- Between 1,300 and 16,000 people may harbour the human
form of BSE, depending on who interprets the findings of a study published
today.
-
- Eight years after vCJD was linked with BSE the Department
of Health-backed study fails to show how many people will eventually die.
-
- The scientist who reports the work said he would rather
not have estimated vCJD prevalence, given various caveats, and the head
of the Prion Unit in London said it was "worrying" and might
suggest current vCJD patients are the first wave of a bigger epidemic.
-
- The findings will increase pressure to use new decontamination
methods, since they underline fears that routine operations may spread
the disease.
-
- The research is published in The Journal of Pathology
by Dr David Hilton, of the Derriford Hospital, Plymouth, and colleagues
who examined 12,674 appendix and tonsils (mostly the former), from people
from the highest risk group, mostly in their twenties.
-
- Three vCJD positives emerged. Extrapolating, Dr Hilton
estimates 3,800 people have human BSE but stressed caution in interpreting
the results.
-
- Given the handful of positives, the survey lacks statistical
power; because the samples were fixed in paraffin wax, the team was unable
to use a definitive vCJD test; nor was it able to establish the genetic
subtype of the affected people; and two of the three positives appear different
from samples taken from vCJD patients.
-
- Dr Azra Ghani, of Imperial College London, the co-author,
listed three possibilities: perhaps there were two false positives, so
the projected number of cases will be 1,300, in line with recent estimates.
-
- Perhaps the level of infection is higher than thought:
the positives are in a different genetic subtype of person than vCJD cases
to date and there could be a second wave of longer incubation outbreaks
in other subtypes.
-
- Perhaps some infected people do not go on to develop
symptoms, consistent with a recent decline in the number of reported vCJD
cases, though may still be able to spread vCJD.
-
- But the real situation could be worse, said Prof John
Collinge, head of the Prion Unit at University College London. The majority
of samples were from appendices, which harbour lower levels of rogue prions
than tonsils.
-
- According to his research on patients who had died of
the disease, only one out of four appendices showed a positive, when tonsils
are always positive in vCJD.
-
- This would imply that the number of affected people is
16,000. Prof Collinge would not be drawn on numbers but said the results
are "very concerning".
-
- "No test is going to be 100 per cent effective,
and you don't know at what stage in the incubation period the test either
on tonsil or appendix will be positive."
-
- He said the Government should re-examine the question
of using disposable surgical instruments.
-
- Advice to use them was introduced for a time but withdrawn
in England about two years ago because of safety worries.
-
- A spokesman for the Department of Health, which has spent
£200 million on sterilisation equipment and throwaway instruments,
said: "The results reinforce the need for a continued precautionary
approach."
-
- The Health Protection Agency is currently engaged in
a major vCJD screening project in which 100,000 fresh tonsil samples will
be directly tested, on an anonymous basis, for vCJD prions and can also
be analysed for genetic subtype.
-
- Prof Pat Troop, the chief executive, said it "should
provide better estimates of the number of people who may be affected".
-
- "This is urgent," said Prof Collinge, "we
need to get on with it."
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- © Copyright of Telegraph Group Limited 2004. http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2004/05/21/ncjd
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