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Impasse over TB has created a situation that's an unholy mess

By Western Morning News  |  Posted: September 12, 2012

A mix of solid data and technology is a better solution than purely political science when it comes to eradicating the problem, argues Pat Bird

Comments (0) As the courts rule on a badger cull, cattle farmer Pat Bird warns that as the debate rages on, TB is the only winner.

Successive ministers of all colours continue to duck their statutory duty for the eradication of bovine tuberculosis, an international obligation to protect human health.

In 1986, the ministry slaughtered 638 cattle and last year 34,617. In 2006, the Department of the Environment, Food and Rural Affairs (Defra) devolved licensing of any badger movements, except rescues, sacked their wildlife operatives and encouraged disparate groups of farmers to take on its responsibilities.

Now different groups want to cull badgers using a map diagram, cull infected setts only, vaccinate badgers and/or cattle. While on the opposite side of the same fence, others blame cattle (or farmers) for the disease and want to "save" badgers. All quote limited, mostly mathematically modelled or assumed "facts" as support.

During our own TB breakdowns and the last culling trial's antics, I asked many questions.

Unless wildlife reservoirs of tuberculosis are controlled, cattle measures make no impact on this disease. This futile route has been tried before in Cornwall and Ireland and failed – as it is failing us now.

The cattle skin test is the international primary test for TB. Many countries have cleared their herds using it, and of those that haven't, this country is unique in abandoning its control of a known wildlife reservoir – with profound public-health implications.

If the mind-blowing figures of cattle which this test is alleged to have "missed" are to be believed, then no country would be TB-free and huge numbers of lesioned cattle would be found by abattoirs. In 2011 just 1,013 cases of TB were confirmed from British abattoir samples out of a kill of around 3.8 million.

Bacillus Calmette–Guérin (BCG) vaccine for badgers was tested for health and safety in 2010, and is a popular soapbox for the vaccine's efficiency. But the 844 badgers described were screened for TB prior to their jabs and 262 took part. After all, what is the point in vaccinating badgers which already have TB?

Much later, Defra spluttered that claims of a 74% success rate for BCG during this trial should not be used. Prescreening revealed an infection rate of 43%, "typical of badgers in that area". To date no details of this work's effect on cattle TB have been published. But in a different project, when BCG efficacy was tested using controlled exposure and post-mortem, all the pre-screened, vaccinated badgers had lesions and were shedding bacteria.

Proposals to vaccinate cattle avoids tackling the cause of their problems. The skin test is showing exposure to increasing environmental contamination with TB, now affecting a quarter of cattle herds in the West, and spilling into other animals and their owners – and vets.

In the face of the enormous challenge to any mammal from bacteria shared by infectious badgers, annual BCG will have little or no effect. Just 70 units of bacteria are needed to introduce TB to cattle and 1,000 units infect a badger. A badger with kidney lesions scatters up to 300,000 units of bacteria in each millilitre of urine; this is dribbled across grassland and sprayed as scent markers or defence.

So what are the options? The latest farmer cull proposal using free shooting, models a 16% benefit to cattle breakdowns. But this figure is pulled from cage-trapping eight nights annually, which the chairman of this charade told a parliamentary committee, was a protocol "imposed by politicians."

Professor John Bourne explained the answer his trial was supposed to deliver. He said: "It was made very clear to us by ministers of the day that elimination of badgers over large tracts of countryside was not an option for future policy. It was on that basis that we designed the trial.

"We repeatedly say 'culling, as conducted in the trial'. Those limitations were not imposed by ourselves. They were imposed by politicians."

So what happened when politicians did not interfere in the control of tuberculosis?

A short, complete clearance of badgers at Thornbury resulted in no cases of cattle TB for a decade. The reason given by Ben Bradshaw, MP was that no other change was identified that could have accounted for the reduction in TB within the area."

No bio security or cattle measures were introduced.

Decades of ministerial prevarication over TB has delivered an unholy mess. History tells us that if all badgers are removed, cattle TB disappears. But is that necessary, or even desirable, when a validated test using the polymerase chain reaction system (PCR) on infected badger setts remains unreported and unused, Animal Health maps showing where reactor cattle have been infected gather dust, tracking skills and bait marking of badger territories are ignored? Surely this mix of solid data and validated technology, has to be a better solution than modelled "political science"? The only winner in this crazy impasse is tuberculosis – and that is a very dangerous victory.

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