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Bovine Tuberculosis

Volume 467: debated on Tuesday 13 November 2007

To ask the Secretary of State for Environment, Food and Rural Affairs if the review group investigating bovine tuberculosis led by Sir David King will take steps to engage with the Independent Scientific Group on Cattle TB. (162061)

Sir David King is arranging a meeting with Professor Bourne and other members of the Independent Scientific Group on Cattle TB to discuss his report on badgers and bovine tuberculosis in cattle.

To ask the Secretary of State for Environment, Food and Rural Affairs what plans he has to introduce the use of reverse transcriptase-polymerase chain reaction for the testing of cattle for bovine tuberculosis. (162818)

Under EU regulations, the tuberculin skin test is (and is likely to continue to be) the primary diagnostic test for TB in live cattle in the field. We foresee only a minor, if any, role for non-immunological assays in the screening of cattle populations for TB.

DEFRA has been funding work using the polymerase chain reaction (PCR) technique to develop tests for Mycobacterium bovis (M. bovis) since 1999. This has included work to develop a reliable and rapid bovine TB screening test that can detect the presence of M. bovis DMA in infected cattle tissues. Work to date shows the value of the application of PCR techniques in certain situations, for example in cattle tissue samples from suspect cases of TB disclosed at routine slaughter, where the speed of the result is of importance.

The use of automated PCR machines has been trialled by the Veterinary Laboratories Agency for use in routine detection of M. bovis in a range of bovine tissue samples in the laboratory. A review of this and its incorporation into routine laboratory diagnostic techniques is currently being planned. However, PCR is not yet as sensitive, specific or reliable as conventional bacterial culture in detecting TB.

DEFRA is investing £1.3 million on work on PCR over the next 3 years that will allow us to tell the difference between M. bovis and similar species from environmental samples. This is not likely to be available as a field test in the short term.

No reverse transcription stage is required for the detection of M. bovis organisms by PCR, as DMA (not RNA) is the constitutive nucleic acid in the genome of mycobacteria.