Examination of Witnesses (Questions 160
- 179)
WEDNESDAY 7 NOVEMBER 2001
PROFESSOR DAVID
KING, PROFESSOR
MARK WOOLHOUSE
AND DR
BRYAN GRENFELL
Mr Lepper
160. Before we leave this question that Austin
Mitchell raised a little while ago, about the speed with which
action was taken to develop the ideas being produced by John Collinge
and his colleagues, you did say, I think, that that is a matter
that you are investigating, or that you are looking at, the allegations
that there had been delays in processing that work?
(Professor King) Let me clarify. My own position is
always to look ahead, so what I am very keen on is to establish
that the tests are conducted as quickly and as well as possible
from this time on. I am not looking backwards to lay blame. So
thank you for the offer to clarify that point. I am not going
to be investigating what went on in the past. I would say, however,
that the prioritisation of TSE research, which is a matter for
the High Level TSE Committee, it is also a matter for DEFRA, is
very much at the centre of this; and we are talking about very
expensive research, we are talking about very large sums of money
being spent on this very difficult area of research.
161. Do you think that those allegations about
delay should be investigated, if not by you by someone else? In
the programme that Austin Mitchell referred to, the `Today' programme
of 2 November, it was not just John Collinge who was expressing
his concern that the work that he and his colleagues had been
doing in 1996/97 had not been taken forward by the VLA at a faster
rate, but David Lindsay, former Head of MAFF's Food Science Division,
in the same programme, made rather more wide-ranging allegations
about the attitudes at the VLA supporting the producers' interests
rather than any others, and delaying other aspects of research,
not just into this particular issue?
(Professor King) Chairman, I know about the allegations,
but, I hope you do not mind my saying, I have little interest
in that area, precisely because I want to move ahead. My appointment
dates back a year and I simply want to move ahead with the best
possible speed from where we are now.
Chairman
162. Just out of interest, the expenditure at
MAFF and DEFRA, the expenditure on scientific research, has that
gone up or down over the last decade; MAFF-cum-DEFRA's expenditure
on scientific research, are you aware of what has happened to
that over the last decade? Being aware, are you happy, and if
you are not aware are you going to find out and then tell us if
you are happy? The science spend from that Department has gone
down consistently over the last ten years, I think, bar one year;
it does look like this always gets the squeeze, does it not?
(Professor King) Can I answer your question more broadly,
and this is not an attempt to duck it at all, but the Prime Minister
has asked me to do a cross-cutting review of the level of science
advice and science activity in all Departments of Government;
and, of course, DEFRA is very much in that cross-cutting review
process. As you probably know, we are about to appoint a Chief
Scientific Adviser to DEFRA, as a result of that process, and
I am confident that the incoming Chief Scientific Adviser in DEFRA
will have a very clear view, in a short period of time, as to
what the research expenditure in that Department should be, what
an appropriate level of expenditure should be. Again, I do not
wish to comment on what has been happening, but I do believe that
the combination of the BSE crisis, the swine fever, the foot and
mouth disease crisis, indicates that we need perhaps a greater
level of scientific research to back up the work of that Department
than we have had.
Chairman: You have still got bovine TB rumbling
along, of course.
Mr Jack
163. The Government have taken powers, in the
Animal Health Bill, seemingly to speed up the elimination of those
genotypes which can carry scrapie. Is it necessary to accelerate
this process, because the industry have argued that the voluntary
work they were doing was sufficient, they were moving as quickly
as they could within their resources to achieve it? I am just
anxious to know if it is scientifically necessary to have these
powers?
(Professor King) If it is scientifically necessary
to have these powers, in order to ...
164. Speed up the process of the elimination
of those sheep which are carriers for scrapie. The industry argue
they are doing enough work as it is, they are moving as fast as
they can with the resources that are available to them to eliminate
the scrapie-prone sheep and replace them with ones that are not
so prone, and yet the Government want to speed this process up
with these powers. Do they need these powers to do that; and,
if so, why?
(Professor King) Let me give a preliminary answer
and then I will ask Professor Woolhouse to help me. The first
answer is that the observation of scrapie in sheep on the land
depends on symptoms developing, and, as we know from cattle, symptoms
tend to develop in older animals; it is true that scrapie symptoms
come through a little earlier, but, nevertheless, the ability
for farmers to pick up scrapie in sheep is therefore not so great
because, on the whole, sheep are killed at one year to 15 months
old. So the level of scrapie currently reported is, I am sure,
a significant underreporting. And so, until we do scientific tests,
I do not think we can have a real certainty about the true level
of scrapie. If you were to ask me what is the current number of
scrapie sheep in the country, I would have to give such a broad
spectrum of answers, somewhere between 1,000 and 20,000; but let
me ask Professor Woolhouse, he is the expert.
(Professor Woolhouse) Scrapie is not a new problem;
some time over 200 years ago Parliament was being petitioned by
sheep-breeders to do something about the scrapie problem then,
over 200 years ago. There has been a lot of selective breeding
since then, and it has not eliminated scrapie from the UK. The
new tool we have is this very rapid genotyping test, but, even
so, selective breeding has always been a slow way of eradicating
a disease, so anything that can be done to speed that up would
certainly be beneficial in terms of the disease control.
Diana Organ
165. The only reason that we have been doing
the looking at whether BSE is in sheep is that, obviously, we
were most concerned when BSE was reported in cattle, because it
moved across to humans in New Variant CJD; is that not right?
We are not particularly concerned about BSE, as such. We have
now taken all sorts of precautions, from removing certain materials,
killing cattle before 30 months, before they go into the food
chain, so that BSE does not jump again to humans. Can I just ask
you two things. One: if we did a test of cattle in the field now,
would we find BSE in bovine brains, in the natal herd?
(Professor King) And what would the incidence be.
166. Yes?
(Professor King) That is a good question, which I
would need to give you a written answer on. I do not know the
numbers. But the answer has to be, yes, that there would be some
incidence of BSE in cattle today, and the incidence is dropping
all the time since we stopped feeding meat and bonemeal in 1996.
So we have a strong decay of incidence of BSE in cattle.
167. Exactly; that is the point of why we did
the IAH study, because, am I right, that the cohort of, say, sheep'
brains that we thought we were looking at were a cohort of brains
that had been fed the same kind of feed that had had animal products
in that feed?
(Professor King) Precisely.
168. So they were the important group of sheep
that may have gone into the human food chain, which is why they
are concerned about human health. But is not the whole problem
with all the other modelling and all the other experiments that
you have done that those cohort of brains were a one-off, we only
had that one group and they are now lost to us? So we do not know,
or ever will know, whether there was BSE in those sheep that had
been fed that unregulated feed and that therefore caused a human
health problem?
(Professor King) I do not think that what you have
just said can be said at this moment until we have seen the audit.
There could well be a pool of sheep brain from that period that
is still capable of being tested, or it might have been tested.
169. But if there is not, for one reason, we
have a real problem, do we not, we will never know whether humans
may get CJD as a result of BSE in that group of sheep that went
into the food chain?
(Professor King) We may never know, this could be
right, but, on the other hand, let me just give you one factor;
if we look at the scrapie incidence in the sheep population as
reported, and I have just said that this is a difficult number,
but, nevertheless, as reported, this number has not changed very
much. So through the period of meat and bonemeal feeding, cutting
meat and bonemeal, we do not see a significant change.
170. Because you were asked at the beginning
by the Chairman about basically can we tell the public is lamb
safe to eat, and you gave the statistical answer, yes, because
the 95 per cent confidence means, and so on and so forth. Could
you make the same assessment of somebody saying was lamb safe
to eat in the early 1990s?
(Professor King) No.
171. Can we move on, actually I am going to
make a huge leap now, we are going to go and talk about the contiguous
cull during the foot and mouth epidemic. My constituency, the
Forest of Dean, had a huge amount of contiguous cull going on,
and it was the most controversial bit of the policy; and I understand,
obviously, from the FMD story, the film, the piece of paper you
have given us, that on your modelling you believed, and probably
it is true to say, that the action of a quick cull of infected
animals followed by a contiguous cull was the way to flatten this
curve of incidence. But you had said, had you not, that there
was only a 17 per cent chance of the virus spreading to each contiguous
property, and I think that is in the House of Commons, when a
question was asked before; so why, early on, did you make this
assumption that that was the answer, that every property that
was a contiguously infected area, it should be culled, was it
not just a case of if in doubt cut it all out?
(Professor King) No, not at all; so thank you for
giving me the opportunity to explain this. If I could start by
saying that if I have a farmer report an infected premise, in
other words, the farmer sees symptoms of disease on one or two
or more of his animals, and the vet comes on site the same day
and confirms this, we then know that we have a virus factory at
that point of the British Isles. And so rule number one is cull
those animals as quickly as possible, stop the virus factory in
its tracks, but it has already been a virus factory for a few
days before the symptoms appeared. So it is very likely, and the
17 per cent, on average, five neighbouring farms to a given farm,
and each farm has the probability of 17 per cent of having been
infected already, the only way you are going to get ahead of an
outbreak is to stop the next virus factory before it becomes one.
So to get ahead of it you have to say, "I will take out all
the neighbouring farms, because if I don't, if I allow ..."
you see, at this point, I do not know which is the farm that has
got a 100 per cent chance, I only know it is 17 per cent. So if
I take them all out I stop the disease in its tracks, but if I
do not, if I leave that farm to develop before I take it out and
then find out which was the one of the five that was going to
go down, it has become a virus factory; and, of course, what it
is going to do is infect, a 17 per cent chance of, its neighbours.
So, eventually, your farm, that was the one that was healthy animals,
that you are saying we took out healthy animals, your farm might
not have gone down with the first farm that went down, but with
the second the chances go up again, and the third. So the problem
is one of statistics, and that is how we had to bring this under
control.
172. But when we were implementing that policy
it was carried out by officials looking at maps, saying, well,
there is this farm, as you say, the farm in the middle and the
possible, statistical five farms around it; there was no taking
into account topography, local climate. I had a situation in one
where between the infected herd there was a river, there was a
ditch, there was an empty field, there was a hill, and then there
was another herd, and the fields in-between had not been used
for grazing. That was never taken into account, it was just, "If
your border borders on the other farm, I'm sorry, you take all
your livestock out." And it seems that really it was sort
of a computer performance rather than what would likely happen
in a spread of disease?
(Professor King) If you were to ask me now would I
again give the same advice, in the same situation, my answer would
be, absolutely; and this disease may well have been stopped now,
Chairman.
Chairman
173. An absolute yes, I take it?
(Professor King) Absolutely, yes. I believe this disease
has now been brought to a stop. I very much hope so. We have got
to keep our—
Diana Organ
174. You would not refine it at all, the contiguous
cull?
(Professor King) The point at which it became refined,
and I was involved in that refinement, was when the arguments
that you are making were made, and we said, fine, if livestock
have not been able to get near a boundary within 50 metres then
we would not do the cull, if, clearly, for all the reasons you
have given, within 50 metres. The problem was, this then gave
rise to lots of discussions on the field and the net result was,
and I can assure you that my colleagues have analysed this in
detail, the reproduction factor for the disease went up in that
period. Injunctions were taken out; as soon as the injunction
is taken out you have got a virus factory for days. And of those
where injunctions were taken out, in some areas, 30 per cent of
the farms went down with the disease while the injunction was
out. So I hope you will understand.
175. But if there had been, which you are saying
now that there is, an active test, as Professor Brown had said,
that we could have carried out to test whether those suspected
animals on the contiguous holdings were animals that did not have
the disease, would we still have gone ahead with the contiguous
cull?
(Professor King) I am going to let Professor Woolhouse
come in, because I know he is dying to deal with this question.
But let me just repeat what we said in answer to an earlier question,
that Professor Fred Brown's fast-cycler has not been validated,
in fact, it has not passed the first hurdle.
176. But if it were?
(Professor King) If it were validated, we would be
in a different situation. If we had vaccines that were smart vaccines
that would produce labelled molecules that would enable us to
differentiate, using serology, between a diseased animal and an
animal that had been vaccinated, we might even have used vaccination,
but the state of science is such that PCR technology was not available
to us. Yes, it would be wonderful to be able to go into those
neighbouring farms and quickly, that is the essence of it, quickly,
find out which of those farms was already going down and just
take that out, that would be ideal.
Chairman
177. This takes us to the heart of the Bill,
of course, and not just for treatment of foot and mouth, the heart
of the Bill. Are you able to come up with any idea of to what
extent the epidemic was accelerated, or promoted, or made more
continuous, because of the attempts to prevent the contiguous
cull taking place, and could you put any sort of figure, or give
us any sort of framework which would enable us to say that people's
attempts, people's taking out injunctions, people's going to a
high court, materially contributed to the spread of the disease?
(Professor King) Chairman, the two colleagues I have
brought with me are the experts in this area, and they have published
a paper recently, I think it has just appeared, which gives a
detailed analysis of the British outbreak in just these terms.
(Professor Woolhouse) Mr Chairman, the first thing
to say, and that bears on an earlier question, is would you do
the contiguous cull again, and the answer is yes, and, yes, that
is the best we have at the moment. And the reason we suspect that
it is a very good way of controlling the disease is because where
it was not done fully, within the neighbourhood of an infected
premises, say, within one and a half kilometres away, that is
where 50 per cent of all new foot and mouth disease cases arose,
they arose in the immediate vicinity of a previously infected
case. Now they were missed for all sorts of reasons, some of them
were not defined as contiguous by the geographic criteria that
was mentioned earlier, some of them were the subject of injunctions,
some of them were spared on veterinary grounds, but that is where
the foot and mouth disease arose, half the time within one and
a half kilometres, or so, of a previous case. And, for that reason,
if we were to revise the policy now, we would have to look very
hard at extending the cull within that immediate area. And I fully
support the comments that were made earlier, that anything we
can do to target that cull more effectively would be very beneficial,
but anything we do that weakens the cull means that we risk losing
control of the disease again, and, therefore, in the long run,
losing more livestock. You have to balance those things. So research,
yes, into targeting, it has not been done yet, it will be done
very rapidly, we hope, and see whether we could minimise the cull
that way; but in the meantime we know where foot and mouth disease
is likely to turn up, and that is in the immediate vicinity of
a previous case.
(Dr Grenfell) Just to reinforce and to come back to
the question of a framework. In our paper and in our analyses
and advice to Professor King, we found, using our modelling, that
use of a very prompt contiguous cull would have led to a significant
reduction in the numbers of infected premises and the numbers
of culls. But the key point is also that four independent sets
of modelling, ours, Professor Woolhouse's independent set of modelling,
the Imperial College team and DEFRA's modelling, all came up with
this qualitative result that, because of the intense local movement
of the infection that we have seen in this epidemic, which is
what Mark has just talked about, we have to do prompt culling
but also in the neighbourhood of infected premises.
Diana Organ
178. Dr Grenfell, you said that, of course,
prompt culling is what has made it so successful, particularly
with the policy of a contiguous cull. How successful were we though
at being prompt about it; did we ever reach the 48-hour contiguous
cull in the areas that were affected? I tell you, in the Forest
of Dean, we did not.
(Dr Grenfell) I think Mark is more of an expert on
the timing.
(Professor Woolhouse) In the early stages of the implementation
of contiguous cull, that target was not met, generally, it was
met occasionally. All the analyses that Dr Grenfell and I have
been involved in that have looked at what actually happened in
the culling, we have not modelled a hypothetical cull of 48 hours,
we looked at what actually happened and tried to gauge the effects
of that. And the effects of that, as Bryan Grenfell has just told
you, were that it resulted in a considerable reduction in the
number of cases and a net saving in the number of livestock lost.
179. You see, I would suggest to you that we
never really hit the targets in the areas of concentrated outbreak,
whether it is Cumbria, Devon, Forest of Dean, we never hit really
the 24-hour or the 48-hour target; so it was a sort of, "Well,
let's have this because this is the policy," but that is
not necessarily how we achieve the statistical tailing off of
the epidemic. But can I go on to another point, because you—
(Professor King) I think we have great difficulty
in the follow-through at the end of your sentence there. We would
say that there is a mountain of evidence to show that the way
this epidemic was brought under control was the attempt to meet
the 24/48-hour cull procedure. Of course, this was advice that
we could give, as optimal advice, it was a target to aim for;
and you may be right that we never quite achieved it. I actually
think that in the last few weeks of the outbreak we came within
a whisker of achieving the 24/48-hour, and that is the point at
which we actually terminated the disease, or I hope we terminated
it. So I do not agree, I think there is a mountain of evidence
to show that the cull policy we were following and pursuing, although
never carried out perfectly, was the policy that was bringing
it under control.
|
