Act now to control bovine TB - FUW

The decision to cull badgers in north Pembrokeshire is scientifically justified, legally sound and has political backing.

Like other farming organisations, the Farmers Union of Wales (FUW) reacted to the final report of the Independent Science Group (ISG) with disbelief.

Here were figures showing reducing badger numbers had a significant and cumulative impact on bTB breakdowns, yet the report concluded ‘badger culling cannot meaningfully contribute to the future control of cattle TB in Britain’.

‘Propaganda’

The statement came as manna from heaven to those who opposed culling, and has appeared endlessly in anti-cull propaganda ever since.

However, few will have read the less sweeping conclusions, published by the same authors a month later in the International Journal of Infectious Diseases, which said: “Careful consideration is needed to determine in what settings systematic repeated culling might be reliably predicted to be beneficial, and in these cases whether the benefits of such culling warrant the costs involved.”

This view is far more typical of the wide berth scientists usually give conclusive statements, especially when there are large numbers of complex variables, mixed findings, and results which have yet to be gathered.

In fact, the inclusion of caveats, which leave the door open to further research and hypotheses, is a cornerstone of modern science, and identifying pitfalls and areas where improvements can be made is one of the main purposes of conducting experiments such as the Randomised Badger Culling Trial (RBCT).

So, sweeping statements aside, what did the RBCT data, as published in 2007, actually tell us about badger culling?

The three most significant results were that:

• In the centre of culling areas, the number of confirmed breakdowns was reduced by about 50 per cent, but this positive effect diminished towards boundaries, due to increased badger movements (perturbation).
• Within the proactive culling areas, the risk of confirmed bTB breakdowns had fallen, year-on-year, following successive culls, to around 32 per cent, and this fall could be expected to continue.
• The number of confirmed breakdowns on the perimeter of culling areas actually rose - again, due to perturbation. However, this adverse affect had diminished over time.

In many ways, these results simply clarified and quantified what was already known - the removal of significant disease vectors has a cumulative positive effect over time.

It also found badger perturbation can increase the rate of bTB transmission close to culling areas - an effect the earlier Irish trials, which achieved reductions in bTB of between 62 and 95 per cent, had been designed specifically to avoid.

Of these three main conclusions, it is perhaps the first which tells us most about the role of badgers in transmitting bTB to cattle in hotspot areas - where 85-90 per cent of bTB incidences occur.

In areas where perturbation was at a minimum, removing around three-quarters of the badger population halved the number of bTB breakdowns.

In other words, notwithstanding margins of error, at least 50 per cent of breakdowns came, directly or indirectly, from badgers.

Moreover, given not all badgers were removed, and bTB incidences fell over time in the culling area as a whole, the real proportion attributable to badgers might well be significantly higher.

For example, if the number of incidences prevented was proportionate to the number of badgers removed, this could suggest around 65 per cent of incidences were attributable to badgers.

How could you even begin to tackle the disease while ignoring such a massive reservoir? The answer was straightforward: without housing cattle for 365 days a year in laboratory conditions - you couldn’t.

While we would have to wait to see whether incidences in and around the trial areas continued to fall over time, the issue of geographic or other boundaries was obviously of critical importance.

Lobbying

In fact, the FUW had been lobbying the Welsh Assembly Government (WAG) since 2005 to investigate what boundaries to perturbation existed within Wales - not just geographic boundaries such as rivers, but other, ‘virtual’ boundaries such as areas with low numbers of cattle or badgers, where perturbation would have less effect.

There was clearly a range of possible factors which could be investigated as a means by which to reduce the effects of perturbation, including the biosecurity measures the ISG believed could reduce the risk of cattle becoming infected by badgers.

Yet the ISG had chosen to divert resources which might otherwise have been used to provide a detailed study of such factors towards considerations Lord Rooker described as beyond its remit.

In July 2007, the FUW presented this evidence to the Rural Development sub-committee, concluding that Wales should proceed with a cull, while taking steps to minimise the adverse effects identified during the RBCT.

That opinion was effectively reflected in the committee’s final recommendations, and has since become a WAG policy, which has cross-party support and has been ratified twice by an overwhelming majority of elected Welsh Assembly Members.

The decision to cull in north Pembrokeshire is one which has both scientific and political backing, and the fact it is more than one-and-a-half times the size of RBCT areas and has significant boundaries means it is expected to produce results far better than those found in England.

Data released since the ISG published its final report, including results for the six-month period to January 2010, shows an ongoing positive effect following the cessation of culling, with incidents down by 37 per cent in the cull areas, and by 3.6 per cent in the surrounding areas; positive effects which are likely to be more significant and longer lasting in north Pembrokeshire.

So how do the positive results anticipated in Wales compare with those of BCG vaccination, the policy favoured by the previous English Government, but seemingly less so by the current administration?

The truth is no-one knows, but many suspect trapping badgers to inject them is likely to be more costly than culling, due to the numbers of badgers which will be re-trapped. Science makes it clear it will take far longer to have any positive effect.

In the long-term, the viable practical options for reducing bTB incidences are limited to:

• Reduce badger numbers over large areas to the levels they were at during the mid-1980s, which has been shown to be very effective.
• Vaccinate cattle, which would require the trialling and licensing of an effective vaccine and significant changes to EU legislation.
• Inoculate badgers with a tried and tested oral vaccine, once one becomes available.

We all agree any kind of practically administrable vaccine would be a blessing, but those who are opposed to culling proclaim it to be the solution to all our prayers. Unfortunately, it is a solution which does not yet exist, and we cannot afford to wait.

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