Bovine TB: What's all the Fuss About?

A Brief History of Bovine Tuberculosis

Introduction

It may seem obvious that the government's proposed badger cull is something that conservationists would protest about. But why is it that bovine TB is regarded as a problem deserving of government intervention? What are the origins to this seemingly intractable problem? Its not as if all animal health problems are a concern for governments. This article briefly sets out some of the historical context to bovine TB. In particular, I draw attention to three moments or transitions which have been instrumental in shaping how the problem of bovine TB is understood and dealt with.

Bovine TB: The Transition to a Social Problem

Bovine TB is one of a group of diseases that first encouraged the UK Government to be concerned about animal disease. Until the mid Eighteenth century, farmers had been quite happy to live with the consequences of diseases such as Foot and Mouth: they were not seen as the kind of disastrous plague they are today(Woods, 2004). Those who pressed for animal health legislation received little support [22], certainly from farmers or from the meat trade who feared for their livelihoods (Perren, 1978). The veterinary profession itself had limited experience or understanding of common diseases of livestock or their implications for public health. Instead their expertise lay largely in equine medicine, and cattle work was less paid and not a significant part of veterinary training.

However, that changed following an outbreak of rinderpest (cattle plague) in the 1860s. Vets' inability to control the disease through ‘treatments’ of individual animals highlighted their poor understanding of disease control. Some prominent vets, however, saw an opportunity to realign the profession with a wider public health agenda by asserting vets’ credentials to speak on matters of animal health. They were assisted in this by agriculturalists and influential members of parliament who had calculated the economic impact from cattle disease and pressed for government intervention.

So it came to pass that a government infrastructure was gradually assembled, starting with a Veterinary Department of the Privy Council was established in 1865, to help manage, eradicate and control the effects of animal diseases. Gradually certain diseases were identified as being necessary to eradicate for either economic reasons or public health reasons. Foot and Mouth Disease become one of the diseases to be eradicated for the effects it had on agricultural productivity, whilst was bovine tuberculosis one that also had a serious impact upon public health. These classifications of diseases (to use the language, they are officially notifiable) still holds today, despite changes in technology, agricultural practices, and social and economic contexts. 

Bovine TB: Transition from public to animal health

The classification of bovine TB as a notifiable disease was not straightforward. For a start, whilst much was known about bovine tuberculosis, it was not made a statutory notifiable disease until 1925, placing it on the same footing as FMD and rinderpest. As Keir Waddington describes in his book the 'Bovine Scourge' (Waddington, 2006)  there was a long fight to fully understand its causes and what should be done about it - both in terms of a public health problem (through the consumption of infected meat and milk) and as an animal health problem (in terms of preventing transmission between cattle) - a fight in which many respects continues today. As a public health problem, the sale of meat unfit for human consumption had been the first object of regulation, but by the inter-war years attention had switched to milk. At the time, approximately 50000 human cases of bTB were recorded annually, killing 5% of those infected, and it was this that led to campaigns focussing on the quality of milk and beef such as those for milk pasteurisation (Waddington, 2004).

Arguably, it was this inter-war period that has proved critical in the setting the direction for the future management of bovine TB. Firstly, milk began to be pasteurised and was generally accepted by the government to be the way forward (although it was not made compulsory until after the war). Until this point the medical profession had been involved with the management of bovine TB - this made obvious sense given its health impacts. The medics believed that as a public health problem, pasteurisation was the last key: along with meat inspection, bovine TB in humans would be a thing of the past. As it happens, they were proved right: these days, the Health Protection Agency consider bovine TB to be an insignficant threat. Any cases are usually reactivated infections amongst the elderly who may drank unpasteurised milk, or associated with migrants who have come to the UK. As far as they were concerned, there was no more to be done (Hardy, 2003).

Maybe this would have been the case except for two things. The first was the recognition that bovine TB was also a disease of cattle that had economic implications for farmers. Already in 1935 a voluntary eradication programme of bovine TB in cattle had been established. The second was the establishment of the State Veterinary Service in 1937. This split the management of bovine TB between medics and vets. Whilst one believed the battle to be over, the establishment of the SVS legitimised further efforts to eradicate it from cattle. Without it, and the current debates around bovine TB may simply have been something for the agricultural industry to worry about rather than the Government. 

It was not until after the second world war when attempts to eradicate the disease in cattle really kicked in. A new voluntary scheme, quickly was replaced by a compulsory national eradication programme was introduced soon after the second world war. On a parish by parish basis, herds were tested using the tuberculin test – more commonly known as the ‘skin test’ - and where infection was found, the whole herd was culled. Farmers were compensated, but they could only restock from parishes where cattle had all tested negative. Subsequently, bTB in the national herd was virtually eliminated. The Ministry of Agriculture and Fisheries celebrated the achievement in their book, "A Centenary of Animal Health" (MAFF, 1965). It turned out to be a false dawn.

Bovine TB: A political transition

In 1971 a dead badger was found on a Gloucestershire farm that had recently suffered a bTB breakdown. Subsequent post-mortem tests revealed that the badger had also been suffering from bTB. This chance discovery reframed bovine TB policy and gave MAFF what it thought was a rather obvious solution: controlling badgers was the key to controlling bovine TB in cattle. This reframing bovine TB as a wildlife issue is central to today's arguments over badger culling. But it is also the key to a third transition: the introduction of the badger problem has meant policy has been driven increasingly by political concerns. 

But if MAFF thought the discovery of the badger was going to make their job easier, then they were wrong. By a strange coincidence, the Badger Act was passed in parliament just two years later in 1973 making it an offence to: ‘kill or attempt to kill, injure, take, cruelly ill-treat, dig for or use badger-tongs on any badger. Also, to sell, offer for sale of have in his possession any live badger’. The act was by no means the first attempt to protect badgers. In fact the UKs first animal protection laws targeted badgers: Badger baiting was officially banned in 1835 whilst the baiting of all animals was made illegal by the 1911 Prevention of Cruelty to Animals Act. In subsequent years, new protection laws were passed and amalgamated (e.g. 1981 Wildlife and Countryside Act and the European Union’s Habitat directive), closing loopholes in the original legislation, resulting in the 1992 Badger Protection Act which provided protection to badger setts as well as the animals themselves. These acts also confirm the UK’s commitment to the pan-European Bern Convention in which badgers are listed as a protected species.

Thus, at the very same time the government were convinced that destroying badgers would resolve bovine TB, it had also committed itself to protecting it. How did it resolve this conflict? The problem of bovine TB took precedence and the government launched itself into a programme of badger extermination using cyanide gas. Across large areas of farmland – as it Thornbury, Gloucestershire – badgers were killed using this method. The results seemed to confirm what MAFF had suspected: killing badgers would reduce bovine TB. But the policy was not without its critics. As Wyn Grant’s history of this episode describes, the policy was met with public revulsion, even amongst farmers (Grant, 2009). 

By the end of the 1970’s, politicians were finding bovine TB difficult to manage. Compared to now, levels of TB were still extremely low, but politicians had become aware that the controlling bovine TB was not easy. In an attempt to defuse the controversy, Peter Walker, the minister in charge of bovine TB, launched a policy review, to be led by Lord Zuckerman. Although the gassing of badgers by MAFF ceased, Zuckerman confirmed the policy should continue. What was most important about the Zuckerman report is that it began a trend of politicians attempting to defuse bovine TB by referring it to an expert or scientific committee – a standard political tactic.

But if this was meant to defuse public concern and distance politicians from the controversy, is didn’t work. The minister was still required to public defend the policy whilst the press ran stories with emotive headlines such as “Farmer’s wife Phyllis Crook weeps as ministry men pump cyanide gas into a badger sett in Lyneham, Wilts’ alongside an appealing picture of a badger.  The same report went on to cast doubt on question the Zuckerman report, describing it as “scientifically spurious, biased and factually misleading”. Public protest and the government’s indecision came to something of a head at Folkington Bowl in 1984 where badgers were being removed by MAFF. In reaction, MAFF withdrew, fearful of what might happen to their staff, but also concerned about the effect of adverse publicity or pictures showing the killing of badgers (Grant, 2011).

In 1986 a second attempt to justify the badger removal policy was made by referring it to another expert review. The subsequent report, known as the Dunnet report, recommended a new approach – what it called an ‘interim policy’. Ironically, it proved to be one of the longest policies affecting badgers. The hope was to cull infected badgers using a ‘live test’. However, the test failed to be validated. Instead, the interim policy – reduced badger culling and only around farms that had experienced a TB breakdown – became the established policy for the next 11 years. Any badger removal operation also had to be sanctioned by members of the ‘badger panel’ – a committee that sat quarterly to determine action around infected farms – another way of distancing politics from the decisions over badgers and bovine TB.

Nevertheless, instances of bovine TB continued to rise. And although the levels were nowhere near today’s heights, civil servants were agitating for a new policy review to provide a firmer direction for policy. Whilst some evidence existed on the effectiveness of badger culling, the fact that levels of bovine TB were continuing to rise suggested the need for a thorough scientific review of the policy. This was granted in 1996, as the Conservative government commissioned John Krebs to review the scientific evidence on badger culling and make recommendations. His review (Krebs et al., 1997) concluded by recommending that MAFF commission a scientific experiment to determine the extent to which badgers contributed to the spread of bTB and the effectiveness of culling badgers as a management tool. This trial was called the Randomised Badger Culling Trial (RBCT) and its recommendation was taken on board by the new Labour government in 1997. This science-led approach chimed with their commitment to evidence-based policy.

To implement the Krebs report, Professor John Bourne was commissioned to lead an Independent Scientific Group. The idea was to assign different policy interventions to 10 triplet areas. In each area, three interventions would be trialled: proactive culling (where all badgers would be killed); reactive culling (where badgers would be killed near farms with bovine TB); and a control area where no interventions would occur. Although this trial was the main body of work that occupied the ISG, they also looked closely at other elements of bovine TB transmission, such as cattle to cattle transmission, diagnostic tools, and risk factors.

The trial was not straightforward. Some landowners blocked access to government employees preventing them from setting traps. In other cases, protestors disrupted trapping by damaging the traps. Perhaps the most serious setback came in 2001 when an outbreak of Foot and Mouth Disease affected the UK. This had two effects. The first was to effectively delay the trial by a year as no trapping could take place. The second was that vets that usually tested cattle for TB were occupied with other duties, or could not access farms because of restrictions. This delay proved disastrous: when testing resumed in 2002, the number of infected cattle increased dramatically. Infected cattle that had been left on farms for over a year will have helped spread the disease to other cattle. 

In one respect, FMD helped epidemiologists: it revealed the extent to which animal movements had become central to the agricultural industry, and also in the spread of the disease. The British Cattle Tracing System had only been implemented following another animal health disaster – BSE, or mad cow disease – but this proved a useful tool to show that cattle moving from “TB areas” to “clean” areas were taking the disease with them. However, in other respects the FMD outbreak represented all that was wrong with the ISG trial. For some, such as farmers, the science was fundamentally flawed: issues over damaged traps, limited trapping and access to land meant that the science could not be trusted. This critique of the ISGs science was particularly loud when the ISG released their results in 2007 (Independent Scientific Group [ISG]. 2007) which suggested that badger culling could make no meaningful contribution to the control of cattle TB in the UK. The ISG had responded to this critique with more scientific analysis, although this deficit model of scientific communication was unlikely to make much difference. What most people had missed was that the RBCT was meant as a real world trial of policy options: scientific perfection was never going to be possible.  This certainly seem to bypass the UK Government’s Chief Scientist when he was asked by Defra ministers to review the ISG’s scientific evidence (King, 2007). The resulting report claimed that the ISGs conclusions were misleading but that the science was sound. The report was put together following a telephone conference between the chief scientist and several experts one afternoon. The credibility of the report and of the chief scientist was questioned, not least by the Environment and Rural Affairs Select Committee whose chairman Michael Jack, seemed incredulous that the chief scientist could suggest that one afternoon of research could trump the ISGs near ten years of work. In the exchange, the chief scientist seemed unable to accept or realise that good science would always reflect public attitudes and concerns. Whilst other forms of badger culling exist to those used by the ISG, the reason they didn’t use them was because it had already been agreed that they were inhumane or impractical or ineffective.  

Perhaps a more serious effect of the FMD, however, was to create a divide between civil servants responsible for bovine TB and the scientists managing the RBCT. The management of FMD created tensions between types of veterinary experts working within or for government. Although the State Veterinary Service were involved in managing the crisis, the government lost confidence in their ability to manage the outbreak and relied on evidence presented to them by epidemiologists based on computer modelling. This resulted in the contiguous cull, and the demotion of field level veterinary expertise to the background. This dispute over professional status also affected bovine TB. Members of the group of epidemiologists advising the government on FMD were also working for the ISG and the sense that ‘real’ vets had been hard done spilled over into the relationships between Defra and the ISG. The relationship had gone from neutral to one of distrust, and was not helped by Defra issuing a consultation on badger control that ran contrary to all the scientific advice the ISG had provided (Independent Scientific Group [ISG]. 2006).

The RBCT did though through up other interesting results. Firstly, the reactive culling policy that for so long had been the way MAFF had culled badgers was shown to be ineffective and scrapped halfway through the RBCT. Interim results had shown that in areas of reactive culling, levels of bovine TB had actually increased. The cause of this was the second key finding from the study: the effect of badger perturbation. In all areas where badgers had been culled, ecological studies revealed that badger behaviour had changed as a result. Rather than stable territories in which badger groups lived, culling disrupted these territories. Badgers roamed greater distances and extended their ranges because there were fewer badgers preserving them (Woodroffe et al., 2006). This “perturbation effect” meant that infected badgers may come into contact with cattle where previously the territories of clean badgers had prevented it. Or, this extra roaming behaviour brought infected badgers into contact with clean ones so passing on the disease. Although these behaviours are theoretically plausible, they also had resonance with the farming community. Farmers have long held believes of “good” and/or “clean” badgers. Some farmers who resisted the ISGs culling trial did so out of a belief that they had “clean” badgers protecting their cows: the last thing they wanted was to lose this defence. Indeed, the idea of perturbation comes as much from farmers as it does from scientists: Dr Chris Cheeseman, for a long time responsible for badger research at Woodchester Park, described how it was through discussions with farmers that its relevance to badger culling emerged – the experiments in the RBCT provided scientific proof .

Badger control is not just about culling. For a long time it has been assumed that vaccination would provide the key to this intractable problem. For an equally long time however, there was no vaccine: just one permanently 10 years away. Experiments with the BCG vaccine, however, suggested that it might have a role to play in preventing the spread of bovine TB and its severity in badgers. In 2009, Defra announced its intention to pursue a policy of badger vaccination in 6 areas of England. By the following year, however, this was reduced to just one area (near Stroud) by the new government on cost grounds. Vaccinating cattle has been equally complex. Again, a vaccine has been permanently promised but never fully materialised until recently. The main problem here is one of distinguishing between animals that have been vaccinated and those that have bovine TB: the current diagnostic test for TB would suggest that a vaccinated animal was infected with TB. The test is required to ensure that EU trade could continue: EU partners want to be sure that they are not importing infected animals. However, even with such a test EU member states are unlikely to be in a hurry to rewrite EU legislation to benefit UK farmers. Farmers may instead be left asking themselves are UK cattle exports worth preserving if we can resolve bovine TB through cattle vaccination?

Farmers have also been asked to improve their on farm biosecurity to help prevent badger to cattle contacts. Until the outbreak of FMD, few people had heard of the word biosecurity. Since then, however, Defra have encouraged farmers to reduce particular farming behaviours known to increase the risk of bovine TB. Commonly, farmers have been asked to fence off badger setts, to secure food stores from badgers, try to restrict access to cattle sheds by badgers, and purchasing cattle from TB free areas. However, attempts to encourage behaviour change amongst farmers have been limited by limited resources and simplistic attempts at risk communication (Enticott, 2008).

The perturbation effect played a significant role in shaping the ISG’s conclusions. When the positive effects of badger culling on incidence of cattle TB were weighed against the negative consequences of perturbation, cost-benefit analyses revealed that it would not make financial sense to pursue such a policy. As time has gone on, so more data has become available on the long term effects of badger culling. The most recent analyses present a more favourable picture to badger culling, but costs still outweigh benefits. It was for this reason that in 2010, the new Coalition government began a consultation on a badger cull paid for by farmers. The proposed methodology – “free shooting” (later called “controlled shooting”) managed to get around the cost-benefit analysis. Free shooting, it was suggested, would be a much cheaper option than cage trapping badgers. However, its effectiveness and practicality are completely untested. 

In Wales, the Welsh Government is in the process of reviewing its approach to badgers. Having announced it was going to cull badgers in North Pembrokeshire, the decision was overturned after a successful legal challenge by the Badger Trust. Although the Welsh Government pressed ahead with its planned cull following some legal changes, a change in the political make-up of the government meant that the plan was put on hold again pending another review of the evidence by a group of experts.

The future: where is bovine TB policy headed?

If there’s one thing this review has shown it is that bovine TB, badgers and politics is a potent mix. Politicians have long realised that the mixture is too hot to handle and sought to find ways to distance themselves from it. This has been a consistent theme over the last 20 years with review upon review. What are the chances of this pattern recurring over the next 20 years? In Wales, the current situation is that the evidence is being reviewed again. In England, although the government has set out plans for a badger cull, the plans are by no means immune to changes in politics. Although farmers complain about the "politicisation" of bovine TB, its strange that they have not argued more vigourously for control over bovine TB - in other words to distance the political system from decision making. In farmers' view, the state has a responsibility to them to sort out the disease. This may be true, but the last 40 years has shown that it is incapable of doing so. If bovine TB is so important to the agricultural industry then why don't they take responsibility for the costs and benefits associated with it? Isnt this the only way that farmers will get what they want? In the face of an epidemic, it seems odd to hang on to old models of governance just for the sake of it.

 

Whilst it will never be possible to completely remove the politics from bovine TB, it is possible to repoliticise bovine TB. One way of doing this is by passing the costs of TB control onto those who receive the benefits of the policy. This makes sense: if there is no public benefit to be had from controlling bovine TB then it is right that those who stand to gain from it should pay for it. This is how TB control effectively works in countries like New Zealand where farmers pay for TB control via a levy on milk and meat production. It means they have more ownership of the policy and a say in how it is run. The downside to this is that this arrangement also legitimises wildlife control: by removing the costs of TB control from the public, the efficiency of badger culling becomes an issue for those paying for it rather than the Government. So long as some basic standards are met in relation to for example the humaneness and safety of badger killing, the long term efficiency is only of concern to farmers: they may choose to monitor it, they may take a risk that it is efficient, or they may decide that after all, the benefits are not worth the costs and decide that badger culling is not worth pursuing. Its unlikely that conservationists would ever accept the risk that this wouldnt happen. But the irony is that if they don't, bovine TB policy will remain where it has done for the last 40 years: stuck.

References

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