RESUMO
Background: A nation wide tuberculin study was undertaken to estimate the Annual Risk of Tuberculous Infection (ARTI) in different parts of India. The study in the rural areas of Kota, one of the districts selected for the survey, is described in this article. Material & Methods: A total of 6264 children 1-9 years of age, residing in 64 clusters were registered into the study. The children were subjected to the standard tuberculin test using 1 TU PPD RT23 with Tween 80 procured from BCG Laboratory, Guindy and the maximum transverse diameter of the induration was measured at about 72 hours. Results: A total of 3157 children without BCG scar and 1520 with BCG scar was successfully test read. The prevalence of infection among children without BCG scar using the mirror image technique was estimated as 13.6% and the ARTI was computed at 2.6%. Using similar technique, the prevalence of infection among the entire study group-irrespective of BCG scar was estimated as 14.9% and the ARTI was computed at 2.8%. Conclusion: The findings indicate a high rate of transmission of tuberculous infection in rural areas of Kota and emphasise the need for further strengthening of tuberculosis control measures.
RESUMO
A tuberculin survey to estimate annual risk of tuberculosis was conducted in Khammam tribal district during 2001-2002. A total of 8637 children were test-read--2991 without BCG scar and 5442 with BCG scar. The tests were performed using ITU PPD RT23 and the maximum size of induration was recorded at about 72 hours after the test. Based on the frequency distribution of reaction size, cut-off point for infection with tubercle bacilli was considered at 12 mm. Using this criterion, the prevalence of infection was estimated at 11.8% among children without BCG scar and 10.6% among children with BCG scar. This difference was found to be statistically insignificant. ARTI rates computed from the prevalence estimates among children without and with BCG scar were 1.6% and 1.5% respectively. It was computed as 1.5% from the prevalence in the combined group i.e. irrespective of BCG scar status.