Examination of Witnesses (Questions 400
WEDNESDAY 24 OCTOBER 2007
Q400 Lynne Jones: In the two paragraphs
you mention the mathematical modelling of the existing data. You
heard the response earlier to that. Are you recommending that
such mathematical modelling is done and, if so, should that not
have been done before you came to your conclusion?
Professor Woolhouse: In answer
to the second point first, I agree that this would be a challenging
job. It is not something you could do quickly. I would not want
to give an immediate estimate on how long it would take but it
would need a significant research body to do that. I am slightly
surprised that Christl was so negative about the prospects of
undertaking mathematical modelling in this area. I would have
thought it was a very natural candidate, given the amount of data
that we have to undertake this sort of exercise. To follow up
the point, I would be very happy personally to take that up with
Christl and have a discussion face to face with her to see why
she thinks that. It seems to me that this is a natural candidate
for mathematical modelling.
Q401 Lynne Jones: But you are advising
Government. Surely, if there is further information to be obtained
from existing data you should be obtaining that information before
coming to a conclusion.
Professor Woolhouse: The paragraphs
state that we think that mathematical modelling would be useful
in extrapolating from the findings of the report. That comment
was also made in the Charles Godfray report in 2004 and I would
stand by it.
Q402 Chairman: I am going to be very
rude and interrupt because it is 32 minutes past the hour and,
Sir David, I am aware that we did give you an assurance that you
could go. However, that does not mean you have to take up the
assurance. We would love you to stay if you have any flexibility
in your timetable, but I do not want you to put you in an embarrassing
Sir David King: I can stay for
another five minutes.
Chairman: I would like to move on then,
because we can come back and ask Professor Woolhouse some of these
more detailed questions, Lynne. David, you wanted to ask a question.
Q403 David Taylor: Lynne has already
covered it, but I have another question. How can it possibly be
the case that a small team of no doubt very eminent scientists
over a working day and a working breakfast on the following day
can come to one or two distinctly different conclusions from data
that have been assembled, analysed and examined and peer reviewed
over a decade? To me that sounds a little bit like scientific
Sir David King: The answer to
your question can only be given in much more specific terms. In
other words, if there are specific details of our report that
you feel were too hastily arrived at then I can give you an answer,
but the quality of our report depends very much on whether or
not it stands up to critical examination, and that critical examination
in my view is rather like the previous comment: it does not include
the statement that these people are not "expert" enough
because the judgment should be made on content.
Professor Woolhouse: I think there
is a small issue of procedure here. As a working scientist I and
my colleagues sitting behind me are regularly asked to make an
assessment of a very large and long term study, possibly covered
by many people, whenever we are reviewing a paper for a major
publication or journal. This is quite routine, so I am less concerned
about it than you, and I certainly reject the idea of scientific
arrogance. That was not the case around the table when this was
discussed at all.
Q404 David Taylor: To be able to
turn round a significant conclusion of the report in what would
appear to be a cavalier and unsustainable fashion is something
that you really ought to respond to.
Sir David King: I simply cannot
see how the words "cavalier" and "unsustainable"
can be used after the debate that we have just had. It is very
clear that the scientists basically agree that up to 40% of herd
breakdown with TB is associated with the presence of badgers in
setts on the land where those cattle are. That is an essential
piece of information we all agree on. That is a valuable piece
of information derived from this report, and if that is the basis
of the science and if I stay within the domain of science advice
then I do not think we are stepping outside any area of propriety
or proper action.
Q405 Mr Drew: Bearing down on bovine
TB is going to largely depend on the practicalities. We can have
all these scientific arguments but somebody has absolutely got
to go out there and do a massive cull of badgers. You have come
to this with the best will in the world using somebody else's
data, working at a secondary level, and in a sense you are trying
to interpret somebody else's primary scientific findings. Part
of the problem with this is that the evidence is very confusing.
There is not a conclusive set of explanations that you can really
state in evidence.
Sir David King: Could I just ask
you, if you do not mind, Chairman, which piece of evidence are
we talking about that is very confusing? Are you questioning whether
badgers are a source of infectivity for cattle?
Q406 Mr Drew: No. What I am questioning
is why you come to a very different set of conclusions from the
Sir David King: I still do not
know whether that was an appropriate way to describe the situation
if we are all agreed on that.
Q407 Mr Drew: Let me phrase this
another way then. In terms of how this could work in practice,
according to your approach to this you are taking the 300 square
kilometres as being a realistic area to which you would want to
cull badgers. Give me some idea of the percentage of badgers that
you would need to cull to begin to make a significant difference
to the level of bovine TB in cattle.
Sir David King: The answer to
that from the ISG report is that around 70 to 80% does bring the
down the incidence of bovine TB significantly, so already, if
I can give this in epidemiological terms, what we want to do is
bring down the reproduction factor below one. It does not have
to be brought down an awful lot but we certainly need to bring
it down and this is one of the factors that would do it, so I
would say 70 to 80% reduction.
Q408 Chairman: Is that in all the
red areas on the map?
Sir David King: That would be
in the areas where there is high cattle TB incidence and those
are not all the red areas. Those sporadic spots that are not in
the large growth area I would not count.
Q409 Chairman: And that would mean
all badgers over a period of four years?
Sir David King: Seventy to 80%.
I was asked what population change of badgers would I perceive
was right, and I am saying a reduction by 70 to 80%.
Q410 Mr Drew: What happens where
you get landowner resistance? Is this commensurate with the Bern
Convention, for example? There could be huge legal cases on the
ability to carry this out.
Sir David King: You are wandering
outside the science report but I am very happy to answer.
Q411 Mr Drew: I know it is outside
the science but unfortunately the science of this particular disease
is highly controversial and very unclear in terms of what could
result from such an intervention, so I am looking at the practicalities
that you will have to meet in order to deliver the scientific
Sir David King: You have asked
me two questions. First, in terms of farmer acceptance of action
Q412 Mr Drew: No; landowner, not
the same thing at all.
Sir David King: In terms of landowner
acceptance of action, the trials demonstrated that there was sufficient
acceptance for the trials to proceed with satisfactory results
within those culled areas. Reduction of cattle TB over the area
was clearly demonstrated. Your second question was
Q413 Mr Drew: The Bern Convention.
Sir David King: If you read my
report right at the beginning, we say we are very clear about
the Bern Convention and a 70 to 80% cull in our view would be
within the terms of the Bern Convention. The Bern Convention states
that you cannot completely remove wildlife from its native area.
Q414 Chairman: Can we stretch your
five minutes? I have got one 30-second question. You have looked
at culling and you have come to some conclusions. Do you think
it would be a good idea if you applied your scientific rigour
to the field of vaccines to address some of the problems that
came out of the evidence that we took on that, not this never-ending
hope that we get there but the question of how do we get there
Sir David King: I took evidence
from exactly the same vaccine expert as you took evidence from
and we refer to that in our report.
Q415 Chairman: You refer to it, but,
in terms of providing advice as to what could be done to fast-forward
the process, is that something that you might now like to do some
further work on?
Sir David King: Absolutely. I
think vaccines are very important in this area, and so it is very
useful that you have asked this question and I am happy to answer
it. The work on vaccines is progressing. You have heard about
that. It will not be available in terms of badger vaccines which
are injectable for at least two years in a practical form, but
oral vaccines are going to be absolutely crucial in terms of implementation
and it is a good few years beyond that before we are going to
see them. Of course we want to see more research in that area
and we point out that this cull procedure that we are suggesting
could be terminated as soon as an effective vaccination procedure
Chairman: We must let you go but there
may be some other questions about methodology which I might ask
Professor Woolhouse if he would kindly field.
Q416 Lynne Jones: In terms of the
70 to 80%, the evidence we have got from the NFU is that they
say that partial control is likely to be worse than no control
at all and the key to a successful cull is to achieve as close
as possible 100%, so you would disagree with the conclusion of
the NFU in that sense?
Professor Woolhouse: I have not
seen that NFU report myself. What I would infer from that is that
they were commenting on the edge effects which are possibly explained
by the perturbation hypothesis, and that was an effect that was
nicely documented and analysed in the ISG report. I am inferring
that that is what they refer to.
Q417 Mr Williams: In coming to your
conclusions did you look at the effectiveness of restriction of
cattle movements, the pre-movement testing?
Professor Woolhouse: The remit
our group was given was to consider the role of badgers in the
transmission of the disease. In other guises, of course, we are
very interested in that, and in terms of some of the geographical
spread of bovine TB in the last few years clearly cattle movements
are extremely important. My understanding is that the general
feeling is not that they are responsible for maintaining, or at
least increasing, the levels of infection in the hotspots alone.
Q418 Mr Williams: But I think your
report concludes that badger removal should go along with restrictions
and control of cattle movements.
Professor Woolhouse: Yes, and
that again would agree with the conclusions of the ISG, that,
although badger control or prevention could have a role to play,
alone it is unlikely to be enough to completely solve the bovine
TB problem in cattle.
Q419 Mr Williams: Is there any further
research on the effectiveness of control of cattle movements to
establish what contribution that plays in eliminating it?
Professor Woolhouse: Again, as
a scientist you would expect me to ask for further research. At
a more practical level I think Defra should certainly be keeping
under review the effects of the movement and testing regimes,
the diagnostic tools they are using and so on, in order to make
sure that we are controlling any spread from cattle movements
as effectively as we possibly can, given any advances in research
knowledge or technology. That is clear.