Tag Archives: bovine tuberculosis

Finding a Heiferlump and curing bovine Tuberculosis

By Gareth Enticott, Cardiff University, UK

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(c) Gareth Enticott

In April 2017, Brian May – the rock star turned badger conservationist – brought together policy makers, scientists, veterinarians and farmers to discuss the continuing problem of bovine tuberculosis (bTB) in badgers and cattle. Whilst most media attention has focused on the controversy of badger culling, my recent paper in Transations of the the Institute of British Geographers, “Navigating veterinary borderlands: ‘heiferlumps’, epidemiological boundaries and the control of animal disease in New Zealand” (Enticott, 2017), examines a fundamental question: how do we even know what bovine tuberculosis is? And, is it the same everywhere, or do we need different ways of seeing disease to meet different local contexts?

Knowing Bovine Tuberculosis

Confronted with disease, most people want to be certain that a disease is present or not – that somehow disease can be routinely and easily diagnosed, and that this diagnosis would be the same anywhere. Such a belief in the universality of disease is popular amongst policy makers and epidemiologists too: it provides the basis for standardised responses to disease throughout an area or country. As my paper shows, though, in the field or on the farm, these universalities can be far from helpful. Rather, than relying on universal perspectives, the paper shows how accepting the mutability of disease by combining different knowledges and understandings can be central to its management.

Heiferlumps and Striking Farmers

The argument made in the paper comes from an historical analysis of attempts to eradicate bTB from New Zealand. Records of meetings held by the Department of Agriculture in New Zealand National Archives show that as the eradication programme was rolled out in the 1960s, the effects upon farmers’ businesses began to be felt, leading many to question the accuracy of the diagnostic tests. The problem was felt most on the West Coast of New Zealand. Farmers here refused to test: their strike causing political consternation. Local vets, too, had their doubts about the accuracy of the test. The problem seemed to be what was known locally as ‘Heiferlumps’ – young cattle testing positive to the skin test used to diagnose bTB, but which had no internal signs of disease at slaughter. One of these vets, Peter Malone, led pleas for a ‘lighter’ interpretation of the test results – what he called ‘reading light’ – but was ignored by senior government vets in the capital, Wellington.

The relationship between vets and farmers on the West Coast and government officials in Wellington turned toxic when Malone admitted to ignoring heiferlumps when interpreting the results of bTB tests. The Department of Agriculture’s leading vet, a Scotsman called Sam Jamieson responsible for the eradication program, and known for his short temper and scientific approach, was outraged. Malone was forbidden from testing, only stoking an air of mutual mistrust between vets and farmers on the West Coast and distant government vets like Jamieson.

In the ensuing controversy, Jamieson turned to a field trial to establish the veracity of the bTB tests and rule out the possibility that there could be local variations in the nature of bTB. It had little effect: although the trial proved the test was good, no test is ever 100% accurate and farmers and vets continued to raise doubts. But rather than more science, what came to settle the dispute was a new kind of science: a version of epidemiology that was not confined to a particular discipline but crossed boundaries to combine different ways of knowing disease .

The paper refers to this new approach as ‘borderland epidemiology’ in which
government vets came to recognize during the 1970’s that bTB was as much a social and moral problem as an epidemiological one. Archive documents show that they began to dispense with the rule-book, and instead working with farmers, to modify and adapt how bTB should be diagnosed, and reflect unique geographical variations. Understanding that managing disease is a balancing act made from negotiations rather than universalisms has since become a principle on which New Zealand has been able to almost eradicate bTB

Lessons for the UK?

Could these experiences from New Zealand be relevant to the management of bTB in the UK? On the one hand, Defra – the government department responsible for managing bTB – look favourably upon the New Zealand approach to managing disease, their recent strategy mentioning them more than any other country (Defra, 2014). Yet, at the same time, there appears to be little room for manouvre to experiment and try new approaches to managing disease. In fact, as revealed at Brian May’s summit, attempts of the kind conducted in the 1970s in New Zealand, but by vets in England, have been ruled illegal and halted, despite their positive impacts upon disease and farmer engagement with disease management process.  In future, however, as my paper argues, adapting and adjusting diagnostics to local geographical variations by working with farmers to develop new kinds of veterinary knowledge may offer the best chance of dealing with disease.

About the author: Gareth Enticott is Reader in Human Geography in the School of Geography and Planning. His research focuses on biosecurity, practices of environmental regulation and governance, and scientific controversies in animal health. His main focus is on the ongoing controversy surrounding bovine Tuberculosis in the UK, as well as the management of the disease in New Zealand.  His work has helped inform policy on bovine Tuberculosis in England and Wales.

books_icon Defra (2014) The Strategy for Achieving Officially Bovine Tuberculosis Free Status for England, London: Defra. 

books_icon Enticott, G. (2017), Navigating veterinary borderlands: ‘heiferlumps’, epidemiological boundaries and the control of animal disease in New Zealand. Trans Inst Br Geogr, 42: 153–165. doi:10.1111/tran.12155

60-world2 Midley O (2017) Rock star Brian May hosts bovine TB debate https://www.fginsight.com/news/rock-star-brian-may-hosts-bovine-tb-debate-20023 FG Insight 

Badgers and bovine tuberculosis: how geographical research can help

By Joseph Bailey, University of Nottingham, UK.

If I mention bovine tuberculosis (bTB), I imagine that a badger, not a cow, would come to mind for many people. British news has recently reported a push for culling these mammals and calls from others for vaccination, with the intention of curbing the spread of bTB. Some famous faces have also engaged in the anti-culling debate (e.g. see ‘Stop the Cull’). There are strong views on both sides because of the damage that bTB can do to cattle herds and farmers’ livelihoods. All parties, of course, want to see a decrease in bTB cases; it is just the preferred means that differ. Here, I outline the debate and move on to discuss how geographical research can help.

Attribution: By H. Zell (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

Attribution: By H. Zell (Own work) [ CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0) ], via Wikimedia Commons

First, why are badgers getting all of the press? Badgers, along with a number of other mammals, are capable of contracting bTB and spreading it to cattle, the result of which can be devastating because cows that test positive are compulsorily slaughtered. Badgers, perhaps justifiably (they can and do infect cows with bTB), perhaps not (reported infection rates vary but can be very low), are often referred to as a natural ‘reservoir’ of the disease and there is now a strong association between badgers and bTB in cattle. The Government has approved badger culls in England, whilst the Welsh Assembly has favoured a vaccination programme. .

The BBC recently reported on the decision for future culls in England to not be independently monitored as they have been previously. Naturally, this has been heavily criticised and it is disturbing considering the outcome of last year’s pilot culls. However, to many, culling generally seems to not be a sensible or sustainable solution, not least because of the high uncertainty surrounding badger numbers and the associated need for highly costly surveys to decrease this uncertainty and reduce the risk of causing local extinctions, costs which potentially make the whole process financially impracticable (Donnelly & Woodroffe, 2012). Most importantly, such local extinctions would be a tremendous natural loss to an area.

Culls in England were criticised by a Welsh Minister earlier this year who referred to ‘promising’ results from the vaccination efforts in Wales. It has been shown that only a minority (even with varying figures) of badgers actually carry bTB (see The Wildlife Trusts infographic and references therein), meaning that many uninfected, healthy badgers are likely to be killed during a cull. Unlike with vaccinations, culling can also cause badger populations to spread unpredictably (known as perturbation), making control of any infected badgers not killed during the cull more difficult, thus potentially increasing the likelihood of the disease spreading.

Nationally, the Wildlife Trusts are leading the way with badger vaccination efforts and no Wildlife Trust allows culling on its land. Given that badgers live for 3–5 years, it is estimated that herd immunity could be achieved within 5 years (see bottom) as infected animals die over time and the proportion of vaccinated animals increases. How to target vaccination efforts, though? This is where geographers can help.

A recent article in Area (Etherington et al., 2014) recognises the importance of landscape isolation and connectivity, alongside data on badger presence and abundance, in mapping the spatial variation in bTB. Such knowledge is potentially very valuable for bTB management strategies. Indeed, understanding badgers’ local or landscape scale population dynamics and their isolation or connectivity within that broader landscape could allow for more effective vaccine distribution within an area surrounding a farm, for example. Namely, if a population is likely to be connected to certain other populations and a certain farm, it follows that these populations should be vaccinated in parallel. That is of course a simplification of reality, but an enhanced understanding of such dynamics will hopefully be able to contribute to bTB management.

It shouldn’t be forgotten that bTB in badgers represents a small, albeit significant, part of the overall bTB crisis. Overall, it seems to me that targeted vaccination of badger populations in combination with enhanced biosecurity (I have not discussed this here but it is a significant part of the solution; e.g. ‘badger proofing’), is clearly a superior solution to culling when it comes to achieving long-term reductions in bTB. Such an approach also ensures the survival and welfare of the badgers that so many people deeply care about.

(For another Geography Directions blog post on bovine tuberculosis, see ‘Badgers, borderlands and security‘ (by Helen Pallett), which discusses the inherent complexities of disease in nature.)

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books_icon Donnelly, C. A. & Woodroffe, R. (2012). Epidemiology: Reduce uncertainty in UK badger culling. Nature 485, p. 582.

books_icon Etherington, T. R., Trewby, I. D., Wilson, G. J. & McDonald, R. A. (2014). Expert opinion-based relative landscape isolation maps for badgers across England and WalesArea 46, 50-58.

Pests, Pathogens and Passports

By Jen Dickie

Entrance to Saltby Estate Dairy Farm.  Biosecurity measures to protect the cattle in this large dairy farm against foot and mouth.  This image is owned by Kate Jewell and is licensed for reuse under the Creative Commons Attribution-ShareAlike 2.0 license. If you have ever visited Australia you will have experienced a force to be reckoned with- the Australian Customs and Border Protection Service; woe betide anyone who forgets the piece of fruit squashed at the bottom of their hand luggage!  Few places exist where the importance of biosecurity is more prominent to the general public than in Australia’s airports where strict regulations are imposed on the importation of food, plant material and animal products to minimise the risk of exotic pests and diseases entering the country.  Whilst public awareness campaigns of biosecurity issues are common in Australia, in the UK it appears that both public and governmental awareness only increase after the damage has been done.

Over the last few weeks, Chalara fraxinea, or ash dieback as it is commonly known, has dominated the news.  This virulent fungal disease is thought to have hitched a lift with imported saplings from Europe and has already been confirmed in over 80 locations (Forestry Commission, 5th Nov).  Patrick Barkham from The Guardian questions whether more could have been done to prevent this outbreak and criticises the government for the “apparently sluggish response” to the disease.  As fears grow over the future of our woodlands, more threats from foreign pathogens to our native species are coming out of the woodwork, with Robin McKie from The Observer warning that the Scots pine “could be the next casualty of a ‘tidal wave’ of tree diseases”.

However, it is not just the plant kingdom that is under threat.  The controversial badger cull to prevent the spread of bovine tuberculosis (bTB) has recently been discussed in parliament.  In an article for The Geographical Journal, Gareth Enticott, Alex Franklin and Steven Van Winden explore different biosecurity strategies and behaviours practiced by farmers in response to bTB.  Their findings suggest that the promotion of biosecurity to farmers should draw on locally situated practices and knowledge rather than taking a standardised approach.  They argue that policy-makers need to “re-evaluate the purpose of disease control and their approaches to it”.

It has taken a series of pest and disease outbreaks for the seriousness of the UK’s biosecurity to hit the headlines.  Lessons can be learned from the Australian approach but as more reports emerge, claiming that the government was aware of the ash dieback invasion three years ago, perhaps more focus is needed on biosecurity risk assessments rather than on mitigation efforts once the problem has taken hold.

 Gareth Enticott, Alex Franklin and Steven Van Winden, 2012, Biosecurity and food security: spatial strategies for combating bovine tuberculosis in the UK, The Geographical Journal, DOI: 10.1111/j.1475-4959.2012.00475.x

 Scots pine could be next casualty of a ‘tidal wave’ of tree diseases, The Observer, 3 November 2012

 The ash tree crisis: a disaster in the making, The Guardian, 30 October 2012

 Badger cull: MPs vote 147 to 28 for abandoning cull entirely, The Guardian,  25th October 2012

 Ash disease found in Essex and Kent, Forestry Commission, 5th November 2012

Transactions of the Institute of British Geographers Content Alert: Volume 37, Issue 1 (January 2012)

The latest issue of Transactions of the Institute of British Geographers is available on Wiley Online Library.

Click past the break to view the full table of contents.

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