Economic analysis of animal disease outbreaks--BSE and Bluetongue disease as examples.

Although there is a long tradition of research on animal disease control, economic evaluation of control measures is rather limited in veterinary medicine. This may, on the one hand, be due to the different types of costs and refunds and the different people and organizations bearing them, such as animal holders, county, region, state or European Union, but it may also be due to the fact that economic analyses are both complex and time consuming. Only recently attention has turned towards economic analysis in animal disease control. Examples include situations, when decisions between different control measures must be taken, especially if alternatives to culling or compulsory vaccination are under discussion. To determine an optimal combination of control measures (strategy), a cost-benefit analysis should be performed. It is not necessary to take decisions only based on the financial impact, but it becomes possible to take economic aspects into account. To this end, the costs caused by the animal disease and the adopted control measures must be assessed. This article presents a brief overview of the methodological approaches used to retrospectively analyse the economic impact of two particular relevant diseases in Germany in the last few years: Blue-tongue disease (BT) and Bovine Spongiform Encephalopathy (BSE).

Mathematical Models for Estimating the Risks of Bovine Spongiform Encephalopathy (BSE).

When the bovine spongiform encephalopathy (BSE) epidemic first emerged in the United Kingdom in the mid 1980s, the etiology of animal prion diseases was largely unknown. Risk management efforts to control the disease were also subject to uncertainties regarding the extent of BSE infections and future course of the epidemic. As understanding of BSE increased, mathematical models were developed to estimate risk of BSE infection and to predict reductions in risk in response to BSE control measures. Risk models of BSE-transmission dynamics determined disease persistence in cattle herds and relative infectivity of cattle prior to onset of clinical disease. These BSE models helped in understanding key epidemiological features of BSE transmission and dynamics, such as incubation period distribution and age-dependent infection susceptibility to infection with the BSE agent. This review summarizes different mathematical models and methods that have been used to estimate risk of BSE, and discusses how such risk projection models have informed risk assessment and management of BSE. This review also provides some general insights on how mathematical models of the type discussed here may be used to estimate risks of emerging zoonotic diseases when biological data on transmission of the etiological agent are limited.

A Markov random field based approach to the identification of meat and bone meal in feed by near-infrared spectroscopic imaging.

Contaminated meat and bone meal (MBM) in animal feedstuff has been the source of bovine spongiform encephalopathy (BSE) disease in cattle, leading to a ban in its use, so methods for its detection are essential. In this study, five pure feed and five pure MBM samples were used to prepare two sets of sample arrangements: set A for investigating the discrimination of individual feed/MBM particles and set B for larger numbers of overlapping particles. The two sets were used to test a Markov random field (MRF)-based approach. A Fourier transform infrared (FT-IR) imaging system was used for data acquisition. The spatial resolution of the near-infrared (NIR) spectroscopic image was 25 µm × 25 µm. Each spectrum was the average of 16 scans across the wavenumber range 7,000-4,000 cm(-1), at intervals of 8 cm(-1). This study introduces an innovative approach to analyzing NIR spectroscopic images: an MRF-based approach has been developed using the iterated conditional mode (ICM) algorithm, integrating initial labeling-derived results from support vector machine discriminant analysis (SVMDA) and observation data derived from the results of principal component analysis (PCA). The results showed that MBM covered by feed could be successfully recognized with an overall accuracy of 86.59% and a Kappa coefficient of 0.68. Compared with conventional methods, the MRF-based approach is capable of extracting spectral information combined with spatial information from NIR spectroscopic images. This new approach enhances the identification of MBM using NIR spectroscopic imaging.

Laboratory activities involving transmissible spongiform encephalopathy causing agents: risk assessment and biosafety recommendations in Belgium.

Since the appearance in 1986 of epidemic of bovine spongiform encephalopathy (BSE), a new form of neurological disease in cattle which also affected human beings, many diagnostic and research activities have been performed to develop detection and therapeutic tools. A lot of progress was made in better identifying, understanding and controlling the spread of the disease by appropriate monitoring and control programs in European countries. This paper reviews the recent knowledge on pathogenesis, transmission and persistence outside the host of prion, the causative agent of transmissible spongiform encephalopathies (TSE) in mammals with a particular focus on risk (re)assessment and management of biosafety measures to be implemented in diagnostic and research laboratories in Belgium. Also, in response to the need of an increasing number of European diagnostic laboratories stopping TSE diagnosis due to a decreasing number of TSE cases reported in the last years, decontamination procedures and a protocol for decommissioning TSE diagnostic laboratories is proposed.

Rapid assessment of bovine spongiform encephalopathy prion inactivation by heat treatment in yellow grease produced in the industrial manufacturing process of meat and bone meals.

BACKGROUND: Prions, infectious agents associated with transmissible spongiform encephalopathy, are primarily composed of the misfolded and pathogenic form (PrPSc) of the host-encoded prion protein. Because PrPSc retains infectivity after undergoing routine sterilizing processes, the cause of bovine spongiform encephalopathy (BSE) outbreaks are suspected to be feeding cattle meat and bone meals (MBMs) contaminated with the prion. To assess the validity of prion inactivation by heat treatment in yellow grease, which is produced in the industrial manufacturing process of MBMs, we pooled, homogenized, and heat treated the spinal cords of BSE-infected cows under various experimental conditions. RESULTS: Prion inactivation was analyzed quantitatively in terms of the infectivity and PrPSc of the treated samples. Following treatment at 140°C for 1 h, infectivity was reduced to 1/35 of that of the untreated samples. Treatment at 180°C for 3 h was required to reduce infectivity. However, PrPSc was detected in all heat-treated samples by using the protein misfolding cyclic amplification (PMCA) technique, which amplifies PrPScin vitro. Quantitative analysis of the inactivation efficiency of BSE PrPSc was possible with the introduction of the PMCA50, which is the dilution ratio of 10% homogenate needed to yield 50% positivity for PrPSc in amplified samples. CONCLUSIONS: Log PMCA50 exhibited a strong linear correlation with the transmission rate in the bioassay; infectivity was no longer detected when the log PMCA50 of the inoculated sample was reduced to 1.75. The quantitative PMCA assay may be useful for safety evaluation for recycling and effective utilization of MBMs as an organic resource.

Direct costs of bovine spongiform encephalopathy control measures in Germany.

On 26 November 2000, the first autochthonous case of bovine spongiform encephalopathy (BSE) was detected in Germany. Since then, a total of 413 BSE cases have been confirmed, resulting in the culling and destruction of 17 313 heads of cattle. In view of the possible risks for human and animal health, Germany has adopted EU regulations along with some additional requirements concerning active surveillance and response measures after detecting a BSE-positive animal. In this study, we used a stochastic model to estimate the costs incurred by the ensuing legislative amendments responding to BSE between November 2000 and December 2010. The total costs were estimated to range between 1847 and 2094 million Euros. They peaked in 2001 (about 394 million Euros) and declined since. About 54% of the costs (approximately 1000 million Euros) were incurred by the extension of the feed ban for animal protein to all farmed livestock. Active surveillance accounted for 21% (405 million Euros), the incineration of animal protein for 13% (249 million Euros) and the removal of specified risk material for 11% (225 million Euros). Only 1% of the costs was related to response measures after detecting a BSE-positive animal, including indemnity payments for culled cattle and confiscated carcasses at the slaughterhouse.

BSE and variant CJD: emerging science, public pressure and the vagaries of policy-making.

Classical bovine spongiform encephalopathy (BSE) was first recognized in 1987 in the United Kingdom and ultimately spread to cattle across Europe and to the Middle East, North America and Japan through the movement of infected animals and contaminated meat and bone meal. The human expression of BSE, variant Creutzfeldt-Jakob Disease (vCJD), likewise was first identified in the UK and now has been observed in many countries due to human exposure to BSE contaminated products or to vCJD contaminated human tissues through transplantation and injection. BSE provides an example of an emerging infectious disease that demonstrates the challenges of policy-making in the face of rapidly changing science and public outrage pushing for action. Lessons learned through the BSE epidemic include: (1) beware of facts as new science continues to emerge; (2) complex issues rarely have simple solutions; (3) evaluate epidemics from a macro-epidemiologic perspective to understand their complexity and devise effective risk management strategies; (4) options always exist for prevention/control; (5) risk communications play a vital role before and during an emerging disease epidemic; and (6) risk management progress involves both science and politics. Adoption of One Health approaches involving systems thinking and shared leadership hold the most promise for effectively managing complex emergency global health issues like BSE.

Agricultural policy, food policy, and communicable disease policy.

Food and agricultural policy is an essential element of a communicable disease policy. The European Union has developed a more systematic and broadly based interest in questions of food safety and animal health and welfare linked to modernization of the Common Agricultural Policy, reflected in a new treaty obligation on animal welfare. Following the bovine spongiform encephalopathy crisis, moves were made to create a European competency, but implementation and enforcement resources reside with the member states. The European Animal Health Strategy is meant to lead to an EU animal health law, but this has already been constrained by fiscal austerity. The development of such a law may lead to a lowest common denominator formula that does little to enhance consumer protection or improve animal welfare. This is an inherent risk with top-down forms of Europeanization; more attention should be paid to lessons to be learned from bottom-up initiatives of the type used to counteract the bovine diarrhea virus. There will always be a tension among what is good policy for reducing the incidence of communicable disease, policy that is popular with EU citizens, and policy that is acceptable to member states.

Animal health surveillance applications: The interaction of science and management.

Animal health surveillance is an ever-evolving activity, since health- and risk-related policy and management decisions need to be backed by the best available scientific evidence and methodology. International organizations, trade partners, politicians, media and the public expect fast, understandable, up-to-date presentation and valid interpretation of animal disease data to support and document proper animal health management - in crises as well as in routine control applications. The delivery and application of surveillance information need to be further developed and optimized, and epidemiologists, risk managers, administrators and policy makers need to work together in order to secure progress. Promising new developments in areas such as risk-based surveillance, spatial presentation and analysis, and genomic epidemiology will be mentioned. Limitations and areas in need of further progress will be underlined, such as the general lack of a wide and open exchange of international animal disease surveillance data. During my more than 30 year career as a professor of Veterinary Epidemiology I had the good fortune of working in challenging environments with different eminent colleagues in different countries on a variety of animal health surveillance issues. My career change from professor to Chief Veterinary Officer (CVO) - "from science to application" - was caused by my desire to see for myself if and how well epidemiology would actually work to solve real-life problems as I had been telling my students for years that it would. Fortunately it worked for me! The job of a CVO is not that different from that of a professor of Veterinary Epidemiology; the underlying professional principles are the same. Every day I had to work from science, and base decisions and discussions on documented evidence - although sometimes the evidence was incomplete or data were simply lacking. A basic understanding of surveillance methodology is very useful for a CVO, since it provides a sound working platform not only for dealing with immediate questions when new or emerging disease situations arise, but also for more long-term activities, such as policy development, contingency planning and trade negotiations. Animal health issues, which emerged during my eight years as a CVO in Denmark from 1999 to 2007, will be used as examples, including BSE, FMD, HPAI and Trichinella testing. Emphasis will be placed on how science-based surveillance methodology and tools were developed, applied and documented.

Geographical BSE risk assessment and its impact on disease detection and dissemination.

Bovine Spongiform Encephalopathy (BSE) rapidly evolved into an issue of major public concern particularly when, in 1996, evidence was provided that this disease had crossed the species barrier and infected humans in the UK with what has become known as "variant Creutzfeldt Jakob Disease" (vCJD). The aim of this paper is to describe the European Geographical BSE risk assessment (GBR) that was successfully used for assessing the qualitative likelihood that BSE could be present in a country where it was not yet officially recognized. It also discusses how this can lead to risk-based and therefore preventive management of BSE at national and international levels. The basic assumption of the GBR method is that the BSE agent is initially introduced into a country's domestic cattle production system through the importation of contaminated feedstuffs or live cattle. This is referred to as an "external challenge". The ability of the system to cope with such a challenge is, in turn, referred to as its "stability": a stable system will not allow the BSE agent to propagate and amplify following its introduction, while an unstable system will. The BSE-status of a country assessed by this system was used by the European Commission as the basis for trade legislation rules for cattle and their products. The GBR was an invaluable tool in evaluating the potential global spread of BSE as it demonstrated how a disease could be transferred through international trade. This was shown to be a critical factor to address in reducing the spread and amplification of BSE throughout the world. Furthermore, GBR resulted in the implementation of additional measures and management activities both to improve surveillance and to prevent transmission within the cattle population.

Assessment of enzymatic methods in the δ18O value determination of the L-tyrosine p-hydroxy group for proof of illegal meat and bone meal feeding to cattle.

The δ(18)O value of the p-hydroxy group of L-tyrosine depends on the biosynthesis by plants or animals, respectively. In animal proteins it reflects the diet and is therefore an absolute indicator for illegal feeding with meat and bone meal. The aim of this investigation was to perform the positional (18)O determination on L-tyrosine via a one-step enzymatic degradation. Proteins from plants, herbivores, omnivores, and carnivores were characterized by their δ(13)C, δ(15)N, and δ(18)O values, the latter for normalizing the positional δ(18)O values. Their L-tyrosine was degraded by tyrosine phenol lyase to phenol, analyzed as (2,4,6)-tribromophenol. Degradation by tyrosine decarboxylase yielded tyramine. The δ(18)O values of both analytes corresponded to the trophic levels of their sources but were not identical, probably due to an isotope effect on the tyrosine phenol lyase reaction. Availability of the enzyme, easy control of the reaction, and isolation of the analyte are in favor of tyrosine decarboxylase degradation as a routine method.

A pilot study of the impact of bovine spongiform encephalopathy on the futures of rural youth and Canadian farming.

There is an abundance of literature examining the economic impact of Canada's bovine spongiform encephalopathy (BSE) outbreak, but few studies examined the impact of such a crisis on health at the individual, family, or community levels. In particular, rural youth represent an under-researched population despite being at risk for a unique set of social and health concerns. In this pilot study, our objectives were to explore how rural youth responded to Canada's BSE crisis and how they perceived themselves, their families, and their communities to have been impacted. Seven youths (n = 7), recruited from within a university setting using a snowball sampling method, were interviewed. They represent a segment of rural, agriculturally based youth who are resilient due to good parental support. Although they reported high stress in their families during the immediate crisis in 2003, they did not report lasting high levels of stress or negative health effects due to BSE. They did report a decline in rural community health, identifying a reduction in community activities and in the participation of families in community activities. Participants identified elements that discourage youth from pursuing farming as a career and expressed concern for the future of family farming. The results are discussed in terms of the ability of agriculturally based youth to make the transition to adulthood. The implications have importance for future research and policy that addresses the structural supports for choice making, the long-term success for rural youth in transitioning to adult status, and the future of agriculture.

Trans-biopolitics: Complexity in interspecies relations.

This article introduces the concept of trans-biopolitics to account for complexity in the intermingling of animal and human bodies, with particular attention to diseases capable of crossing the species divide from animals to humans. While zoonotic diseases never disappeared, they had re-emerged as pressing concerns by the 21st century. The concept of trans-biopolitics takes into account the power relations inherent in human and nonhuman lives in contemporary global, industrial, and technological formations. More specifically, trans-biopolitics revolves around practices determining whose lives are possible or legitimate to prolong, whose bodies are sacrificed in order to preserve the vitality of other bodies, and whose bodies are sustained yet ultimately rendered insignificant. To illustrate, we examine connections between bovine spongiform encephalopathy and feline spongiform encephalopathy, to show how certain bodies (humans, livestock) are taken into consideration in terms of health and food regulations, whereas other bodies (pets) remain at the periphery. Acknowledging human-animal relations in contemporary technological and global contexts challenges us to rethink ways in which the politics of health continues to evolve.

[Protection from BSE : Efforts, measures, success, and costs]. / Schutz vor BSE : Anstrengungen, Massnahmen, Erfolge und Kosten.

By the mid 1980s, bovine spongiform encephalopathy (BSE) emerged in the United Kingdom (UK) and reached its peak in the early 1990s with up to 37,000 cases. In the year 2000, BSE was diagnosed for the first time for a cow born in Germany. Since then, 413 cases of BSE have been detected. About 10 years after the first BSE cases were detected, variant Creutzfeldt-Jakob disease (vCJD), a new variant of Creutzfeldt-Jakob disease (CJD), was described in the UK. Legal measures for protection from BSE are described. The number of cases of vCJD and the development of the BSE situation in Germany and Bavaria until 2009 are presented.

Modelling BSE trend over time in Europe, a risk assessment perspective.

BSE is a zoonotic disease that caused the emergence of variant Creuzfeldt-Jakob disease in the mid 1990s. The trend of the BSE epidemic in seven European countries was assessed and compared, using Age-Period-Cohort and Reproduction Ratio modelling applied to surveillance data 2001-2007. A strong decline in BSE risk was observed for all countries that applied control measures during the 1990s, starting at different points in time in the different countries. Results were compared with the type and date of the BSE control measures implemented between 1990 and 2001 in each country. Results show that a ban on the feeding of meat and bone meal (MBM) to cattle alone was not sufficient to eliminate BSE. The fading out of the epidemic started shortly after the complementary measures targeted at controlling the risk in MBM. Given the long incubation period, it is still too early to estimate the additional effect of the ban on the feeding of animal protein to all farm animals that started in 2001. These results provide new insights in the risk assessment of BSE for cattle and Humans, which will especially be useful in the context of possible relaxing BSE surveillance and control measures.

Assessment of exposure to bovine spongiform encephalopathy in a hypothetical country.

The authors present a basic quantitative spreadsheet model to evaluate the risk of bovine spongiform encephalopathy (BSE) within a national setting. The model is based on information from BSE risk assessments undertaken in Latin American countries. The analysis focuses on the level of regulatory implementation and its impact over different time periods and estimates the potential impact if one BSE-infected animal is introduced into the production cycle. The information is consolidated so that the results of the evaluation can be presented for a hypothetical country, 'Country X'. Evaluating the BSE cycle within a country may help in making decisions on where preventive or control measures should be placed and/or enforced. Such an evaluation may also be used as the exposure assessment of a risk assessment, recommended by the World Organisation for Animal Health to determine the BSE risk status of a given country.

Estimating the impact on the food chain of changing bovine spongiform encephalopathy (BSE) control measures: the BSE control model.

The decline in the bovine spongiform encephalopathy (BSE) epidemic in Great Britain (GB) demands a review of control strategies to ensure that they remain proportionate. Amongst controls that are subject to review are those intended to minimise the risk of BSE exposure of consumers through food. Such risk mitigation steps are costly, and the relative impact of each in terms of human exposure to BSE infectivity is not known. This risk assessment, termed the BSE Control Model, aims to estimate by use of stochastic simulation the impact of testing of cattle at slaughter and the removal of Specified Risk Materials (SRM) on potential BSE infectivity consumed. This paper describes the use of the model to investigate the effect of different risk management methods that have been or could be implemented between 2005 and 2010. Our results suggest that the amount of infectivity consumed in 2005 with the Over Thirty Month (OTM) rule in place was a mean of 0.03 bovine oral ID(50) (BO ID(50)). This is an extremely low amount, particularly considering that it would be spread over, on average, 236 infected carcases that would be further sub-divided into portions for human consumption. The highest contributor to the total amount of infectivity consumed per year is spinal contamination at carcase splitting (35%). In 2006 the OTM scheme was discontinued and head meat was again permitted into the food chain. These changes resulted in an increase in the amount of infectivity consumed, rising to an estimated 28 BO ID(50) in 2006, and 19 BO ID(50) in 2007. In 2008 the age at removal of vertebral column was raised from 24 to 30 months, and an estimated 24 BO ID(50) of infectivity was consumed. At the beginning of 2009 the age at testing of cattle was raised to 48 months for healthy slaughter, emergency slaughter and fallen stock. Under these conditions, an estimated mean of 24 BO ID(50) will be consumed in 2009, decreasing to 20 BO ID(50) in 2010. Even though presented in terms of bovine rather than human oral ID(50), such estimates represent an extremely low exposure of the British population. Considerable uncertainty would surround any attempt to try to convert such exposure into estimates of new cases of vCJD, but the most recent estimates of the size of the species barrier between cattle and humans (4000, EFSA, 2006) suggest that there would be few, if any, new cases of vCJD arising from such exposure levels.

Evaluación de riesgos aplicado a la prevención y la vigilancia de la encefalopatía espongiforme bovina (EEB) en los países de la región de las Américas / Risk assessment applied to the prevention and surveillance of bovine spongiform encephalopathy (BSE) in the countries of the Americas region

Se desarrolló un modelo bayesiano para evaluación de riesgos de EEB. Conjuga registros y opinión experta con datos de muestreo. Se compararon percentiles de probabilidad de EEB obtenidos con la evaluación de riesgo, muestreo y Bayes a partir de datos de Argentina y de escenarios hipotéticos. Bajo un escenario hipotético de incertidumbre, la importancia del muestreo y de la estimación bayesiana fue evidente. Los resultados ratifican la coherencia del Código de OIE y la condición de Argentina de riesgo insignificante y muestran la conveniencia de aplicar regularmente modelos similares.(AU)

A Bayesian model for BSE risk evaluation was developed. It conjugates records and expert opinion with sampling data. EEB probability percentiles by sampling, risk evaluation and Bayes were compared using data from Argentina and from hypothetical scenarios. Under a scenario of uncertainty, sampling and Bayesian estimation importance was evident. Results ratify coherence of the OIE Code and Argentinean condition of insignificant risk and show the convenience of applying similar models regularly.(AU)

The price of the precautionary principle: cost-effectiveness of BSE intervention strategies in The Netherlands.

Since 1996, bovine spongiform encephalopathy (BSE) in cattle has been linked to a new variant of Creutzfeldt-Jakob disease (vCJD), a fatal brain disease in man. This paper assessed the cost-effectiveness of BSE control strategies instituted by the European Commission. In a Monte Carlo simulation model, a non-intervention baseline scenario was compared to three intervention strategies: removal of specified risk materials from slaughter animals, post-mortem testing for BSE and the culling of feed and age cohorts of BSE cases. The food risk in the baseline scenario ranged from 16.98 lost life years in 2002 to 2.69 lost life years in 2005. Removing specified risk materials removal practices, post-mortem testing and post-mortem testing plus cohort culling reduced this risk with 93%, 82.7% and 83.1%. The estimated cost-effectiveness of all BSE measures in The Netherlands ranged from 4.3 million euros per life year saved in 2002 to 17.7 million euros in 2005. It was discussed that the cost-effectiveness of BSE control strategies will further deviate from regular health economics thresholds as BSE prevalence and incidence declines.