its human form may be able
to jump the species barrier and be highly infective even when a person
or animal with the disease shows no signs of it, appears to confirm some
of the worst fears scientists have about the fatal condition.
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- The disease, bovine spongiform encephalopathy, has already
caused a cattle epidemic costing more than £4bn, and its human toll
of 73 deaths so far - all except three being Britons - is climbing steadily.
Its eventual impact on the health of the human population and the cost
to the NHS, is almost impossible to measure. Yet when the cattle disease
first emerged in 1986, government advisers dismissed any threat to people.
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- Now Europe quakes. Scientists believe that countries,
such as Germany, which profess not to have BSE, are likely to have some
cattle suffering from it even if the disease has not yet taken sufficient
hold for it to be obvious. The first known case of BSE, in a cow on a farm
in Pitsham, Sussex, occured in December 1984, almost two years before the
disease was identified. In fact, the illness may have begun to set in during
the early 1970s, but at such a low level that vets and farmers did not
recognise it as a new disease.
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- Feeding practices, in dairy farms particularly, where
cows' diets included the groundre mains of other cattle and sheep, probably
sent the disease into its catastrophic spiral. Even now cases in Britain
far outstrip those anywhere else. There have been more than 177,000 cases,
nearly 780 confirmed so far this year. By contrast, Ireland has had a total
of 489 BSE cases, Portugal nearly 350 and Switzerland 365.
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- France, with whom the beef war drags on ,has had just
over 100 cases, with 28 this year. There have also been two cases of human
BSE in that country and one in Ireland.
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- There have been numerous forecasts about the eventual
human death toll. Some estimates, putting it at less than 100, already
look too optimistic. Others have judged it be hundreds of thousands. Oxford
statisticians earlier this month painted a worst case scenario of 136,000.
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- After years in which warnings of death through eating
infected meat met public scorn, in March 1995 the fatalities began. But
it was March 1996 before scientists made the first connection. The first
victim to die was Stephen Churchill, aged 19, though the first person to
show symptoms is thought to have been a 50-year-old, in January 1994.
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- Even now it is thought victims are most likely to have
been infected by exposure to cheap meat-cuts from highly infective parts
of cattle before the first anti-BSE controls to protect human health were
in troduced in 1989. The agriculture minister, John MacGregor, banned the
use of certain offal in food against the earlier advice of civil servants.
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- Even though the ban was not as rigorously observed as
it should have been over the next six years, the measure probably stopped
the collapse of the beef and dairy industries in 1996 when the link to
human deaths was made, and reduced the prospects of a far worse human death
toll from infected beef when BSE was at its height in the early 1990s.
Other measures have been added, including from December 1997, for two years,
a ban on selling beef on the bone.
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- Measures to stop humans spreading the disease have included
changes to blood transfusions, the use of more disposable equipment and
more rigorous sterilisation.
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- The problem for the government, even after the new findings
suggesting human BSE might be spread more easily than had been assumed,
is deciding just how much should be spent on seeking to prevent an unquantified
risk.
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- The latest research means the assumptions - that a species
barrier between humans and the animals they eat would cut the number of
people who might succumb to BSE, and that there might have to be a high
dose of infective material to induce the disease - must be re-addressed.
Cows appearing healthy may also be capable of infecting people more easily
than had been supposed. So scientists will have to consider whether they
are removing enough offal from the food chain and whether barring cattle
over 30 months for sale is sufficient. Cattle far younger than 30 months
have displayed BSE signs - although not since 1996 - and the 30-month rule
does not apply in many other countries that have BSE.
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- European-wide offal bans are only just being introduced,
and scientists have suggested that just one cow slipping through the net
could infect up to 500,000 people.
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- There is also the suggestion that transmission of BSE-like
diseases through different species may create new, more virulent strains.
Some scientists believe that scrapie, a BSE-like disease in sheep not known
to be harmful to humans, is now disguising the BSE agent that has entered
sheep through animal feed and been recycled through the generations. Scrapie-infected
sheep brains are being tested with mice in the laboratories. Last month,
the food standards agency suggested such a BSE-like strain might be identified
"at any moment".
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- Contingency plans , including altering slaughterhouse
and butchery practices, are already being prepared to try to avert another
food panic. Britain does not routinely test for BSE in cattle planned for
human food. And, unlike other countries, the UK does not destroy all
the animals of a herd when a BSE case is identified.
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- Millions of cows over 30 months old have been destroyed
under compensation schemes, and there is a suspicion that this has made
it look as if BSE is dying out faster than it really is.
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- The recent research suggests cattle can harbour the disease
it without showing outward signs of it. Random tests on 3,000 cows last
year revealed 18 had BSE without showing clinical symptoms. Such checks
will be increased to 10,000 this year and there will be surveys on 3,000
animals which die unexpectedly on farms or have to be slaughtered through
illness or injury.
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- But ministers will have to consider whether also to check
animals going into the food chain. That could improve consumer confidence
- but not if the monitoring shows BSE is more widespread.
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- The government plans to follow France and Switzerland
by introducing rapid cattle post mortem examinations from January with
results in one to two days.
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- The problem is whether these will be sensitive enough
to detect BSE in its early stages. Such measures would assume that the
eating of infected meat has been the cause of variant CJD.
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- But billions of pounds-worth of preventative measures
are already in place. And the question remains, how much more needs to
be spent?
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