Monday, October 22, 2007

A long time coming

In a report released today, October 22nd, the Chief Scientific Adviser, Sir David King paves the way for a badger cull in areas of endemic cattle Tb. The report was originally submitted to the Secretary of State, Department of Environment, Food and Rural Affairs (Defra) on 30th July. The report unpicks much of the RBCT Badger Dispersal Trial data and many of its conclusions. It emphasises that this is not a badger 'elimination' exercise. It begins;
...I have had regard that the overiding aim is to control Tb in cattle. As badgers are a continuing source of infection in certain areas of high cattle Tb prevalence, a secondary aim is to control Tb in these badger populations. It is not to eliminate badgers; any removal of badgers must be done humanely and within conservation considerations (including the Bern Convention). Thus references to removal in this report are to reducing the number of badgers in an area rather than completely removing them from that area.
Sir David comments on the surge of new herd breakdowns, and recommends "strong action to reverse the upward trend". He sees badger removal coming parallel to current and 'future' cattle controls. Any description of 'future' ones are not expanded upon. But the ISG described them in a fair amount of detail. After stressing that removal of badgers should only take place "in those areas of the country where there is a high and persistent incidence of TB in cattle", the report concludes:
Removal of badgers is the best option available at the moment to reduce the reservoir of infection in wildlife. But in the longer term, alternative or additional means of controlling Tb in badgers such as vaccination, may become available. Research into these should continue.
The report seems to have taken on board the complete shambles achieved by the ISG in their 8 night hit-and-run visits, repeated annually if at all.
Badger removal programmes should be sustained (unless replaced or supplemented by alternative means of control)
Removal which is improperly carried out, or which is fragmented in space and time, could cause detrimental effects on the incidence of cattle TB.
With that, we would not disagree. Badger dispersal the RBCT most certainly was, and yup, it caused havoc in many a closed herd - including those of our contributors.
On badger behaviour and population density the report is rather less clear, but attributes the RBCT Badger Dispersal Trial published results as 'indirect field signs' and 'an informed guess' at badger density.
Over the whole duration of the RBCT, badger density was reduced by about 70 per cent in each of the proactive trial areas (though the data are indirect field signs and this is, therefore, an informed guess) As the ISG note, removal of badgers disrupts their social structure. When a social group is disrupted, the population density is reduced, other badgers move in rapidly (possibly within days). There will be mixing within groups neighbouring the removal areas. Overall there will be net immigration into the removal areas. If removal is not sustained the badger population is likely to recover over time, although this may happen slowly.
So, ten years and over £50 million, and the ISG works on 'indirect field signs' on which they and Sir David's team thus make an 'informed guess' at data flow? Clever stuff this 'science' then? The report continues:
Dispersed infectious badgers are more likely to come into contact with uninfected susceptible badgers through fighting over mates and territory and via close general contact. Therefore they are more likely to spread TB to new areas.
And on the 'dispersal' of badgers by the ISG;
Because of the dispersal effect brought on by removal, [TB] clustering was disrupted over the course of the trial and there is evidence that the prevalence of infection in badgers in those areas increased.If removal is not sustained, there is a risk that the population of badgers could return to pre-removal levels, but with an increased prevalence of infection. It is therefore extremely important that removal is carried out effectively and be sustained.
Don't 'disperse' the problem in other words. Just what we said. But Sir David's team describe badger disruption as transient or 'temporary'. That is, it is not a continuing factor if the whole social group is removed. This gives a more stable population and reduces badger-to-badger transmission. They note that even using Bourne's hit-and-run occasional visitsthe ISG report's data, any detrimental effect on cattle outside the removal area reduced with successive removals.

And on the conclusions drawn by the ISG: they find that the "ISG statement 'That badger culling cannot meaningfully contribute to the control of cattle TB in Britain' is not supported by the RBCT data and as such it was an 'Unqualified conclusion'. They find some data is 'unsound', confidence levels for the detrimental effect on Bourne's 'edges' are 'very large'. (the levels not the diminutive Prof's edges) They criticise the time frame for resulting cattle tests after the conclusion of the trial and urge caution over interpretation of the first year results. (We would urge extreme caution over most of the results - but let that pass) And the report has concerns that the rug was prematurely pulled from the Reactive culls, and say they are unable to comment on the published results 'with confidence.'
We have concerns about the biological plausibility of the ISG's interpretation of the results and do not consider that the evidence in the ISG report should be used either to support or to rule out reactive removal strategy.
It would have helped if they'd 'reacted' at all, Sir David. Arrival would have been good, or at least more than once in three years, as would a stay longer than 8 nights.

Finally, the report concludes:
In our view, a programme for the removal of badgers could make a significant contribution to the control of cattle TB in those areas of England where there is a high and persistent incidence of TB in cattle, provided removal takes place alongside an effective programme of cattle controls.
Good as far as it goes, but if those bolt on cattle measures upon which Bourne was so insistent, are more of a problem than the disease itself ....

So finally, may we caution those VIP stakeholders on T-BAG: any challenge to these measures must bring up short introduction of any new cattle measures - which are totally unecessary anyway. Otherwise Bourne's Trojan Horse will cut a swath through the cattle herds of the west, with absolutely no reduction in cattle TB, just a reduction in cattle and bankruptcy for cattle farmers.

Farmers Weekly has the story and a link to the full report (pdf)

7 comments:

Anonymous said...

Well, well.........now that DEFRA have just completed the sacking of all of their Wildlife Unit staff, this one turns up ! Hooray for Sir David ! Common sense has(might ?) prevail at long last. His thoughts are exactly what the WLU staff have been suggesting for years now, but how will it be implemented ? If agreed, the welfare groups will insist the job is done by professionals - the Government have already stated that " there will not be state funded culling", so where does that leave us ? I see a bunfight coming on here that will further draw out the decision on when/how it might be done. It is time for the Government to rescind their decision and reform the WLUs. It might cost a few millions, but it will be worth it in the medium to long term. Sir David wants the culling to start immediately. I firmly believe that without the expertise of the WLUs being available, it could fail at the first hurdle. The NFU must take the lead and insist the Govt both fund the cull and use their own already trained professional staff to undertake it.

Matthew said...

Anon 8.50
The WLU staff were sacked before the end of the 'consultation' on badger culling.
Farmer's organisations we understand have offered their members as a substitute. This will not work under the Bern Convention rules. And control of b.tuberculosis is a governemnt responsibilty - not that one would notice. Shared responsibility is one thing, abdication of one 'partner' is quite another.

Meanwhile the BBC have spun this report to wild hysteria with phrases like 'elimination of badgers' over huge areas. Which is not what was said at all.

The Badger Trust, reassured both its members and the public with the words "It won't happen".

What worries us is that such wild semantics will bring on the cattle measures - and still no control whatsover of the most successful maintenance wildlife reservoir of bTb.

Jim said...

A lot has been said on this site about peer-reviewing. Well, now it seems that Bourne himself has been well and truly peer-reviewed. In a very polite and understated way, the Chief Scientist has effectively demolished the ISG report as far as I can see. In pointing out what he gently calls the "differences" between his conclusions and those of the ISG on various key issues the Chief Scientist is eloquently cutting:
"the data do not support such an unqualified conclusion..."
"the ISG's view...is unsound..."
"the confidence intervals are very large..."
"it was unclear whether it had been considered..."
"we are concerned about the time frame..."
"this time lag does not seem to have been taken into account..."
"the results...should be viewed with extreme caution..."
"we were not fully persuaded by it..."
"we have concerns about the biological plausibility of the ISG's interpretation of the results..."

At the same time as this welcome outbreak of common sense, it has been sad to see a lot of predictable comments on the BBC website - sad because so many of them betray such utter ignorance: such as that farmers are too greedy to spend 2p vaccinating their cattle against TB, or that cattle get TB because they are kept in underheated buildings, or that it's because they are fed a hormone-laced diet, or because cattle and sheep are kept in the same fields, etc. etc.

One wonders how many of the Badger Trust's "96% against a cull" would think the same way if they knew the real facts.

Matthew said...

A succinct overview Jim. Thankyou.
We have been hauled over the coals for daring to suggest that the ISG had not had their final report peer reviewed; in fact they had published bits of the trial, but never the conclusions reached from the sum of those bits.

Sir David has expressed grave concerns about the final tally of those soundbites. We would go further and express extremely grave concerns about the 'assumed' and 'hypothesised' input into the 'roughly equal' basic data which fed the 'simple mathematical models'.

All those adjectives were used by Bourne and the ISG to describe their input data in the Final Report; with the spread of infectious disease, that is a very weak basis on which to draw any conclusion at all.

The 'gold standard' for epidemiology is still the Evans postualtes, which followed the Koch postulates of 1895. Current knowledge of bTb in badgers and in cattle indicates that the majority of these are fulifilled. The spoligotype maps added a further dimension. There was absolutely no need for the RBCT at all. But all of the people with this wealth of knowledge were kept totally out of the Bourne 'magic circle', thus he made some extremely fundamental 'assumptions' which were not subsequently not supported.

Interestingly, two of the members of Sir. David's team (Tim Roper and Mark Woolhouse) have published extremely good work on badger activity which we have quoted on this site - particularly Roper's night photography, which comprehensively trashed Defra's biosecurity advice.

I too am horrified by the diet of pap that so many will absorb unquestioningly. But their informers will not let such a minor thing as 'facts' get in the way of a good myth. Polarisation fuels such focus groups.

Anonymous said...

You can be certain that if DEFRA created an Independent Study Group, it was going to be far from independent. Their behavior throughout have been tailored to trying to deflect the problem (to farmers), to limit the options (through closure of the WLU) and to ensure that the view of the vocal lobbyists (on behalf of the "animal welfare" organizations) take precedence over common sense and good fact based science.

Anonymous said...

A report that was on a ministers desk for months, was it being held back until after the election?

Matthew said...

Anon; 10.33
Hadn't thought of that!
Nice one.