- The government's advisers on BSE and its deadly human
form, CJD, are to urgently reconsider whether BSE-like diseases in cattle
may have links to more than one fatal brain condition.
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- And there may be more than one type of BSE: scientists
in Italy have reported that a form of the disease discovered in some animals
tested in their country has a signature resembling sporadic CJD in people.
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- They advise caution in linking diseases in two species
but their report in the online edition of the Proceedings of the National
Academy of Science is bound to revive debate about whether eating cheap
beef may be responsible for some cases of sporadic CJD as well as the less
common variant CJD traditionally linked to eating infected cattle.
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- This hypothesis was first suggested by a British scientist,
John Collinge, 15 months ago when he said that injecting mice with BSE-infected
material seemed to result in some having a signature which was the same
as vCJD, but others a signature that was similar to one of three strains
of sporadic CJD, a disease which affects older people than vCJD.
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- Professor Collinge's hypothesis was regarded as plausible
by the government's spongiform encephalopathy advisory committee (Seac)
but last year members of the committee believed his work did not provide
strong enough evidence.
-
- The new research will raise further questions about the
risks to humans from food, contamination from medical procedures and other
routes of infection. It also revives questions about the origins of BSE,
perhaps indicating that there was a form of sporadic CJD in cattle before
the cattle epidemics which were blamed on grinding up cows and sheep for
feed.
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- Other scientists have preferred the theory that BSE was
a deadly form of scrapie, a sheep disease apparently harmless to humans
but turned into a killer when the agent responsible was eaten by cows.
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- The Italian research comes from a different angle from
that of Prof Collinge. It suggests there are different types of BSE-like
diseases in cows, adding to suspicions also emerging from work in France
and Japan. The Italian team, led by Salvatore Monaco which is calling the
new disease Base, will use laboratory mice to develop its work further.
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- This may even lead to the identification of at least
three types of BSE-like diseases in cattle. The research seems to point
to a different form of the deformed and deadly prion protein thought linked
to BSE from those suggested by Prof Collinge. British scientists have never
found different types of BSE, but scientists such as Prof Collinge say
this is because the government has never looked.
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- "It has always been on the cards, but it has not
been a terribly popular thing to suggest," he said last night. The
Italian work "adds an extra dimension" even if "it is not
good news".
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- He said : "One positive thing is that it challenges
two dogmas - that there is only one form of BSE and that sporadic CJD is
a uniform process that arises out of the blue and has nothing to do with
the environment." His work used British BSE-infected cows. But Prof
Collinge said it was difficult to answer whether these carried only one
strain of the disease and it changed in some genetically-engineered mice
or whether there were two strains in some cattle and the genetically-engineered
mice selected from one of them.
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- Seac said the Italian paper was "very interesting"
and would be considered by the committee next Wednesday.
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- Guardian Unlimited © Guardian Newspapers Limited
2004
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- http://www.guardian.co.uk/bse/article/0,2763,1150434,00.html
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