Contact tracing of a 15-year-old girl with smear-negative pulmonary tuberculosis in Tehran.

Early detection of tuberculosis (TB) cases and supervised treatment are vital for control of the disease. To assess TB transmission from a sputum smear-negative pulmonary TB case, the contacts of a 15-year-old Iranian girl diagnosed with smear-negative TB in 2010 were traced. In all, 52 classmates and close friends and 15 school staff were screened by tuberculin skin test and chest X-ray. Those with a positive skin test or abnormal chest X-ray were further evaluated by chest spiral computed tomography (CT) scan and triple gastric washing. All classmates and close friends were Iranian and female. Of the 52 girls, 17 (32%) had latent infection (either positive skin test or abnormal chest X-ray) and 3 (5.7%) had active TB (abnormal CT or positive culture additional to positive skin test or abnormal X-ray). None of the staff had abnormal findings. Contact tracing should be considered for contacts of all children with symptomatic pulmonary TB, even those who are smear-negative.