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United States Department of Agriculture

Agricultural Research Service

Research Project: PREVENTION AND CONTROL STRATEGIES FOR TUBERCULOSIS IN CATTLE AND WILDLIFE RESERVOIRS Title: Diagnosis of Mycobacterium bovis infection in cattle

Authors
item Buddle, Bryce -
item DE Lisle, Geoffrey -
item Waters, Wade
item Vordermeier, H -

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: April 14, 2014
Publication Date: N/A

Technical Abstract: Bovine tuberculosis (TB) caused by Mycobacterium bovis continues to be a major animal health problem, having adverse impacts on socioeconomic conditions, public health and trade of animals and animal products. Worldwide it has been estimated that approximately 50 million cattle are infected with M. bovis. The most effective strategy for the control of bovine TB requires identification and removal of infected animals from herds. Cellular immune assays can efficiently identify M. bovis-infected animals as they can detect infection at an early stage and have a high relative sensitivity. For more than 100 years the tuberculin intradermal test has been used for this purpose. The application of the tuberculin intradermal test and removal of test-positive (reactor) cattle, have been responsible for the eradication of bovine TB from many countries including Australia, many European Community countries, Canada and most states in the USA. However, eradication has proven to be more difficult in countries with wildlife reservoirs of M. bovis infection, such as the brushtail possum (Trichosurus vulpecula) in New Zealand and the badger (Meles meles) in the UK and Ireland and white-tailed deer in Michigan, USA. In these countries, management of the disease must also include control of the disease in the wildlife reservoir of infection. In a control programme, the early detection of disease is critical. Bovine TB in cattle is a chronic disease and the development of lesions is a consequence of the immune response to the infection. Discernible lesions at post mortem may take years to develop and early diagnosis is dependent on the use of ante mortem immunological assays rather than identification of clinical disease. M. bovis is an intracellular pathogen of macrophage/monocyte cell lineages and the immunological response is predominantly affected by T lymphocytes. Hence, cellular immune assays are routinely utilised to identify M. bovis-infected cattle and the tests used are the in vivo tuberculin intradermal test and the in vitro, (blood based) interferon-gamma (IFN-gamma) assay. Within this review, recent developments with current and emerging TB diagnostic tests are described with insights into future applications.

Last Modified: 7/28/2014
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