Tuberculosis is currently one of the most important public health problems in the developing world and has therefore been declared a global emergency by the World Health Organization. The continuing increase in the number of cases in many countries, the association with HIV/AIDS and the difficulties linked with drug-resistant bacilli give rise to concern. In developed countries, tuberculosis is less widespread but is still regarded as a potential source of infection. Measures to avoid transmission to sensitive persons, particularly health-care workers, are currently a subject of intense discussion.