Select Committee on Environment, Food and Rural Affairs 2004 Written Evidence
Written Evidence ordered by the House of Commons to be printed 30 June 2004.
CONTENTSMemorandum submitted by the Family Farmers' Association
1. I am glad that you are studying this subject again. With due respect, I did not feel that the conclusions and recommendation in your previous report reflected the urgency of the situation. Since that time facts and statistics have confirmed the gut feeling of farmers that the disease is almost completely out of hand. It is increasing at 20% annually and it is quite clear that the more time that elapses before there is effective action to get rid of it, the more difficult and expensive the task will be.
2. In that report you expressed surprise that more is not done to test and practice better husbandry methods. The simple reason is that farmers believe that it is totally impossible to keep cattle away from badgers and their excreta. Studies and parliamentary questions have shown that determined badgers, and particularly those emaciated by TB, can gain access to the most well designed buildings and that their urine can remain infectious in pasture for a very long time.
3. We all agree that the road traffic accident survey is potentially a most useful tool in discovering just how widespread the infection is in badgers. Unfortunately it has been impossible for me to discover its extent. I have been told of people who have asked to have dead badgers tested and had the request refused.
4. Recently, the Godfray report, which you are no doubt studying, has come to many of the conclusions farmers had reached, as to the seriousness of the situation and the probable lack of usefulness of the Krebs trials. Then Defra instituted local consultation gatherings, and I sincerely trust you will have details of the results of these.
5. I went to the one in West Devon. A lot of farmers who had had TB outbreaks, in some cases very serious ones, were there. (Personally I have never had a reactor, but I live in fear as it is all around me.) The participants were unanimous that the government must take action before the situation gets even worse. The conclusion of the meeting was that Defra must realise the urgency of the crisis. Some farmers say openly that they have a limited number of badgers on their farm and that therefore they remain free of TB. All are convinced that sad experience, local unofficial action and official experiments in Ireland and other places has proved the connection between badgers and TB, and that removing badgers is the only effective way of stopping serious TB outbreaks.
6. I was impressed by the amount of knowledge some of the farmers had of badger habits, and by their desire not to eliminate badgers but only to restore the badger stock to health, along with the cattle. Many of them had been struggling with TB for years.
7. Figure 2 in Defra's consultation document really says it all. The growth of breakdowns was illustrated graphically at the meeting and is truly horrifying. TB was very nearly eliminated about 1979. If only the then policy had continued, we would not now be in this disastrous predicament. It seems that there was then an effective way of culling badgers where they were found to be infected in the neighbourhood of a breakdown among cattle. We have not yet got to the point of studying the best method of removing badgers, but there seemed to be a general opinion among farmers, as well as badger groups, that the present method employed in the Krebs trials is neither efficient nor humane. This ineptitude has greatly increased the opposition to badger culling.
8. I believe that infected, unhealthy badgers must be eliminated, and that the subject to study seriously is how to do this both efficiently and humanely. Being too concerned about immediate cruelty, such as in killing cubs, can only lead to much greater slaughter being necessary in the long run.
9. The alternative to culling badgers is to admit defeat and make cattle farming uneconomic in most of Britain. No doubt stricter controls on movement will delay the spread, but they are only in the nature of holding operations, they are not going to remove any infection that already exists and is maintained by the badger population. No doubt if left unchecked TB may become endemic in many other species, which is another reason for urgent action.
10. There was no mention, among a large and well informed gathering, of any connection between TB and trace elements. (Or at least I heard none.) When attributing the present incidence to various aspects of modern farming, it must be remembered that TB was endemic until something like 60 years ago, so it is no use advocating old fashioned customs in this case.
11. As for vaccination, I have been reading the ISG's report on this and found it very discouraging, although I admit I have not yet got to the end of the long paper. Whether a sufficient allocation of funds could produce an entirely new method I don't know. But the main problems seem unlikely to be solved: how to find a test that will distinguish between a vaccinated and an infected animal, and even how to produce an effective vaccine. (I well remember having a vaccinated heifer react to a brucellosis test and having to be killed, although she lived through enough inconclusive tests to produce a healthy calf. It was a relief when brucellosis vaccination ended.) My choice would be to forget trying to develop a bovine TB vaccine and concentrate the scientific activity on improving the human one, which I gather is far from perfect. Meanwhile the urgent necessity is to do with badgers as is done with cows in the hope of eliminating the infection.
12. It cannot be stated too often that it is essential to take effective action immediately to remove Mycobacterium bovis from Britain. Obviously it will be difficult, and testing of cattle will need to continue so long as any remains in wildlife. But there is at least hope if this course can be followed determinedly. The present policy, or even the suggested ones, if one can call them policies, give no hope whatever for a long term solution.
13. One practical suggestion, which is not greatly canvassed, is that Defra should give more information as to the whereabouts of TB infected herds. On the few occasions when I have bought cattle, I have asked Defra if there is TB in the relevant parish, and they have told me the answer. But I gathered at the large meeting that this is by no means the universal response. I believe that in the past the address of infected farms was made public. No doubt the farmers concerned would object, but such action would hasten elimination of the disease. It may be impractical now TB is so widespread. But once the government starts effective action and there is a decline, public knowledge of its whereabouts would hasten the decline in incidence.
Chairman, Family Farmers' Association
May 2004Memorandum submitted by the Royal College of Veterinary Surgeons
1. The Select Committee is well-informed about the problem of bovine tuberculosis as a result of its past inquiries, and it is aware of the concerns of the Royal College of Veterinary Surgeons. This brief note therefore confines itself to commenting on the issues in the light of the Government's consultation paper, "Preparing for a GB strategy on bovine tuberculosis", and the report of the Independent Scientific Review chaired by Professor Charles Godfray.
2. RCVS found the consultation document disquieting. The proposed short-term measures to reduce transmission between cattle are reasonable but will do nothing to control transmission between cattle and wildlife. The maps and chart in paragraph 3.3.8 present an unmistakeable picture of a disease which is out of hand, but the document offers no convincing strategy for getting it back under control. Indeed, the first question posed suggests that the target for the next 10 years should be only "to contain and progressively reduce spread, incidence and economic costs of the disease and to continue to develop the science base to inform future strategy". When a building is on fire, the aim of the fire brigade is to put the fire out, not just to slow down the rate at which it spreads. The Government's aim should be to return to the position where most of the country is free from bovine TB, with only sporadic outbreaks which can be contained by movement restrictions and slaughter.
3. The consultation document addresses the question of transmission between cattle and wildlife, but in terms which seem to revert to an earlier stage in the debate. Seven years ago, as the Select Committee knows, the Krebs report advised that the evidence strongly supported the view that in Britain badgers were a significant source of infection in cattle. The report acknowledged that the evidence was indirect but said that "in total the available evidence, including the effects of completely removing badgers from certain areas, is compelling". In August 1998 Ministers announced the decision to launch the Randomised Badger Culling Trial "in order to find out when culling is an effective approach and when it is not". Yet now the consultation document asks whether "in the light of current evidence, policies should be developed (including badger culling) that seek to control transmission of bovine TB between badgers and cattle". It also asks under what circumstances a badger culling or management policy would be acceptable. It makes no obvious sense to raise these questions when the culling trial is at an advanced stage. The decision to mount the trial implied that transmission between badgers and cattle had to be dealt with, and that culling, if it worked, would be an acceptable control measure. Professor Godfray's report has now confirmed, if confirmation were necessary, that policy should be "based on the assumption that badgers are involved in disease transmission as a wildlife reservoir".
4. It is also a matter of concern that the consultation document betrays a wish to distance Ministers from responsibility for the strategy. Question 4 asks "Does Government need to intervene in the control of bovine TB?". At some point it may be worth considering this question, but it seems strange to raise it at a time when a zoonotic disease is spreading rapidly in livestock, farmers have no power to deal with the wildlife vector except through husbandry measures, and the established control system rests on the exercise of statutory powers. To return to the earlier analogy, it is a bit like discussing the pros and cons of privatising the fire brigade when there is a fire to be put out. Similarly, the document asks questions about "effective partnership" and "governance arrangements" for a new strategy. Consultation and involvement of stakeholders in the formulation and implementation of policy are of course desirable, but the real need is for Ministers to make decisions and take firm action.
5. Admittedly this is easier said than done. Whatever Ministers do (or fail to do) is liable to be condemned, and those who criticise ought to offer positive advice. The advice which RCVS would offer is that the Government should reconsider its strategy now on the assumption that the culling trial will prove inconclusive. Reactive culling as carried out in the trial has been abandoned, and it will not be surprising if proactive culling turns out to be ineffectual. This is because it is not thought to remove more than 80% of the badgers from the area. Indeed, a Written Answer to Mr Owen Paterson MP on 29 April, col 1189, said that the efficiency of trapping might vary between 30% and 80%. Section 5.6 of the Krebs report made it clear that, in both the reactive and proactive culling areas, the aim should be to remove all badgers. If the object is to control a disease by slaughtering potentially infected animals in a defined area, it is optimistic to expect this to work when a substantial proportion of them survive to spread the disease. It would therefore be rational to work on the basis that proactive culling as practised in the trial will not be effective. If it does work it will offer Ministers a relatively comfortable policy option, but they would be ill-advised to pin their hopes on this.
6. In setting up the culling trial Ministers hoped to be able to make and defend policy decisions on the basis of good science. If it becomes clear that the trial is not going to prove anything there may be a temptation to call for further evidence. Sometimes, however, it is necessary to act on the basis of imperfect information. The advice already available to the Government, most recently from Professor Godfray's report, is that the transmission of bovine TB from the wildlife reservoir must be dealt with. It would be good if transmission could be controlled through husbandry measures, and Professor Godfray has suggested a publicly-funded experiment in badger-proof farming. A good idea, but such an experiment will inevitably take time and husbandry may prove not to be an answer. The same comments apply to vaccination to control the disease in badgers. In the meanwhile there is clear historical evidence that the systematic removal of all badgers in an area around an outbreak can work. The evidence may not come up to the best scientific standards, but as the epidemic continues to accelerate Ministers may not be able to afford the luxury of further research before taking action. The publication of the results of the Irish experiments should in any case cast fresh light on the effectiveness of culling which is designed to remove all badgers from an area.
7. RCVS hopes that the Select Committee will encourage the Government to recognise that its present policy of waiting for the outcome of the culling trial is not sustainable.
Royal College of Veterinary Surgeons
Select Committee on Environment, Food and Rural Affairs Written Evidence
Memorandum submitted by the National Farmers' Union
1. The incidence of bovine tuberculosis continues to increase despite the presence of statutory controls and the imposition of a routine cattle testing and culling programme over a very long period of time. We are further from eradication now than we were in the 1970s.
2. The NFU sees two fundamental reasons for this failure in dealing with the problem. First, a known wildlife reservoir of M (Mycobacterium) bovis—the badger population—is left untouched while enormous expense and effort are devoted to trying to keep the infection down in cattle. Irish work on the role of badgers in the epidemiology of the disease should be referred to here. Second, that there is no way of preventing cattle from being vulnerable to the infection that is around them, whether that be in other cattle, in wildlife, or simply in the environment.
3. The solutions may be obvious, but we know that they are not simple. In the short term there must be measures to address the incidence of M.bovis in the badger reservoir, and we have set out strategies for doing this on many occasions in the past. In the longer term the development of vaccines to protect cattle herds is probably the only realistic route to eradication.
4. It is this latter, scientific, aspect—in the main—that the present Inquiry addresses. We must stress yet again however that we believe bovine tuberculosis to be multi-factorial in its aetiology, and that the approach to dealing with the disease must recognise this. The fundamental need for a control/eradication programme is re-emphasised. While the original purpose of public health protection is largely achieved, the fall-out from this is being increasingly felt by cattle farmers to the extent that many are going out of business, and many more suffering crippling financial, social and psychological damage. Add to this the growing disquiet that a major element in the Governments projected Animal Health and Welfare Strategy (AHWS) is manifestly failing to achieve its aims, and the need for urgent solutions is underlined.
5. We have been told for a decade or more that a TB vaccine for use in cattle is between five and 10 years away, and this is apparently still the case. The NFU is not qualified to comment on or judge in scientific terms the progress, or lack of progress, in this direction, but the worsening disease situation clearly calls for a redoubling of effort.
6. It is not clear to us whether material resources are the stumbling block here, or whether it is an "intellectual" breakthrough that is needed. We understand that the likelihood that current work on new human vaccines will be transferable is remote, but that genomics could help generate candidate vaccines that would protect cattle better than BCG. Increased resources and fast track approval procedures should be sought to hasten the developmental process.
7. The development of BCG for use in badgers seems to pose different problems. Even with a proven effective product one of the main obstacles to its introduction would be the problem of delivery. On-going work in Ireland suggests a greater potential for BCG in badgers than in cattle, but its realisation would depend on at least two factors. First, that badgers are indeed a major source of infection for cattle; and second, that maximum effective uptake at optimum dose rates can be guaranteed. We would like to see regularly published information on progress in this area, and guidance as to its potential application under field conditions in infected areas in England and Wales.
8. While the disease situation calls for urgent short and medium term measures to bring the level of infection under control, the ultimate aim still has to be eradication. It is clear to us from discussions with scientists involved in research in this area that a successful vaccination policy is the only sure way of achieving this. We can only concur with the recommendation of the Independent Scientific Group Vaccine Scoping Sub-Committee that "it will be imperative to maintain the current effort on development and testing of vaccines" and that "the well developed and effective international collaborations with scientists working on vaccines for both animal and human TB must be maintained and built on".
9. Another critical aspect of any genuine attempt at a control/eradication strategy is the accuracy of diagnosis. A greater efficiency in routine clinical diagnosis would give greater purpose and precision to the cattle cull. The standard comparative intra-dermal skin test is very good on a herd basis, but not particularly useful as an individual animal screen. Again, we understand that post genomic studies could help in the development of a more effective method. In the meantime the wider employment of gamma-interferon could be approved to supplement the tuberculin test. The Veterinary Laboratories Agency must continue to improve the test by using different and more specific antigens; this could significantly increase its usefulness both as a screening tool, and as a pre-movement test.
10. To complement the development of a cattle vaccine for widespread use there must be a properly validated test available to distinguish a vaccinated animal from one exposed to natural TB infection. Improved genomics could help here in differentiating between M.bovis and BCG (or equivalent) genomes.
11. Developments in these areas clearly depend on the continuing availability of resources to carry them through to a conclusion.
12. There are still a number of questions unanswered in relation to susceptibility and resistance among animals of the same group, or between groups of animals. Why, for example, do certain animals in a herd succumb to the disease and not others, and why do some herds in a heavily infected area remain clear? Resistance to infection may indeed be related in particular cases to levels of trace elements such as selenium—and there are those who suggest that it is—and attempts should be made to establish the significance of this one way or another.
13. A related question is why some animals respond to the comparative test but do not show pathological signs? The NFU is not in a position to attempt to answer these questions, but we can emphasise the importance of knowing more about the basis of resistance (or perhaps immunity) to M.bovis.
14. The particular areas being addressed by this Inquiry offer the possibility of long-term solutions to a very serious disease presence that also requires urgent, short term, attention. We therefore repeat our concern that current measures to reduce infection in the cattle population are mirrored by strategies to deal with the wildlife reservoir of M. bovis. It does not seem logical or sensible to address the problem in one affected species and not in another that lives in close proximity to it. It is important that evidence from current Irish work is examined as part of any decision on the value of culling as a basis for moving forward on this issue.
15. The development of longer-term measures is also of course an integral part of the eradication process. We made the point above that success will only be achieved by application of a series of interlinked strategic elements. These must include—as well as selective cattle and badger culling—better diagnostic methods, vaccination of cattle and/or badgers, and on-farm bio-security preferably built in to a specific health plan.
16. It is important to regard bovine tuberculosis and the means of combating it as part of the evolving Government Animal Health and Welfare Strategy. It is inevitable that the success of the two strategies will be seen as closely linked.
National Farmers' Union
May 2004Memorandum submitted by the Society for the Eradication of Tuberculosis Transmission (SETT)
1. EXECUTIVE SUMMARY
Since the demise of the Clean Ring badger culling strategy, the introduction of the Interim and subsequent "strategies" and the passing of the Badger Protection Act in 1992—bovine TB in cattle has increased exponentially. SETT respectfully reminds EFRA Committee members of its proposal made to Defra in April 2003 which has now formally been taken up by Ian Pearson, MP, Northern Island Minister for Agriculture and Rural Development. SETT members seek an early movement towards a holistic, practical, sustainable and cost-effective political solution involving the licensed management of wildlife "locally"; an arrangement which should incidentally also embrace the equally challenging issue of "hunting with hounds". A document is also enclosed illustrating numbers of cattle slaughtered within different badger culling strategies during the period 1978-2003 (Annex A).
2.1 It is now just over a year since EFRA Committee published its "Badgers & Bovine TB" Seventh Report of Session 2002-03 (April 2003).
2.2 Since then government ministers have ceased the proactive element of the Krebs Trials, answered many hundreds of questions concerning bTB and continually refer to a (one-sided) bTB "control strategy". Throughout the year we have witnessed politicians playing scientists and scientists playing politicians. The bTB politician/scientist interface has gone the way of all such relationships—BSE and FMD included—and as such only serves to confuse both the issue as well as other interested parties. Devolution has also presented considerable differences of strategy interpretation—although primarily due to cost implications.
2.3 The Krebs trial—somewhat naively conceived for "laboratory" conditions and both translated and predictably implemented appallingly—has been a cock-up from start to finish. Ministers do not have, sadly, a bTB "control strategy" to speak of—only an exercise which will prove little (scientifically) and serves only to delay the inevitable—ie the substantial and thorough culling of badgers in appropriate areas: for if the Trials have proven anything at all—it is surely that it is only worth culling badgers on a 100% community group basis. Nothing less!
2.4 The New Labour government of 1997 ceased badger culling immediately on gaining office. In 1997 annual cattle slaughtered due to bTB exceeded some 6,000; today—seven years later—it is some 30,000. A graph illustrating the exponential increase of cattle slaughtered from 1978-2003 with the then current badger culling strategy indicated is attached separately.
3.1 It has been said by many (SETT in particular) that this New Labour administration understands little and cares even less about folk that live and work in the British countryside. Trying to live up to promises made before May 1997 about land management, farming animals and country pursuits in the UK have—for a now-perceived "centre of centre" political party—proven difficult to implement and live with.
3.2 The government's dilemma is this—does it ban hunting with hounds that kill the vermin fox but which process also demonstrably illustrates a harmonious balance with nature? The rural fox population has never been healthier. Does it allow a bTB infected but protected species (badger) to inflict harm to both cattle health and farmers' livelihoods? Thus—conversely—the badger population has never been so relatively unhealthy. By definition today's protected badger qualifies as "vermin" to a greater extent than does the "healthy" fox!
3.3 The key to controlling mammalian wildlife today is not so much scientific as political. If this government (and for that matter previous ones also) had bitten on the bullet and culled tuberculous badgers as and when they manifested their infectivity—today's cattle farmer would be living harmoniously with a healthy sustainable still-protected nationwide badger population. After all—scientists have proven that this is the outcome of such practices. Having ignored the solution for so long politicians and so-called "conservationists" now fear WMD—wildlife mass destruction—due entirely to wholesale political ignorance and cowardice! Field working MAFF (as was) and Defra staff know the truth but policy somehow threatens the truth. It is as though the real life bTB experiences jointly shared by farmer, veterinary surgeon and professional MAFF/Defra staff over fifty years have been air-brushed out by New Labour policy and those experiences changed into anecdote and mythology. True bTB science started in 1997! Anything before that does not exist!
4.1 In its previous submission to EFRA Committee—included in the April 2003 report (Appendix 15)—SETT proposed that government got together "local wildlife management committees populated with stakeholders".
4.2 SETT was pleased to see the announcement made recently (5 May 2004) that Ian Pearson, MP, Northern Island Minister for Agriculture and Rural Development, announced the establishment of such a Stakeholder Group to consider the potential need for a badger management strategy to help reduce Bovine TB levels in Northern Ireland. He said "I am pleased to say that a range of environmental, veterinary and farmer interests have agreed to nominate representatives to this Stakeholder Badger Group".
4.3 SETT further proposes that only a local licensed solution that is also self funding will solve the problem. Ideally the solution should also embrace a licensed hunting regime with the current farmer/huntsman relationship extended to include the management of all wildlife (particularly the tuberculous deer in the South West) within a "stakeholder group" regime. SETT feels sure that this additional responsibility for huntsmen will be received as a natural extension to their current duties including the disposal of fallen stock. Pilot schemes should be introduced immediately following the production of a blueprint methodology for agreement at national level of all those organisations with an interest. Today's Defra Ministers may be pleasantly surprised to find that implementing this proposal will be considerably easier than continuing to justify the obviously tainted now "out of time" policy decision of 1997. And the Balance Sheet improves immeasurably!
"Locally appointed people—living and working locally in rural communities—licensed to responsibly manage its area's wildlife population within a local stakeholder group framework and answerable to a higher enabling authority".
Society for the Eradication of Tuberculosis Transmission (SETT)
BADGER CULLING STRATEGIES: 1978-2003
In 1980 Lord Zuckerman wrote: "The basic and incontrovertible fact is that TB in badgers is now (1980) a significant second reservoir of the disease in parts of the South West, dangerous for badgers and cattle alike. Given the policy of the Government to suppress bovine TB, the disease cannot be allowed to spread in the badger population. I cannot therefore see any reason for continuing the moratorium on the campaign to eliminate tuberculous badgers."
Society for the Eradication of Tuberculosis Transmission (SETT)
Memorandum submitted by the Department for Environment, Food and Rural Affairs
Memorandum submitted by Christine Chester
Being invited to submit further evidence on the problem of Bovine TB, the first thought, which occurs to me is that, the machinations of this Committee will thus be delayed until the next General Election, in the hope that should a Conservative Government be elected, then the Labour Party would have the pleasure of dropping this particular "hot potato" ie Badger Culling, into the hands of the incoming Administration.
New Scientist 17-4-2004 reads:—"Interim results are in, but the scientists running the trial want to withhold them". Obviously Defra knows more than I do, but curiously the likes of me are invited to make further comment.
To introduce myself, my name is Christine Chester; I come from generations of farming families. I am nearly 74 and, until three years ago, lived my life to the rhythm of the dairy farm. The uneconomic price of milk and the trauma and costs of being under TB restrictions made us realize there was no future for the family dairy farm.
I can well remember the eradication of TB and brucellosis in the m1960s, we started farming in 1952 with TT cattle and had over 40 years of TB free farming. The great increase in badger numbers and the relocating of urban badgers and foxes, by so-called animal lovers have caused the present increase in herd breakdowns. It is a well-known fact that the badger thrives where there are dairy cows. I attended the Stake Holders Conference at Harper Adams University College recently and was horrified to see the spread of Bovine TB demonstrated on the computerized maps and graphs.
I am largely ignorant on the progress towards a vaccine. It is usually a fixed 10 years up the line. I do not know if this research is adequately funded. No mention is ever made as to who will pay for it, or how the vaccination programme is to be organized. Another ear tag? Does it give life long protection? A lot of unanswered questions. Who pays? I think that if HMG insists in harbouring an infected species then HMG should foot the bill, and also the bill for field damage caused by ever enlarging badger setts.
The trials in the Republic of Ireland definitely indicate a connection between badgers and Bovine TB. The work done by Denny and Wilesmith in Northern Ireland and reported in Vet Record (1999) 144 pp 305-310 reads "the two main associations with TB breakdowns are the presence of badgers and the presence of contiguous neighbours that had confirmed TB breakdowns."
3. Trace Elements
The high yielding dairy cow needs a scientifically balanced diet and will not get in calf unless her nutritional requirements are met. We paid a consultant to make up a ration based on summer grazing and silage. We always "buffer-fed" during the grazing season including a mineral mix specific to our requirements.
To me this is yet another "red herring" thrown up by NFBGs et al, that cattle are short of trace elements , making them prone to infection by TB, another myth laid to rest.
Solving the problems of Bovine TB is inevitably clouded by political decisions, those involving funding of the Labour Party by bodies such as the P. A. L and the desire to keep certain Members of Parliament in their seats.
Does HMG want farmers or badgers? No other EC or Western nation has treated farming as badly as the present Administration, and the Tories were bad enough. The recent suggestion that a levy be raised on milk and beef to pay TB compensation shows the lack of understanding of HMG to the lack of profit especially in dairy farming.
When we suffered our first case of TB we had not had a TT test for four years. This must indicate a serious lack of funding to the SVS. This is not acceptable; for years the SVS has been reduced, under funded and had much of its work undervalued and handed over to the Trading Standards.
This new Inquiry is merely a delaying tactic and HMG should be ashamed of such actions. The financial costs to both HMG and the farming community is enormous, as is the distress and worry to the individual farmers. Perhaps the members of Defra should stand back and take a look historically.
Very few cases of Bovine TB were experienced from the eradication of TB in the 1960s until the huge increase in the badger population in the late 1990s.
No cow-to-cow transmission.
No problems with trace elements.
No need to vaccinate.
This submission is from myself, as a member of a farming community in NE Staffordshire, which has seen nearly every farm suffer a TB breakdown. We live in the Churnet Valley, an area of steep valleys and dense woodland.
PROGRESS ON CONSIDERING SOLUTIONS TO THE PROBLEM OF BOVINE TB, INCLUDING PROGRESS MADE TOWARDS DEVELOPING A VACCINE, THE EXPERIENCE OF IRELAND AND THE ROLE PLAYED BY TRACE ELEMENTS
1. This report gives an update on progress on the Government's five-point plan for dealing with bovine tuberculosis since EFRAC's 7th Report of Session 2002-03 on Badgers and Bovine TB, published on 9 April 2003. The Government's reply to the Committee's report was published on 24 June 2003.
2. Ben Bradshaw provided oral evidence to the main EFRA Committee on 10 December 2003, focussing on the suspension of the reactive cull element of the badger culling trial.
3. This submission has been agreed with the Devolved Administrations.
4. In February 2003 the Secretary of State announced a review of GB policy on TB. This is an opportunity to ensure Government's approach on bovine TB is consistent with the Strategy for Sustainable Farming and Food and the Animal Health and Welfare Strategy. Government spent £75 million on bovine TB controls across GB, including research, in 2002-03 and remains committed to finding a sustainable way forward on bovine TB, based on best available evidence. Provisional outturn for 2003-04 is £88 million. A breakdown of expenditure is at Annex A.
5. Defra published on 9 February 2004 a consultation document that represented the outcome of the first stage of the review of the TB strategy. Separate but parallel consultations have been issued in Scotland and Wales.
6. The consultation closes on 4 June, having been extended by 1 month to allow stakeholders to take into account the recommendations of the Independent Scientific Review of the Randomised Badger Culling Trial and associated epidemiological research that was published on 6 April.
7. A robust, fair and cost-effective settlement on bovine TB is required, one that sets out where Government and stakeholders hope to be in 10 years time and reconciles the contending perspectives of stakeholder groups. Achieving everybody's aspirations is unlikely. Challenging but realistic targets and indicators of success need to be developed which recognise the regional distribution of the disease and scientific uncertainty around the effectiveness of TB control tools including wildlife interventions. The consultation document asks questions covering all of these issues.
8. Defra is also committed to action in the short term to address some of the immediate problems of bovine TB. A number of policy options were set out in Defra's submission to EFRAC on 24 February 2003 (see Annex B) and progress is reported below. The remainder are set out in the consultation document as proposals for action to:
— Reduce the risk of spreading TB from high to low incidence areas through cattle movements;
— Ensure early detection and prevention of developing TB hotspots;
— Increase efficiency and transparency of TB surveillance and alignment with EU Directive 64/432/EC.
9. A key proposal is the introduction of a legal requirement for the pre-movement testing of cattle moving from one and two year tested herds to other herds, for which farmers will pay. Government for some time has advised this as best practice.
10. The written consultation has been complemented with regional meetings to discuss the issues raised with a wide range of stakeholders. After closure of the consultation Government will work to implement the short-term measures as soon as is practicable, and develop draft proposals for the longer term.
PROGRESS UNDER THE FIVE-POINT PLAN
Protecting human health
11. Public health protection measures (ie pasteurisation of milk and post-mortem inspection of carcases) continue. The threat to public health remains low and the disease is treatable. The Government is not complacent however and continues to work in liaison with the Department of Health to monitor the situation.
Continued regular testing of cattle herds for TB and slaughter of suspect animals, and where possible strengthening of these controls
12. There have been a number of developments since Defra's last written submission to EFRAC in early 2003:
— With the co-operation of Local Veterinary Inspectors and farmers, the number of overdue TB herd tests built up during the Foot and Mouth Disease (FMD) outbreak in 2001 has been reduced to pre-FMD levels. There were nearly 27,000 overdue tests at the end of 2001. This had been reduced to 7,000 at the beginning of 2003 and now stands at under 4,000.
— Automatic restrictions were imposed on herds with TB tests overdue by more than three months from the start of October 2003, to reduce the risk of spreading bovine TB. This has acted as a powerful incentive for farmers to get tests done promptly. At the end of March 2004 84% of overdue herd tests were less than three months overdue.
— Mycobacterial culture capacity at the Veterinary Laboratories Agency has been trebled. By the end of 2003 the additional culture facilities had resulted in the elimination of the backlog of bovine tissue samples awaiting culture.
— A field pilot of the gamma-interferon blood test, begun in autumn 2002, has continued. The pilot was set up to determine whether the gamma-interferon test, used in tandem with the skin test, significantly improves the detection of infected cattle and shortens the duration of confirmed TB incidents. Up to the end of April, 108 herds had been recruited into the pilot. Consideration is being given to ways to improve recruitment. In addition, since November 2003 the State Veterinary Service has allowed ad-hoc gamma-interferon testing in specific situations. Details are at Annex C.
— General movement licences were introduced in October 2003 for clear testing cattle destined for slaughter from herds under TB restrictions, significantly streamlining procedures and reducing paperwork.
— In spring 2004, research carried out by Reading University into the economic impacts of bovine TB and alternative control policies, showed whilst most farmers suffered a loss due to TB some farms (20% of dairy, 35% of beef herds surveyed) made a net gain from the breakdown. Net losses ranged from £37 to £17,021.
— A survey of badgers (killed in road traffic accidents) and deer (culled or found dead) in South West Cumbria was announced in December 2003. The objective of the survey is to determine whether or not there are badgers and deer infected with TB in this part of Cumbria. The results of the survey will be used along with the results of two cycles of cattle testing at six- to 12-month intervals, to determine the future herd testing frequency in the area.
13. The following developments describe progress on a number of the short-term policy options flagged to EFRAC in February 2003. The remainder are being taken forward as part of the current TB consultation (see para 10):
— Increasing the pool of people trained to test for TB has been taken forward in the consultation on a proposal to introduce an Exemption Order, under the Veterinary Surgeons Act 1966, to permit suitably trained and competent non-veterinarians to administer the tuberculin skin test, read and record the results. Consideration is now being given to how best to proceed.
— A National Audit Office report on TB compensation in Wales was published in 2003 which noted that compensation payments in 2002 were on average 50% higher, and in some cases over 100% above the underlying market price. An internal Defra audit in summer 2003 similarly found that TB valuations appeared to be significantly higher than market prices. A number of changes have been introduced to help ensure valuations are a fair reflection of market price, including improved data handling procedures, provision of market price information to valuers to act as a benchmark for valuations, and a letter to valuers reminding them of the conditions under which valuations should be carried out. In October 2003 Defra consulted on proposals to rationalise compensation for animals slaughtered for all notifiable disease including TB. The aim is to strike a balance between practical disease control and responsiveness to individual circumstances. It is hoped that reviewing the compensation procedures will help speed up removal of reactor cattle from farms. This was flagged to EFRAC as one of the short-term policy options in February 2003. Next steps are being considered.
— On-farm management to reduce TB risk to cattle was another of the options identified. Under the Animal Health and Welfare Strategy, Defra is working closely with Devolved Administrations and interested parties, particularly vets and the different livestock sectors, to take forward a number of initiatives to promote farm health planning and improve training and advice.
— The State Veterinary Service (SVS) is developing improved guidance, training and contractual arrangements for Local Veterinary Inspectors, including TB testers, and enhancing its quality assurance procedures. The timing of implementation is dependent on negotiation with the British Veterinary Association.
— The SVS has also developed an IT system for Veterinary e-Business (VeBus). This allows Local Veterinary Inspectors and SVS staff to receive worklists and submit completed forms electronically. Full rollout is scheduled to be completed by October 2003.
— The SVS Business Reform Programme is re-engineering business processes and improving the delivery of field services between 2004 and 2008. TB is the primary focus and initial efficiency gains will be implemented in 2004 through improved data handling.
Research to develop an M.bovis vaccine
14. The timetable for producing an effective vaccine against bovine tuberculosis remains broadly in line with that set out in the Krebs Report.
15. In January 2002, the Independent Scientific Group on Cattle TB established a Vaccine Scoping Study Sub-Committee (VSSSC) to advise Defra Ministers on whether a TB vaccination strategy for either cattle or wildlife would be feasible. The VSSSC reported to Ministers in July 2003 (published December 2003). This advised on research requirements, but cautioned that a vaccine (for cattle or badgers) remains a long-term policy option. Many obstacles still have to be overcome.
16. An Inter-Departmental Vaccine Steering Group, chaired by the Chief Veterinary Officer, is working to identify administrative and legal procedures to allow a potential vaccine to be authorised for use in both badgers and cattle. A new Vaccine Programme Advisory Group (following on from the VSSSC) provides advice on the science needed to progress towards a vaccine for use in the field.
17. The Vaccine Advisory Group has recommended developing options for a field experiment using BCG in badgers and a series of transmission and vaccination studies (BCG and heterologous prime boost) in cattle. The Vaccine Steering Group has agreed in principle that these proposals should be investigated further.
18. In 2002-03, Defra spent £1.5 million on vaccine research. Exploiting the sequencing of the M.bovis genome has led to the development of a test that distinguishes between vaccinated and infected cattle for experimental use. However, more work is needed before the test can be used for wide scale application in the event that a vaccine based on BCG is introduced. 48 possible vaccine candidates have been tested in small animal models. These include two live attenuated M. bovis vaccines, subunit recombinant protein and DNA vaccines. Concurrent work to determine the best adjuvant/vaccine combination for use in cattle is in place. Diagnostic reagents and vaccines are being tested in collaboration with New Zealand as well as in the UK.
19. Researchers at the Veterinary Laboratories Agency are collaborating with the Republic of Ireland in conducting challenge studies using BCG in badgers.
20. A review of the ecological implications of a vaccination strategy for badgers covering the various aspects of badger ecology that must be considered has been published.
21. At the end of April 2004 a workshop was held with the animal pharmaceutical industry to discuss how Defra, working in partnership with industry, might take BCG vaccine forward for use in badgers. The aim of the workshop was to identify the most suitable plan for complying with the many regulatory obstacles for use of a vaccine in the field.
Other research to improve knowledge of the disease and its transmission to and between cattle and other species
22. The Committee will consider the possible role of trace elements. There is anecdotal evidence that trace element deficiencies in soils are related to susceptibility to tuberculosis in cattle. At present this link is scientifically unproven. The ISG have not dismissed the possibility of a nutritional link. However, they have advised that given the available resources, and the difficulty in devising informative experimental protocols, this area of research should be given low priority. Preliminary data from the TB99 survey may help to shed some light on nutritional issues.
23. There have been a number of recent developments in the wide-ranging research programme supported by Defra (full details of which are on Defra's website):
— Studies on the virulence and pathogenesis of M.bovis have found that certain strains are found in specific geographic locations. Different molecular typing methods are currently being evaluated to better understand the development of different M.bovis strains in the UK. Additionally a Polymerase Chain Reaction (PCR) detection system for M.bovis has been developed that could be used as part of the routine strain identification process.
— Recently published work highlights that the use of farm buildings and cattle troughs by badgers can constitute a TB risk to cattle. A study of possible badger/cattle interactions and how cattle husbandry methods may limit these is underway.
— Other work looks at the effects of removing badgers from an ecosystem, both in terms of the possible perturbation effects on the local badger population and the effect of removing badgers on the wider ecosystem and associated species. Nearing completion are two research projects investigating the risk to cattle from wildlife species other than cattle in areas of high herd breakdown risk.
— A cattle pathogenesis programme is providing information on how TB develops in cattle and is looking at cattle-cattle transmission. Results have shown that, in laboratory conditions, the route of M.bovis challenge has implications for the shedding pattern of bacteria subsequently seen and that some infected but skin test negative animals could be identified that would not be detected by current tests. Work has shown that the effect of repeated skin testing prior to infection with M.bovis does not invalidate the use of the skin test.
A BADGER CULLING TRIAL TO TEST THE EFFECTIVENESS OF BADGER CULLING IN REDUCING TB IN CATTLE
Randomised Badger Culling Trial (RBCT)
24. All 10 triplets were enrolled into the Randomised Badger Culling Trial (RBCT) by the end of 2002. All 10 proactive areas have been culled at least twice and culling had taken place in all but one of the reactive areas before the suspension of operations in November last year.
25. Ministers suspended culling operations in reactive areas on 4 November 2003 following advice from the Independent Scientific Group on Cattle TB (ISG) that their latest interim analysis, of data collected up to the end of August 2003, indicated that, after appropriate statistical adjustments, the incidence of herd breakdowns in reactively culled areas was consistently greater than expected. This increase, compared with the survey only areas, was estimated by the ISG to be 27%, with 95% confidence that the increase lay between 4.8% and 53%. A more conservative analysis would give confidence limits of between a 2.4% decrease and a 65% increase. The ISG's most recent analysis of data collected to mid-February 2004 indicated an increase of 28% with confidence limits of between 1.1% and 62% using the wider confidence limits recommended by the Independent Review panel.
26. Following the suspension of culling in reactive areas, the ISG considered whether to convert some of the reactive areas to proactive areas. They advised that data on cattle breakdowns in at least six reactive areas should continue to be collected and analysed, along with data from the proactive and survey only areas, at six monthly intervals. Proactive data from the remaining areas would add little value to the dataset, as there would be insufficient time to see an effect in these areas before the end of the trial; the resource could be better used to carry out culling operations in the existing proactive areas at the most advantageous times of the year.
TB99 Epidemiological Survey
27. The first analysis, of data collected from the survey before the FMD outbreak, has been completed. A report on this is expected very shortly. An analysis of more recent data collected is ongoing.
28. The structure of the TB99 questionnaire is being revised for 2005, to focus on those aspects which, from the analyses undertaken so far, seem to be the most significant. The revised form will also be shorter and easier to complete in the field. Additional data sources, such as the Cattle Tracing System, will be used to remove time consuming parts of the questionnaire and standardise the data collected across the study area. In the meantime, collection of TB99 data during 2004 is focussed on the completion of 100 datasets, each comprising a case and three controls (if available), across three of the 10 triplets.
Road Traffic Accident (RTA) Survey
29. At 31 March 2004, 1,744 carcases had been collected from the seven counties covered by the survey (Cornwall, Devon, Dorset, Gloucestershire, Worcestershire, Herefordshire and Shropshire). An analysis of the results from the post-mortems of these is underway and will be finalised shortly.
Independent Scientific Review of the Randomised Badger Culling Trial and associated epidemiological research
30. As part of a wider review of Defra Science, Elliot Morley announced in April the 2003 establishment of an independent scientific panel to review the randomised badger culling trial and related research. This work is being overseen by the ISG, which has been providing guidance and monitoring the RBCT since its establishment in 1998.
31. The Review was chaired by Professor Charles Godfray FRS, director of the Natural Environment Research Council's Centre for Population Biology at Imperial College London. The panel comprised experts from the fields of veterinary and wildlife population epidemiology, applied statistics and population biology. Their report, the ISG's response and comments from Professor Mollison, the statistical auditor of the RBCT, were published on 6 April 2004.
32. The review's conclusions will inform Defra's wider review of TB strategy. The recommendations are complex and have potentially far reaching consequences for TB policy. There are also areas of disagreement between the Review Group and the ISG. This often occurs when challenging science is being undertaken and Defra will be considering carefully how to move forward.
The "four area" badger culling trial in the Republic of Ireland
33. The results of the "four area trial" in the Republic of Ireland have not yet been published. We will look closely at the methods and results once published to establish what we can learn and apply in GB.
Department for Environment, Food and Rural Affairs
BREAKDOWN OF GOVERNMENT EXPENDITURE IN GREAT BRITAIN ON BOVINE TB
17.6 13.3 5.4 24.7 33.0 Compensation 5.3 6.6 9.2 31.9 33.3 Culling Trial 4.6 6.6 6.0 6.5 8.5 Other Research 3.8 5.3 6.1 6.8 7.1 Veterinary Laboratory Agency 2.4 3.5 3.7 4.1 5.3 Headquarters/Overheads 4.5 0.9 0.1 0.7 1.0
38.2 36.2 30.5 74.7 88.2
THE SHORT-TERM POLICY OPTIONS FLAGGED TO EFRAC IN FEBRUARY 2003
The 10 options were:
— clearer implementation of EU legislative requirements;
— a review of test frequencies to ensure compliance with the EU;
— tailoring TB controls according to TB risk by area and/or herd health history;
— the introduction of pre-movement testing;
— requiring on-farm management action to reduce TB risk to cattle;
— review to identify possible need for test frequencies above the EU requirements in certain areas;
— improvements in delivery of TB controls which might be made through the development of a new relationship between the State Veterinary Service and Local Veterinary Inspectors;
— increasing the pool of people trained to test for TB and available to deliver testing;
— streamlining service delivery processes within the SVS in order to improve efficiency and reduce administrative delays; and
— speeding up removal off farms of cattle that react to the tuberculin test.
AD-HOC USE OF THE GAMMA-INTERFERON TEST
In addition to the gamma-interferon field pilot, since November 2003 the State Veterinary Service (SVS) has conducted ad hoc gamma-interferon testing in specific situations, namely:
— as an aid to decision making in relation to whole or partial herd slaughter in severe TB breakdowns;
— as a "parallel" (ie adjunct) test for non-reactor cattle in ongoing, confirmed TB incidents that do not qualify for the field trial, but have a chronic TB problem; and
— as a "serial" (ie confirmatory) test, to resolve skin test reactors or inconclusive reactors in prolonged unconfirmed TB incidents within low TB prevalence areas, where there is a suspicion of non-specific reactivity to the skin test.
In the first two instances, the blood test is used to enhance the overall sensitivity of TB testing. In the third, the blood test complements the skin test results to achieve better specificity. In 2003, almost 1,000 cattle in 12 non-trial herds in England (6), Wales (5) and Scotland (1) were gamma-interferon tested by the SVS under one of the three scenarios described above.
Department for Environment, Food and Rural Affairs
Memorandum submitted by the British Cattle Veterinary Association
1. The BCVA is a specialist division of the British Veterinary Association comprising 1500 members of whom over 1000 are practising veterinary surgeons working with cattle in farm animal veterinary practice. In this respect a large number of our members come into direct contact with TB control policies as they affect their client's farms. BCVA are represented on the DEFRA TB Forum and are members of various stakeholder groups affecting the industry. We are very grateful for the opportunity to submit comments to the EFRA Committee Review.
2. BCVA's policy with respect to the control of bovine TB is an holistic one. A strategy developed to combat an infectious disease must take into account all reservoirs of infection in order to be successful. In the case of bovine TB reservoirs exist not only in cattle, but also in wildlife species such as the badger and deer. Any control strategy must take account of such reservoirs if true control is to be achieved.
3. The following comments are firstly grouped into the three specific areas addressed in the Inquiry remit, namely; vaccination, the Irish experience and trace elements. Any additional comments then follow.
VACCINATION FOR BOVINE TB
4. BCVA support the research and development of potential vaccines for the control of bovine tuberculosis in both the badger and cattle and consider it one of the most important potential elements of a long-term strategy for the control of bovine tuberculosis.
5. BCVA do not consider the development of a suitable vaccination strategy is likely within the medium term (ie next 10 years). This conclusion is based on reports and views from scientists in the field, and in particular the report of the ISG's vaccine scoping sub-committee. The practical difficulties of developing a candidate vaccine, devising a delivery system and subsequently identifying vaccinates from non-vaccinates if used in livestock are immense.
6. BCVA is concerned that no progress is being made in the control of TB within hotspot areas and that the new strategies being developed, whilst required and supported by BCVA, are primarily being aimed at the prevention of spread of disease from these areas rather than control within.
7. BCG vaccine has been shown to have some efficacy in the reduction of pathology, disease, bacterial burden and haematogenous spread of TB. As a result, the use of BCG in badgers may be of benefit in the short term as a method of control by reducing the overall load of infection. We are disappointed that this strategy has not been investigated in greater depth.
8. BCVA would anticipate that the delivery of a vaccine to badgers would have to be via trapping and injection. Oral delivery strategies carry the risk of inadvertent environmental contamination of BCG via faecal shedding of viable bacteria by vaccinated badgers. This would result in the accidental vaccination of cattle and the potential for false positives reactors being found at herd testing.
9. BCVA recognise that a badger vaccination strategy carries considerable practical difficulties, particularly if repeat vaccinations are required for example. Such a strategy, however, would create the opportunity for other work to be undertaken concurrently. The use of blood tests to identify infected setts would be a good example of this, thereby facilitating the identification and possible removal of reservoirs of infection outside cattle. Such a combined strategy of vaccinating of "healthy" badgers and removing infected badgers may be of benefit in alleviating the pressure of infection within the cattle population.
10. BCVA encourage field trials of such a strategy to be undertaken as soon as possible to investigate its worth.
11. BCVA concur with the Godfrey report that immediate action must be taken in relation to wildlife reservoirs. Defra cannot afford to wait for the outcome of the Krebs's trials whilst this disease continues unchecked in hotspot areas despite cattle controls. The damage caused by inactivity whilst waiting for the RBCT results could be mitigated by adopting a sound medical approach; enhance the immunity of disease free badgers by vaccination, identify infected badgers for removal and generally reduce the overall infectious load.
THE IRISH EXPERIENCE
12. BCVA are fortunate to have strong links with Irish researchers into TB and consequently have been privy into unpublished material into TB control. Much of this data is still unpublished and confidential in nature and consequently the following summary of our understanding of the Irish experience has been tailored to honour this understanding.
13. We are very grateful to Professors More and Doherty for their help in providing information and it is in particular a summary document by Professor Simon More reviewing the current status of Irish research that this submission is based on albeit in an extremely abbreviated format.
THE INFECTED HERD
Source of infection
14. Analysis of epidemiological investigation reports completed in association with confirmed herd breakdowns have produced some potentially significant findings:
— A range of sources are considered important.
— It is often impossible for field Veterinary Investigators to attribute the cause of the outbreak to a single source.
— The relative importance of these sources has changed over time.
ATTRIBUTED CAUSE OF CONFIRMED TB BREAKDOWN IN EIRE
O'Keeffe and Higgins 2003
Lateral Spread 14.8 Bought in 7.2 Residual 8.5 Mechanical 0.3 Wildlife 33.7 Not certain 35.4
15. Prof More has summarised the work performed on the importance of cattle-to-cattle transmission both within Eire and also the US, UK and the Netherlands. He reports that based on the light of available evidence and assuming early detection via testing programmes some workers concluded that cattle to cattle transmission was rarely the source of infection (Griffin and Dolan 1994).
16. Further work by Griffin (2003) via modelling estimated that in Ireland 60% of reactors could be attributed to an external source, 38% are false positives and only 3% are due to within herd transmission. (These calculations are based on a positive Tb skin test and not on confirmed infection).
17. The role of slurry spreading and the survivability of Tb in waste material have indicated that the spread of slurry has the potential to spread disease.
18. These findings would suggest that the poor sensitivity of the Tb single intradermal test is not a major factor for the persistence of high levels of Tb within the herd following breakdown and that more effort needs to be directed in preventing the introduction of disease from external sources, be this from cattle (bought-in stock) or wildlife.
TRANSMISSION FROM WILDLIFE
19. The Irish have performed two major trials to attempt to define significant evidence of the role of badgers in bovine tuberculosis. These have been the East Offaly Badger research project and the Four Area Badger Project.
East Offaly Badger research project (EOP) (1989-95)
20. At its most basic description, this trial compared the relative level of bovine TB in a project area where badgers were removed, to a control area where they were not. Results indicated a significantly lower proportion of new confirmed Tb cases within the badger removal area as compared to the control. This effect has persisted with the rate of herd restrictions in the removal area being one third of the present national average.
The Four-Area Badger Project (1997-2002)
21. This project was designed to replicate the above EOP trial but with paired removal and reference areas in each of four counties that were considered representative of main landscapes in Ireland. Furthermore, in contrast to the EOP, the boundaries of removal areas were designed wherever possible to incorporate natural barriers eg rivers to reduce the effect of inward immigration of badgers in the study period. Results have not been published at the time of writing, however, personal communication to BCVA members lead us to believe that similar results in terms of a significant positive reduction in Tb incidence in removal areas will be reported.
22. Criticism has been raised that the real effect of badger removal has been distorted as a result of perturbation effects in the control areas. However the Irish researchers have found no evidence to suggest that this has occurred. Further work is on going to assess this concern.
23. Of further note is that the average disease prevalence within the captured badgers in the removal areas was 19.5% with further work using detailed microbiological assessment increasing the prevalence up to 50% infected.
24. BCVA find these conclusions compelling evidence that there is an important link between the badger and cattle in the epidemiology of bovine TB and that more emphasis needs to be placed by Defra in breaking this link. Furthermore if the prevalence of TB in the badger population is anywhere near this level in the UK, (although previous work has suggested that this might not be the case), then it would suggest the pointlessness of only directing efforts to the removal of the bovine reservoir.
SPATIAL DISTRIBUTION OF M. BOVIS ISOLATES FROM BADGERS AND ASSOCIATION WITH CATTLE BREAKDOWNS
25. Irish research would suggest that Tb infected badgers are clustered within setts ie setts tend to be either free or diseased. Despite this finding there is only limited evidence that infected setts are geographically clustered. Little evidence could be found when strain typing was employed between a clustering of a given strain of TB in the badger and the bovine at a particular locality but there was within a larger Geographical area. This could be considered a result of long distance movement of badgers within an area.
26. Defra should consider the trapping and identification via ELISA testing of infected setts in TB hotspot areas. The current sensitivity of the test is poor for individual animals, however if TB is clustered within a sett, then testing a proportion of the animals belonging to that sett gives a higher degree of certainty to the infection status of that sett. This would help remove a potential reservoir for cattle infection. Concurrent vaccination of non-infected sets with intradermal BCG could also be considered within this protocol (see para 10 & 11 above).
MINIMISING CONTACT BETWEEN BADGERS AND CATTLE
27. The Irish have identified areas where transmission between badgers and cattle is likely. Similar work has been undertaken in the UK. The likely benefit of any such control measures has not been quantified.
RISK FACTORS FOR TB
28. The Irish have identified within their research the following risk factors for an increased incidence of disease:
— An increase in herd size though this may be artefactual in that the TB intradermal test is not 100% specific.
— Region. As in the UK, Ireland has hotspots.
— Previous history of disease.
— Higher severity of the disease at breakdown ie more reactors per breakdown.
29. The Irish have concluded that at present the sensitivity of the gamma-interferon test is similar to the current single intradermal test but that it detects a different population therefore its in combination with the intradermal test increases the overall sensitivity to around 97% and is therefore of use in herds with a chronic problem. The poor specificity at present (95%) negates its widespread use although some suggest that this aspect could improve with newly developed antigens.
FACTORY (ABATTOIR) SURVEILLANCE
30. The Irish consider that abattoir surveillance for disease is critical to their whole program. In the years 1993-2001 between 27% and 46% of all herd breakdowns were detected using this method. The Irish however are concerned about a potential large variance of the efficiency of detection between plants and are investigating potential causes and why such a high proportion of reactors slip the net of testing and are only detected at the abattoir.
31. Pre-movement testing was mandatory until 1996 and then became voluntary. Research on the benefits of pre-movement testing concluded that there were two main advantages:
(i) Early identification of infected animals in the exporting herd thereby reducing opportunities for within herd disease transmission.
(ii) Reduction in spread of disease to new herds. In 1993 a total of 989 cows from 543 herds were identified as reactors by this method. This presumably reduced the potential for spread to a large number of buying herds.
32. No cost benefit analysis has been performed in relation to pre-movement testing but it was noted that the benefits largely accrued to the government whereas the costs were borne by the farmers.
BCVA COMMENT REGARDING IRISH WORK
33. The BCVA believe that there is much to be learnt from the Irish experience of controlling bovine TB and will be considering this subject further in the creation of our response to the Defra consultation entitled "Preparing for a new GB strategy on bovine TB".
34. BCVA supports the general intention to base policy on sound science, but harbours some concern regarding the interpretation of the term sound science. It is often the case that scientific research tends to stimulate further scientific research, with definitive answers being difficult to achieve. Both the Krebbs trials in the UK and the field research in Ireland have already courted criticism in their design prior to the publication of any results. Organisations with vested interests will use any potential flaws in scientific procedure to argue their case when a result falls against them, and base their argument on the availability of sound science. This results in stalemate.
35. The control of infectious disease in all species, including humans, relies heavily upon the common sense interpretation of the information available at any given time. Absolute scientific justification for action is often a holy grail in such circumstances. BCVA believe that such common sense decision making has been belittled in the development of bovine TB strategy for some years, and that this is largely to blame for the current situation in which the industry finds itself. The BCVA submission to Defra regarding the strategy for bovine TB will be based on such common sense interpretation of the science to date, and we encourage the EFRAC's inquiry team to judge both international and home-grown research in a similar light.
36. The role of Vitamin E and selenium within the immune response of the bovine has been the subject of considerable research. Both agents have a role in the removal and production of toxic lipid peroxides. Deficiencies impact on the effectiveness of the immune system primarily via an effect on leucocyte function. Consequently it is conceivable that deficiency of one or both of these agents may impact on animal's susceptibility to disease.
37. BCVA assume that the EFRAC inquiry interest in this subject has been stimulated by a submission enclosed in the EFRAC Seventh Report of Session 2002-3 "Badgers and Bovine TB" by Dr Helen Fullerton.
38. BCVA have concerns over this paper, believing that it contains too many assumptions and flaws. Namely:
(i) That a failure of the test to detect false negatives cases (diseased but not detected) is directly linked to a failure of the delayed type hypersensitivity response. This may not always be the case. Failure could result from operator error for example.
(ii) A failure of the delayed type hypersensivity could be linked to suppression of Th1 lymphocytes which in turn could be induced by
(a) zinc and selenium deficiency
(b) high levels of cortisone either as a result of steroid administration or stress and
(c) parasite load which in turn could be linked to cobalt and/or zinc deficiency.
39. BCVA have not seen any scientific evidence to support these assumptions and indeed believe them to be completely erroneous. Consultation regarding Dr Fullerton's claims with Professor Philip Duffus of Bristol University, a leading veterinary immunologist, corroborated this view noting that while the above factors may affect immune response (eg selenium deficiency may impact on neutrophils or lymphocyte response) there is no evidence to suggest that it would have an impact on the delayed type hypersensitivity response and thus the intradermal tuberculin test, features central to Dr Fullerton's claims.
40. Furthermore Dr Fullerton maintains TB hotspot areas overlap the areas of the country where soils often deficient of cobalt, selenium, copper, iodine and zinc are to be found. If an assumption is made that the effect of mineral status is via an effect on the immune response, and thus a predisposition to disease, it might also be reasonable to assume that other diseases apart form TB may show a varying incidence in the UK dependent on the background mineral profile. No such evidence is forthcoming.
41. BCVA have consulted Dr Neville Suttle, formerly of the Moredun Institute, a leading authority on mineral and trace element nutrition. Dr Suttle rejected the Dr Fullerton's premise and stated that there was no evidence to suggest that a marginal deficiency of any trace element would predispose to infectious disease. This is supported by a review by Laven (2000) on the current knowledge on Vitamin E, a vitamin intrinsically linked with selenium and concluded that supplementation provided little benefit in the control of infectious diseases other than mastitis. BCVA see no further evidence to change this view.
42. BCVA do not dispute that immuno-suppression may be a factor within the epidemiology of the disease. In fact papers presented to BCVA have questioned and presented anecdotal evidence of the potential role of BVD. This is an endemic virus within the UK cattle population, over 90% of herds thought to be infected, which has known immunosuppressive properties. BCVA would suggest that if further work into the role of immuno-suppression was to be performed BVD virus should receive a higher profile than mineral status.
43. Finally in relation to Dr Fullerton's concern over the Irish trial the EFRAC inquiry should understand that the setting of reference ranges for virtually all minerals is based on incomplete research. In fact different countries often have entirely varying views on what constitutes deficiency within a particular mineral category and within a particular production system. While this may support Dr Fullerton if further evidence suggested that the Irish had indeed set their reference ranges too high, the opposite might equally be true. In summary this refute of Irish work is again based on conjecture.
44. In summary BCVA would concur with Professor Bourne and the ISG that the current evidence to support mineral deficiency as an important factor in the epidemiology of TB is extremely low and that this area should not be prioritised.
45. BCVA considers the bovine TB issue to be integral to the success of the overall Animal Health and Welfare Strategy being developed for the UK. BCVA is committed to the success of such a strategy, and is willing to contribute to any discussion during its development.
46. BCVA thank the EFRAC inquiry team for the opportunity to contribute to this important inquiry. BCVA would be glad to offer evidence in person to the team should that be required, but in any event would be more than willing to provide further information should it be requested.
British Cattle Veterinary Association