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Animal Diseases

Dáil Éireann Debate, Thursday - 9 December 2021

Thursday, 9 December 2021

Questions (50)

Denis Naughten

Question:

50. Deputy Denis Naughten asked the Minister for Agriculture, Food and the Marine if he will expand the use of the gamma interferon test to eradicate bovine tuberculosis in the national herd; and if he will make a statement on the matter. [60284/21]

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Written answers

The gamma interferon test is a valuable tool for detecting TB infection in cattle. It has been widely used as a core part of the TB eradication programme in Ireland since 2015, following many years of research and testing in specific problem herds.

As with tests for many other diseases, none of the tests currently available allow a perfectly accurate determination of the M. bovis infection status of cattle.

The single intradermal comparative tuberculin skin test is universally regarded as the best screening test in a general population of animals. However, in a group of animals where TB infection is known to be present, the gamma interferon test is used because it detects infection at an earlier stage; in other words, it has higher 'sensitivity' than the skin test. When used alongside the skin test, the gamma interferon blood test can help to resolve TB problems in a herd more quickly by identifying cattle at an early stage, before they can spread infection onwards.

However, the gamma interferon test is not suitable for use as a general screening test in the way the skin test is used, because it has lower 'specificity'. Using it in herds not thought to be TB-infected would result in more false positive results.

The gamma interferon test is used as standard in herds that have experienced a significant TB breakdown (for example, five or more reactors, 5% of the herd, or where necessary on epidemiological grounds). The gamma interferon test is also used as a quality control measure on skin test reactors.

Under the new Bovine TB Eradication Strategy, the gamma interferon test is used to reduce the risk posed by animals that yield inconclusive results to the skin test. Other policies being developed under the TB Eradication Strategy, focusing on herds with chronic or recurrent TB problems, will also use the gamma interferon test as appropriate.

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