TUESDAY 16 FEBRUARY 1999

PROFESSOR JOHN BOURNE, DR CHRISTL DONNELLY AND DR ROSIE WOODROFFE

  240.  Dr Donnelly?
  (Dr Donnelly) Yes.  I think the difficulty is in viewing husbandry as an issue similar to the badger one, where we can imagine randomising—because husbandry is so multi-factorial and if it were the fact that husbandry was just a yes or a no then probably we would have given that consideration and might have been likely to have gone with a trial which involved also trying to randomise husbandry factors if it was just one thing or the other, but it is so multi-dimensional we would not know which particular aspects were important to focus on.  It would be impossible to imagine randomising all the different aspects which might intervene.  That is why we need to go with the risk analysis approach where we see what people have done and compare are the husbandry issues of these various factors the same or different between farms that are heavily affected and farms that are not.  In that way we can decide over a range of issues which ones jump out as being important.  They might well be very important.
  (Professor Bourne) If I could add, there has been a suggestion that one could approach this by doing a range of field experiments where one identifies a risk factor and deals with it.  There are so many variables that simply would not give, in our view, any sensible results.  The only sensible approach to this is through risk analysis which can analyse a whole range of effects which are just not accessible to ordinary scientific investigation.

  241.  If I can move on to a final question, which we have touched on, about badgers being killed in road accidents.  Is there a common sense guess which may well be proved to be otherwise that badgers killed in road accidents are more likely to be infected by TB than those who are not since they are less fleet of foot to escape the oncoming car?
  (Dr Woodroffe) Could I pick up that one? I should begin by saying that TB infection in badgers is in most cases not a very serious disease, that is one of the reasons they are so good at maintaining it in their populations because most badgers that have TB do not die of TB.  There are really relatively few tuberculous badgers staggering around.  I think it is very unlikely that is a very biased estimate of TB prevalence in badgers.

  242.  Could be suicide?
  (Dr Woodroffe) They bury their dead you know.  Some people believe that.  Certainly my experience of having known marked animals killed on the roads is that it is a pretty random assortment of animals that get killed on roads.  It is not particularly old animals, it is not particularly young animals, it is quite a random selection of badgers.  I would be surprised if there was any serious bias in favour of tuberculous badgers being killed in road accidents rather than the uninfected.

  243.  It is surprising, a sick badger would be less likely—
  (Dr Woodroffe) They are not sick.  They are not ill.
  (Professor Bourne) The answer is we do not know what the clinical incidence and the clinical effects of TB is in badgers.  If you look back at the clinical effects of TB in the bovine animal, and if I take you back, say, 30/40/50 years when TB was rife in cattle and widespread throughout a herd with maybe 50 or 60 per cent of open reacted animals shedding large numbers of TB, you would not identify those as being sick.  They were not under-producing.  They were maintaining themselves quite well.  TB is a debilitating disease but only in its very late stages.  You cannot really draw conclusions between clinical states and the number of organisms that are being excreted and the level of infectivity.

  244.  The only reason I raise this is, as you will appreciate, Professor, there are all sorts of factors which can distort the sort of findings we have and random samples of those killed on roads may be one.
  (Dr Donnelly) One of the reasons why we are so keen to get the road traffic accident survey going as soon as possible and to particularly target, at least in this first instance, areas that we would expect later to include some of the areas enrolled in the trial is that it will allow us to look at the proportion that have been observed in road traffic accidents compared to the trial badgers that are taken in the proactive cull.  We will be able to correlate the estimated prevalence from the road traffic accident with the estimated prevalence from those taken in the proactive cull and that will give us a quantitative measure of whether or not there is a bias.  If there were for some reason to be such a bias we could then adjust for later observations from road traffic accidents.

  245.  Do we have any idea at this stage how many badgers are killed in road traffic accidents?
  (Dr Woodroffe) We do but I cannot quite remember the number.
  (Professor Bourne) Sixty per cent of the badger population.

  246.  Sixty per cent of the whole badger population?
  (Professor Bourne) Sorry, 60 per cent of deaths per year are attributed to cars.  There is a turnover of a third of badgers each year.
  (Dr Woodroffe) It is a very high proportion of badger deaths of animals caused by road accidents.
  (Professor Bourne) You are talking of 60,000 a year probably.
  (Dr Woodroffe) I think that there are groups who could give you a number, I am not entirely sure what the number is.

  247.  A final question for my own interest.  The badger population, as I understand it, has been increasing over the years.
  (Dr Woodroffe) Yes.

  248.  The number of badgers killed by cars presumably is dramatically rising.  What is the factor that is leading the badgers to be so prolific?
  (Dr Woodroffe) The answer is we really are not sure.  There have been all sorts of suggestions put forward, things like people growing maize except that I have personally seen the badger population that I have done research on double and there is no maize for miles, so maize is not it.  There is a variety of suggested changes in agricultural practice which could be involved.  There is also, of course, the increased protection of badgers and more focus put on badger protection so that could also be a factor.  The truth is that we are really not sure.

  249.  It does have a predator, does it not, as we said earlier, the predator is the motorcar but presumably before that other than man hunting it it did not have any predators?
  (Dr Woodroffe) Not for a long time in this country, no.

  250.  This Committee is not going to recommend reintroducing wolves.
  (Dr Woodroffe) That is a shame, I would have been quite pleased if you did.

  251.  One of the main predators of the study is the Bern Convention.  What view do you have about the Bern Convention itself? Is this something that is held in high regard?
  (Professor Bourne) We did take legal advice from MAFF, as you know.  The Bern Convention was brought to our notice by MAFF.  They believed it not to be an issue and we are persuaded subsequently that it is not an issue.  Although we are dealing with a protected species, we are not dealing with a threatened species.  We believe our approach towards controlling cattle TB and TB in the badger is a realistic approach, we do not think there is any other way one can do it.

  252.  How are you advising Government ministers as to how they should deal with the Bern Convention's view that the culling experiment should stop forthwith?
  (Professor Bourne) That is an issue for MAFF and for ministers, it is not an issue for us.

  253.  So you are not offering any advice to them as to how they respond to it?
  (Professor Bourne) No.

  Chairman: Professor, thank you very much indeed.  You just said the badger was a protected and not an endangered species, I had a very pleasant visit to Bristol Veterinary College only on Friday where I spoke to local Conservatives, a species that is not protected.  The English was the subject of my address.  Professor, thank you very much indeed, we are very grateful to you for your time and trouble and to your colleagues for answering our questions so fully and so interestingly.  Thank you very much indeed.