Select Committee on Environment, Food and Rural Affairs Minutes of Evidence


Examination of Witnesses (Questions 400 - 419)

WEDNESDAY 24 OCTOBER 2007

SIR DAVID KING AND PROFESSOR MARK WOOLHOUSE

  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 position.

  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 arrogance.

  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 ISG.

  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 rationale.

  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 quicker?

  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 was available.

  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.


 
previous page contents next page

House of Commons home page Parliament home page House of Lords home page search page enquiries index

© Parliamentary copyright 2008
Prepared 27 February 2008