Badger culling to control bovine TB.

Tuberculosis in humans and animals: are we a threat to each other?

SummaryBovine tuberculosis (TB) occurs in cattle and badgers in the UK and control efforts are undertaken to reduce the spread of the disease.This study evaluates relationships predicted by nine epidemiological two‐host models of disease spread generated by various combinations of density‐dependent, frequency‐dependent and environmental pathogen transmission. The relationships of interest are between measures of TB in cattle and in badgers from 10 sites which were randomly selected to be proactive badger culling sites in the UK Randomized Badger Culling Trial. The data are from the initial badger cull only.There was most support (Akaike weight = 0·562,R2 = 0·869) for models that predicted a positive linear relationship between density of infectious cattle per square kilometre and the density index of infectious badgers. There was less support (Akaike weight = 0·060) for a model that predicted a positive linear relationship between density of infectious cattle per square kilometre and the proportion of badgers infectious withMycobacterium bovis.A correction to reduce effects of badger carcase storage and an examination of effects of the 2001 foot‐and‐mouth disease epidemic had little impact on estimated relationships.Synthesis and applications. The results provide support for two‐host disease models of TB in cattle and wildlife such as badgers, although the form of disease transmission cannot be identified clearly by these analyses. The implication of the results is that the best‐fitting models predict that, in the absence of intervention‐related changes in badger behaviour, a reduction in density of infectious badgers should reduce the density of infectious cattle. However, analysis of bait‐marking data collected following experimental badger culls indicated that culling badgers profoundly alters their spatial organization as well as their population density, potentially influencing contact rates. Effective vaccination of badgers, were it to become available, would be expected to reduce the density of infectious badgers without directly affecting their behaviour.

Bovine tuberculosis (TB) is a zoonotic disease that can have serious consequences for cattle farming and, potentially, for public health. In Britain, failure to control bovine TB has been linked to persistent infection of European badger (Meles meles) populations. However, culling of badgers in the vicinity of recent TB outbreaks in cattle has failed to reduce the overall incidence of cattle TB. Using data from a large-scale study conducted in 1998-2005, we show that badgers collected on such localized culls had elevated prevalence of Mycobacterium bovis, the causative agent of bovine TB, suggesting that infections in cattle and badgers were indeed associated. Moreover, there was a high degree of similarity in the M. bovis strain types isolated from cattle and associated badgers. This similarity between strain types appeared to be unaffected by time lags between the detection of infection in cattle and culling of badgers, or by the presence of purchased cattle that might have acquired infection elsewhere. However, localized culling appeared to prompt an increase in the prevalence of M. bovis infection in badgers, probably by disrupting ranging and territorial behavior and hence increasing intraspecific transmission rates. This elevated prevalence among badgers could offset the benefits, for cattle, of reduced badger densities and may help to explain the failure of localized culling to reduce cattle TB incidence.

Risk compensation theory suggests that behaviours are modified in response to interventions that remove risks by substituting them with other risky behaviours to maintain a 'risk equilibrium'. Alternatively, risk reduction interventions may result in spill-over behaviours that seek to minimise risks further. This paper assessed evidence for these behavioural risk responses among farmers in response to badger culling that seeks to remove the risk of bovine tuberculosis in cattle. Data from the UK's randomised badger culling trial were re-analysed, comparing farmers' cattle movement practices in proactive and reactive culling areasand control areas. Analysis compared cattle movementsduring and after the trial using zero-inflated negative binomial regression. The analysis found no strong evidence of risk compensation behaviours among farmers who experienced proactive culling. However, strong evidence for a reduction in cattle movements in reactive culling areas was found. The results indicate high levels of inertia within farming systems in relation to cattle purchasing. Data do not account for the risk of cattle purchases and reflect previous policy regimens. Evidence from recent badger culling interventions should be analysed. Proactive badger culling was not associated with risk compensation behaviours, while reactive badger culling was associated with decreased risk taking among farmers.

Biological hurdles to the control of TB in cattle: A test of two hypotheses concerning wildlife to explain the failure of control

A recent news report ‘Vets criticise government on TB proposals’ ( VR , 28 April 2018, vol 182, p 473) caused me to review some of the thinking that has...

Bovine tuberculosis (bovine TB) is a controversial animal health policy issue in England, which impacts farmers, the public, cattle and badgers. Badgers (Meles meles) act as a wildlife reservoir of disease. Policy options for badger control include (1) do nothing, (2) badger culling, and (3) badger vaccination. This paper argues for mandatory Animal Welfare Impact Assessment (AWIA) for all policy that significantly affects sentient animals. AWIA includes (1) species description, and (2) AWIA analysis stages. In this paper, AWIA is applied to impacts of bovine TB policy options on cattle and badgers. Over 4 years, 85,000 badgers will be culled to prevent the slaughter of ~17,750 cattle over 9 years. Hence, about five badgers are culled for every cow which avoids slaughter. The AWIA analyses the impact of badger vaccination on cows and badgers based on a set of stated assumptions. The AWIA estimates badger vaccination to reduce the number of cows slaughtered by 11,600, i.e. a 12.5% reduction. Additional to the harm of killing, culling has greater welfare impacts on badgers compared to non-culling options. Actors in animal health and welfare policy were interviewed about the concept of AWIA. Policy actors supported the idea of AWIA to provide objective data to feed into policy making. The paper concludes with the proposal that AWIA is a necessary stage of just policy making where sentient animals are impacted by government policy.

Control of bovine tuberculosis (TB) in cattle has proven particularly challenging where reservoirs of infection exist in wildlife populations. In Britain and Ireland, control is hampered by a reservoir of infection in Eurasian badgers (Meles meles). Badger culling has positive and negative effects on bovine TB in cattle and is difficult, costly and controversial. Here we show that Bacillus Calmette-Guérin (BCG) vaccination of captive badgers reduced the progression, severity and excretion of Mycobacterium bovis infection after experimental challenge. In a clinical field study, BCG vaccination of free-living badgers reduced the incidence of positive serological test results by 73.8 per cent. In common with other species, BCG did not appear to prevent infection of badgers subjected to experimental challenge, but did significantly reduce the overall disease burden. BCG vaccination of badgers could comprise an important component of a comprehensive programme of measures to control bovine TB in cattle.

As a part of bovine tuberculosis eradication strategy, the Welsh Government has proposed a badger cull in a defined area in and around North Pembrokeshire, and has published information on...

Summary The incidence of bovine tuberculosis (TB) in British cattle has risen markedly over the last two decades. Failure to control the disease in cattle has been linked to the persistence of a reservoir of infection in European badgers Meles meles, a nationally protected species. Although badger culling has formed a component of British TB control policy for many years, a recent large‐scale randomized field experiment found that TB incidence in cattle was no lower in areas subject to localized badger culling than in nearby areas where no experimental culls occurred. Indeed, analyses indicated that cattle incidence was higher in culled areas. One hypothesis advanced to explain this pattern is that localized culling disrupted badgers’ territorial behaviour, potentially increasing the rate of contact between cattle and infected badgers. This study evaluated this hypothesis by investigating badger activity and spatial organization in 13 study areas subjected to different levels of culling. Badger home ranges were mapped by feeding colour‐marked baits at badger dens and measuring the geographical area in which colour‐marked faeces were retrieved. Badger home ranges were consistently larger in culling areas. Moreover, in areas not subjected to culling, home range sizes increased with proximity to the culling area boundary. Patterns of overlap between home ranges were also influenced by culling. Synthesis and applications. This study demonstrates that culling badgers profoundly alters their spatial organization as well as their population density. These changes have the potential to influence contact rates between cattle and badgers, both where culls occur and on adjoining land. These results may help to explain why localized badger culling appears to have failed to control cattle TB, and should be taken into account in determining what role, if any, badger culling should play in future control strategies.

Re-evaluation of statistical analysis of the Randomised Badger Culling Trial (RBCT) by Torgerson et al. 2024 was rebutted by Mills et al. 2024 Parts I and II. The rebuttal defended the use of count rather than rate when considering bovine tuberculosis herd incidence. The defence makes biologically implausible use of Information Criterion for appraisal diagnostics; overfits data; and has erroneous Bayesian analyses. It favours 'goodness of fit' over 'predictive power', for a small data set, when the study was to inform application. Importantly, for 'total' bTB breakdown: ('confirmed' (OTF-W) +'unconfirmed' (OTF-S)), where modern interpretation of the main diagnostic bTB test better indicates the incidence rate of herd breakdown, there is no effect in cull and neighbouring areas, across all statistical models. The RBCT was a small, single experiment with unknown factors. With respect to the paradigm of reproducibility and the FAIR principles, the original RBCT analysis and recent efforts to support it are wholly unconvincing. The 2006 conclusion of the RBCT that "badger culling is unlikely to contribute positively to the control of cattle TB in Britain" is supported, but the route to such a position is revised in the light of modern veterinary understanding and statistical reappraisal.

Continuing to presume that complex policy problems are simple problems that can be solved through the adoption of simple designs that are given general names, such as private property, government ownership, or community organization, is a dangerous academic approach. Elinor Ostrom (2005 p. 256) Understanding Institutional Diversity . Princeton University Press, Princeton and Oxford 16.1 Introduction If we think of property as an entitlement to a benefit stream, there is a sense in which we all have some proprietorial interest in the countryside. Even if we do not own land ourselves, we each hold rights of access and we have expectations in terms of our capacity to enjoy landscape, wildlife and living space and to benefit from marketed products, increasingly characterised in terms of ecosystem services. At the same time, landowners hold rights to use their land for their own purposes, free from unreasonable interference. As individual aspirations and social priorities, circumstances and the distribution of power and influence change, rights, duties and incentives are reformed and recast to reflect new situations. There is thus a constant flux along margins of interaction between conflicting aims and interests. As a result, the very nature of property itself is modified over time. 16.2 The shifting dimensions of governance Governance is the process whereby these aspirations and divergent interests are resolved into rules, incentives and norms that determine outcomes on the ground. There is no single or correct model of governance, but rather a permanently shifting contest between different stakeholders to coordinate their actions and influence the character of the benefit streams that arise from the countryside and to gain access to them. Demands to change the outcomes from this process are pursued at multiple levels constantly and simultaneously: to achieve a legislative body that implements rules sympathetic to particular interests, to influence a government department to approach an issue in a particular way, or to persuade those on the ground to take or not take particular actions. These contests are played out in respect of many different issues, whether it is the public right of access to open land, the ownership of forests, the development of greenfield land for housing or the introduction of fracking. Sometimes new benefit streams emerge or old ones disappear, and the debates surrounding them become distorted or conflated with other issues. Take for example the issue of the control of bovine TB through badger culling.

We are writing to express our extreme concern following recent media coverage1, 2 relating to the methodology being used by contractors to kill badgers under licence, as part of the...

At its Council meeting last month, the BVA agreed that, under certain circumstances, controlled culling of badgers is necessary to control the spread of bovine tuberculosis (bTB).

Veterinary RecordVolume 190, Issue 9 p. 372-372 Bovine TB Badger culling to control bovine TB M Hancox, Corresponding Author M Hancox biologist hancoxm17@protonmail.com 17 Nouncells Cross, Stroud, Gloucestershire, GL5 1PTSearch for more papers by this author M Hancox, Corresponding Author M Hancox biologist hancoxm17@protonmail.com 17 Nouncells Cross, Stroud, Gloucestershire, GL5 1PTSearch for more papers by this author First published: 06 May 2022 https://doi.org/10.1002/vetr.1763Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume190, Issue97/14 May 2022Pages 372-372 RelatedInformation