Diagnosis of Mycobacterium bovis infection in cattle

Bovine tuberculosis (TB) caused by Mycobacterium bovis continues to be a major animal health problem, having adverse impacts on socio-economic 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 (Hope and Villarreal-Ramos, 2008). 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 (Cousins, 2001). However, eradication has proved to be more difficult in countries with wildlife reservoirs of M. bovis infection, such as the brushtail possum (Trichosurus vulpecula) in New Zealand (de Lisle et al., 2001), the badger (Meles meles) in the UK and Ireland (Delahay et al., 2001; Griffin et al., 2005) and white-tailed deer in Michigan, USA. (O’Brien et al., 2011). In these countries, management of the disease must also include control of the disease in the wildlife reservoir of infection. ... The aim of this review is not to provide a comprehensive review of ante-mortem and post-mortem diagnosis of bovine TB, as detailed reviews on these topics can be found elsewhere (Monaghan et al., 1994; Adams, 2001; de la Rua-Domenech et al., 2006; Schiller et al., 2010a). Rather, this review is focused on documenting how different tests can be used and on new developments in diagnostic testing.