badger culling increases risk of bovine TB outbreak

Posted on February 10, 2012

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Today (10th February), an item was posted on isciencemag.co.uk, the online science magazine of Imperial College, London titled ‘Badger, Badger, Badger (Part 2)’, written by Joel Winston.

‘… In my last post we saw how, following an 8 year trial of badger culling in 2007, the Independent Scientific Group (ISG) concluded that culling could make no meaningful contribution to Bovine Tuberculosis control. This was due to the ‘pertubation effect’ where culling caused badgers to scatter and spread the infection further afield. Following a backlash from pro-cull lobby groups, the advice was ignored by the Government at the time, which then decided to have its own Chief Scientific Adviser, Sir David King, conveniently publish his own report which supported culling as a control method. This was condemned by the scientific community, and ended up being an embarrassment to the Government.

But rather than dwell on the past, we should really be looking at the scientific evidence the current Coalition Government has considered, in the run up to their decision in December to go ahead with badger cull pilots.

Perhaps we should be thankful for reassurances from the Environment Secretary and Conservative MP, Caroline Spelman, who, in the House of Commons in July (transcript), said how important and pivotal the question of science was. She referred to the continuing study of the incidence of TB in the trial areas, and more recently published and peer-reviewed findings on the long-term effects of culling by Professor Christl Donnelly (member of the former ISG). “In the longer term,” says Spelman, “the reduction in TB herd breakdowns is sustained within the culled area and the negative perturbation effect falls away 12 to 18 months after the culling ceases. That is the science and those are the facts… I encourage the hon. Lady [Mary Creagh MP, Shadow Environment Secretary] to read Christl Donnelly’s most recent publication.”

Well, I think our ‘scientifically-minded’ Environment Secretary should probably have sat down and read Professor Donnelly’s paper herself. She might have been surprised to find that the paper actually says that “the risk of a confirmed bTB breakdown significantly increased with the presence of any reactive badger culling activity” and that their findings “provide additional evidence of the detrimental effect of localized reactive badger culling on bTB risk for British cattle”. Clearly the Environment Secretary’s misrepresentation of the scientific evidence is extremely misleading.

However, there are further issues that need to be resolved in the Government’s proposals. In the Randomised Badger Cull Trial, badgers were trapped in cages and then shot. However, as stated in the latest policy document, the Government is also permitting ‘controlled shooting’, which is when marksmen shoot badgers as they roam at night. This is claimed to be much cheaper, allowing farmers to control a larger area more rigorously, thereby reducing the risk of extra infections due to pertubation.

But the effectiveness of ‘controlled shooting’ has never been tested. Not only is it thought that this will be more difficult to monitor than trap-and-shoot methods, but some experts believe it will be even more disruptive and increase TB through pertubation. However, Professor Bob Watson, Spelman’s Chief Scientific Adviser, still believes this is science-led policy. Speaking to the BBC last year he said, “the one difference between the trials and what’s being proposed is controlled shooting versus trap and shoot, so the only question is whether there’s a difference in perturbation. We don’t know the answer, but there’s no reason to believe it would be worse… [but] that’s not evidence, it’s expert judgement.”

Hardly reassuring, is it? If this was truly science-led, then the Government and its advisers would recognise the risk of implementing a cull with the added wildcard of ‘controlled shooting’, and put in place some appropriate monitoring of the effects. But apparently they are no plans to even do that. Monitoring will be restricted to evaluating the humaneness and safety of the shooting (nice of them, isn’t it?), and the effectiveness of culling on TB within the cull zone (i.e. not pertubation). So not only is this policy based on extremely limited scientific evidence, but with a lack of monitoring, the Government could then potentially protect itself from any later challenges of ignoring evidence of the pertubation effect.

With a lack of evidence, the badger cull policy simply appears to be a knee-jerk reaction to the TB issue, but an enormously beneficial one for the Government. Not only does it show that Ministers are proactively dealing with the concerns of farming communities, and allowing them the freedom to handle their Bovine TB problems in a way they believe is correct, but psychologically it is also a very powerful tool. By allowing farming communities, who may see the badger as a symbol of TB propagation, to shoot and the destroy them in their areas, the Government is in a way prescribing the equivalent of a placebo, which will make communities feel better about the problem, regardless of whether TB rates decline or not.

It seems to me that this issue demonstrates that supposedly ‘science-led’ policy is as susceptible to spin and political manipulation as any other policy area. But it’s also worth considering the internal politics of the Coalition. Caroline Spelman recently caused the Coalition a huge embarrassment with her backtracking on plans to sell off England’s forests. Although this shows a ‘listening’ Government, these U-turns tend to weaken Government positions on other reform plans. So did she really have any other choice than to go ahead with the badger cull pilots, if she wanted to guarantee her position in the Cabinet?

As a final point, in matters such as this, where the objective is to tackle something as serious as TB, the most effective way of finding the solution is by properly considering the robust scientific evidence available. But it’s clear that this isn’t the only factor in policy-making, and we know how governments are under pressure to also make political decisions to appease an electorate. Just please don’t try and justify these political choices in the name of science! …’

Read the item and add your comment online at www.isciencemag.co.uk/blog/badger-badger-badger-part-2/

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