From: TSS ()
Subject: Britain 'faces CJD epidemic' from infected beef
Date: November 10, 2007 at 9:41 am PST
Britain 'faces CJD epidemic' from infected beef
By Roger Highfield, Science Editor
Last Updated: 12:01am GMT 10/11/2007
The nation faces the possibility of a major epidemic of lethal brain disease
as a result of the consumption years ago of beef contaminated with mad cow
disease, BSE, according to Britain's leading expert on vCJD, or "human BSE".
'Dramatic' results of CJD treatment
Prof John Collinge of University College London, a Government advisor, made
the comments yesterday when unveiling a new theory of what causes bovine
spongiform encephalopathy, Creutzfeldt-Jakob disease and other
Although the incidence of variant CJD in Britain has been declining, with
only four deaths so far this year, Prof John Collinge believes that only
people who are genetically susceptible have succumbed to the devastating
illness so far. "I continue to be worried," he told The Daily Telegraph.
Official records show that 162 people have died of vCJD, after a peak of
incidence in 2000. But Prof Collinge said that many millions of infectious
doses of contaminated beef were eaten between 1980 and 1996 and there is
evidence the disease could silently incubate in a person for many decades,
without producing symptoms.
In a related human disease called kuru the shortest incubation periods are
around five years and he said it was it remarkable that, despite exposure of
babies to BSE in contaminated baby food, there has not been any cases in a
children younger than 12.
That has the "chilling" implication, he said, that the average incubation
period of the cattle disease BSE could be much longer than kuru, which is
not surprising because kuru is a human disease.
Given that kuru can incubate in a person for four decades, he would expect
even longer incubation periods of the cattle disease BSE in infected people,
depending on a person's genetic makeup. "I am afraid there are a lot more
cases in the pipeline," said Prof Collinge.
The key issue - the potential number of cases - cannot be estimated from the
current number of patients. However, based on a preliminary survey of 12,000
appendix samples scientists would expect around 237 cases per million, which
works out to be some 14,000.
Prof Collinge said, however, that because of uncertainties about the tests
used to detect the presence of CJD, this "could be a considerable
Prof Collinge made his comments while discussing a new theory he has set out
in the journal Science with colleague Anthony Clarke that provides a new
insight into how these diseases kill brain cells.
Most diseases, such as those caused by viruses and bacteria, contain genetic
materials. But BSE and vCJD are caused by a quite different kind of
infectious agent consisting of abnormal proteins. The new theory shows how
prions, the mis-shapen proteins responsible for lethal diseases such as BSE
and vCJD develop in the brain and kill nerve cells.
Earlier work placed emphasis on how abnormal prions convert normal prion
protein in the brain to form damaging lumps of mis-shapen protein, called
amyloid, in a kind of molecular domino effect. However Prof Collinge
provides evidence that this rogue protein itself does not damage the brain
His new theory focuses on how the abnormal proteins link together and
identifies smaller clumps of the abnormal proteins as the ones that kill
brain cells, not the relatively huge amyloid deposits seen in the brain.
These small toxic molecules represent "the missing piece of the puzzle,"
Prof Collinge said yesterday.
The work is striking because it suggests that other attempts to find drugs
that treat the disease by smashing up the amyloid clumps of abnormal protein
could produce the smaller, more lethal variety. "Hitting that is not the
thing to do."
His team, with the backing of GlaxoSmithKline, is working on drugs that, in
lab tests, could stop the toxic form of abnormal prion from being made in
the first place. Although this effort is still at the level of basic
research, "so far so good," he said.
This drug development work has wider implications, since other degenerative
diseases, such as Parkinson's and Alzheimer's, are thought to be caused by
Thus if this approach can be used to treat CJD, it could work in these other
diseases, which are much more common: around 120,000 people in the UK have
Parkinson's and another 700,000 have dementia.
The theory also explains some scientific puzzles, not least how
abnormally-shaped proteins can spread from one species to another, crossing
the so-called "species barrier," and how they form different strains of the
"This way of thinking can in principle explain all these different
phenomena," said Prof Collinge.
"This is a fundamental change of thinking and this model fits every piece of
data we have got. Of course, now it is the job of other scientists to try to
falsify this idea."
Major academic/industry collaboration to find a drug to treat CJDToday, an
unprecedented collaboration between the UK’s leading academic research group
working on CJD – the Medical Research Council’s Prion Unit based at the
Institute of Neurology, University College London – and the UK’s largest
pharmaceutical company – GlaxoSmithKline (GSK) - is announced.
The occurrence of variant Creutzfeldt-Jakob disease (vCJD) and the
recognition that this is caused by exposure to the infectious agent or prion
responsible for bovine spongiform encephalopathy (BSE) has led to fears of
an epidemic of human infection with BSE prions - as many in the UK
population will have been exposed to BSE prions prior to the introduction of
rigorous controls to limit dietary exposure in 1996. Although the number of
patients developing vCJD so far is thankfully relatively small (around 150),
incubation periods for prion infections are known to span decades in humans
and the number who may be silently infected and eventually develop disease
is unknown, as are the numbers of secondary infections that may occur via
contaminated blood products or surgical instruments. Because of these
uncertainties, the development of an effective treatment to eradicate prion
infection during the window of opportunity provided by the prolonged latent
period of prion infection is considered a strategic priority. However, the
rarity of CJD makes it an “orphan” disease which means normal commercial
drug development is unrealistic.
A major effort has been underway for some years at the MRC Prion Unit to
understand the fundamental and unique processes involved in the propagation
of prions – the remarkable infectious agents that cause CJD in humans and
BSE and scrapie in animals. Much of this laborious and long term work has
been to identify and validate the best target against which to develop a
drug to block prions replicating. Prions are misfolded or rogue forms of one
of the body’s own protein molecules – the prion protein – and the Unit has
shown in prion-infected laboratory animals that the disease process in the
brain can be halted by targeting this protein, without apparent deleterious
effects. The aim is now to develop a drug that is capable of readily
entering the brain and binding to the normal prion protein blocking the
change in shape involved in it turning into the rogue prion.
To do this requires screening literally hundreds of thousands of potential
drug-like molecules from large compound collections or “libraries”. One of
the largest and best characterised such libraries in existence is that of
GSK – which contains over a million such compounds. Such libraries form one
of the most important commercial assets of any pharmaceutical company and
making such a library available to an academic group in this way is
unprecedented. Peter Machin, Senior Vice President Chemistry & Screening
Sciences at GSK said:
“We are delighted to provide our compound collection of high quality,
drug-like molecules to accelerate the search for compounds that may prove
useful in the treatment of CJD”
The programme of work towards development of a candidate drug for potential
trial in humans is estimated to take at least a further six years and the
first phase of this work, which has followed a large scale initial pilot
study will start soon. The UK Department of Health has agreed to fund the
work through a grant award to the Institute of Neurology,UCL. The
partnership now forged between GSK, the MRC Prion Unit,and UCL, brings
together for the first time all the relevant expertise and resources to make
such a development feasible and may act as a stimulus to such
academic-industy collaborations in other areas of medicine.
Professor John Collinge, Director of the MRC Prion Unit and Head of the
Dept.of Neurodegenerative Disease at the Institute of Neurology,UCL, said:
“Many person years of very difficult work at the MRC have been invested to
get to the stage where development of a drug to completely block prions
appears realistic. My colleagues and I, at the Unit, are absolutely
delighted at the opportunity now to translate these advances in laboratory
research into real benefit for patients affected by these dreadful diseases
“There is only so far we can take things on our own as academic scientists
and, while there is no guarantee of success, now having the enormous
resource and expertise of GSK with us is extremely exciting”.
For further information contact the MRC Press Office on 020 7637 6011
Notes for Editors
The Medical Research Council (MRC) is a national organisation funded by the
UK tax-payer. Its business is medical research aimed at improving human
health; everyone stands to benefit from the outputs. The research it
supports and the scientists it trains meet the needs of the health services,
the pharmaceutical and other health-related industries and the academic
world. MRC has funded work which has led to some of the most significant
discoveries and achievements in medicine in the UK. About half of the MRC’s
expenditure of £450 million is invested in its 40 Institutes, Units and
Centres. The remaining half goes in the form of grant support and training
awards to individuals and teams in universities and medical schools. Web
site at: http://www.mrc.ac.uk
The Institute of Neurology is a specialist postgraduate Institute of
University College London. The Institute is closely associated in its work
with the National Hospital for Neurology & Neurosurgery, and in combination
they form a national and international centre at Queen Square for teaching,
training and research in neurology and allied clinical and basic sciences.
Website at: http://www.ion.ucl.ac.uk
Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob disease in
the United States
i am reminded of a few things deep throat (high ranking official at usda)
told me years ago;
The most frightening thing I have read all day is the
report of Gambetti's finding of a new strain of
sporadic cjd in young people.........Dear God,