Abstract
Introduction. In Tuscany, Tuberculosis incidence is more thantriplicate from 1982 to the beginning of the third millennium.The impact of this trend on open population is not known, asupdated studies on Tuberculosis prevalence are not available.Tuberculin skin test provides the currently most widely used toolfor assessing Tuberculosis transmission in a community and theprevalence of infection as well.The objective of this investigation was the evaluation of tuberculin index by means of the Mantoux test in adolescents eighteen-years old.Results. The study was carried out in 21 secondary schools ofSiena and its Province; 1,138 students participated to this survey.The overall prevalence of subjects with a skin reaction size >5 mm was 1.6%; if the standard cut-off of 10 mm was used, the overall prevalence of a positive skin reaction was 0.4%. Riskfactors for a doubtful or positive reaction were previous immunization with BCG and migration from high-endemicity countries. Discussion. In Italy, studies on tuberculin index in young adultsare scanty and controversial: our results show a very low Tuberculosis prevalence and an epidemiological pattern typical ofcountries with low Tuberculosis endemicity.Conclusions. The slightly increase in Tuberculosis incidencehas no impact on the prevalence of latent Tuberculosis infection on our geographical area. We conclude that skin-test screening for Tuberculosis should be addressed to high risk population as migrants from Countries reporting high transmissionrate, those recently exposed to an infectious case and healthworkers.
