Risk factors for the detected presence of Mycobacterium bovis in cattle in south central Spain

Tuberculosis (TB) is a chronic bacterial disease of livestock and wildlife, which has major social and economic costs. In Spain, cattle test-and-slaughter schemes have dramatically reduced TB levels, but a wildlife reservoir of the disease is thought to be preventing total eradication. We aim to identify the risk factors for the presence of TB in cattle in Spain. In this case-control study, we combined a farmer-based questionnaire and participatory mapping with government records in Almodovar, Spain. Data were collected from a mixture of TB-free and TB-infected farms, yielding a total sample of 73 farms. Generalised linear modelling and information theory were used to identify the risk factors strongly associated with TB, and farmers were also asked their opinions on TB and wildlife management. The risk factors most strongly associated with TB on a farm were the presence of wildlife, the number of streams per hectare and feeding volume foods (e.g. hay) on the ground. Farmers' opinions about TB were influenced by their experience of the disease and their interactions with wildlife. The results highlight the complexities of managing TB, and demonstrate the need for a system-level understanding of the inter-relationships among epidemiological, ecological, environmental, social and political risk factors.