Management Of Bovine Tuberculosis Research Articles

Public debate on bovine tuberculosis eradication: Topics and metaphors in the trans-Pyrenees region (Spain and France) 2018–2020

The management of bovine tuberculosis (bTB) is a controversial issue due to the different positions of stakeholders regarding diagnosis and treatment. Considering how they conceptualize bTB might influence the acceptability of eradication programmes, we analyse communication materials published by a range of sources in Spain and France, two countries dealing with this disease. We use content and discourse analyses to investigate topics associated with bTB and to detect metaphorical frames used for talking about it. We identify disease detection and control as a dominant issue bolstered by metaphors of battle and war and by images of farmers having to obey other stakeholders' orders. We argue instead in favour of a less warlike perspective in institutional and scientific communication, which also gives farmers more visibility in bTB management.

Effect of selective removal of badgers (Meles meles) on ranging behaviour during a ‘Test and Vaccinate or Remove’ intervention in Northern Ireland

The role of the Eurasian badger (Meles meles) as a wildlife host has complicated the management of bovine tuberculosis (bTB) in cattle. Badger ranging behaviour has previously been found to be altered by culling of badgers and has been suggested to increase the transmission of bTB either among badgers or between badgers and cattle. In 2014, a five-year bTB intervention research project in a 100 km2 area in Northern Ireland was initiated involving selective removal of dual path platform (DPP) VetTB (immunoassay) test positive badgers and vaccination followed by release of DPP test negative badgers ('Test and Vaccinate or Remove'). Home range sizes, based on position data obtained from global positioning system collared badgers, were compared between the first year of the project, where no DPP test positive badgers were removed, and follow-up years 2-4 when DPP test positive badgers were removed. A total of 105 individual badgers were followed over 21 200 collar tracking nights. Using multivariable analyses, neither annual nor monthly home ranges differed significantly in size between years, suggesting they were not significantly altered by the bTB intervention that was applied in the study area.

Mapping careful epidemiology: Spatialities, materialities, and subjectivities in the management of animal disease

As a geographical tool, epidemiology represents a distinct way of seeing and knowing disease. Used as a governmental rationality to control animal disease, changes in epidemiological practice have been understood as technological evolutions. In doing so, however, this view disguises the “messy realities” of epidemiology, the relationship between different epidemiological practices, and the work required to make epidemiology “matter.” Drawing on a case study of the management of bovine tuberculosis in England and Wales, the paper examines how epidemiological practices are developed, replaced, and contested. By focusing on practices of epidemiological record keeping and mapping, the paper argues that epidemiology arranges different spatialities, materialities, and subjectivities in order to enact the presence of animal disease. The paper tracks changes to these arrangements over time, showing how they seek to redefine the appropriate people, places, and practices that allow disease to be seen. In doing so, however, the paper shows how versions of epidemiology deposit “residues of practice” that influence how new epidemiological arrangements are received and negotiated in use. A central theme to these negotiations is an attempt to accommodate complexity by employing a caring and/or careful approach to epidemiology, as revealed through the practices of “re‐recording” and “re‐mapping.” Whilst this demonstrates the contextual and in‐situ nature of epidemiology, highlighting the contribution of a caring/careful epidemiology also serves to make these practices relevant for future iterations of epidemiological practice by making them “matter.”

Monitoring European badger (Meles meles) reproduction under evolving bovine tuberculosis management in Ireland

Wildlife disease management often relies on altering population abundance and density to reduce the susceptible host population. Understanding the vital rates and ecology that influence wildlife population dynamics is important for assessing the outcomes of management policies. European badgers (Meles meles) in Ireland have historically been managed for bovine tuberculosis (TB) using culling, but are now being vaccinated instead. We used data from 6847 badgers submitted for postmortem examination from 2016 to 2018 to inform population monitoring of badgers under this management change. Female reproductive status varied strongly by month, and a considerable proportion (25–40%) of females had evidence of premature cessation of lactation. Teat lengths may offer a crude guideline for rapid antemortem assessment of probable reproductive status. Body weight for males and females declined throughout the capture period, and we report reference ranges for normal male and female body weight during each month. Increasing body weight was associated with an increased odds of pregnancy (OR 2.52, 95% CI 2.20–2.93, p < 0.001). Prior capturing at the sett where a badger was captured did not affect the odds of pregnancy (OR = 0.99, 95% CI 0.96–1.03, p = 0.77) or influence litter size (β = − 0.0012, SE = 0.014, p = 0.93). Assessing changes in badger reproduction will ensure that management is adapted for a badger population likely to expand and contribute to a successful TB eradication program in Ireland.

Push and pull factors driving movement in a social mammal: context dependent behavioral plasticity at the landscape scale.

Understanding how key parameters (e.g., density, range-size, and configuration) can affect animal movement remains a major goal of population ecology. This is particularly important for wildlife disease hosts, such as the European badger Meles meles, a reservoir of Mycobacterium bovis. Here we show how movements of 463 individuals among 223 inferred group territories across 755 km2 in Ireland were affected by sex, age, past-movement history, group composition, and group size index from 2009 to 2012. Females exhibited a greater probability of moving into groups with a male-biased composition, but male movements into groups were not associated with group composition. Male badgers were, however, more likely to make visits into territories than females. Animals that had immigrated into a territory previously were more likely to emigrate in the future. Animals exhibiting such “itinerant” movement patterns were more likely to belong to younger age classes. Inter-territorial movement propensity was negatively associated with group size, indicating that larger groups were more stable and less attractive (or permeable) to immigrants. Across the landscape, there was substantial variation in inferred territory-size and movement dynamics, which was related to group size. This represents behavioral plasticity previously only reported at the scale of the species’ biogeographical range. Our results highlight how a “one-size-fits-all” explanation of badger movement is likely to fail under varying ecological contexts and scales, with implications for bovine tuberculosis management.

Bovine Tuberculosis Management in Northwest Minnesota and Implications of the Risk Information Seeking and Processing (RISP) Model for Wildlife Disease Management.

Bovine tuberculosis (bTB) is an infectious, zoonotic disease caused by Mycobacterium bovis that can spread between domestic and wild animals, as well as to humans. The disease is characterized by the progressive development of lesions that compromise the victim's lungs and lymph system. The disease was first identified in northwest Minnesota in both cattle and white-tailed deer (Odocoileus virginianus) in 2005. Due to its risks to human and animal health, bTB has numerous implications related to population management, policy outcomes, stakeholder relations, and economic impacts. When dealing with complicated risks, like bTB, individuals often seek out and process information as a method to learn about, and cope, with the risk. We developed a questionnaire that adapted components of the Risk Information Seeking and Processing (RISP) model and surveyed northwest Minnesota deer hunters. Our objectives were to better understand how stakeholders perceive and act on information regarding disease management in wildlife and to understand the utility of the RISP model for such management contexts. We drew a random proportional sample of licensed deer hunters (n = 2100) from the area affected by bTB and conducted a multi-contact mail survey. We found that 43% of the variability in the information-seeking behaviors of respondents was explained by demographics, hunting importance, personal risk perceptions, attitudes, and subjective norms. However, these results are largely attributable to the factors in the RISP model encompassed by components of the Theory of Planned Behavior (i.e., attitudes, subjective norms, perceived behavioral control, and behavioral intentions). This information can help managers contextualize individuals' perceived risks to better frame communication efforts to address stakeholder concerns and develop best practices for disease communication. While the state of Minnesota is currently considered free of bTB, future outbreaks remain possible in Minnesota and elsewhere. Understanding the key factors in the processes through which deer hunters seek out information pertaining to the disease can help managers collect the data necessary to aid decisions about desired future management outcomes. In addition, testing RISP model performance in applied research improves its future use across a broad spectrum of topics throughout veterinary disease management.

Pathologies of policy learning: what are they and how do they contribute to policy failure?

We analyse policy failure as a degeneration of policy learning. Analytically, we drill down on one type – epistemic learning. This is the realm of evidenced-based policymaking (EBPM), where experts advise decision-makers on issues of technical complexity. Empirically, we present the management of bovine tuberculosis (BTB) in England since 1997 as a failure of epistemic learning. Drawing on elite interviews and documentary analysis, weaknesses in government’s management of its relationship with an epistemic community are analysed as problems of learning about different aspects of organisational capacity. We conclude discussing the value of learning theories as conceptual lenses for policy failure.

Valuing conservation benefits of disease control in wildlife: A choice experiment approach to bovine tuberculosis management in New Zealand's native forests

We assess the non-monetary environmental benefits that accrue incidentally in New Zealand (NZ) from pest management conducted primarily to control an animal disease, bovine tuberculosis (TB). TB is an infectious disease that is one of the world's most serious animal health problems and, in many parts of the developing world, still a major mortality risk for humans. The incidence of TB in New Zealand (NZ) farmed livestock has been reduced progressively over the last 20 years, largely due to extensive and sustained population control of the main wildlife reservoir of disease, the introduced brushtail possum. Possums are also major pests that threaten indigenous forest biodiversity, and so extensive possum control for TB mitigation also incidental benefits conservation, but the extent and public value of this benefit has yet to be quantified. We conducted a choice experiment survey of the NZ public in an effort to value the native forest biodiversity benefits of TB-related possum control. We find strong public support for conservation outcomes consequent to TB-possum control in public native forests. The public place substantial value on the most observable biodiversity benefits of TB possum control, such as improved forest canopies and presence of native birds. The benefits, costs and values of TB-possum control are discussed in relation to the future directives of NZ's TB control programme, which is headed toward first regional and then national level disease eradication.

How well do farmers know their badgers? Relating farmer knowledge to ecological survey data

Knowledge of badger distribution is important for the management of bovine tuberculosis. At the farm level, typically the only information on badger activity available is from the farmers themselves. This...

Fecal Volatile Organic Ccompound Profiles from White-Tailed Deer (Odocoileus virginianus) as Indicators of Mycobacterium bovis Exposure or Mycobacterium bovis Bacille Calmette-Guerin (BCG) Vaccination.

White-tailed deer (Odocoileus virginianus) serve as a reservoir for bovine tuberculosis, caused by Mycobacterium bovis, and can be a source of infection in cattle. Vaccination with M. bovis Bacille Calmette Guerin (BCG) is being considered for management of bovine tuberculosis in deer. Presently, no method exists to non-invasively monitor the presence of bovine tuberculosis in deer. In this study, volatile organic compound profiles of BCG-vaccinated and non-vaccinated deer, before and after experimental challenge with M. bovis strain 95–1315, were generated using solid phase microextraction fiber head-space sampling over suspended fecal pellets with analysis by gas chromatography/mass spectrometry. Chromatograms were processed using XCMS Online to characterize ion variation among treatment groups. The principal component scores resulting from significant (α = 0.05) ion responses were used to build linear discriminant analysis models. The sensitivity and specificity of these models were used to evaluate the feasibility of using this analytical approach to distinguish within group comparisons between pre- and post-M. bovis challenge: non-vaccinated male or female deer, BCG-vaccinated male deer, and the mixed gender non-vaccinated deer data. Seventeen compounds were identified in this analysis. The peak areas for these compounds were used to build a linear discriminant classification model based on principal component analysis scores to evaluate the feasibility of discriminating between fecal samples from M. bovis challenged deer, irrespective of vaccination status. The model best representing the data had a sensitivity of 78.6% and a specificity of 91.4%. The fecal head-space sampling approach presented in this pilot study provides a non-invasive method to discriminate between M. bovis challenged deer and BCG-vaccinated deer. Additionally, the technique may prove invaluable for BCG efficacy studies with free-ranging deer as well as for use as a non-invasive monitoring system for the detection of tuberculosis in captive deer and other livestock.

Public attitudes to badger culling to control bovine tuberculosis in rural Wales

This paper examines public attitudes to wildlife control to prevent the transmission of disease between wild and farmed animals. In Great Britain, there has been considerable controversy amongst farmers, the public, scientists and politicians over the role of badger culling in the management of bovine tuberculosis. This paper examines public attitudes to badger culling in rural Wales, the reasons why culling is rejected and/or accepted and the level of trust the public place in different organisations responsible for badger culling. Variations in public attitudes between areas of differing degrees of rurality and disease incidence are analysed. Results indicate moderate levels of support for badger culling, but respondents do not believe the current scientific evidence on the effectiveness of a cull is acceptable. Respondents in rural fringe areas and low disease incidence are more likely to favour badger vaccination. The results have implications for future policy and methods of communicating wildlife control policies to the public.

Researching controversial and sensitive issues: using visual vignettes to explore farmers' attitudes towards the control of bovine tuberculosis in England

This paper addresses the potential difficulties associated with researching controversial and/or sensitive issues. Drawing on the findings from in‐depth interviews with farmers, the paper provides a reflexive commentary on the use of visual vignettes to explore farmers' attitudes towards the control of bovine tuberculosis in England – currently a highly controversial subject. Five short video clips were shown to interviewees to prompt discussions about different aspects of disease control, including methods to vaccinate and cull badgers. Visual vignettes have not been used widely outside the fields of health and social care. The method is used here to encourage interviewees to discuss sensitive issues related to badger control, including their trust in various stakeholders involved in the management of bovine tuberculosis, their own knowledge and understanding about disease control, and their attitudes towards control methods. The results suggest that visual vignettes have a number of advantages that could benefit research in human geography and the wider social sciences.

Animal disease and narratives of nature: Farmers' reactions to the neoliberal governance of bovine Tuberculosis

This paper examines the relationship between neoliberal styles of animal disease governance and farmers' understandings of disease and nature. In the UK, new styles of animal disease governance has promised to shift the costs and responsibilities of disease management to farmers, creating opportunities for farmers to take responsibility for disease control themselves and opening up new markets for disease control interventions. Focussing on the management of bovine Tuberculosis (bTB) and drawing on interviews with 65 cattle farmers, the paper examines how farmer responses to these new styles of animal disease governance are shaped by their own knowledges and understandings of nature and disease. In particular, the paper examines how two key narratives of nature – the idea of ‘natural balance’ and ‘clean and dirty badgers’ – lead farmers to think about the control of bTB in wildlife (such as the choice between badger culling and/or vaccination) in very specific ways. However, whilst discourses of cost and responsibility appear to open up choice opportunities for farmers, that choice is constrained when viewed from the perspective of farmer subjectivities and narratives of nature. Discourses of neoliberalism as control rather than choice are therefore revealed, drawing attention to the complexities and plural strategies of neoliberal governance.

An example of life history antecedence in the European badger (Meles meles): rapid development of juvenile antioxidant capacity, from plasma vitamin E analogue

The way organisms cope with oxidative stress, to quench potentially toxic oxygen free radicals while maintaining oxygen species functionality, is crucial in shaping life-history traits. Antioxidant capacity plays an important role in this process. Here we use multi-model inference procedures to examine the age-class-dependent non-enzymatic antioxidant capacity of the European badger (Meles meles), testing non-enzymatic plasma antioxidant capacity and expressing the results as vitamin E analogue (VEA) equivalent units. Despite immaturity (ca 16 weeks old), cubs exhibited plasma antioxidant capacity equivalent to those of prime-age adults (1–5 years old). Compared to individuals aged 6 years and over, cubs exhibited significantly higher non-enzymatic plasma antioxidant capacity. There was no association between plasma antioxidant capacity and sex or other physiological variables, such as body condition or presence of wounding. We consider the adaptive significance of this life-history strategy with respect to pandemic endoparasitoses that affect badger cub survival, as well as a possible link to the free radical theory of ageing. Our finding on the interaction between age and antioxidant defences (linked to immune function) has implications for the controversy surrounding effective badger bovine tuberculosis management strategy in the UK.

Tuberculosis infection in wildlife from the Ruaha ecosystem Tanzania: implications for wildlife, domestic animals, and human health

Mycobacterium bovis, a pathogen of conservation, livestock, and public health concern, was detected in eight species of wildlife inhabiting protected areas bordering endemic livestock grazing lands. We tested tissues from 179 opportunistically sampled hunter-killed, depredation, road-killed, and live-captured wild animals, representing 30 species, in and adjacent to Ruaha National Park in south-central Tanzania. Tissue culture and PCR were used to detect 12 (8.1%) M. bovis-infected animals and 15 (10.1%) animals infected with non-tuberculosis complex mycobacteria. Kirk's dik-dik, vervet monkey, and yellow baboon were confirmed infected for the first time. The M. bovis spoligotype isolated from infected wildlife was identical to local livestock, providing evidence for livestock-wildlife pathogen transmission. Thus we advocate an ecosystem-based approach for bovine tuberculosis management that improves critical ecological functions in protected areas and grazing lands, reduces focal population density build-up along the edges of protected areas, and minimizes ecological stressors that increase animals' susceptibility to bovine tuberculosis.

Reducing Eurasian wild boar (Sus scrofa) population density as a measure for bovine tuberculosis control: Effects in wild boar and a sympatric fallow deer (Dama dama) population in Central Spain

Research on management of bovine tuberculosis (bTB) in wildlife reservoir hosts is crucial for the implementation of effective disease control measures and the generation of practical bTB management recommendations. Among the management methods carried out on wild species to reduce bTB prevalence, the control of population density has been frequently used, with hunting pressure a practical strategy to reduce bTB prevalence. However, despite the number of articles about population density control in different bTB wildlife reservoirs, there is little information regarding the application of such measures on the Eurasian wild boar (Sus scrofa), which is considered the main bTB wildlife reservoir within Mediterranean ecosystems.This study shows the effects of a management measure leading to a radical decrease in wild boar population density at a large hunting estate in Central Spain, in order to assess the evolution of bTB prevalence in both the wild boar population and the sympatric fallow deer population.The evolution of bTB prevalence was monitored in populations of the two wild ungulate species over a 5-year study period (2007–2012). The results showed that bTB prevalence decreased in fallow deer, corresponding to an important reduction in the wild boar population. However, this decrease was not homogeneous: in the last season of study there was an increase in bTB-infected male animals. Moreover, bTB prevalence remained high in the remnant wild boar population.

Facts and dilemmas in diagnosis of tuberculosis in wildlife

Mycobacterium bovis, causing bovine tuberculosis (BTB), has been recognized as a global threat at the wildlife-livestock-human interface, a clear "One Health" issue. Several wildlife species have been identified as maintenance hosts. Spillover of infection from these species to livestock or other wildlife species may have economic and conservation implications and infection of humans causes public health concerns, especially in developing countries. Most BTB management strategies rely on BTB testing, which can be performed for a range of purposes, from disease surveillance to diagnosing individual infected animals. New diagnostic assays are being developed for selected wildlife species. This review investigates the most frequent objectives and associated requirements for testing wildlife for tuberculosis at the level of individual animals as well as small and large populations. By aligning those with the available (immunological) ante mortem diagnostic assays, the practical challenges and limitations wildlife managers and researchers are currently faced with are highlighted.

An Inter-Laboratory Validation of a Real Time PCR Assay to Measure Host Excretion of Bacterial Pathogens, Particularly of Mycobacterium bovis

Advances in the diagnosis of Mycobacterium bovis infection in wildlife hosts may benefit the development of sustainable approaches to the management of bovine tuberculosis in cattle. In the present study, three laboratories from two different countries participated in a validation trial to evaluate the reliability and reproducibility of a real time PCR assay in the detection and quantification of M. bovis from environmental samples. The sample panels consisted of negative badger faeces spiked with a dilution series of M. bovis BCG Pasteur and of field samples of faeces from badgers of unknown infection status taken from badger latrines in areas with high and low incidence of bovine TB (bTB) in cattle. Samples were tested with a previously optimised methodology. The experimental design involved rigorous testing which highlighted a number of potential pitfalls in the analysis of environmental samples using real time PCR. Despite minor variation between operators and laboratories, the validation study demonstrated good concordance between the three laboratories: on the spiked panels, the test showed high levels of agreement in terms of positive/negative detection, with high specificity (100%) and high sensitivity (97%) at levels of 105 cells g−1 and above. Quantitative analysis of the data revealed low variability in recovery of BCG cells between laboratories and operators. On the field samples, the test showed high reproducibility both in terms of positive/negative detection and in the number of cells detected, despite low numbers of samples identified as positive by any laboratory. Use of a parallel PCR inhibition control assay revealed negligible PCR-interfering chemicals co-extracted with the DNA. This is the first example of a multi-laboratory validation of a real time PCR assay for the detection of mycobacteria in environmental samples. Field studies are now required to determine how best to apply the assay for population-level bTB surveillance in wildlife.

Management of bovine tuberculosis in Michigan wildlife: Current status and near term prospects

Surveillance and control activities for bovine tuberculosis (bTB) in free-ranging Michigan white-tailed deer ( Odocoileus virginianus) have now been underway for over a decade. Significant progress has been made, lowering apparent prevalence in deer in the core area by >60%, primarily via reduction of deer densities through hunting, and restrictions on public feeding and baiting of deer. These broad strategies of the Michigan Department of Natural Resources (MDNR), implemented with the cooperation of Michigan deer hunters, halved the deer population in the bTB endemic area. However, as hunters see fewer deer, their willingness to sustain aggressive harvests has waned, and public resentment of control measures has grown. During the past four years, apparent prevalence in core area deer has held approximately steady just below 2%. After bottoming out in 2004 at an estimated 10–12 deer/km 2, deer numbers have since rebounded by ∼30%. Public compliance with baiting and feeding restrictions has been variable. In general, hunters in the core area do not perceive bTB as a problem, in spite of 13 years of MDNR outreach. To date, MDNR has expended more than US$23 million on TB-related activities. Of late, a substantial portion of that funding has been diverted to support other programs which have suffered from budget shortfalls. Livestock herd breakdowns continue to occur sporadically, averaging 3–4 per year 2005 to present. In total, 46 cattle and 4 captive deer herds have been diagnosed bTB positive statewide, the majority yielding only 1 positive animal. Five cattle herds were twice infected, one thrice. Michigan Department of Agriculture (MDA) policy emphasis has shifted towards obtaining producer support for wildlife risk mitigation and farm biosecurity. Funding has proven a limiting factor, with the majority of the US$63 million spent to date devoted to whole herd testing. Nevertheless, some initiatives justify cautious optimism. Promising research to support eventual vaccination of wild deer continues. Some hunters and landowners have begun to recognize the costs of high deer densities and supplemental feeding. A peninsula-wide ban on baiting and feeding was enacted. Some cattle producers, recognizing their precarious circumstances, have begun work to change long-held prevailing opinions among their peers about farm biosecurity. Yet formidable challenges remain, and evidence suggests that eradication of bTB, if it can be achieved, will take decades, and will require greater public and political resolve than has been demonstrated thus far.

Recent advances in the management of bovine tuberculosis in free-ranging wildlife

Established foci of Mycobacterium bovis (the causative agent of bovine tuberculosis [bTB]) in free-ranging wildlife are currently under various stages of management on three continents (Africa, Europe and North America) and in New Zealand. Other, as yet undiagnosed, foci seem likely to exist elsewhere. The complex roles that these wildlife foci play in the ecology of bTB remain among the greatest challenges facing bTB control globally. Conceptually, management of bTB in free-ranging wildlife can be thought of as progressing from the discovery of an outbreak through frequently overlapping stages of epidemiological characterization, initial control, simulation and forecasting, focused control, and verification of eradication. Surveillance in its various forms remains a critical component of assessment throughout. Since the Fourth International M. bovis Conference in 2005, research on management of bTB in free-ranging wildlife has encompassed such areas as the human dimensions of wildlife management, mitigation of bTB risks from wildlife on cattle farms, vaccine biology, and epidemiology, with a major contribution from simulation modeling. In order to advance the actual field management of bTB, however, research must be sufficiently grounded to aid development of practical, affordable and politically defensible management interventions which stand a reasonable chance of being implemented. The current management of two wildlife reservoirs of bTB, brushtail possums ( Trichosurus vulpecula) in New Zealand, and white-tailed deer ( Odocoileus virginianus) in Michigan, USA, serve as contrasting examples of different wildlife management strategies aimed at achieving a common goal. In New Zealand, the importance of agricultural export markets and the status of the possum as a non-native pest have facilitated direct, aggressive management of the disease reservoir, resulting in considerable progress towards bTB freedom since 1994. In Michigan, the relative importance of the hunting economy and of whitetails as a game animal have made such aggressive culling politically untenable. This has forced reliance upon publicly supported, and implemented, management tools, and so provided impetus to better understand social support for wildlife management policy, its limitations, and ways to employ it in disease control policy development.