Bovine TB is a complex infectious zoonotic disease of animals and humans. In this presentation BVA explain more about this disease, how it is spread and BVA policy approaches to badger culling. This was a presentation given to UK Parliamentarians on the 27th October 2015.
2024: The FAR, Federal Acquisition Regulations - Part 29
Bovine TB - BVA Parliamentary briefing
1. Bovine TB
BVA Parliamentary briefing
Tuesday 27 October 2015
Sean Wensley
BVSc MSc Grad DMS MRCVS
BVA 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
7. bTB: the problem
Regions of England
• High Risk Area (HRA)
• Edge Area (EA)
• Low Risk Area (LRA)
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]”
15. 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)
16. 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. 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
19. 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
20. Policy approaches across the UK:
England
Regionalisation
• High Risk Area (HRA)
• Edge Area (EA)
• Low Risk Area (LRA)
21. Policy approaches across the UK:
England
Cattle controls
•High risk = Annual herd testing
•Edge = Annual herd testing
•Low risk = Four yearly testing
•High & edge = Routine pre-
movement tests
•Post-movement tests
•Targeted use of interferon-gamma
assay (IFN-γ)
•Defra consultation on increased
cattle controls (Oct 2015)
Badger controls
•Two pilot cull areas (from 2013) to
test method of culling
•Independent Expert Group
assessment of safety, efficacy and
humaneness
•New cull area in Dorset (from 2015)
•Badger Vaccine Deployment Project
to test deliverability
22. Policy approaches across the UK
Scotland
•Officially
tuberculosis free
• Decision Sept
2009
• Implementation
Feb 2010
•Risk-based testing
Wales
•“Intensive Action Area”
•Badger vaccination
deployment
•Cattle testing: Check
Test Wales
NI
•Separate epidemiological unit
•Cattle testing
•Modelling a “TVR” policy =
Test and vaccinate or remove
badgers
23. 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
24. 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
25. 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
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
JOHN
Not only does the incidence keep going up, but it is spreading northwards and eastwards across the country.
And…….
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.
