BACKGROUND Tuberculosis is an infectious disease which is nearly forgotten in Germany because of its low incidence. CASE REPORT We report on a 14-year-old german girl who was disregarded when active case-finding of her uncle's active pulmonary tuberculosis was carried out three years before. As a result she herself developed a severe infectious pulmonary tuberculosis. The delay between onset of symptoms and diagnosis gives cause for concern and led to active tuberculosis in her brother and her girl friend as well. The lack of information about tuberculosis in population and delay of medical detection in this case led unnecessarily to the continuing chain of infection. CONCLUSIONS This case report shows that there are severe infectious courses of tuberculosis even in childhood which might get epidemiologically important. For earlier diagnosis and successful interruption of chains of infection tuberculosis in the German population even today has to be taken into account. Case detection through contact investigation of adults is of great importance in childhood and adolescence.