Transmission of tuberculosis from a seven-year-old child in a Sydney school

To determine whether a 7-year-old child with extrapulmonary and pulmonary tuberculosis (TB) and direct smear positive sputum for acid-fast bacilli was infectious to home and school contacts, and to ascertain potential adult sources of infection for these contacts.

Contact tracing by Mantoux testing was conducted on 220 children at a primary school and after-school care facility, and 59 selected adults considered potential sources of infection.

The participation rate for the children was 98% and 92% for the adults. Mantoux positivity (induration >/= 10 mm, or >/= 15 mm with previous BCG) among children was 13% at the school (anticipated rate 2-3%), 26% among school staff, and 7% among children at the after-school care centre where the index case attended. One exposed adult hospital staff member converted from Mantoux negative to positive. No other cases of TB disease were detected among children or adults tested.

Although spread of TB from children to others is rare, the findings of this investigation indicate that transmission of TB from a young child to other children and an adult may have occurred, and that sputum testing and contact tracing for sputum smear positive children should be considered.