Knight, Andrew

McGill, Iain

Winchester Research Repository

veterinary TimesYOUR VIEW30 Data shows ‘no reduction in bTB herd prevalence’Dear editor,We note Defra minister George Eustice’s statement on 13 September1 referring to epidemiological data on bTB in cattle in badger culling zones2. He claims that: “Today’s figures showing reductions in TB cases in Somerset and Gloucestershire are evidence that our strategy for dealing with this slow moving, insidious disease is delivering results1.”Examination of that data in detail demonstrates no reduction in the prevalence of bTB infected herds in Gloucestershire or Somerset as a result of culling2. Prevalence is a measure of the percentage of cattle herds in badger culling zones with bTB, taken at a specific point in time. It involves relatively simple calculations, giving hard data, and is important for considerations of control. Prevalence is a measure of the force driving infection between animals within a herd, between adjacent herds and between distant herds3.The prevalence in cattle is no lower than it was before culling2, despite the killing and removal of 1,879 badgers in Gloucestershire and 1,777 in Somerset. A total of 3,656 badgers have been killed with no perceivable disease control benefits. When ministerial statements are used as justification for the slaughter of badgers on an industrial scale across swathes of England, it is vital that they are accurate and reflect the best available veterinary and scientific advice.The incidence rate is the calculated measure of new bTB breakdowns in herds, and Defra claims it has fallen after four years of badger culling2. The methods used to interrogate the raw data to divine this conclusion merit analysis. Defra uses complex and sometimes obscure calculations to obtain the figures for incidence. These calculations have been made using data that are, by Defra’s own admission, unstable over time. The explanation of data set parameters2 reveals a conscious filtration of data was necessary over the four years of culling, with lost herds over time, new herds, merging herds, herds in existence and cohorts – the studied cattle exposed to badger culling – all subject to qualitative review and re-allocation for data purposes.In addition to our reservations on analytical method, the measure of 100 herd years at risk is opaque, and impossible to confirm independently without raw data. The results of statistical analyses always vary dependent on rules governing the choice of data set. We request Defra releases to us and other groups the data its calculations for incidence and prevalence are based on. Data generated by the Randomised Badger Culling Trial, which the Government cites as the basis for its policy, were made openly available for independent verification3. The location and date of all bTB breakdowns is already publicly available via the Govern-ment’s own ibTB website4.Greater clarity can be obtained by focusing on prevalence rather than incidence. In Gloucestershire, the prevalence was 11.9 per cent three years before culling started, falling for three years without culling to 6.9 per cent, before plateauing to 7.1 per cent after four years of culling. In Somerset, the prevalence was 17.2 per cent three years before culling started, which then fell successively for three years without culling to 6.1 per cent before plateauing to 7.2 per cent after four years of culling. The prevalence values before culling and after culling are not signif-icantly different. The additional free veterinary assistance and biosecurity advice farmers in cull zones have been given5, when compared to farmers outside the zones, renders the badger cull’s failure to reduce bTB even more striking.The only discernible qualitative trend from the data is a rapid decrease in prevalence in both cull zones in the three years before culling started. Badger culling is associated with the arrest of this steep decline and a plateauing of prevalence at that level.One peculiar thing about these figures is that, although Defra maintains the incidence has been falling steadily, the prevalence has remained the same. By now, a persistent reduced incidence might be expected to translate into a lower prevalence, but it has not. Perhaps confounding factors exist relating to the amalgamation or disappearance of problem herds. For example, the number of cohort herds in Gloucestershire fell by 20.6 per cent from 214 herds to 170 during the four years of culling. The number of cohort herds in Somerset fell by 18.8 per cent from 154 to 125. That is a disappearance of approximately one fifth of herds exposed to badger culling in both areas.If these herds were culled out, or merged so they collectively present one data point, this could seriously affect the accuracy of calculated incidence. Perhaps Defra could clarify exactly what happened to these 73 herds and what their bTB status was prior to disappearance?Put simply, approximately the same proportion of bTB affected herds exists now as before culling started. Badger culling has not resulted in a decrease in bTB in cattle in cull zones, for the prevalence remains unchanged. Any statement made to the contrary is, in our view, simply untrue.The very title of Defra’s document is incorrect, claiming: “New Where you see the  icon, you can enter the code in the search bar on jobs.vettimes.co.uk to apply for this vacancy onlineLetters.indd   30 26/10/2018   13:35Name:Date:Approved  New Version Comments: Steven CooksonOctober 26, 20182 errors okNovember 5, 2018YOUR VIEW 31GET IN TOUCHThe Editor, Veterinary Times, Olympus House, Werrington Centre, Peterborough PE4 6NApaulimrie@vbd.co.ukvet times.co.uk facebook.com/vettimesuk @vettimesuk linkedin.com/company/vet-times @vettimesukSpace limitations mean not all letters can be published. In some instances, and at the editor’s discretion, letters will be shortened. The views and opinions expressed in any letter published are not necessarily those of the publication, the editor, Veterinary Business Development or any sta  working for it.ISSN 1352-9374 Veterinary Times is published 50 times per year and is sent free to selected veterinary professionals. Readers should note Veterinary Times is not peer reviewed, and the views expressed in the publication are not necessarily those of the editor or publisher. ©2018 Veterinary Business Development Ltd (no part of this publication may be reproduced in any form without the written permission of the publisher). Veterinary Business Development, Veterinary Times and vet times.co.uk are registered trade marks of Veterinary Business Development Ltd. All other trade marks acknowledged.News desk:David Woodmansey 01733 383561davidwoodmansey@vbd.co.ukNews editor:James Westgate 01733 383547jameswestgate@vbd.co.ukFeatures:Jackie Morrison 01733 383540jackiemorrison@vbd.co.ukProduction enquiries:Jenny King 01733 383542jennyking@vbd.co.ukDisplay advertising sales:Ian Morris 01733 383535ianmorris@vbd.co.ukSubscriptions:Nikki Dartnell 01733 383539nikkidartnell@vbd.co.ukWe are committed to reducing the environmental impact of our publications wherever possible; therefore, all our publications are printed using soya-based inks and FSC-certifi ed papers. When you have no further use for this magazine and the polywrap, please recycle it.Designed and produced by Veterinary Business Development Ltd. Printed in Great Britain by Pensord, Blackwood, Gwent.VBD is committed to the highest standards of accuracy and fairness, but mistakes can occasionally occur. For full details of our formal editorial complaints procedure, visit www.vettimes.co.uk/?p=558VBD is a member of the Independent Press Standards Organisation (IPSO). For full details, visit www.ipso.co.uk/IPSO/veterinarybusiness developmentVeterinary Business Development Ltd, Olympus House, Werrington Centre, Peterborough PE4 6NAAverage net circulation Jan-Dec 2017 19,104Business Publication of the Year 2017data shows drop in bovine TB as further measures to  ght disease unveiled.” There has been no such “drop in bovine TB”2. Perhaps Mr Eustice or Mr Gove could kindly explain the total failure of four years of badger culling to lower the percentage of herds affected by bovine TB in culling zones?The Zoological Society of London is in agreement with us, recently stating: “Thus far there is no robust evidence that England’s policy of mass culling is reducing cattle TB. A minister’s claim that the approach is ‘delivering results’ is based upon a Government report, which states explicitly that it ‘cannot demonstrate whether the badger control policy is effective in reducing bovine TB in cattle’6.” The omission of data from matched control areas not subject to badger culling2 further invalidates the Government’s claims.Widely published video footage of a cage-trapped badger that took a minute to die after being shot by a cull contractor7,8 was viewed by millions. The badger cull has produced no measurable reduction in the percentage of bTB infected herds in cull zones, but has produced a well-documented increase in badger harm. The policy clearly compromises badger welfare, both as part of the Government sponsored cull7,8,9,10 and by the associated increases in sett tampering and the proliferation of animal abuse, such as baiting lactating badgers with  ghting dogs11. Neither the veterinary pro-fession nor the public will tolerate such animal abuse in plain sight.The data on which Mr Eustice bases his statement provide no evidence whatsoever for his claimed “reductions in TB cases in Somerset and Gloucestershire”. We respectfully request Mr Eustice withdraws his inaccurate statement and that, having consulted Mr Gove and Defra’s CVO, he issues a corrected statement on a newly entitled document that accurately re ects bTB prevalence in cattle after four years of badger culling in Gloucestershire and Somerset.When proven harm is committed to animals on a very large scale, accompanied by documented animal abuse and entirely unaccompanied by any disease control bene ts, the only option for any responsible Government is to abandon the policy immediately.Yours faithfully,IAIN MCGILL, BVetMed, BSc(Hons), MRCVS, director, Prion Interest Group,ANDREW KNIGHT, MANZCVS, DipECAWBM(AWSEL), DipACAW, PhD, FRCVS, SFHEA,ANDRE MENACHE, Bsc(Hons), BVSc, DipECAWBM(AWSEL), MRCVS,RICHARD SAUNDERS, BSc(Hons), BVSc, FRSB, CBiol, DZooMed(Mammalian), DipECZM(ZHM), MRCVS,BRONWEN EASTWOOD, BSc(Hons), CertGP(SAP), BVetMed, MRCVS,FIONA DALZELL, BVSc, BA(Hons), MVetMed, MRCVS,PHILL ELLIOTT, BVM&S, MSc(Wild Animal Health), MRCVS,BEV IRVING, BVetMed, MRCVS,MARK JONES, BVSc, MSc(Stir), MSc(UL), MRCVS, head of policy, Born Free Foundation,PHILIP MANSBRIDGE, UK director, International Fund for Animal Welfare,DOMINIC DYER, chief executive, The Badger Trust,TONI SHEPHARD, PhD(Animal Behaviour), executive director, Animal Equality UK,GLORIA DAVIES, chief executive, Network for Animals,ELISA ALLEN, director, People for the Ethical Treatment of Animals,ADAM GROGAN, BSc, MCIEEM, head of wildlife, Wildlife Department Science and Policy Group, RSPCA.References1. Defra (2018). New data shows drop in bovine TB as further measures to  ght disease unveiled, https://bit.ly/2PXjlkb2. APHA (2018). Bovine TB in cattle: badger control areas monitoring report For the period 2013-2017, https://bit.ly/2EU4FS23. Independent Scienti c Group on Cattle TB (Bourne J, chair; 2007) Bovine TB: the scienti c evidence; a science base for a sustainable policy to control TB in cattle; an epidemiological investigation into bovine tuberculosis;  nal report of the Independent Scienti c Group on Cattle TB, https://bit.ly/2CGUVaT4. IBTB (http://ibtb.co.uk)5. Defra/APHA (2015). TB advice for farmers in badger cull areas, https://bit.ly/2z3m7Ny6. Zoological Society of London (2018). Eradicating TB from cattle and badgers – a review of evidence, https://bit.ly/2JhkKzz7. Doward J (2018). Secret  lming reveals hidden cruelty of licensed badger culls, The Guardian, https://bit.ly/2z8E0dM8. BBC News (2018). Culled badger “took a minute to die”, https://bbc.in/2yzg9Vs9. Report by the Independent Expert Panel (Munro R, chair; 2014). Pilot badger culls in Somerset and Gloucestershire, https://bit.ly/2PVmTDr10. BBC News (2014). Anger at badger’s “cruel” death in cull zone, https://bbc.in/2O7606Y11. Dalton J (2018). Crime gangs selling badgers for up to £700 for baiting with dogs, fuelling high-stakes gambling, Independent, https://ind.pn/2JgwhPCTB in hounds: infected meat possibly to blame? Dear editor,Your correspondents McGill and others (17 September and 15 October issues), with their self-serving allega-tion that foxhounds spread TB across the countryside, demonstrate, in my view, a profound ignorance of the pathogenesis of TB in hounds and other mammals.TB is essentially a respiratory disease of all mammals that spreads horizontally by protracted and close contact exposure. This is clearly not the case with foxhounds moving across the countryside and is presumably behind Defra’s statement that “there is no evidence to suggest that dogs play a signi cant role in the persistence of TB in England or that hunting with dogs contributes to the spread of disease in cattle”.The 2017 outbreak in kennelled hounds, however, revealed another possible route of infection for TB, namely ingestion of infected meat, but in this case hounds were clearly the unfor-tunate recipients of the disease, not the primary transmitters – although they became secondary transmitters within the con nes of the kennels.The only other present-day example of the oral/respiratory route of infection is for cattle from badgers in the terminal stages of disease – the so-called super-excretors that excrete vast numbers of tubercle bacilli into the environment in urine, which again, is clearly not the case with healthy foxhounds moving across the countryside.Yours faithfully,LEWIS H THOMAS, PhD, FRCPath, MRCVS, secretary,Veterinary Association for Wildlife Management,Smiths Cottage,Chieveley, Newbury,Berkshire RG20 8UA.SPVS looking for new board membersDear Editor, We are pleased to invite applications for SPVS board members. SPVS members include veterinary surgeons, non-veterinary owners, corporate entities and joint venture partners, as well as clinical directors and leaders of other veterinary businesses. They present a range of needs and interests that are at the heart of our strategic vision for 2019-21.We are looking forward to enhancing the skillset and diversity of the board.We would like to receive applications from any individuals working within the veterinary profession who have an interest in developing a culture of responsible leadership. The board spaces available are for one general board member and one board member with an interest in well-being and mental health – with the capacity to oversee the administration of the SPVS/Mind Matters Initiative Wellbeing Awards.For full details visit the https://spvs.org.uk/Yours faithfully,NICHOLA WATSON, chief executive, SPVS Ltd, Unit 19a, Hatton Country World,Hatton, Warwick CV35 8XA.SPECIAL OFFER     SPECIAL OFFER     SPECIAL OFFER     SPECIAL OFFER     SPECIAL OFFER     SPECIAL OFFER     Letters.indd   31 26/10/2018   13:35Name:Date:Approved  New Version Comments: Steven CooksonOctober 26, 20182 errors ok

Data shows ‘no reduction in bTB herd prevalence’

https://cris.winchester.ac.uk/ws/files/2118481/2108572_Knight_DataReductionBTB_original.pdf

Data shows ‘no reduction in bTB herd prevalence’

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