The political economy of bovine tuberculosis in Great Britain.

A brief history of bovine tuberculosis (bTB) and its control in Great Britain (GB) is presented. Numerous diverse policies to control the disease in humans, cattle and wildlife have been pursued over the last 100 years and many millions of pounds have been spent. After notable success in reducing the incidence and prevalence of bTB in cattle in GB from the 1950s to the mid-1980s, the geographical spread of the disease and the number of cattle slaughtered have increased continually since that time, with a high point of bTB incidence in 2008. This increase appeared to coincide with changing policy regarding the control of the disease in badgers, with a more humane approach adopted and with strengthened protection for badgers through legislation. Indeed, there has been much controversy in the debate on the role of badgers in disease transmission to cattle and the need for their control as vectors of the disease. The issue has attracted the attention of the media and there have been various commissioned research projects, trials and public consultations. The findings of two social science investigations presented as examples showed that citizens generally believed that bTB in cattle is an important issue that needs to be tackled, but objected to badgers being killed, whilst cattle farmers were willing to pay around £17/animal/year for a bTB cattle vaccine. It is noted that successes regarding the control of bTB in other countries have combined both cattle and wildlife controls and involved industry working in close partnership with government.

L'auteur retrace brièvement l'histoire de la tuberculose bovine et de la lutte contre cette maladie en Grande-Bretagne. Diverses mesures sanitaires ont été appliquées au cours des cent dernières années afin de maîtriser la maladie chez l'homme, chez les bovins et dans la faune sauvage, pour une dépense totale de plusieurs millions de livres. Après la chute remarquable de l'incidence et de la prévalence de la tuberculose bovine en Grande-Bretagne enregistrée depuis les années 50, la situation s'est inversée au milieu des années 80 et tant la distribution géographique de la maladie que le nombre de bovins abattus n'ont cessé de croître depuis cette date, l'année 2008 marquant le pic de l'incidence de la tuberculose bovine. Il est désormais établi que cette hausse a coïncidé avec l'évolution des politiques de lutte contre la tuberculose chez les blaireaux, à la faveur d'une approche plus respectueuse du bien-être animal qui s'est traduite par une protection renforcée des blaireaux dans la législation. En effet, le rôle des blaireaux dans la transmission de la tuberculose aux bovins et l'impératif de lutter contre les blaireaux en tant que vecteurs ont fait l'objet de très fortes controverses. Cette question a attiré l'attention des médias et il y a eu de nombreux projets de recherche commandités sur le sujet, d'expériences et de consultations publiques. D'après deux enquêtes sociologiques citées par l'auteur, les citoyens étaient généralement convaincus de l'importance de la tuberculose chez les bovins et de la nécessité de s'y attaquer mais ils s'opposaient aux mesures d'abattage des blaireaux, tandis que les éleveurs de bovins étaient disposés à payer environ 17 livres par bovin et par année pour pouvoir vacciner leurs bovins contre la tuberculose bovine. L'auteur fait observer que les succès enregistrés dans d'autres pays dans la lutte contre la tuberculose bovine sont liés à l'application combinée de mesures de contrôle chez les bovins et dans la faune sauvage et à une étroite collaboration entre les éleveurs et le gouvernement.

El autor repasa sucintamente la historia de la tuberculosis bovina y de su control en Gran Bretaña. En los últimos 100 años se han aplicado numerosas y variadas políticas y se han invertido muchos millones de libras para combatir la enfermedad en el ser humano, el ganado vacuno y la fauna silvestre. Entre mediados del decenio de 1950 y mediados del de 1980 se trabajó con notable éxito para reducir la incidencia y prevalencia de la enfermedad en el ganado vacuno británico. Pero a partir de ahí hubo una progresión constante en la propagación geográfica de la enfermedad y en el número de cabezas de ganado sacrificadas, con un máximo de incidencia registrado en 2008. Tal incremento parece coincidir con una inflexión de la política aplicada para luchar contra la enfermedad en los tejones, con la adopción de métodos más clementes y de medidas legislativas que instauraban un mayor nivel de protección de los tejones. Ha habido en efecto una gran controversia acerca del papel de los tejones en los procesos de transmisión de la enfermedad al ganado vacuno y la necesidad de controlar a esos animales como vectores de la infección. El tema ha suscitado gran atención mediática y ha sido objeto de una serie de proyectos de investigación, experimentos y consultas públicas. Según demuestran las conclusiones de dos investigaciones de ciencias sociales presentadas como ejemplo, en general los ciudadanos pensaban que la tuberculosis bovina en el ganado era un problema importante al que había que dar respuesta, pero se oponían al sacrificio de los tejones, a la vez que los ganaderos estaban dispuestos a pagar alrededor de 17 libras/animal/año por la vacunación antituberculosa de sus rebaños vacunos. El autor señala que los éxitos obtenidos en otros países a la hora de combatir la tuberculosis bovina pasan por instaurar controles a la vez en el ganado y en la fauna silvestre y por lograr que la industria trabaje en estrecha asociación con las instancias públicas.

Cost-benefit analysis of vaccination against Mycobacterium avium ssp. paratuberculosis in dairy cattle, given its cross-reactivity with tuberculosis tests.

Johne's disease (JD), or paratuberculosis, is a chronic enteric disease of ruminants, caused by infection with Mycobacterium avium ssp. paratuberculosis (MAP). Johne's disease causes considerable economic losses to the US dairy industry, estimated to be over $200 million annually. Available control strategies include management measures to improve calf hygiene, test-and-cull strategies, and vaccination. Although the first 2 strategies have shown to reduce the prevalence of MAP, they require dedicated and long-term efforts from dairy producers, with often relatively slow progress. As a result, uptake of both strategies has not been as wide as expected given the economic benefits especially of improved hygiene. Vaccination has also been found to reduce the prevalence and economic losses of JD, but most economic estimates have been based on simulation of hypothetical vaccines. In addition, if an animal is vaccinated, cross-reactivity between MAP antibodies and bovine tuberculosis (BTB) antigens may occur, decreasing the specificity of BTB tests. Therefore, MAP vaccination would cause additional indirect costs to the BTB surveillance and control program. The objective of the present study was to use data from a MAP vaccine trial together with an epidemiologic and economic model to estimate the direct on-farm benefits of MAP vaccination and to estimate the indirect costs of MAP vaccination due to the cross-reactivity with BTB tests. Direct economic benefits of MAP vaccination were estimated at $8.03 (90% predictive interval: -$25.97 to $41.36) per adult animal per year, all accruing to the dairy producers. This estimate is likely an underestimation of the true direct benefits of MAP vaccination. In addition, indirect economic costs due to cross-reactivity were $2.14 per adult animal per year, making MAP vaccination economically attractive. Only in regions or states with a high frequency of BTB testing (because of, for example, Mycobacterium bovis outbreaks in a wild deer population) and areas where typically small groups of animals are BTB tested would MAP vaccination not be economically attractive.

Cost estimate of bovine tuberculosis to Ethiopia.

While bovine tuberculosis (BTB) has been eliminated in some industrialized countries, it prevails worldwide, particularly in Africa. In Ethiopia, BTB is prevalent as numerous studies have shown its occurrence in livestock and in abattoirs but it has not been demonstrated in wildlife and only very few cases have been found in humans. The objective of this study is to estimate the cost of BTB to Ethiopia with the aim of informing Ethiopian policy on options for BTB control. BTB in livestock affects both animal productivity and herd demographic composition. The Livestock Development Planning System (LDPS2, FAO) was modified to allow for stochastic simulation of parameters. We performed an incremental cost of disease analysis, comparing livestock production with and without BTB. For the rural scenario we considered an endemically stable 4 % comparative intradermal test (CIDT) prevalence and for the urban scenario an endemically stable 32 % CIDT prevalence among cattle. The net present value of rural Ethiopian livestock products in 2005 is estimated at 65.7 billion (thousand million) Ethiopian Birr (95 % Confidence Interval (CI) 53.8-77.7 billion Birr), which is the equivalent of 7.5 billion US$ (95 %CI 6.1-8.9 billion US$) at a rate of 8.7 Birr per US$ in 2005. The cost of BTB ranges from 646 million Birr (75.2 million US$) in 2005 to 3.1 Billion Birr in 2011 (358 million US$) but is within the range of uncertainty of our estimate and can thus not be distinguished from zero. The cost of disease in the urban livestock production ranges from 5 to 42 million Birr (500,000-4.9 million US$) between 2005 and 2011 but is also within the range of uncertainty of our estimate. Our study shows no measurable loss in asset value or cost of disease due to BTB in rural and urban production systems in Ethiopia. This does not mean that there is not a real cost of disease, but the variability of the productivity parameters and prices are high and would require more precise estimates. This study does not preclude in any way the urgent need to control BTB in the urban dairy herd of Addis Ababa for other than financial reasons.

Diminishing returns in bovine tuberculosis control.

Mycobacterium bovis causes bovine tuberculosis (bTB) in many mammals including cattle, deer and brushtail possum. The aim of this study was to estimate the strength of association, using model selection (AICc) regression analyses, between the proportion of cattle and farmed deer herds with bTB in New Zealand and annual costs of TB control, namely disease control in livestock, in wildlife or in a combination of the two. There was more support for curved (concave up) than linear models which related the proportion of cattle and farmed deer herds with bTB to the annual control costs. The curved, concave-up, best-fitting relationships showed diminishing returns with no positive asymptote and implied TB eradication is feasible in New Zealand.

Modelling the feasibility of bovine tuberculosis eradication in Argentina.

The ability of countries to control and eradicate bovine tuberculosis (TB) has been jeopardised by various epidemiological and ecological features of the disease. The authors have used epidemiological modelling to develop an analytical framework to assess the likely success of a national TB eradication programme in Argentina. Study results suggest that the current control programme is financially feasible in the long term. However, considering that the costs of the TB eradication programme in Argentina are entirely borne by the producer, the initial investment required and the long-term horizon needed to gain revenue may prevent producers from endorsing the programme. Regionalised programmes that allow differential control strategies to be implemented in specific regions may increase the likelihood of success. This methodological approach could be extended to design and evaluate control and eradication programmes for TB and other infectious diseases in other regions of the world.

Control of bovine tuberculosis in British livestock: there is no 'silver bullet'.

Bovine tuberculosis (bTB; Mycobacterium bovis) is a bacterial infection of cattle that also affects certain wildlife species. Culling badgers (Meles meles), the principal wildlife host, results in perturbation of the badger population and an increased level of disease in cattle. Therefore, the priority for future management must be to minimize the risk of disease transmission by finding new ways to reduce the contact rate among the host community. At the farm level, targeting those individuals that represent an elevated risk of transmission might prove to be effective. At the landscape level, risk mapping can provide the basis for targeted surveillance of the host community. Here, we review the current evidence for bTB persistence in Britain and make recommendations for future management and research.

Farm costs associated with premovement testing for bovine tuberculosis.

Sixty cattle farmers in England were questioned about the costs associated with premovement testing for bovine tuberculosis (TB). On average, the farmers had premovement tested 2.45 times in the previous 12 months, but the majority had tested only once. An average of 28.6 animals were tested on each occasion, but there were wide variations. The average farm labour costs were 4.00 pounds per animal tested, veterinary costs were 4.33 pounds and other costs were 0.51 pounds, giving a total cost of 8.84 pounds, but there were wide variations between farms, and many incurred costs of more than 20 pounds per animal. A majority of the farmers also cited disruption to the farm business or missed market opportunities as costs, but few could estimate their financial cost. Most of the farmers thought that premovement testing was a cost burden on their business, and over half thought it was not an effective policy to control bovine TB.

A cost-benefit analysis of culling badgers to control bovine tuberculosis.

Bovine tuberculosis (TB) is an important economic problem. The incidence of TB in cattle herds has steadily risen in the UK, and badgers are strongly implicated in spreading disease. Since the mid-1970s the UK government has adopted a number of badger culling strategies to attempt to reduce infection in cattle. In this report, an established model has been used to simulate TB in badgers, transmission to cattle, and control by badger culling. Costs were supplied by the UK Government's Department for Environment Food and Rural Affairs (Defra) for badger trapping and gassing. Regardless of culling intensity or area simulated, an overall reduction in the herd breakdown rate was seen. With a high culling efficacy and no social perturbation, the mean Net Present Value of a few simulated culling strategies in an "ideal world" was positive, meaning the economic benefits outweighed the costs. Further work is required before these results could be considered definitive, as it is necessary to evaluate uncertainties and simulate less than perfect conditions.

Tuberculosis, Brucellosis and Leucosis in Cattle: A Cost Description of Eradication Programmes in the Region of Lazio, Italy.

The eradication of tuberculosis, brucellosis and leucosis in cattle has not yet been achieved in the entire Italian territory. The region of Lazio, Central Italy, represents an interesting case study to evaluate the evolution of costs for these eradication programmes, as in some provinces the eradication has been officially achieved, in some others the prevalence has been close to zero for years, and in still others disease outbreaks have been continuously reported. The objectives of this study were i) to describe the costs for the eradication programmes for tuberculosis, brucellosis and leucosis in cattle carried out in Lazio between 2007 and 2011, ii) to calculate the ratio between the financial contribution of the European Union (EU) for the eradication programmes and the estimated total costs and iii) to estimate the potential savings that can be made when a province gains the certification of freedom from disease. For the i) and ii) objectives, data were collected from official sources and a costing procedure was applied from the perspective of the Regional Health Service. For the iii) objective, a Bayesian AR(1) regression was used to evaluate the average percentage reduction in costs for a province that gained the certification. The total cost for the eradication programmes adjusted for inflation to 1 January 2016 was estimated at 18 919 797 euro (5th and 95th percentiles of the distribution: 18 325 050-19 552 080 euro). When a province gained the certification of freedom from disease, costs decreased on average by (median of the posterior distribution) 47.5%, 54.5% and 54.9% for the eradication programmes of tuberculosis, brucellosis and leucosis, respectively. Information on possible savings from the reduction of control costs can help policy makers operating under budget constraints to justify the use of additional resources for the final phase of eradication.

Cost-effectiveness evaluation of bovine tuberculosis surveillance in wildlife in France (Sylvatub system) using scenario trees.

Bovine tuberculosis (bTB) is a common disease in cattle and wildlife, with health, zoonotic and economic implications. Infected wild animals, and particularly reservoirs, could hinder eradication of bTB from cattle populations, which could have an important impact on international cattle trade. Therefore, surveillance of bTB in wildlife is of particular importance to better understand the epidemiological role of wild species and to adapt the control measures. In France, a bTB surveillance system for free-ranging wildlife, the Sylvatub system, has been implemented since 2011. It relies on three surveillance components (SSCs) (passive surveillance on hunted animals (EC-SSC), passive surveillance on dead or dying animals (SAGIR-SSC) and active surveillance (PSURV-SSC)). The effectiveness of the Sylvatub system was previously assessed, through the estimation of its sensitivity (i.e. the probability of detecting at least one case of bTB infection by each SSC, specie and risk-level area). However, to globally assess the performance of a surveillance system, the measure of its sensitivity is not sufficient, as other factors such as economic or socio-economic factors could influence the effectiveness. We report here an estimation of the costs of the surveillance activities of the Sylvatub system, and of the cost-effectiveness of each surveillance component, by specie and risk-level, based on scenario tree modelling with the same tree structure as used for the sensitivity evaluation. The cost-effectiveness of the Sylvatub surveillance is better in higher-risk departments, due in particular to the higher probability of detecting the infection (sensitivity). Moreover, EC-SSC, which has the highest unit cost, is more efficient than the surveillance enhanced by the SAGIR-SSC, due to its better sensitivity. The calculation of the cost-effectiveness ratio shows that PSURV-SSC remains the most cost-effective surveillance component of the Sylvatub system, despite its high cost in terms of coordination, sample collection and laboratory analysis.

Towards eradication of bovine tuberculosis in the European Union.

This paper reviews the developments and progress towards eradication of bovine tuberculosis in the European Union (EU). A historical view of the EU legislation aimed at mainly approximating provisions on intra-community in cattle trade explains the present EU policies. The variety of cattle breeding systems and environmental conditions in the EU leads to different epidemiological situations. The current situation of bovine tuberculosis in the EU Member States is summarised, and current policy in the EU is outlined.

Regionalization: a strategy that will assist with bovine tuberculosis control and facilitate trade.

It is expected that the revised chapter on bovine tuberculosis in the Terrestrial Animal Health Code of the Office Internationale des Epizooties (OIE) will embrace regionalization as a functional means of assisting countries, states or regions to meet the requirements for freedom from tuberculosis and to facilitate trade. The benefits and applications of regionalization, which comprises zoning and compartmentalisation, are discussed. Regionalization requires that a country's veterinary administration is able to implement transparent and auditable biosecurity measures that will ensure that the tuberculosis-free status of a subpopulation of cattle is maintained despite the presence of infection in another cattle subpopulation, or in other domestic or wild animal species. Zoning, which requires cattle subpopulations to be separated by geographic boundaries, provides a practical basis whereby countries, states or regions, can progress towards freedom from tuberculosis, regardless of the source of infection for defined cattle subpopulations. Compartmentalisation however, requires that husbandry or management practices will be used to prevent a tuberculosis-free cattle subpopulation from contacting interspecific and intraspecific sources of infection. This will be difficult to achieve except for specialised cases such as artificial breeding centers.

Costs to farmers of a tuberculosis breakdown.

An on-farm survey of 151 cattle farmers who had experienced a bovine tuberculosis (Mycobacterium bovis) breakdown on their farms was undertaken in 2003 to assess the costs associated with the breakdown. In 90 per cent of cases the cost was estimated to be less than 18,513 pounds sterling for dairy herds and less than 11,462 pounds sterling for beef herds, but with a range from 229 pounds sterling to 103,817 pounds sterling. The main cost was the slaughter of reactor cattle. For the majority of the farmers, the compensation payments seemed to meet most of the costs of their breakdowns, although a majority was still left with net losses.

Control and eradication of tuberculosis in cattle: a systematic review of economic evidence.

Bovine tuberculosis (TB) is a disease of zoonotic importance for which control and eradication programmes have been carried out in many countries for decades. While the impact of these programmes on public health is still uncertain, the impact on trade is significant because of movement restrictions for animals, costs of testing and culling. The objective of this systematic review was to provide a contribution to the general debate over costs against benefits for the control and eradication of bovine TB in cattle. The search strategy was performed on four electronic databases following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The selection process, data abstraction and quality appraisal were carried out according to the Cochrane Collaboration guidelines. The search identified 66 articles out of which eight fulfilled the inclusion criteria. The evidence gathered in this review by combining the conclusions of the most methodologically sound articles supports the idea that, when multiple cost and benefit components are taken into account, efforts to control or eradicate bovine TB may be effective in reducing disease prevalence, economically viable and worth doing.

Bovine tuberculosis in Burdur, southern Turkey: epidemiological, pathological and economic study.

SETTINGS: Burdur is the most important dairy cattle breeding and milk production area of Turkey, and Burdur slaughterhouse is one of the biggest slaughterhouses in the southern part of the country. No scientific information is available on the prevalence of tuberculosis (TB) in cattle in Burdur. A survey was therefore undertaken to determine the prevalence of disseminated TB infection in cattle in this district. OBJECTIVES: To implement a disease monitoring system in Burdur slaughterhouse to estimate the annual prevalence of disseminated TB in cattle slaughtered and inspected in 2003-2004. DESIGN: Epidemiological survey. RESULTS: Prevalence of bovine TB was investigated in Burdur slaughterhouse from January 2003 to December 2004. All of the affected animals were Holstein breed. The prevalence of disseminated TB in all slaughtered cattle was 0.38% in this period. The value of the condemned meat and organs was calculated to establish economic loss. CONCLUSION: Despite a strict eradication programme, bovine TB is still an important health issue among cattle and remains one of the greatest threats to cattle and human health in southern Turkey. Veterinarians and cattle producers in this region are encouraged to develop and work on herd plans aimed at controlling and eradicating TB.

Risk-based testing of imported animals: A case study for bovine tuberculosis in The Netherlands.

In intra-EU trade, the health status of animals is warranted by issuing a health certificate after clinical inspection in the exporting country. This certificate cannot provide guarantee of absence of infection, especially not for diseases with a long incubation period and no overt clinical signs such as bovine tuberculosis (bTB). The Netherlands are officially free from bTB since 1999. However, frequent reintroductions occurred in the past 15 years through importation of infected cattle. Additional testing (AT) of imported cattle could enhance the probability of detecting an imported bTB infection in an early stage. The goal of this study was to evaluate the effectiveness of risk-based AT for bTB in cattle imported into The Netherlands. A generic stochastic import risk model was developed that simulates introduction of infection into an importing country through importation of live animals. Main output parameters are the number of infected animals that is imported (Ninf), the number of infected animals that is detected by testing (Ndet), and the economic losses incurred by importing infected animals (loss). The model was parameterized for bTB. Model calculations were optimized to either maximize Ndet or to minimize loss. Model results indicate that the risk of bTB introduction into The Netherlands is very high. For the current situation in which Dutch health checks on imported cattle are limited to a clinical inspection of a random sample of 5-10% of imported animals, the calculated annual Ninf=99 (median value). Random AT of 8% of all imported cattle results in Ndet=7 (median value), while the median Ndet=75 if the sampling strategy for AT is optimized to maximize Ndet. However, in the latter scenario, loss is more than twice as large as in the current situation, because only calves are tested for which cost of detection is higher than the expected gain of preventing a possible outbreak. When optimizing the sampling strategy for AT to minimize loss, only breeding and production cattle are selected for AT resulting in Ndet=1 (median value). Loss is; however, reduced by 75% if compared to the current situation. We conclude that the effectiveness of AT can greatly be improved by risk-based sampling. The optimal sampling strategy for risk-based AT for bTB is highly dependent on the objective of AT. If economic losses are to be contained, AT should focus on breeding and production cattle originating from high-risk countries.