Epidemiological and economical impact of tuberculosis in an adolescent girl in Lausanne (Switzerland)

Patients with pulmonary tuberculosis (TB) can infect people in their enviro nment but children and adolescents are rarely contagious. A recent case of an adolescent girl in Lausanne, however, proved to be infectious and requir ed extensive contact tracing. Subjects and methodology: The source case was a 15-years-old adolescent gir l of African origin. Upon her arrival in Switzerland in 1994 the tuberculin skin test was 14 mm. The patient did not receive preventive treatment. She developed smear-positive pulmonary tuberculosis in May 1999. Contact traci ng identified contacts in the surrounding population. The contact persons w ere divided into 3 groups according to their proximity. The first group con sisted of close family and friends, the second of classmates and teachers a nd the third of more distant contacts. Costs were also evaluated. Results: Of the 53 people examined, 24 (45%) were infected and required tre atment. Eight out of 9 cases (88%) were infected in the first group (includ ing another case of culture-positive pulmonary tuberculosis). Fourteen out of 33 cases (42%) in the second group and 2 of 11 (18%) to the third group. Passing from one proximity group to the next decreased the relative risk o f infection 4 fold. The costs of contact tracing and treatment are estimated at over CHIT 24 00 0. Conclusions: (1) Pulmonary TB can be contagious even in adolescents. (2) Su bdividing contacts into proximity groups allows for better targeting of the people to be screened. (3) Contact tracing and the high costs involved cou ld have been avoided if the patient had received preventive chemotherapy up on her arrival in Switzerland.