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IN the current international panorama of increasing animal movements and trade, bovine tuberculosis (TB) maintains its leading role among the threats to the livestock sector's profitability, as well as to cattle health and welfare. Moreover, its zoonotic potential remains a major public health concern, not only in the developing countries, but also in many European countries where there is the risk of consumption of contaminated food products (primarily raw milk and raw milk products) and direct contact with infected animals. In its latest report on zoonoses and foodborne outbreaks (EFSA and ECDC 2012), the European Food Safety Authority (EFSA) reported a rising trend from 2006, in the number of confirmed cases of human TB due to Mycobacterium bovis . In 2009, 10 EU member states reported 133 cases, with Germany, Ireland, the Netherlands, Spain, and the UK accounting for 87 per cent of cases; and with mortality at 5.3 per cent.
Internet search resources accessible on the Web of Knowledge platform cite around 3000 papers concerning bovine TB over the past 10 years (2003 to 2012). When the search is narrowed by combining the search items 'bovine TB' and 'epidemiology', a relatively large number (649 of 2975) can still be retrieved, which indicates the extent of concern about the risk issue in the scientific community. Risk factors have been variously investigated and characterised, providing a clear picture of the main epidemiological features of bovine TB and the general mechanisms underlying the spread and the persistence of the disease (Humblet and others 2009, Schiller and others 2010, Skuce and others 2012). From these epidemiological studies, we learn about the most relevant factors at the animal, herd and region levels. For instance, the age of the animal or its body condition, immune status and genetic susceptibility may all play a role. More important are the factors affecting the probability of cattle-to-cattle and wildlife-to-cattle transmission routes. In developed countries, the factors acting at the herd level include: herd size; management (eg, a trend toward fewer but larger production units, spreading of slurry on...