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Bovine TBWelsh Assembly Briefing
21 September 2016
Dr Neil PatonBVMS BSc MRCVS PhDBVA Welsh Branch President
John Blackwell BVSc MRCVS
BVA Senior Vice President
Overview• Bovine TB: what is the problem?• How bTB spreads• Controls:
− cattle− badgers− other species• Government approaches across the UK
• BVA position• Questions
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
• 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?
bTB: the problem
All herds tested
3y Scot & Wal, 2y Eng
M bovis tuberculin replaces M tuberculosis
4 yr testing
FMD
120,000 herds 80,000 herds
Badgers Act 1973
6-year trend in new bTB incidence, herd prevalence and animal level risk (number of reactors per 1000 animals tested)
bTB: the problem
bTB: the problem
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”.
How does bTB spread?• Transmission
− Cattle to cattle− Badger to cattle
(& vice versa)
• Translocation− Locally− Greater distance
• Amplification
Spoligotype translocation
Post FMD 2001
How does bTB spread?Critical control points
• Translocation• Transmission• Amplification
• Transmission• Amplification
Controls in cattleTB Testing•Routine•Pre-movement•Post-movement
Risk based trading
Surveillance
Biosecurity
Farm Health
Planning
Questions around TB testing
• Accuracy of the test• Frequency• Quality assurance
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]”
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
Controls in badgers
• Biosecurity• Culling• Vaccination• Other?
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)
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?
Badger control: Other
Research:•Contraception•Oral vaccine•Humane whole sett culling methods•Trap- and sett-side diagnostics
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
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
A comprehensive approachTB Testing•Routine•Pre-movement•Post-movement
Risk based trading
SurveillanceBiosecurity
Farm Health Planning
Vaccination
Culling•Targeted•Humane
Research•Cattle vaccine•Oral badger vaccine•Badger contraception•Improved diagnostics
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
Policy approaches across the UKScotland•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
BVA position: the ethics of cullingEthical 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
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
BVA position: A comprehensive approach
TB Testing•Routine•Pre-movement•Post-movement
Risk based trading
SurveillanceBiosecurity
Farm Health Planning
Vaccination
Culling•Targeted•Humane
Research•Cattle vaccine•Oral badger vaccine•Badger contraception•Improved diagnostics
