- As a scientist, it feels as if I have been holding my
breath for 13 years while the BSE epidemic took hold, was exported to much
of the world, and then the human form got going. Now at last, it looks
as if breathing can start again: the good news is starting to come through.
- Only a few weeks ago things were still looking fairly
dire. In the UK, we have had 181,294 cases of BSE. It hit a peak in 1993
and we don't expect to see our last cases until after 2006. The disease
is now rising rapidly on mainland Europe with, for instance, seven cases
in Germany in 2000 and 94 already this year. We had exported 25,000 tons
of the infectious meal and bone meal (MBM) - by then banned for feeding
to cattle in the UK - to Europe in 1989, and consequently their BSE epidemics
may not be over until after 2010.
- In the UK, one of the major problems was that we did
not know which cow was infected before it had any symptoms. As a result
we ate six out of every seven of them. This represents over 800,000 infected
cattle entering the human food chain and the population eating 50 meals
each made of their tissue.
- So far, 106 cases of variant CJD have been identified,
with between 1,000 and 10m potential cases incubating the disease.
- We don't know who to treat, whose blood to avoid at blood
transfusion, who represents a risk at surgery or dentistry, or which asymptomatic
cattle to dispose of. A diagnostic test is urgently needed, but we would
need to be able to look for less then 1,000 molecules of the infectious
agent in blood or urine - less than one thousandth of the amount that can
be sought by the best test available so far.
- The BSE inquiry report last year showed how, through
inadequacy rather than villainy, the government convinced itself that the
risk to humans was minimal. Why, then, waste money on research?
- Early in the epidemic it was difficult for scientific
researchers to get hold of BSE tissue samples just to use for tests. The
government refused to fund any research to look for treatment "because
it would suggest to the population that there may be a risk to them".
- In the early 1990s I was the only researcher looking
for treatments for the disease and had to do the work in my garage. One
scientist, Iain McGill, quit the government research group after warning
of risks being taken. He was told it would be illegal to tell anyone what
he had found. When vCJD appeared, the government still considered whether
or not to tell the public.
- But at last the hiding of information, blocking of research,
denying of facts and damning of anyone speaking out in this field appears
to be over.
- A group in Switzerland has now found a way to increase
the number of prion molecules in a sample - perhaps enough to be able to
identify these triggers for vCJD. From Israel we have data showing that
urine contains lots of the prion molecules and that these appear long before
any symptoms. A London company can now look for 1,000 molecules of other
proteins and is using this to look for prions. There is now an official
supply of tissues and blood fractions to try out on any new tests.
- Companies around the world have realised just how much
money they could make if they had a test for vCJD in its incubation period
- and ideas are appearing out of the woodwork. I would be surprised if
we did not have one by this time next year. But what could doctors do then?
Will it be like the test for HIV in the 1980s? "Thank you for donating
your blood, Mr Smith, but I am afraid that you have vCJD and we will not
be able to treat you."
- In fact, a treatment is also on the way, too. In 1997
the UK government invited the pharmaceutical industry to a meeting with
the BSE/vCJD scientists. Only three companies turned up - there was no
money to be made, so why should they? In 1999 Laura Mannuelidis at Yale
showed that an anti-leprosy drug, dapsone, increased the incubation period
of scrapie in mice dramatically. Last year, an anti-malarial drug, quinacrine,
was demonstrated in the US to stop prions growing in cell culture.
- The story of Rachel Forber, the British woman treated
for symptomatic vCJD in the US with quinacrine, has just been published.
A patient in London has also started the treatment. There are now over
40 drugs that are active against prion infection and we have some that
are of adequately low toxicity to permit testing on patients.
- We expect that some of these drugs and diagnostics will
also be useful against Alzheimer's disease, a condition that is extremely
difficult to experiment on with animals or in test tubes. So we may well
find, in the end, that BSE had a silver lining. We might even end up with
government that does not deny bad news and avoid research in case of what
it may find.
- Stephen Dealler is a consultant medical microbiologist