23. We are due a statement quite soon on that. Can I turn to some of the details of this issue now? I was very struck by a letter from Colin Fink, a clinical microbiologist at Micropathology Limited, University of Birmingham, in The Times last August. You are probably familiar with it. You, in your report said that you welcomed the potential of molecular typing to establish the linkage but samples for molecular analysis are currently too sparse in time and space and do not cover enough of the wildlife species intensively to enable conclusions to be drawn. Colin Fink says something very different in The Times. He says: "The scientific community now has exquisitely sensitive molecular methodology for detecting DNA and these methods may be applied to deliver careful field work ...". He suggests that this would be a totally non-intrusive method of investigation with a good chance of success and also it would avoid the justifiable criticisms raised against the presently proposed study. What do you make of Dr Fink's claims?
  (Professor Sir John Krebs) I would like to know exactly which techniques Dr Fink was talking about. It is easy to make a sweeping generalisation that there are molecular techniques, but you have to ask which molecular techniques. When we wrote our report, there were a number of what might be loosely called "DNA fingerprinting techniques" available analogous to the fingerprinting that is used in human forensic science now, but none of the techniques that were available and still are available now were of sufficient sensitivity to fingerprint on a very, very fine scale of resolution. They would be analogous to a fingerprint that would say that this individual came from Winchester and that individual came from Birmingham, which is useful but it is not actually definitive if you want to know who was the person involved in the crime. We need more work on refining fingerprinting techniques and that is coming along rapidly because the genome sequence of microbacterium bovis is likely to be completed within the next year or two through a joint project from MAFF and the Wellcome Trust. Furthermore, once we have those refined techniques, we need to apply them in the field, in detailed studies that will enable you to identify who got the disease from whom. We did all the analysis that we could on the available molecular data. That is in our report. What that shows is that, given the techniques available, if you go to particular localities in the countryside, you will find that in 84% of cases badgers and cattle carry the same strain of TB.[2] That is a bit like saying you and your spouse got a cold at the same time but there is an argument. Did you give it to your spouse? Did you spouse give it to you, or did you both catch it from the milkman? It does not nail it down to show that two individuals have the same molecular type at the same time. What you have to nail down is the sequence: who caught it from who? That is what we suggest is done. I agree with this chap from Birmingham that molecular technology will provide definitive evidence on whether or not cattle are getting the disease from badgers. The "exquisitely accurate" fingerprinting techniques are not yet available. There are techniques that are less than perfect which could be used in the interim but once the techniques are available then the field data has to be longitudinal. It has to actually study who is catching the disease from who, not just the static picture of who has that particular strain of the disease at the same time. I do not think that guy has judged the situation correctly. He is leaping forward two or three years.

  24. In two or three years' time there is some real potential here?
  (Professor Sir John Krebs) I think there is, yes.

  25. The ISRG report notes that badger behaviour varies in response to local factors such as density of badger population, climate and the presence of field boundaries. That can then affect the likelihood of particular badger setts transmitting TB. The report recommends more work needs to be carried out in this area. What new insights would this produce?
  (Professor Sir John Krebs) When we got hold of all the data from MAFF and plotted it on a map, we looked at the incidence of herd breakdowns and TB in cattle. We demonstrated what had been said descriptively before but we analysed it in more detail. There are local pockets of high and low risk. In general, the disease is more common in cattle in the south-west, Herefordshire, Worcestershire, South Wales and now appearing to some extent in the West Midlands, but within that geographical location in the south-west there are certain hot spots where the disease recurs in the same herd or occurs in neighbouring herds. That is what we called repeat or contiguous breakdowns. Having analysed this, you would think that the first question that would have been asked and perhaps answered is why are there these local hot spots whilst you can go perhaps 10 or 15 miles away into an area where there is a much lower risk? We found, when we looked at all the work that had been done, that no one had actually analysed this question properly. We suggested it was very important to understand why there are certain places that are at high risk and other places at a much lower risk. Not only had the analysis not been done fully, but also not all the data necessary for the analysis had been collected. The analysis is a bit of a fishing trip. You do not know which factors to look for -- and this perhaps goes back to some of the earlier questions. You do not just want to look at the presence or absence of badgers; you want to look at a whole raft of other things that you might be interested in as possible contributing factors. The data to do that analysis had not been systematically collected so we suggested, as a matter of urgency, that MAFF should do the analyses of existing data but, equally importantly, collect new data and do the full analysis that we propose. In this regard, Northern Ireland is slightly ahead of us in that they had carried out, we found, a risk contribution analysis. In the estimates they made on a subset of farms in Northern Ireland, badgers contributed about 40 per cent of the risk of TB in cattle. Their analysis was less complete than the one we envisage.

  26. How will you use the information that you gather? Do you have a very sophisticated model in order to compute all that information?
  (Professor Sir John Krebs) Yes. It is not me; there are standard models in the statistical literature which any highly qualified statistician would be able to use. It is not difficult to do the analysis; it is simply a matter of having the right data and asking the right questions.

  27. As this is a one-off study into wildlife, how are you making a difference, weighting the use of information between density of badger population, climate and field boundaries?
  (Professor Sir John Krebs) We could easily get into a very technical discussion here. I will try to avoid that since I suspect you do not want to go down that route.

  Mr Marsden: The argument comes down to the detail. It is a controversial issue and there is a danger with sweeping statements that you use off the shelf analysis.

  28. I do not think it is going to be helpful for the Committee to have a detailed, technical explanation now but if you can point us to individuals who can give us notes of how those procedures can be conducted, not in oral evidence but in written evidence, that would be helpful.
  (Professor Sir John Krebs) Three of the members of the Bourne Group, Dr Christl Donnelly, Sir David Cox and Professor John Gettinby, are all experts in this sort of field and will be able to give you the detail. Do you want me to give an outline answer?

  29. Please do.
  (Professor Sir John Krebs) What the analysis will do is assign an importance value to the different factors that you feed into the model. That importance value will be the importance of those factors in explaining the variation in risk.

  30. It will do as I suggested, so it is not off the shelf.
  (Professor Sir John Krebs) The answer is not off the shelf; the technique is off the shelf.

  31. How does this experimental cull affect these local level factors?
  (Professor Sir John Krebs) It is really a separate issue. What we proposed and what MAFF has accepted is that the experimental cull should be targeted on the highest risk areas, on the subset of those high risk areas. The cull is not asking why are some areas at high risk and others at low; it is asking what is the effect, the impact and the cost effectiveness of removing badgers as a control strategy. Let me tell you where I see this analysis of risk leading to. The point about the analysis of risk, why risk varies from one place to another, is that that might and should provide some strong steers for ways in which risk could be reduced through husbandry. That was another one of our recommendations. We clearly said at the beginning that this is a multifaceted problem; it is complex; there is no simple, quick fix. I realise that some of you may feel disappointed there is no simple, quick fix but that is just the way life is. The analysis of risk will help to point to what might be done to reduce risk. If the only thing that would reduce risk is removing badgers, that will be supported by the analysis of risk. If there are other factors that contribute to risk, like the way in which the cattle are housed or the way in which field margins are kept, that might provide some useful steers to the farming industry.

  32. I am interested in the point that Stephen Harris and Dr Chris Cheeseman of MAFF have made about what they delicately call the dunging behaviour of badgers. The argument seems to be that badgers prefer the field margins and the boundaries to shit and that is where the cattle prefer to graze. Is there research which proves some consequences there?
  (Professor Sir John Krebs) Yes. I am aware -- and we say in our report -- that Stephen Harris has shown that badgers scent mark their territories by urinating and defecating.

  33. It is a question of urine, not dung?
  (Professor Sir John Krebs) It is in urine in particular but also in dung. The bacillus is found in very high concentrations in badger urine as well as badger spit.
Chairman

  34. It is what is called the aerosol transmission, is it?
  (Professor Sir John Krebs) Aerosol is thought to be the main mechanism. We do not actually know how cattle are getting it from badgers.

  35. When they are marking the boundaries, those are the boundaries of a field, are they?
  (Professor Sir John Krebs) Yes, the boundaries of their territory which would tend to include linear features like hedges and fences. It may be that one kind of husbandry technique would be to somehow alter pastures in a way to discourage badgers from urinating along the edge of fields.

  Mr Mitchell: You could put up signs.

  36. Potty training?
  (Professor Sir John Krebs) I asked farmers about this when I was doing the report. I went and spoke to farmers in the West Country who are suffering from TB and they pointed out that if you try to keep badgers away from the fences at the edges of fields by putting another fence up, you very soon get into reductio ad absurdum.

  37. Has research been done?
  (Professor Sir John Krebs) I think that more effort should be put into understanding transmission and not enough has been put into it. We in our report had to confess that we did not actually have thought out ideas about what that research should consist of. We suggested to MAFF they should talk to the scientific community and see if there are any good ideas out there. It is relatively easy to understand where the badgers might be depositing the bacterium but it is not that easy to show what the major routes of transmission are.

  38. Can I talk to you a little bit about the recommendations, about the experimental cull, because that is the sensitive issue in all of this. First of all, when you outlined that this would be the way forward, did you give any consideration to the fact that you were going to be turning the landscape of certain parts of the UK into a laboratory?
  (Professor Sir John Krebs) Yes. If you want to use that phrase, yes, we were aware that we were proposing that culling should be part of a scientific experiment and study.[3]

  39. Did you appreciate fully that, because we are doing this trial in the living landscape where there are farmers, wildlife groups and individuals with different emotions and interests, over a five year period this was not going to be the easiest thing to take forward?
  (Professor Sir John Krebs) Yes. I did appreciate that it would be difficult to take forward. The option was open to ministers not to accept that on the grounds that it was scientifically elegant but infeasible.