Controlling bovine TB – what can lessons can be learned from across the Irish Sea?

TWO countries. Two similar problems. Two very different approaches. And two very different outcomes.

A decade ago, the UK and the Republic of Ireland both had tough decisions to make about how to deal with rising incidences of bovine TB in cattle, and the potential role played by badgers in spreading it.

The UK set up the Randomised Badger Culling Trials (RBCT) in 1998 to gauge the impact of badger culling on bTB incidence.

During the 10 years it was taking to find no solutions to the problem, a ban was imposed on badger controls outside the trial areas.

Meanwhile, bTB incidence was trebling from just over 700 confirmed herd outbreaks in 1998 to around 2,000 in 2005 and 2006.

Trials

Ireland took a different approach. Shorter and more straightforward trials between 1997 and 2002 convinced the Government that the only way it was going to get on top of the bTB problem was to tackle both sources of infection.

An ‘interim’ badger culling strategy was put in place, while resources were pumped into establishing a longer-term vaccination policy.

Since 1998, the number of cattle bTB reactors in Ireland has fallen by 46 per cent.

While acknowledging that the badger culling is only one of a number of contributing factors, Irish Agriculture Minister Mary Coughlan said recently she was ‘satisfied that the badger removal policy had made a significant contribution to the improvement of the situation’.

“A pragmatic response, based on sound science, to a complex problem,” was how she described the approach, in response to attacks from badger welfare groups.

Surely this must all be of interest to Hilary Benn and his new team at Defra as they become the latest Ministers to grapple with the bTB conundrum?

After all, his predecessor David Miliband had showed a keen interest in the Irish work and promised to look at ‘all the available evidence’ in making a decision on badger culling.

Not so, says the Independent Scientific Group on bovine TB, which has gone out of its way to stress that the Irish experience is not relevant to the UK.

Presenting his report at an open meeting in London, ISG chairman John Bourne played down the success of badger culling in Ireland, suggesting it was not having the impact the figures coming out of there suggested.

More importantly, differences in badger populations, environmental conditions, farming practises, trial design, capture methods and social attitudes add up to make the Irish trial and policy irrelevant to the UK, he said.

Plus, he said, the current Irish badger culling policy ‘seeks to eliminate badgers from 30 per cent of the land mass’, a situation that would be ‘politically unacceptable’ in the UK.

Policy approach

Contacted by Farmers Guardian, Ireland’s deputy chief veterinary officer Michael Sheridan agreed that the Irish experience could not be used as the basis for a specific culling policy in the UK, echoing some of the reasons outlined by the ISG.

But what became clear as he outlined how Ireland has set about tackling the problem is that the UK has an awful lot to learn from its attitudes and broad approach.

Mr Sheridan explained how the approaches differed from the start. “While the RBCT was comparing policy options, we had a very simple experiment to assess whether the disease in badgers was a constraint to making progress on the bovine side.”

“In the Four Area trials (1997-2002), we took badgers out of an area as far as possible and it showed clearly that if you do, that you make significant progress on the bovine side. Existing measures begin to work and you go well beyond where you are.”

While the RBCT showed only marginal benefits from culling, in the Irish Four Areas trial, it was associated with a 60 per cent drop in bTB in cattle herds under restriction.

Mr Sheridan said this was hardly surprising, given the way the trials were set up. The four areas chosen in Ireland were much larger than the 100sq km RBCT areas and, unlike the RBCT, were specifically designed to prevent the so-called ‘edge effect’.

Culling took place within defined boundaries – where possible, natural barriers like the sea, mountains and rivers, or otherwise artificial boundaries in the form of culled ‘buffer zones’.

Snaring, used to capture badgers during the trial, was more efficient than the trapping system used in the RBCT, Mr Sheridan added.

All of this, combined, crucially, with the lower badger densities in Ireland, meant that perturbation, the dispersal of infection by badger groups disturbed by culling, was much less of a problem in Ireland. Hence the different results.

“We did it efficiently and effectively. Subject to the constraints they (ISG) had, the type of study that it was, the level of efficiency they achieved and also badger densities, they had a very difficult job,” Mr Sheridan said.

“When you look at all those issues you cannot extrapolate one from the other.”

Vaccination

Having established that the presence of bTB in badgers was a major constraint to eradicating from cattle, the Irish Government was then able to set about solving the problem.

“The trials showed if you succeed in taking badgers out of the equation you make progress with eradicating the disease. The next logical step was to invest in the only long-term solution that is allowable and feasible – vaccination. So have put our efforts into that,” Mr Sheridan said.

“But that is still a few years away, so in the meantime we have introduced an interim culling policy.”

This approach enabled the Government to gain the support of farmers and the acceptance, at least, of the public and Irish animal welfare groups, who, he said, appreciate that culling is a ‘necessary’ medium-term measure while a more ‘environmentally acceptable’ one is developed.

Culling controls

Mr Sheridan refuted Prof Bourne’s claims, also spelled out in the ISG report, about the scale of the culling policy.

“It’s wrong to say we are doing it over 30 per cent of the country – that is an upper limit and it is not a target. Currently 11 per cent of the land mass is subject to culling controls,” he said.

“It is also not eradication. It is a reactive cull that takes place where there is clear epidemiological evidence badgers have caused major breakdowns. We do not see it as a long-term solution, but it is necessary until we get a vaccination policy in place.

“John Bourne may have misinterpreted what he was told, but I am not saying he has said anything wrong. He can say whatever he wants.”

Field trials looking at the benefits of using the BCG vaccine in badgers are due to begin early next year, and the intention is that the culling policy will be replaced by a vaccination policy within the next five years.

“We have done seven to eight years work on the BCG vaccine and we are pretty happy that it works,” Mr Sheridan said.

Again, the contrast with the UK is stark. The doubts over the likely efficacy, practicality and cost-effectiveness of vaccination appear greater, the appetite for funding development in the field is less and progress, therefore, is slower.

The ISG warns of ‘many obstacles’ to the development of a wildlife vaccine and is not seen as anything but a possible long-term solution in the UK.

What the Irish experience cannot tell us is whether this culling policy or that vaccination policy would work in the UK.

What it demonstrates, however, is that where there is a will there is a way. The Irish approach has been geared to finding solutions, backed by common sense, science and political consensus – from the way the trials were set up, to the decision-making process and the development of practical policies.

While UK has waited and waited for a trial, that cynics say appears designed only to prolong the wait further and still cannot find the political will to move forward, Ireland has been acting. And bTB incidence is falling.

Mr Sheridan said Ireland now had a ‘road map’. The reactive culling policy was moving it ‘in the right direction’ until a more sustainable long-term solution is found. He was adamant, too, that the Irish approach was cost-effective when placed against the ‘to do nothing’ approach that would see disease incidence continue to rise in cattle.

“Our policy all along has been to deal with diseases in both species,” he said. “Addressing the disease in cattle on its own won’t work – you have to deal with the badger issue in parallel. You can’t remove a herd of cattle and leave a sett of diseased badgers behind. You have to act realistically and deal with both sides of the problem. It is worth putting proper effort and resource into having a healthy badger population and a healthy cattle population.”

Can we really afford to ignore what is happening just across the Irish Sea?

The Irish approach

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• Four Area trials (1997 -2002) over large areas, using physical boundaries and snares to capture badgers.

• Culling in trials associated with 60 per cent drop in herds under bTB restriction.

• Badger disruption – ‘perturbation’ – not a major problem.

‘Interim’ reactive culling policy put in place, able to cover upper limit of 30 per cent of land (currently covering 1 per cent).

• Field trials on badger vaccine to begin in February 2008, with a view to vaccination replacing culling in five years.

• Number of TB rectors down from 45,000 in 1998 to 24,200 in 2006, a 46 per cent drop.

The British approach

Credit: © FARMERS GUARDIAN please contact 01772 799445.

• Randomised Badger Culling Trial (RBCT) (1998-2007) over 10 ‘triplet’ areas made of 100sq.km zones, not set within physical boundaries and using cages to trap badgers.

• Reactive culling in trials associated with increased disease incidence in cattle, proactive culling produced only very marginal benefits.

• Perturbation a major problem. Higher badger density said to partly explain difference.

• No badger culling allowed outside trial areas since trials began.

• Badger vaccine research programme but no firm plans for field trials or wildlife vaccination policy.

• Number of confirmed breakdowns trebled from 700 in 1998 to around 2,000 in 2005 and 2006.