Examination of Witnesses (Questions 420
WEDNESDAY 24 OCTOBER 2007
Q420 Mr Drew: In terms of the pure
practicalities of this, what evidence did you take separately
from those who would be tasked to carry out badger removal operations?
In particular, what means would need to be applied to achieve
even a 70 to 80% level of removal, and did that play any part
at all in your conclusions?
Professor Woolhouse: I am beginning
to feel very exposed if you are going to ask me about the procedures
under which the Chief Scientific Adviser does his operation.
Chairman: Do not go beyond what you feel
comfortable in answering.
Q421 Mr Drew: You can just say that
you are unhappy with that, but it is an important question that
we try and wrestle with, and this goes back to my earlier point
Professor Woolhouse: In terms
of the input on the practicalities, we did have present in the
meeting for background information the Chief Scientific Adviser
for Defra, Sir Howard Dalton, and the Chief Veterinary Officer,
Debbie Reynolds, and a number of their colleagues, and they were
helpful in commenting on that as a practicality and so on, but
that is not within the remit of the scientific group that Sir
Q422 Chairman: Just on one practical
point in your report, you comment that the badger population should
be "monitored". Did you come to any conclusions as to
who should do it and with what frequency? Was it going to be UK-wide
monitoring, England, Wales, what? What conclusion did you draw
Professor Woolhouse: Again, I
am not specifically a badger expert, and Rosie Woodroffe can no
doubt address this more clearly for you, but there are attempts
to survey the population density of badgers from time to time
in the UK. The feeling was that if you are going to implementand
it is beyond my remit to say whether you should or notany
kind of badger control you need to be very clear about what you
have actually achieved on the ground, for two reasons. One is
to understand why you have succeeded, but the second, if things
do go wrong, is to understand why you failed, and that is a very
important part of trying to assess the performance of any kind
of large-scale intervention. That would apply in a lot of different
circumstances from controlling TB in badgers. You need to understand
what is going on.
Q423 David Taylor: You say you are
reluctant to comment on practical methods of carrying out culling
and so on. Do you recall any of the discussion that took place
with the Defra people and others there about what would be the
most humane and effective means of removing badgers? Do you know
what they meant by that or was that referred to in regard to snaring
Professor Woolhouse: Snaring was
discussed because, of course, that was one of the methods used
in the Irish trials, and my understanding is that that is not
felt to be humane and sustainable on a large scale in the UK.
You really do need to talk to some animal welfare experts.
Q424 David Taylor: Do you recall
which ones were broadly left as viable options?
Professor Woolhouse: The one that
has already been rejected, as you well know, is gassing, which
was rejected some time ago, so we are left with trapping and shooting
as the alternatives, as I understand it, but you really need to
talk to someone who is expert in these areas.
Q425 Chairman: Can I just take you
backand I am sorry this is a little bit random but there
were a lot of points that came out of your reportto paragraph
46 where you say the following: "This time lag does not seem
to have been taken into account when the ISG collected data on
cattle TB incidence immediately after the first proactive cull"?
You said at the opening of your remarks that you basically came
at this subject from the same data as the ISG, implying the analysis
was okay, and yet in this particular paragraph you do seem to
be hitting them head on about the measurement of the effect in
the first year of culling. You say you cannot really read anything
until you have done it for two years. That does seem to me to
be a challenge in methodology as a layman reading those words.
Why did you choose, if you like, to come to that particular conclusion,
because obviously it questions the analysis of the effectiveness
of culling, does it not?
Professor Woolhouse: It certainly
does not challenge the data or the analysis of the data that they
received. It is a question of how much weight you place on the
first year's results in an intervention of this kind. There are
a number of studies that have shown quite clearly that these sorts
of interventions are going to take a number of years before they
have their full effects and the Irish trial is a very good example
of that. Not only does it take in that case four or five years
in order to achieve the full effect they saw at the end of that
trial, but, if you like, the way to that final effect is quite
noisy. Even in the Irish trial in some years in some sites the
incidence of bovine TB in cattle went up as it was going down.
These are very stochastic processes. There is a lot of variation
in the trajectory, so it is difficult to draw firm conclusions
from just one year's data, and that, of course, was one of the
difficulties that was highlighted by everyone.
Chairman: I deliberately picked that
because you have made a statement that says it is very difficult
to draw conclusions from one year's data, but if I understood
the ISG's work correctly (and they can answer) they did put quite
a lot of weight on what happened in year one. I suppose one of
the factors that we are trying to sieve out is how much you are
having a go at the way they interpreted the information, and there
does appear to be a difference of opinion about the year one effect,
as you have just enunciated. They take a different view. The difficulty
for the lay person is whose view is right and how do we decide
whose view is right, because it is effectively lay people with
the benefit of advice who are going to have to ultimately take
the decisions as to what is going to happen to deal with the disease
pool which Sir David King, quite rightly, identified as a major
problem that had to be dealt with. I am going to leave that as
a statement because you may not be able to help us adjudicate
and Mr Drew wanted to come in with a further point.
Q426 Mr Drew: Did you actually read
any of the papers around the Thornbury experiment, which obviously
was the most comprehensive study of badger removal over a long
period of time, even though most of those papers have been destroyed?
Do you know about Thornbury?
Professor Woolhouse: I know of
Thornbury. If you are going to start quoting it at me I am going
to have to
Q427 Mr Drew: It would be interesting
to know about that, because if you were coming to that conclusion
you would have to look in a sense at what the existing history
of culling was in this country, and Thornbury is as close as you
can get to some scientific investigation, so did that play any
part at all in you coming to the conclusion that you came to?
Professor Woolhouse: It is not
cited in the report, I believe.
Q428 Mr Drew: No, it is not cited.
Professor Woolhouse: Although
the experts around the table would have been aware of it to some
degree, I would not say it was a major contributor. The major
contributor, as Sir David has said repeatedly, was the ISG's report
and the publications arising from that.
Chairman: Thank you very much for staying
on and answering those additional questions. You are very welcome
to stay in whatever capacity you like and listen to the next bit
because we did say at the outset that there were some more questions
that we wanted to put to John Bourne and his colleagues, but we
also wanted to afford them the opportunity of providing us with
a commentary if they wanted to. They do not have to if they do
not want to but the opportunity now exists for him and his colleagues
to say a few words about what they have heard from Sir David King.
It might help us as lay people to understand what it is that we
have been told, so, Professor Woolhouse, you can either move to
the end or go to the back, whichever you feel comfortable with,
and we will invite the ISG former members to resume the witness