Prevalence and risk factors for bovine tuberculosis in Minas Gerais State, Brazil

The aim of the present study was to estimate the prevalence and regional spread of bovine tuberculosis in the state of Minas Gerais, Brazil, to identify herd-level risk factors, and to provide guidance for disease control and mitigation of its impact in public health. The study comprised a large-scale random sample survey of 22,990 animals and 1586 herds, distributed in seven regions. A questionnaire was applied on each farm to collect epidemiological and herd management data. Overall, 5.04 % of herds and 0.81 % of animals were positive for bovine tuberculosis. The highest herd prevalence was found in Alto Paranaiba, an expanding dairy region. The more technologically advanced dairy herds showed a prevalence ratio of 2.83 compared to others and are obvious candidates for risk-based surveillance and herd accreditation schemes. Small farms cannot be left out of disease control efforts because they are the vast majority of herds, albeit with lower individual risk. With regard to public health, there is widespread practice of producing homemade fresh cheese with raw milk and of slaughtering culled cows in places without sanitary inspection. This poses a risk to consumers and limits the efficacy of surveillance at slaughter.