Bovine TB

Question 1

What is bovine TB

Answer 1

Chronic bacterial infection of cattle caused by mycobacterium bovis
Zoonotic. but not the primary cause of TB in people
Average cost of a herd TB breakdown in £34,000 (£20,000 of which bourne by the government)

Question 2

What are the 3 management zones for bovine tb and how often is testing at each area

Answer 2

High risk area (HRA)- 6 months
Edge area (EA)- 6 or 12 months
Low risk area (LRA)- 2 years

Question 3

Skin test fro TB (SICCT)
specificity and sensitivity

Answer 3

2 injections (avian and bovine tuberculin)
Outcome: Clear, inconclusive, reactor
Standard/severe interpretation
Specificity = 99.98%
Sensitivity = 50=80%

Question 4

IFN blood test for tb
sn and sp

Answer 4

Used in addition to skin testing in some breakdown herds
Specificity = 96.5%
Sensitivity = 90%

Question 5

Antibody blood test for TB

Answer 5

Occasionally used as a third line test. Specificity = 98%, sensitivity = 65%

Question 6

Post mortem test for TB

Answer 6

All cattle are inspected, but reactors/cattle from restricted herds have more detailed inspection.
Approx. 60% of skin test reactors have no visible lesions at PM – due to insensitivity of this as a diagnostic technique.

Question 7

Cattle vaccination for tb

Answer 7

Can’t currently vaccinate and test
BCG vaccine has protective effect in cattle BUT – it causes cattle to react to the TB test.
International trade requires cattle to be TB tested
A DIVA test (tells between infected and vaccinated cattle) is required to allow both vaccination and testing
DIVA test developed, and both that and cattle BCG going through UK marketing authorisation processB

Question 8

Badger vaccination for TB

Answer 8

2010 BCG licensed for use in badgers.
Reduces lesion development and shedding, but won’t ‘cure’ an infected badger.
Requires trapping of sufficient animals for a social group to have ‘herd immunity’
Oral vaccine in development