Fifty cases of tuberculosis (TB) have been diagnosed in association with a school in the city of Leicester in the English Midlands. Forty-four of the cases identified are students of the school, which has about 1200 students aged 11 to 16 years, two are teachers, and four are family contacts (2-4). None is currently in hospital. All of the cases have started treatment. The isolates obtained so far are all fully susceptible to standard antituberculosis drugs. A further 100 students with strongly positive tuberculin skin test results have no signs of active disease and are receiving chemoprophylaxis. Contacts of all the cases in the outbreak are being screened. All staff at the school have been offered chest radiography but no cases have been identified, apart from the two teachers, neither of whom had infectious disease.
The index case was a 13 year old student at the school, in whom TB was diagnosed in August 2000. Subsequent investigation, following the guidelines of the British Thoracic Society (5), indicated the possibility of transmission at the school and led to screening of all children and staff at the school.
Over 90% of the school are of South Asian ethnic origin. Eighty per cent have previously received BCG immunisation. The outbreak is not therefore linked to the interruption to the routine schools BCG programme in England and Wales in the academic years 1999/2000 and 2000/2001. This programme is due to re-start in September (6).
Identifying the source(s) of the outbreak and the circumstances leading to its occurrence is a priority for the local investigation team. It is likely that more cases will be identified as a result of follow up of any students not yet screened and contacts of the known cases.
Some of the cases may be incidental, detected as a result of the outbreak investigation in a population subgroup with a high incidence of TB. Other cases of potentially infectious TB have been identified in children in other schools in the city, as would be expected each year in the population of Leicester. Other children and staff in these schools are to be screened. No links have been identified between these cases and the outbreak.