Control of bovine tuberculosis and Johne's disease in cattle

If the diagnosis of mycobacterial disease in cattle is challenging, the diagnosis of infection is even more so. This is because of the biology of the organisms involved, the pathogenesis of the diseases characterised by uncertain, frequently prolonged and non-linear progression and intermittent shedding of the infectious organism, and limitations, particularly with respect to sensitivity, of the commonly used testing technologies and strategies. Infected animals, however, need to be identified and managed if disease is to be controlled and perhaps even ultimately eradicated. Possible strategies to facilitate this are discussed.