Controlling bovine TB contagion
Both domestic and wild animals are vulnerable to the bacterium Mycobacterium bovis that causes bovine tuberculosis (TB). The infection can have serious economic consequences, causing animal deaths and decreased production. The disease can also be passed on to human beings. This is the problem that the 'Strategies for the eradication of bovine tuberculosis' (TB-STEP) project set out to address. Eradication of bovine TB has traditionally been carried out through a policy of test-and-slaughter, with mixed results. In some EU countries this policy has proved successful, while in others it has failed despite the application of major financial resources. One problem has been the existence of infected wildlife, such as badgers in the UK and Ireland and wild boar in Spain. Oral vaccination of badgers and wild boar with Bacillus Calmette-Guérin has resulted in reduced levels of infection for the two species. Scientists have also isolated and characterised M. bovis antigens that can trigger the production of antibodies, which can be used in immune tests and vaccine candidates. Researchers have developed new tools for identifying wildlife overabundance and monitoring the impact of management changes on population and disease indicators. A risk factor analysis of current wildlife management practices in Mediterranean habitats has been carried out, particularly for the risk attached to the consumption of carrion and hunted animals. Scientists have examined the diversity of strains of TB and evidence of transmission of infection between cattle and badgers. Mathematical models based on field studies have been used to quantify the risk of TB posed by the various wildlife livestock. The models can be used to determine effectiveness of disease control strategies, including their sensitivity to local environmental conditions. The TB-STEP project will help to stop the transmission of TB from wildlife to domestic animals and the human population. The initiative will therefore help prevent the slaughter of animals, protect human health and reduce economic losses.
