Authors : Farhad Salehzadeh , Shahnam Arshi and Shahram Habibzadeh
Abstract: The control of Tuberculosis (TB) is a major health problem in developing countries. Annual Risk of Infection (ARI) is an index used for evaluating the programs against tuberculosis. This index shows the incidence of this infection within a society during 1 year. This study carried out among primary school students during 2 successive years in order to evaluate the results of tuberculin test (PPD) in the 1st year and to determine the variation in the 2nd year. In this study from the northwest of Iran (Ardabil), 780 primary school students randomly selected from 17 primary schools. The age was 8-14 years and mean age was 9.92±1.29. All the subjects injected tuberculin skin test (Pastor Institute 5 IU) in May 2005 and May 2006. In both tests, the results recorded after 48-72 h. PPD >10 mm considered positive. Among the subjects, 55 cases (7.1%) had positive PPD in both tests, 614 cases (78.7%) had negative PPD in both tests, in 33 cases (4.2%) PPD converted from negative (1st year) to positive (2nd year) and in 78 cases, the results were unreliable. Overall, BCG had injected 98.1% of subjects on the vaccination schedule. According to the results, with the passing of time, BCG vaccination dose not affect tuberculin test of schoolchildren. On the other hand, the conversion rate in PPD from negative to positive was (4.2%), which shows the high rate of tuberculosis in this region.
Farhad Salehzadeh , Shahnam Arshi and Shahram Habibzadeh , 2009. Tuberculin Skin Test (PPD) and Its’ Conversion after One Year in School Children. International Journal of Tropical Medicine, 4: 37-40.