A tuberculin skin test survey among Afghan children in Kabul.

SETTING: Kabul, Afghanistan, October to November 2000. OBJECTIVE: To determine the prevalence and the average annual risk of infection with Mycobacterium tuberculosis (ARTI). METHODS: A cluster sampling method was selected to carry out the survey. Sub-divisions of Kabul's districts were chosen, and door-to-door visits were carried out to register the children. The prevalence of tuberculous infection was determined using a cut-off point to denote infection and mixture analysis. The average ARTI was derived algebraically from the prevalence estimates. RESULTS: The tuberculin skin test was administered and read in 89% of registered children. Utilising a cut-off point of > or = 8 mm in duration, the estimated prevalence of tuberculous infection was 4.3% and the calculated average ARTI was 0.61%. Using mixture analysis, the average ARTI was estimated to be 0.34% (95% credibility interval 0.23-0.54). This indicates a substantial decrease from the estimated ARTI of 2.55% calculated in the 1963 survey. CONCLUSIONS: There has been a large decrease in the risk of tuberculous infection in Kabul since the last assessment. The adverse situation in the past decades does not appear to have severely affected the epidemiological situation.