- Scientists responsible for monitoring whether BSE has
spread from cattle to sheep on farms are investigating an unusual form
of brain disease found in a four-year-old ewe.
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- Tests on brain tissue at laboratories in Britain and
Europe have not confirmed the condition as BSE. But results do not resemble
known types of scrapie, a similar disease to BSE in cattle but not thought
lethal to humans.
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- The Food Standards Agency last night was not advising
against eating lamb but said "uncertainties still remain on this issue."
It could take researchers at least five years to establish exactly what
the disease is, by feeding brain tissue to mice.
-
- This is frustrating the farming industry, whose recovery
from the BSE epidemic in the 1990s and the foot and mouth outbreak of 2001
remains slow. Another such crisis in farming would be disastrous.
-
- Scientists will not identify unexplained cases as "BSE
in sheep" unless they carry the same signatures as those revealed
by sheep deliberately infected in the laboratory.
-
- This case did have similarities in one test, known as
the Western Blot, but two other methods did not suggest anything BSE-like.
-
- Danny Matthews, chairman of an advisory group of European
scientists who discussed the case last week, said: "It is important
for us to get this right because of all the implications."
-
- The FSA said last night: "On the best scientific
evidence to date, the agency's advice to consumers remains the same. We
are not advising against the eating of lamb and sheep meat."
-
- The problem is there are no tests that can definitively
tell the difference between BSE and scrapie. They can only identify a case
as a transmissable spongiform encephalopathy, or TSE, the class of diseases.
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- However, known forms of scrapie and the one certain strain
of BSE leave distinctive signatures.
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- Guardian Unlimited © Guardian Newspapers Limited
2004 http://www.guardian.co.uk/bse/article/0,2763,1188080,00.html
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