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Bovine TB - BVA Welsh Assembly briefing
- 1. Bovine TB Welsh Assembly Briefing 21 September 2016 Dr Neil Paton BVMS BSc MRCVS PhD BVA Welsh Branch President John Blackwell BVSc MRCVS BVA Senior Vice President
- 2. Overview • Bovine TB: what is the problem? • How bTB spreads • Controls: − cattle − badgers − other species • Government approaches across the UK • BVA position • Questions
- 3. What is bovine TB? • A complex infectious zoonotic disease of animals and humans • Caused by the bacterium Mycobacterium bovis • Maintenance hosts: cattle, badgers • Spillover hosts: various mammals inc humans, deer, camelids, goats, pigs, dogs, cats
- 4. • Direct effects on cattle • Production efficiency • Indirect effects of disease • Business viability in face of control measures • Trade within and beyond the European Union What is the problem?
- 5. bTB: the problem All herds tested 3y Scot & Wal, 2y Eng M bovis tuberculin replaces M tuberculosis 4 yr testing FM D 120,000 herds 80,000 herds Badgers Act 1973
- 6. 6-year trend in new bTB incidence, herd prevalence and animal level risk (number of reactors per 1000 animals tested) bTB: the problem
- 8. How does bTB spread? The Randomised Badger Culling Trial report (2007) established: •that badgers “contribute significantly to the disease in cattle” and •that “cattle-to-cattle transmission is also very important in high incidence areas and is the main cause of disease spread to new areas”.
- 9. How does bTB spread? • Transmission − Cattle to cattle − Badger to cattle (& vice versa) • Translocation − Locally − Greater distance • Amplification Spoligotype translocation Post FMD 2001
- 10. How does bTB spread? Critical control points • Translocation • Transmission • Amplification • Transmission • Amplification
- 11. Controls in cattle TB Testing •Routine •Pre-movement •Post-movement Risk based trading Surveillance Biosecurity Farm Health Planning
- 12. Questions around TB testing • Accuracy of the test • Frequency • Quality assurance
- 13. Controls in cattle • Cattle vaccination? • BCG (vaccine) does not fully protect any species • Differentiating Infected from Vaccinated Animals (DIVA) test is not yet validated • Currently illegal in EU European Commission (2013): “Possible EU rules on vaccinated animals… to enter intra-Union trade…. [2023]”
- 14. Cymorth TB • Opportunity for free farm visit from farmer’s private vet • Benefit of Cymorth TB training, local knowledge, overview of breakdown herd health and an established working relationship • Advice on disease control measures essential for the eradication of bTB and the control of other diseases
- 15. Controls in badgers • Biosecurity • Culling • Vaccination • Other?
- 16. Badger control: Culling • Randomised Badger Culling Trial (1998-2006) • Proactive culling of badgers reduces the incidence of bTB in cattle herds • Net benefit 4.5 years post culling = 16% (Key conclusions from a meeting of scientific experts held at Defra on 4th April 2011)
- 17. Badger control: Vaccination • Injectable BCG • Not proven to protect from infection • Reduces the severity of the disease in infected animals • Test to differentiate is unreliable • No evidence of impact on bTB in cattle • Oral vaccine?
- 18. Badger control: Other Research: •Contraception •Oral vaccine •Humane whole sett culling methods •Trap- and sett-side diagnostics
- 19. Intensive Action Area • Pembrokeshire but includes small parts of Ceredigion and Carmarthenshire • A range of measures to reduce the level of infection within all species: • stricter cattle controls • improved biosecurity measures • testing all goats and camelids • badger vaccination
- 20. Control in other species • Spillover hosts, eg: • Deer • Camelids (llamas and alpacas) • Goats • Pigs • Dogs • Cats • Control measures inc biosecurity, testing, notification, and compulsory slaughter
- 21. A comprehensive approach TB Testing •Routine •Pre-movement •Post-movement Risk based trading Surveillance Biosecurity Farm Health Planning Vaccination Culling •Targeted •Humane Research •Cattle vaccine •Oral badger vaccine •Badger contraception •Improved diagnostics
- 22. Policy approaches in Wales Cattle controls •Programme overseen by the TB Eradication Programme Board •Cymorth TB •Annual TB testing •Stricter controls in Intensive Action Area •Pre-movement testing •Biosecurity •Targeted use of IFN-γ Badger controls •No culling •Badger vaccination in the Intensive Action Area •Ongoing badger found dead survey Tuberculosis (Wales) Order 2011 to deal with TB in camelids, goats & deer
- 23. Policy approaches across the UK Scotland •Officially tuberculosis free • Decision Sept 2009 • Implementation Feb 2010 •Risk-based testing England •Cattle controls by risk area •Routine pre- and post- movement testing •Targeted use of IFN-γ •Badger culling and BEVS NI •Separate epidemiological unit •Cattle testing •Modelling a “TVR” policy = Test and vaccinate or remove badgers
- 24. BVA position: the ethics of culling Ethical review process •Ethically justifiable? •Scientific basis? •Feasible and deliverable? •Exit strategy? •Area of cull? •Cost benefit analysis? •Ecological impact? Ethical framework – the 3 Rs (reduce, refine, replace) Targeted, effective and humane
- 25. BVA position: Badger culling • We support badger culling as part of a comprehensive strategy provided it is targeted, effective and humane • We have withdrawn support for the use of controlled shooting, but acknowledge there are different views with the veterinary profession • We have called for the wider roll-out of culling using cage trapping and shooting only, in carefully selected areas
- 26. BVA position: A comprehensive approach TB Testing •Routine •Pre-movement •Post-movement Risk based trading Surveillance Biosecurity Farm Health Planning Vaccination Culling •Targeted •Humane Research •Cattle vaccine •Oral badger vaccine •Badger contraception •Improved diagnostics
Hinweis der Redaktion
- NEIL BVA is the national association for veterinary surgeons and students in the UK and we have over 15,000 members BVA Welsh Branch represents all BVA members in Wales, bringing together representatives of all of BVA’s specialist and territorial divisions, government, academic institutions and research organisations in Wales Structure of the session – 15-20 minute presentation followed by plenty of time for questions Expect varying degrees of knowledge of the subject within the room and have pitched the presentation at the educated lay person – opportunity at the end to clarify issues or go into more detail
- NEIL Brief overview of what we will cover in the session. Introduce yourself and BVA team John Blackwell, BVA Senior Vice President, leads on bovine TB policy issues for BVA. He is a large animal practitioner and former president of the British Cattle Veterinary Association. John will explain what the disease is and how it spreads look at the various options available for controlling the disease and the science and theory behind them I will then look at the policy options being taken by governments across the UK, in Wales specifically, and outline BVA’s own policy position. There will be plenty of time for questions or please feel free to follow up with the BVA team afterwards. Hand over to John.
- JOHN Brief overview of what bovine TB is. Key points: It is zoonotic – which means it affects and can pass between humans and animals It is bacterial – which becomes important when we look at the options for controlling the disease
- JOHN SO, what is the problem? Why do we care about it? Risk to humans is very low – pasteurisation of milk and abattoir surveillance. In cattle the effects are not drastic – low morbidity – but there is an impact on production efficiency Energy given to dealing with bovine TB diverts time and resources from other endemic diseases, eg Johne’s and BVD = unsustainable for British agriculture. Importantly, if we don’t do something about it we cannot trade because EU law requires Member States to eradicate bovine TB and to have plans in place to do so
- JOHN This graph shows The number of cattle tests in blue The number of reactors (which is those reacting to the skin test) in orange And the number of cattle slaughtered in red In Great Britain since the mid-1950s. It shows that the disease has been on the increase since the 1990s and dramatically so since 2001 when we had the Foot and Mouth Disease outbreak. It also shows that disease incidence fluctuates so we need to be very careful focusing on a single year’s results or couple of years; we need to look at the general trends. Since 2010 when this graph ends we have seen numbers of cattle slaughtered in the mid to low 30,000s each year. NOTE: ADDITIONAL STATS IF NEEDED 2011 - 33,453 cattle slaughtered as reactors 2012 - 37,050 2013 - 31,715 2014 - 31,733 2015 - 19,458 so far
- Here we a similar Welsh-specific graph, showing the data since 2010 – the 6-year trend in new bTB incidence, herd prevalence and animal level risk. Showing the number of reactors per 1000 animals tested by quarter in Wales since 2010 This graph shows The number of new incidents per 100 live herd tests in blue The number of herds under restriction due to bTB incidence per 100 live herds in green The number of reactors per 1,000 animals tested in purple This graph doesn’t show the numbers of cattle slaughtered but again there are variances (not sure if you want to list out the following, but FYI): in 2010 this was 7,237 in 2011 7,460 2012 8,901 2013 5,883 The latest data from 2014 was 5,852 reactors slaughtered Again we see the disease incidence fluctuates so we need to be very careful focusing on a single year’s results or couple of years. More data can be found in your briefing pack on a print out of the Wales TB Dashboard for Quarter 1 2016. NB. FYI this surveillance data is from APHA Weybridge
- JOHN Not only does the incidence keep going up, but it is spreading northwards and eastwards across the country. And…….
- JOHN So, how does TB spread? Until recently the mainstream media has aired the view that badgers are not implicated in the spread of bovine TB but thankfully the debate has now shifted, largely thanks to the indisputable evidence from the Randomised Badger Culling Trial. Here you can see two of the key findings that it established in relation to how bovine TB spreads: badgers and cattle. So, it is a FACT that badgers contribute to the incidence of the disease in cattle.
- JOHN Transmission of the disease occurs between cattle and between cattle and badgers Translocation occurs when cattle are moved around the country You can see from the picture on the left that as farms were restocked after the FMD outbreak of 2001 unfortunately cattle were moved from what we now call the high risk area to the north of England (and elsewhere) which increased the spread of TB Amplification occurs within a herd. Work has been done that shows once an infected badger has infected a cow and some studies put this amplification effect at up to 50% of incidents being attributed to infectious badgers
- JOHN So, this slide sums up where those transmission routes are and therefore where the critical control points are. Importantly, we have to tackle ALL routes……
- JOHN In order to stop the transmission of the disease we need to consider controls in cattle, in badgers, and in other species. This slide outlines all of the cattle controls at our disposal: TB testing – testing cattle and removing reactors. Risk based trading – to mitigate the chance of spreading the disease from high risk to low risk areas Surveillance – carried out in slaughterhouses with information fed back to vets and farmers Biosecurity – to minimise the contact points between the wildlife reservoir and cattle (often via feed). All of this is underpinned by Farm Health Planning between farmers and their vets.
- JOHN There are some questions around the role of TB testing as a control measure: On accuracy it is true to say that the test isn’t perfect but it is the best we’ve got and anywhere that TB has been eradicated in the world, the TB test has been used The frequency of testing is a policy decision underpinned by evidence and we have different approaches across the UK which we will talk about later On quality assurance vets carrying out the test are validated to undertake the work
- JOHN We get asked a lot about cattle vaccination and it is something that we are all working towards BUT Important to remember that the BCG vaccine is not fully protective so it will definitely be an important tool but not necessarily the silver bullet that some hope In order to trade animals we need to be able to differentiate between vaccinated and infected animals and the test to do that has not yet been validated (although work is ongoing) Because of this vaccination is currently illegal in the EU In 2013 the European Commissioner wrote to Defra setting out a provisional timetable for the use of vaccination in cattle by 2023. However, some of the milestones set out in that timetable have been missed so we expect that would be the earliest possible date.
- NEIL? Programme funded by the Welsh Govt (WG) to help farmers who have TB breakdowns. Cymorth TB was rolled out across Wales last November yet, disappointingly, only a proportion of the 300 government subsidised training places have been taken up - stilting the programme’s progress. BVA and BVA Welsh Branch is encouraging vets to fully engage with this important project.
- JOHN NB THIS IS AN OVERVIEW SLIDE – DON’T SPEND LONG ON IT Moving to the other route to transmission we will look at controls in badgers outlined here. And I will say a bit about each of them……
- JOHN Badger culling is a method of population control to minimise the likelihood of contact points between infected wildlife and cattle. The Randomised Badger Culling Trial found that proactive culling of badgers does reduce the incidence of TB in cattle herds. Again, this is a FACT that scientists are agreed upon. The question is about how to carry out a cull and we will come on to that later.
- JOHN Another control method in badgers is vaccination and it is deployed using an injectable vaccine. However, as with BCG vaccine in other species it does not confer immunity but reduces the severity of the disease. A test to differentiate infected from vaccinated badgers exists but it is unreliable (50/50). We have no evidence of the impact on cattle. And deployment is difficult, time consuming and costly, which is why research is ongoing into an oral vaccine.
- JOHN DON’T READ THESE OUT And there are a number of other control methods in badgers that are currently being researched – some new options and some to improve existing options, such as better diagnostics.
- NEIL Programme funded by the Welsh Govt (WG) to help farmers who have TB breakdowns. Increased cattle surveillance and controls came into place on 1 May 2010. All cattle owners in the area are also involved in a project to improve biosecurity on their farms to reduce the risk of TB getting into their herds. Over 5,000 doses of badger vaccine have been administered.
- JOHN In addition to control measures in cattle and badgers we need to think about the need for control measures in other species – the spillover hosts – to make sure we are tackling the disease from all angles. In farmed animals these measures include biosecurity, testing and slaughter.
- JOHN This slide summarises the different transmission routes and the various control measures that are available, as well as highlighting where we need more research. I’ll now hand over to Neil who will outline the policy approaches to the disease across the UK and explain BVA’s position.
- NEIL? This slide summarises the policy position in Wales where controls on cattle and wildlife are part of Defra’s 25 year eradication strategy. Feel free to elaborate detail on cattle controls. As John outlined earlier, we know from the RBCT that badger culling can have an impact on the disease in cattle. BUT the culls in the RBCT were government-led and used cage trapping and shooting of badgers and Defra proposed industry-led culling using a combination of cage trapping and shooting and controlled shooting. Because this was introducing a new method of culling badgers that had not been tested in the field the culls were established as “pilots” so that the safety, efficacy and humaneness of controlled shooting could be monitored.
- NEIL You will also be aware that the devolved administrations are doing things differently. Scotland is officially TB free and is a fantastic example of what else can be achieved when farmers and vets aren’t constantly battling against the disease. Scottish Government has been working with vets and farmers on an eradication programme for bovine viral diarrhoea. The main differences between England and Wales and Northern Ireland is the approach to the wildlife reservoir ie badgers Northern Ireland is modelling a “TVR” policy – testing badgers and then vaccinating or removing them. This is in the very early stages and we are very interested in the outcomes. Modelling of a TVR policy in Wales suggested that it wasn’t viable because the test is so unreliable so it will be interesting to see how developments in diagnostics may have an impact. Wales had planned a government-led cull under the coalition government but changed its policy to one of badger vaccination in the intensive action area. Wales also has a strict cattle testing policy “Check Test Wales”. It’s too early to draw any conclusions on the impact of the vaccination policy but we are watching with interest.
- NEIL So that’s an overview of what governments are doing and I’ll talk a bit about what the British Veterinary Association position is. I’ll start with the contentious issue of badger culling. As a profession we accept that it can sometimes be necessary to humanely control wild species, in order to protect food, other species or prevent the spread of disease. Whenever we consider these issues we think of them in terms of an ethical review process to weigh up the costs and benefits, and then apply them using an ethical framework, such as the 3Rs which you may be familiar with in relation to lab animal work. And in considering this ethical approach we have concluded that badger culling does have a roll but that it absolutely must be targeted, effective and humane.
- NEIL This slide outlines our position in more detail. I explained that at the end of the first year of the pilot culls the Independent Expert Panel found that it had not met the criteria set for humaneness and effectiveness (and it’s important to note that effectiveness here means the numbers or percentage of badgers removed). The Panel also made recommendations to Defra, which Defra took on board and so BVA agreed that Defra should be given the opportunity to improve on humaneness and effectiveness in the second year. Unfortunately at the end of the second year of culling, Defra could not demonstrate that it had significantly improved on humaneness and effectiveness and BVA took the decision to withdraw support for controlled shooting. However, we have not withdrawn our support for culling and we support the use of the tried and tested method of cage trapping and shooting. It is important to note here that there are different views within the profession. Our specialist division that deals with wildlife – the British Veterinary Zoological Society – is against the use of controlled shooting, but our specialist cattle division – the British Cattle Veterinary Association – supports the ongoing use of controlled shooting. And amongst our wider membership there will be a whole range of views. But our position was developed through consultation and remains supported by the available science. We have called for the wider roll-out of culling using cage trapping and shooting only.
- NEIL But our support for culling must be seen in the context of a comprehensive strategy that is informed by scientific evidence. Bovine TB is a devastating disease and it is essential that we tackle the disease from ALL angles. Research into many aspects of TB is ongoing and we continue to refine our policy as we learn more from this research.
- Neil Thank you very much for your time and interest. We are very happy to take questions now, or if you would like to follow up with us afterwards our contact details are on the slide and in the handout packs.