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BSE-The Untold Story
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Richard Uridge investigates reports that a new version
of the brain disease CJD is taking hold in young people across the Atlantic,and
asks whether American Scientists are right to question Britain's strategy
for dealing with Mad Cow Disease,and it's equivalent in humans.
Richard Uridge :
Mad Cow
Disease.Three simple words with an almost humorous ring,but there's nothing
remotely funny about Bovine Spungiform Encephelopathy,so far it's
claimed 40 lives in Britain,and no one's sure how many more people will die.
[Compare the 40 dead people to the thousands who die of lung cancer from
smoking,or the number involved in drink driving accidents or from alcohol
damage to the brain or liver and, purely in terms of numbers and risk,one
wonders why.Perhaps because it was perceived that it would permeate the human
food chain? BSE is such a scare story -LB]
"I think we were in real difficulty with these diseases,they're biologically
obscure,they have very long incubation periods and we simply didn't have
some of the information that people would have liked us to have and we still
don't."
Richard Uridge : BSE has cost British tax payers a staggering 4 billion
pounds.More than 3 million cattle have been slaughtered,and British farming
ears to recover.Yet there's the possibility that our whole response to the
disease is will take many ybased on an incorrect hypothesis.This programme
investigates the challenges to the pillars of conventional wisdom on BSE,and
its human equivalent new variant Creuzfeld-Jacob disease.
"If we're wrong,and the route of transmission is not through eating beef,then
we have decimated an industry,and we have frightened millions of people totally
unnecessarily"
Richard Uridge : In fact,there's a serious body of scientific opinion
that believes BSE got into people through the blood stream,not the stomach.Right
or wrong,last week the British government started importing one blood
product,plasma from the US,where officially there is no BSE,and no new variant
of CJD.But American experts have told us that Britain could be making a big
mistake because there's mounting concern that a new strain of CJD is taking
hold on the other side of the Atlantic.
"We have our own BSE problem here.You know we're facing what the UK faced
a few years ago."
"Is it a time bomb,is it just something that a few people seem susceptible
to,it makes for a very bad science-fiction movie."
Richard Uridge : So our story begins in America.Older people have
been sporadically and apparently spontaneously contracting CJD for may years,but
now younger Americans are being affected,and bearing in mind that it was
young people getting CJD here that alerted Britain to a possible link with
mad cows,the trend is worrying an increasing number of people across the
Atlantic.Andrew Kimbrel is a lawyer in Washington DC,and Director of the
Centre for Food Safety.His particular concern is that the picture is
confused,because no one is monitoring the disease properly,as the case of
Douglas McKewan suggests.
Andrew Kimbrel : He was one of 7 cases in a cluster in Utah,in the
past year.Now when I spoke to Tracy McKewan,his wonderful wife,the story
that she told,what it took for her to get this disease diagnosed was
extraordinary,and they put them through every test you can imagine.He was
a man in his 30s,young kids,good job,just a regular guy. Comes home feeling
sick,feeling disorientated,not sure what's going on with him.They decide
that he's mentally ill.
Well she doesn't believe it.She thinks something's terribly wrong.So she
happens to see a guy on TV talking about one of the other CJD cases in their
area,and she says "That's what my husband has,that's what he has".So she
calls her doctor,and he says,you know,"Darling if I had to listen to everybody
who sees things on TV,and says "That's what I have" or "My husband has"...".She
says "No,that's what he has",and she then has to go to another hospital,
they won't do it,she then has to go to Washington here,where she finally
gets some NIH people to do the proper tests,and of course she has the variant
CJD,and he died.
For all we know there could be 50 or 100,but 7 who had enough courage,enough,to
get the special test,to go the next step,to figure out what's going on.This
is a very fast .....people are dying in months,they waste away in months.
[It sounds like Roy Neary in Close Encounters -LB]
Richard Uridge : Jay Whitlock is wasting away from CJD in Oklahoma.doctors
say it's a sporadic case.His wife Julie is not so sure.One - because he's
just 27 years old.Two - because the symptoms she describes are almost identical
to those who've suffered from new variant CJD in this country.It's a critical
distinction,and one which she outlined for us in this, her first ever media
interview.
Julie Whitlock : Right now,he's in a field nursing facility.He's
uncomprehensive [I think she means incomprehensible -LB],having some
hallucinations,incontinent.He still does,know me,he will hug me and hold
me,use names.He started having memory trouble in January of this year 1999.He
was forgetting phone numbers,and then when we would be heading somewhere
to go eat,he'd go past the restaurant,and I'd say "What are you doing?" and
he'd say "Well where are we going?",and I'd tell him again,and we'd be heading
home and he'd take different routes to get home,and I'd say "What are you
doing?" and he'd say,"If you want to drive,you get over here and drive".So
you know,the next time he'd take different directions somewhere,I would think
"Okay,he's testing me",you know? I'd think it was just a man thing,he was...you
know,just doing that on purpose,and then...that was through January,and it
was February 1st,his employer talked to me,and said,"You know,he's
forgetting...are you having trouble?",Jay said,"Well he's forgetting some
stuff",he said "Well he's doing it at work too",and I didn't have any idea
about that.So that's when I got him to the doctor the next day.
Most times, I feel like we're living a nightmare,and,you know,the
children,Zachary,he's...the youngest is 3,and he knows daddy's sick,he doesn't
understand any more.But the oldest,he knows there's no medicine to make daddy
better,and he will pray to God to find the medicine [A lot of good that will
do -LB] to make his daddy better.You know,so the kids are..you know it's
just continuous stress,worry and heartache.
Richard Uridge : Sadly there is no cure for CJD,and proof of whether
Mr Whitlock does indeed have the new variant will have to wait until after
his death.Only then can tests be conclusive.But if the tests are positive,how
might he and the other American victims have contracted the disease? One
theory is that it comes from eating deer or elk meat infected with a Spungiform
Encephelopathy,similar to Mad Cow Disease,but it is only a theory.Even in
Britain there is still no absolute proof,that eating mad cows gave humans
CJD,and that's something that bothers June Goodfield,a zoologist,and campaigner
for the public understanding of science.
June Goodfield : It isn't enough just to say,"In the absence of any
other viable hypothesis,this is the best one".It isn't enough,because we
have a number of things,including the fact that we have not reproduced it
experimentally in non-hum,an primates,weighing against it.It is
vitally important we find out why.It's important because,if we're
wrong,and the route of transmission is not through eating beef,then we have
decimated an industry,and we have frightened millions of people totally
unnecessarily,and I believe we could nail it down.
Richard Uridge : She says that there are experiments that could establish
this one way or another,and she argues that if eating meat was the cause,we
should have seen many more cases by now.
June Goodfield : If you think of the tons of BSE infected hamburgers
that have been fed, probably,to British children,if eating BSE infected meat
was the cause of new variant CJD in human beings,we would would be expecting
to see evidence of this in that age group and we are not seeing it.[Not if
it has very long incubation periods-LB]
That is a very significant epidemiological fact.
Richard Uridge : The mainstream consensus among British experts that
is despite the lack of absolute proof,the government had to act on what remains
a very probable explanation.Alan Dickinson,carried out much of the ground
breaking work on Scrapie,the sheep brain disease, which many people believe
was the cause of BSE in cows.He thinks eating infected material from mad
cows is almost certainly the way humans got new variant CJD.His careful not
to blame per se,he says the more likely culprit is infected brains,spinal
chord or offal,which then got into pies,sausages and burgers.
[If this is true why aren't dogs and cats suffering from CJD or BSE as,those
products are more likely to end up in dog and cat food? -LB]
Alan Dickinson : The fact that 20-30 people have got BSE,I think
is indisputable.The fact that they have got it from something that you would
be likely to buy in a supermarket or a butchers shop,I think is a very,very
high, probability. Alternative probabilities,I see
no reasonable ones for accepting.If you have a hit-and-run accident,and the
car is never found,you are in a reasonable position to conclude that it was
a car that did it,for a variety of reasons.I think we're in this same position,of
saying,a bovine product of some sort.....a bovine food product of
some sort,has been the origin of these cases in humans.
Richard Uridge : Our search for clues now takes us back to the late
1950s,when the American Nobel Prize winner Carlton Gadusek,was working with
the Foray people in Papua New Guinea.He was intrigued by a brain disease
called "kuru".Why,he wanted to know,did only the women and children of the
tribe suffer from it.June Goodfield is one of Dr Gadusek's contemporaries.
June Goodfield : The men of the Foray were the ones who were responsible
for going hunting, and they went off,and they would sort of kill a few wild
pig or what have you.But they kept the spoils of the hunting for themselves.On
the whole,the women of the Foray ate vegetables,roots and tubers and what
have you,the occasional rodent.But often had very little meat,and they would
from time to time,as they prepared the bodies for burial,put slivers of the
meat from the flesh,and eat them and give them to the children,or they would
put the brain tissue into a little bamboo and steam it and eat it.But anybody
who says that Carlton Gadusek believes that cannibalism was the route,is
misrepresenting what Carlton Gadusek thinks,and I know because I've asked
him,and I've quoted it in my book,and I know because I've asked Joe Gibbs,and
I've quoted it in my book.
[There was a TV programme that claimed that a tribe,maybe the same one,had
the women and children eat the brains of the dead males,maybe this was the
misrepresentation -LB]
Richard Uridge : Gibbs worked with Dr Gadusek,so we spoke to him in
his office in Maryland,and asked him about his experiments with chimpanzees
to test the theory that eating brains spread kuru in the Foray tribe.
Joe Gibbs : The first experiments we did were to put stomach tubes
into the animals,as you would for a gastric analysis,and through those tubes,we
introduced copious amounts of highly infectious,known to be transmissible
kuru,CJD,and nothing has ever happened to those animals.
June Goodfield : Faced with the fact that experimentally they could
not reproduce this route of transmission,that is eating,in the laboratory,they
were faced with the fact,"How on Earth did the young children and the women
of the Foray get the infected agent?".The only way that Gadusek and Gibbs
could experimentally reproduce this,was by inoculation in some form.
Joe Gibbs : Somewhat later,in the course of our studies,I designed
an experiment,in which I took squirrel monkeys and starved them for two or
three days,then allowed them to handle the infected tissues,from other primates
that had developed the diseases,kuru,CJD and Scrapie and in doing so,they
consumed the infected tissues.I think in most cases it was upwards of around
80 grams of tissue and all of these squirrel monkeys,both,for kuru,CJD and
Scrapie, all developed disease.They have positive pathology and we extracted
the prion protein
from their brain.So it was,yes we transmitted orally,but letting the
animals handle the tissue and consume the tissue,rather than putting it directly
into the stomach of chimpanzees and other small
monkeys.
June Goodfield : And they finally came to the conclusion that if you
looked at the kids and the women,you know they're not living in
antiseptic,sterile conditions,they're living in close contact with the
Earth,where they have cuts and sores on their hands,where if they are scrabbling
with their hands in the bodies or the brain tissue,their inoculating themselves
through open wounds or they've been handling a bit of material and they rub
their eyes,and it's coming in through the mucus membrane,or they're picking
their noses and and it's going in through the mucus membrane there.They believe
it was self inoculation.it's inoculation through some way getting into the
blood stream.
Joe Gibbs : And they had multiple,multiple,multiple,routes of
inoculation.Lesions on their skin, in their eyes,in their mouths,and other
lesions caused by puni grass cuts and by leeches on their bodies and so
forth,mosquito bites.All these provided a ample means of infectivity.
Richard Uridge : Put simply,these experiments suggest that primates
are infected while eating,but not by eating.In other words by inoculation
rather than by ingestion.But "so what if it does?",says Dr Ros Ridley,of
the School of Vetinary Medicine in Cambridge.
Ros Ridley : Whether the infectious material got in through cuts
in the skin,cuts in the mouth, perhaps with bad teeth or whatever,or whether
it was because they swallowed it,is,in a sense, immaterial.They contaminated
each other with the brains of their dead relatives by handling that material.Now
if we look across now to the new variant CJD and we look at those people
who have become infected,they are absolutely,perfectly normal people leading
perfectly normal lives in Britain.They have not inoculated themselves with
some strange material.They don't have strange professions.They don't work
in abattoirs,or they don't dissect animals up,or anything of that sort.They're
just ordinary people.What they have done,of course,is to eat beef in many
forms,not just the recognisable meat form,but prepared foods of various
types,everything from sausages onwards,potentially contains beef from various
parts of the carcass,and so in their case,the likelihood that it is eating,rather
than some other means of introducing bovine material into the body,seems
overwhelming,because they are such ordinary people.
Richard Uridge : In the course of making this programme,we discovered
that despite the proclaimed ordinariness of its victims,an abattoir worker,Jason
Keat,has died of new variant CJD,and if transmission is through blood,as
we have already heard that some scientists believe,could vaccines or or other
medicines containing things like calf serum,have played a part?
The year long BSE enquiry which was due to have reported its findings next
month,has looked into that possibility,and sections of the food industry
have perhaps naturally,been keen to cast doubt on the infected meat theory.So
could it have been vaccines? Professor Robert Will heads Britain's CJD
Surveillance unit based in Edinburgh.
Robert Will : I personally believe that's highly unlikely,because
if there was any infectivity in calf serum,it will have been at a very,very
low level.
[People are worried about the very very low level of microwaves in cell phones
which may be producing brain tumours.Level is not the question.In principle
is the question.As Chaos theory shows,small things can have big effects.So
how low the level is may not be relevant.Although longer time exposure and
power level may be relevant in cell phones,so maybe level is important -
LB]
Whereas I think that we know there probably was a high level of exposure
orally to BSE infection through the food chain.The other issue is that when
vaccines are given,they are only given in a very tiny dosage,once,and so
the level of exposure,as far as I'm concerned is likely to be minute,compared
to other types of exposure that almost certainly did take place.
There is further concern,however,about the issue of blood and perhaps surgical
instruments. As far as I'm concerned from the evidence we have on classical
CJD,I don't think there is any good evidence that this form of CJD has been
transmitted through blood or blood products.We can't be absolutely certain
about that,which is why more work is being done, epidemiologically,and also
to do with transmission studies.However,new variant CJD might be different,and
the reason for that is that I believe it's due to a different infectious
agent,and we have evidence from Dr Ironside's work that the tissue distribution
of infectivity in the body foe example,in the lymph nodes and spleen,is likely
to be much higher in new variant CJD than it is in the ordinary form of CJD,and
that does raise legitimate concerns about the possibility of blood or blood
products resulting in on ward transmission of new variant CJD from an individual
who is incubating it to someone who receives the product,and for that
reason,although there are enormous uncertainties about the type of risk
[Ref:Video:BB14:RI 3; N30:The Numbers Game;OB4
Equinox
{Living Dangerously};Protext Files;Green
File Mindfld.wri;Red File:
Reith992.wri],that's involved,or the level of
risk,a number of actions have been taken,for example in the UK plasma
products,that are derived from blood, will be sourced from plasma...derived
from outside the UK,from the middle of this year,and there's also plans to
remove the white cells from all blood donations throughout the UK. So,I
think,although this is a theoretical risk of onward transmission,it's something
that has been taken very seriously,and action has been taken.
Room for a Moo? |
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A FARMER hit hard by the rural crisis is giving away his cows
to anyone who can offer them a good home. Broadbottom farmer David Gould
says plummeting market prices are making life near impossible for dairy farmers.
Prices have dropped so low that some farmers routinely shoot calves dead
just after birth in an attempt to stem spiralling losses.
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Richard Uridge : The process of leuko -depletion - filtering out white
cells,in which the infective agent is thought to be more concentrated,won't
start until November.But the Department of Health told us that the decision
to source plasma from countries without BSE came into effect just last week.Then
they told us that the imports are coming from the US, where as we've been
hearing,there are growing concerns that CJD is spreading to much younger
people than normal,27 in at least one case.but Professor Will says there's
no evidence of a new variant of CJD that can't be traced to Britain,and anyway
these are only precautions against a theoretical risk.Alan Dickinson
agrees,although he did find the infective agent of the sheep brain disease
Scrapie,in blood during his research.
Alan Dickinson : You're not dealing with solid tissues,you're dealing
with serum and blood which can have small amounts of infectivity.I think
I was the first person to show that.I regarded finding it on a small proportion
of occasions ,in heart,blood,as really an index that my crude method of
extracting blood from a heart,was sufficient to incorporate quite a lot of
heart tissue and blood cell lining tissue.I'm sure I was doing it far more
crudely,and one would hope that more is known now about this.....you can
hear me perhaps doubting this,more is recognised and appreciated about the
ease of cross contamination of these kinds of products when people think
they are dealing in clean room situations with safety cabinets.These words
are dangerous in their own right.
Richard Uridge : There are other doubts about the official British
position on CJD,and again they arise from the investigations into kuru,in
the Foray tribe of Papua New Guinea,and later work by Joe Gibbs.Essentially
the question boils down to how new is new variant CJD? Twenty years ago a
neurosurgeon died in Boston,apparently of sporadic CJD,but as Joe Gibbs
explains,later examination of his brain,revealed the classic symptoms of
the new variant.
Joe Gibbs : I maintain that the so-called florid or daisy plaques
that they refer to in new variant, occurs outside of the UK in cases,and
I've shown them in kuru,chronic wasting disease of deer and elk are
massive plaques with vaccules around them,and then the paediatric neurosurgeon
in Boston who died.he was first diagnosed has having a very rare skin disease
called Almeyer Dago's Disease,and that disease he did have,but then he started
to develop neurological signs,and ultimately died and we received the autopsy
tissues on him.We demonstrated that he had the prion protein in brain and
in lung tissue and it turned out to be the very clear sporadic type of CJD.Now
my argument here is that,I'm not sure what are the restrictive clinical and
pathological characteristics of so-called new variant,because I can show
a number of these things in sporadic cases.I can show people that have gone
for psychiatric evaluation,then they developed ataxia and had an extended
period of clinical progressive disease over a period of 18 months - 2 years,but
they turned out not to have new variant,according to the UK description.
Richard Uridge : British CJD experts have also examined the Boston
neurosurgeon's brain tissue.Professor Robert Will believes Joe Gibb's theory's
based on a misunderstanding.
Robert Will : Well I think there's a whole wealth of evidence now,that
suggest that new variant CJD is a new disease.For example,when the original
paper was published in April 1996,one of the things we put in that paper,was
the importance of reviewing other neuropathological information from the
past,in other countries,to see whether this disease had been seen before
elsewhere,and since then we have not been informed or been able to identify,any
other case which fulfils the neuropathological appearances of new variant
CJD.Now I think there's a slight misunderstanding here,because although florid
plaques are a very important component of the diagnosis,neuropathologically,the
fact that there is a single or one or two, florid plaques,is not the issue.The
issue is that these plaques are widely distributed throughout the brain.So
it is true that occasionally,a type of florid plaque has been seen other
cases,you know single or one or two florid plaques,for example,in the case
you mentioned,of the neurosurgeon,and also in another case,with dura mater
related CJD,but these cases have been reviewed by Dr Ironside and by other
neuropathologists,and the view I think,is clearly that the occasional florid
plaque does happen sometimes,but the overall neuropathological appearances
do not look at all like new variant CJD,and the general consensus among the
neuropathological community is,according to my understanding,that new variant
CJD is indeed a new disease.
Richard Uridge : Another of the commonly held beliefs about BSE concerns
the role played by the animal feed industry.However unsavoury it sounds,renderers
turned animals carcasses into animal feed.Sheep were fed to cows,and cows
were fed to cows.
[Then if the farming community was decimated they have only their greedy
exploitative selves to blame -LB]
Everything went into the pot and was cooked to produce meat and bone meal,then
the temperature of the whole process was reduced,ostensibly to save on fuel,and
the assumption is it was no longer hot enough to kill off the infective
agent.More recent experiments have shown that's probably not true,because
even the higher temperature doesn't work.Only one condition does.It's called
"pressure cooking",and is now widely used in mainland Europe.Paul Foxcroft
is Sales Director of the rendering company Prospa de Molder. He doesn't dispute
that BSE was spread by infected feed,but now thinks a combination of things
caused BSE to explode in Britain and only in Britain.
Paul Foxcroft : You've got more,unknown to anybody,more active Scrapie
agent in the meat and bone meal,year upon year,as more and more sheep are
slaughtered.Perhaps a sudden boost of active Scrapie agents within the meat
and bone meal again as if there was an increase in the incidence of Scrapie
within the sheep flock.You have more meat and bone meal,more then of that
meat and bone meal going into the dairy feed,you then have more of that dairy
feed being put into the cow.Now I don't believe that combination of circumstances
has existed anywhere else in the world,at that same time.We could be perhaps
a little mischievous and raise the possibility of organophosphates as maybe
a predisposing factor.There certainly could will be genetic factors in terms
of genetic susceptibility,as the gene pool is narrowed if you like,with
artificial insemination over the last several decades, where we've perhaps
used bulls with a susceptibility,or lack of resistance,whichever way you
want to term it,into the herd...national herd.Therefore,it's almost a
lottery,we've hit this horrendous jackpot,at least we got all the numbers.There
are plenty of other countries out there that have perhaps only got 1,2,or
3,or 4 of the numbers and for that they get nothing.
Richard Uridge : So why are the numbers coming up in America now?
What special combination of circumstances exists across the Atlantic? Michael
Hanson of the US Consumers Association believes his governments rules about
what goes into animal feed are far too lax,and that they just aren't looking
hard enough into the problem of CJD.
Michael Hanson : There is the problem of "if you don't look,you don't
find".They tend to be concentrating on supposedly looking for a British style
BSE case,they're not focusing on intensively sampling animals that might
be at risk.So the brain chemistry,the neuropathology that they're looking
at,they're looking for the very obvious signs,like you see in BSE cattle
in Britain.They're not looking for more subtle signs,and even though there
is a quotes "surveillance system",we think it's highly flawed,and while there's
no direct evidence,I think there's indirect evidence that there might be
a TSE existing in food animals,in the US.
Richard Uridge : Andrew Kimbrel,the lawyer from the Centre for Food
Safety,who told us that America was having its own BSE crisis has a shopping
list for his government.
Andrew Kimbrel : We just filed a formal legal petition saying "make
CJD a reportable disease" which it is not in this country,even though we've
seen explosions of cases,for goodness sake "stop feeding ruminants to
ruminants".We're asking exactly for the UK regulations on feeding animals
to animals,which we don't have in this country."Blood Supply",and an
investigation on why in the world our wildlife is coming down with TSEs,at
such an alarming rate.
Richard Uridge : So what are we to make of the developments in America?
And what can they tell Britain about its pillars of conventional wisdom on
mad cows and CJD? I went to see the man who advises the British government
on these issues,the chairman of the Spungiform Encephelopathy Advisory Committee
or CEAC,Professor Sir John Patterson.I asked him first about the cases of
CJD in younger people,and the claims that America now has a new variant of
the disease.
John Patterson : It's very difficult to comment on that usefully.All
my experience on the UK CEAC tells me that you really need to know all the
details of any cases or any problems that are being posed before commenting
on them.But if it's true that there are some cases of human Spungiform
Encephelopathy in unusually young people,then I think now we have some clear
definitions of the clinical state of those patients,we have some modern imaging
techniques,for doing MRI scans,and most particularly we have some laboratory
based biochemical tests that can be applied to material from these patients
which should be able to define the situation much more clearly,and I think
you need to get all those details first,before judging what the significance
might be.
Richard Uridge : But it wouldn't surprise you,or perhaps it would,if
there were 40 cases eventually, in America over the next 2-3 years?
John Patterson : Oh I think it would surprise me enormously if that
were the case,and that's why one would want to know all the details of any
such case,let alone 40,before commenting on it.
Richard Uridge : One of the conventions,with BSE is that it was caused
by people ingesting the infected agent...infected meat,yet some experiments
carried out by Carlton Gadusek in he 1950 showed that it might actually be
through blood contact.Has his work been disregarded in building the current
hypothesis?
John Patterson : No,not at all,I mean it's clearly recognised that
there are a number of ways of transmitting Spungiform Encephelopathies.You
refer of course,to the peripheral route of inoculation,blood to blood,and
you would have to say that in that context,the most vulnerable people would
be those that are occupationally exposed because they work in abattoirs,and
to date,there have been no cases of variant CJD in abattoir workers which
would link the occupation with the exposure.
Richard Uridge : What about the death of Jason Keat? He was an abattoir
worker in his 20s, on his death certificate it says that he died from new
variant CJD?
John Patterson : You,you...I mean I ....It may surprise you to know
of course that I can't relate individual names to individual cases.It is
true that there are one or two people that who've classical CJD who've worked
in abattoirs,and if you tell me that Jason Keat was one of those with variant
CJD who also worked in an abattoir,then I accept that,but then there 39 other
cases,who didn't and it's very difficult to unify those 39 cases with a
hypothesis about blood to blood transmission.Whatever his occupation he
probably,like the other 39 cases,was a consumer of beef products,which would
be the most likely hypothesis for the way in which BSE was contracted.
Richard Uridge : You don't think 1 in 40 or 1 in 41 is significant
then?
John Patterson : Er no,I don't think it is,in the same way that one
of the cases we know had been a vegetarian for many years,but if you trace
back the history of that individual,to the point at which she became a very
strict vegetarian,then it's most likely we think,that she was exposed to
beef products before she became a strict vegetarian and the occurrence of
one case we don't feel necessitates altering our proposal about the most
likely route of transmission.
Richard Uridge : But it is just a hypothesis,at this stage.Is it possible
that another hypothesis would explain transmission and that is that is that
vaccines have somehow played a role?
John Patterson : I think that the CJD surveillance unit and Professor
Will in quite a long and extensive questionnaire to the families of each
of these cases,and looking all the time for occupational exposure,geographic
clustering,medical histories,histories of operations which might unify all
these 40 cases,then you cannot find such evidence.
Richard Uridge : And in the absence of any other evidence,the current
hypothesis is the best one,in your view?
John Patterson : I think it is,yes.
Richard Uridge : If I can turn to the use of blood and blood products.Is
there a concern that BSE or new variant CJD should I say,could be spread
through blood products?
John Patterson : Yes,and this is going back a little while now,but
of course CEAC made some recommendations to the government about
that,particularly in relation to removing the white cells from blood
transfusion,and the technique which is called leuko-depletion is being extended
to become comprehensive in the UK blood transfusion service as soon as possible.
Richard Uridge : Because the white cells actually carry a greater
proportion of the infective agent?
John Patterson : Again the evidence is very incomplete in this,but
if you think about it intuitively,and you say "we must apply the precautionary
principle",then it seems logical to remove the white cells,as the most likely
component of blood which would transmit the infection.
Richard Uridge : Why is it that precautionary measures are being taken
only now?
John Patterson : Well it takes quite a long time of course to set
some of these processes in train....
Richard Uridge : That's 3 years potentially in which people could
have been infected person to person.
John Patterson : There is a possibility that if variant CJD is
transmissible by blood or blood products,and that some of the cases we know
have been blood donors,that it might have been transfused from one individual
to another,that's exactly the sort of eventuality that one is trying to
prevent,from people who are currently incubating variant CJD,but haven't
actually manifested it,yet.That's why those precautions are being taken.
Richard Uridge : Might it not have been more sensible to take that
precautionary measure at the outset? It didn't seem that it was a problem
taking precautionary measures as far as the beef industry was concerned
quickly,so why not the medical industry?
John Patterson : I think that's exactly right,because of course the
proposition was that the source of cases of variant CJD was oral exposure
to beef products which contained some of the specified offals,most notably
brain and spinal chord.So it was important really to shut that door as quickly
as possible.There was then a need to look at the evidence about the transmission
of classical CJD via blood transfusion,and there the evidence is conflicting,and
by and large there,the conclusion has to be that classical sporadic CJD is
only very rarely transmitted by blood transfusion, if at all.
However,it then became clear that variant CJD was behaving
differently,particularly in relation to the phase of the infection in humans,in
the lymphoid tissues.You can find the agent of variant CJD in the spleen
and in the tonsils and in the lymphoid tissue in the appendix,and so one
had to recognise that it was possible that circulating lymphocytes also contained
this agent.There was also a developing body of knowledge about animal
experimentation using mice,which led one, taking all this into account,to
recommend to the government that leuko-depletion would be a sensible
precautionary measure.Now that all took time to develop,time to think about
and then of course,once you've made the decision,time to implement.So that's
where you get the apparent delay from.
Richard Uridge : Finally,are we now any nearer to breaking the deafening
silence on the crucial question? How many more people will die from variant
CJD in Britain? We've seen estimates prepared for the Royal Society,based
on the number of cases so far.Depending on how you interpret them,the projections
are either good news or chilling reading.They indicate there could be as
few as a dozen or so more deaths,or as many as 13 million.
John Patterson : That was one of the major questions that was asked
immediately on March 20th 1996,and the answer then was that there was a very
broad range of possibilities.Three years later and fortunately the range
of possibilities still remains very wide,and so,to be honest I think the
only that we will tell,is to wait for another 2 or 3 or 5 years before we
can answer...we can narrow down that range usefully for you.
Where did BSE
come from? |
Is any meat safe to eat? |
Why was the public
told that beef was safe and that BSE could not be transmitted to humans?
| Channel 4 Report