Bovine TB: 7 The Wider Research Programme
- 7.1 Evaluation and analysis of previously collected data
- 7.2 Vaccine development
- 7.3 TB in wildlife other than badgers
- 7.4 Ecological consequences of badger removal
- 7.5 Badger ecology
- 7.6 Molecular epidemiology
- 7.7 Economic evaluation of policy options
- 7.8 Husbandry factors
- 7.9 Field trial collateral research
7.0.1 A broad programme of research projects has been put in place complementing the other measures discussed earlier in this report. A variety of research institutions is involved in the programme, and a wide range of expertise in the various areas is being tapped, at both national and international level. Some work has been commissioned directly by MAFF from its own agencies, but the largest spend is on projects which have been put out to open competition - in line with current MAFF policy and the recommendations of the Krebs Review team.
7.0.2 The projects are summarised at Appendix F, which is correct at the time of going to press, but will be supplemented in the near future in the light of our recommendations on further research into cattle pathogenesis and diagnosis. The rest of this chapter provides details on key areas of research.
7.1 Evaluation and analysis of previously collected data
7.1.1 MAFF holds a large body of data on TB in both cattle and badgers, including information on incident management (through the old TB49 form), cattle testing, badger removal operations, post mortem examinations, road traffic accident carcase surveys and strain typing. In addition, data from the Central Science Laboratory's Woodchester Park research facility are available. There are also other relevant data, including farm census, Geographical Information Systems (GIS) and meteorological data. The Group has held from the outset that thorough evaluation and analysis of these data could help answer many of the questions posed, identify areas which merit closer investigation, help to inform the production of guidance leaflets, and complement other ongoing research activity (including the risk analysis work deriving from the TB99 epidemiological questionnaire). It is our hope and expectation that the first wave of results from these analyses will be completed by the end of 2000 (see Chapter 8 on data handling).
7.2 Vaccine development
7.2.1 The ISG recognises the need for effective vaccines and strongly supports the implementation of the vaccine research programme, focusing on cattle vaccines, while retaining an interest in badger vaccines. There are intrinsic advantages in working on developing a cattle vaccine. Studies on cattle immunology and immuno-genetics are well advanced, immunological reagents and research tools have been developed and can be rapidly applied to M. bovis, and potential vaccine candidates can be evaluated in the target species. Cattle vaccine development can be expected to provide a launch pad for possible badger vaccines. The various vaccine projects will also benefit from developments in molecular epidemiology and notably the sequencing of the M. bovis genome.
7.2.2 We supported MAFF’s decision to appoint an independent programme co-ordinator, and are satisfied that the research work is both adequately funded and progressing along the right lines. Through the programme co-ordinator, Dr Jo Colston, Head of Mycobacterial Research at the National Institute of Medical Research, we are assured that the programme is benefiting from the best cross-fertilisation of ideas and understanding available in both animal and human medicine at national and international level. Dr Colston will be producing regular reports for MAFF; the Group will consider these and provide any necessary comment and analysis.
7.2.3 The Group also supports the Ministry’s intention to establish an official vaccine steering group to chart progress from the development of candidate vaccines up to the time of marketing the finished product. The steering group will look at issues such as intellectual property, regulatory aspects (at both UK and EU level), the trade framework, industry partnership and marketing, in parallel to the research work. The ISG will be represented on the vaccine steering group.
7.2.4 Although the vaccine programme is being undertaken by leading experts in the field, we would caution that success cannot be guaranteed, even in the long term. Despite a heavy research effort only limited progress has been made in developing a new human vaccine and there would be a number of practical problems to address with the use of both cattle and badger vaccines. It may well be possible to overcome these in the course of time, but it is our view that a vaccine would be unlikely to provide the whole solution to the problems posed by TB. A combination of measures, built around the epidemiological information our studies produce, will probably prove necessary to manage the disease in both cattle and wildlife.
7.3 TB in wildlife species other than badgers
7.3.1 The Group accepts that little is known about the role of badgers in the dynamics of M. bovis infection in cattle in Britain. The same holds true for the role of other wildlife species and two parallel studies, one in trial areas, are being funded to address this gap in knowledge. These will involve surveying multiple sites to collect data on the ecology of potential M. bovis reservoirs, investigation of the prevalence of M. bovis in wildlife species and degree of excretion in target species through post mortem examination (including bacteriological culture) and attempted diagnosis in the live trapped animal. Quantification of the relative risks to cattle will involve modelling and risk analysis through the integration of ecological and epidemiological data.
7.4 The ecological consequences of badger removal
7.4.1 The ISG recognises the necessity of carrying out an ecological survey to understand the consequences of badger removal. Before the trial began the Central Science Laboratory (CSL) was commissioned to produce an Environmental Impact Assessment, based on existing literature relevant to the area of badger removal. The executive summary of their report was published in the Group’s first report.
7.4.2 Evaluation of badger culling as a potential means of TB control demands a detailed investigation of the ecological consequences which may arise from the implementation of such a policy. The Group therefore advised that CSL be commissioned to carry out a full study in trial areas.
7.4.3 The ecological consequences project began in February 1999; the coverage and emerging findings from this research project will be kept under review by both MAFF and the ISG.
7.5 Badger ecology
7.5.1 If badger control were to form part of cattle TB control policy in the future, we believe that accurate methods for assessing badger numbers which do not involve capture of the animals would be essential. At present there is no available observational procedure which allows accurate estimates of badger populations in a given area. The ISG has fostered two separate projects to develop observational techniques for estimating population size.
7.5.2 The trial itself will allow us to test theories concerning how social group structure and perturbation affect the distribution, prevalence and severity of TB infection. An initial genetic analysis, using material from badgers trapped in the Putford proactive cull, has been carried out and we have recommended to MAFF that this work be extended. Elsewhere, outside the trial, a study has been underway for several years into a badger population perturbed by past removals; we will be cross-referencing findings from that project, together with data from CSL’s Woodchester Park facility, with our own observations from the proactive and reactive treatment areas.
7.5.3 Despite previous extensive badger research there remains much we do not know about aspects of badger ecology and behaviour relevant to TB control. The field trial and its linked studies - including the ecological consequences of badger removal - offer opportunities to extend our knowledge in this area. The Group has recommended that these opportunities be exploited.
7.6 Molecular epidemiology
7.6.1 Scientific advances in the field of molecular biology over the last decade have produced investigative tools that could not have been envisaged even 25 years ago. For the purposes of our work, developments in genetic fingerprinting and in the strain typing of M. bovis will allow the genetic relationships of tubercle bacilli from and within different animal populations - cattle, badgers and others - to be examined, complementing the epidemiological study in determining potential routes of transmission. These technologies will also be used in the ongoing work on vaccine development and on improving diagnostic tests, and in our studies into the pathogenesis of the disease in cattle.
7.6.2 Under the broad heading of molecular epidemiology we have endorsed a number of research projects. In addition to the vaccines and diagnostic work in cattle, research focused on the development of an accurate test for TB in live badgers, genetic analysis of badgers from trial areas, strain typing and the joint MAFF/Wellcome Foundation funded sequencing of the M. bovis genome are all in progress at various centres of excellence in the UK and abroad. The genome sequencing project is to be completed in 2000, and this should pave the way for further advances in understanding the epidemiology and pathogenesis of tuberculosis.
7.6.3 Although these technologies may be described as "cutting edge", current molecular typing methodologies are not yet sufficiently discriminatory to answer questions on, for example, transmission, with the precision that we require. We also recognise that when more discriminatory techniques are available there will still be a need for comprehensive epidemiological data to supplement molecular investigations. The Group highlights the importance of maintaining the current research levels in molecular epidemiology studies, and to encourage the involvement of research workers with expertise in population genetics and molecular genetics, and possibly other disciplines, in the analysis and interpretation of data.
7.7 Economic evaluation of policy options
7.7.1 TB in cattle has potentially severe economic consequences, both in terms of the loss of productivity of the animals affected and the (private and public) costs of veterinary testing and other measures that have to be instituted to control its spread. It is clearly important to know the likely magnitude of these impacts - on the incomes of farmers, on the agricultural economy and on public expenditure - at different levels of disease incidence, as this information is an essential part of the framework Ministers will employ in deciding ultimately on a long term control policy. Should such a policy involve some control of the badger population in particular areas, then a further consideration will be the economic weighting that might be attached to badgers and other wildlife. In keeping with our aim to establish the widest possible rigorous information framework on which TB control policy can be based, we believe this more elusive area of economic valuation could usefully be explored.
7.7.2 To provide the information base that will allow an appropriate evaluation of the economic dimensions of possible control policies we therefore recommend that specific research is undertaken in the following three areas:-
- farm-level effects of bovine TB and its control.
- the wider economic effects of TB in the agriculture sector.
- the "ecological economics" dimension.
Results from these studies must be available by the time the Group is ready to prepare and examine possible sustainable TB control policies. We recommend, therefore, that these studies are commissioned in the year 2000.
7.7.3 A more detailed explanation of the economic studies proposed by the Group is at Appendix D.
7.8 Husbandry factors
7.8.1 In its report earlier this year the Agriculture Select Committee concluded that insufficient attention had been paid to the possible benefits of different farm management practices, and recommended among other things that MAFF institute an assessment, via an independent panel, of the available knowledge in this area.
7.8.2 The Group accepts that, logically, husbandry is likely to play a part in the overall TB picture. Common sense would dictate that farm management will have an impact on disease control: this is the philosophy behind the recent publication by MAFF of simple guidance leaflets on TB. On balance we support the Select Committee’s recommendation that this area be reviewed, although we have some doubts as to the prospect of any new solutions for TB control emerging at this stage. The scientific literature on husbandry and TB is limited and far from rigorous, and the acceptance of anecdotal evidence is inconsistent with the scientific approach the ISG is trying to establish in its studies of the problem. We are, however, ready to play our part in reviewing the panel’s findings; MAFF has advertised for experts to take this exercise forward.
7.8.3 It has been suggested that on-farm experiments could be put in place now to measure husbandry effects. Given the multitude of possible variables involved, it remains the ISG’s view that the only practical way to tackle the wider issue of what predisposes certain farms to outbreaks of the disease is through comprehensive risk analysis, using a questionnaire-based epidemiological survey (see Chapter 3.0).
7.9 Field trial collateral research
7.9.1 The Group emphasises the importance of maximising the research opportunities provided by the field trial, subject to constraints on MAFF resources and to data confidentiality considerations. We have therefore recommended a number of research projects (covered elsewhere in this report) which draw directly on or benefit directly from, the work on the trial itself. In addition, measures have been put in place to bank serum and genetic material from the badgers caught, to encourage further studies in the future from interested scientists as resources and new technologies become available.
7.9.2 A number of specific requests have been put to the Group for consideration and, subject to protecting the confidentiality of the farms concerned, we have been pleased to give our support for them. For example, one of these was for material to be used in a project looking at wildlife reservoirs of M. paratuberculosis (to come from badgers from farms known to have had incidents of Johne’s disease in cattle).
7.9.3 Each request for access to trial material (which must include details of the work being or about to be undertaken, and the relevance of or need for the material concerned) is examined by MAFF and the ISG on a case by case basis. (Researchers wishing to pursue opportunities in this area should contact MAFF on 0207 904 6052 or email: tbresearch@ahvg.maff.gov.uk)
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8 - Data handling 
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Page last modified:
12 August 2003
Page published: 5 February 2003