Prevalence of tuberculosis in a rural area by an alternative survey method without prior radiographic screening of the population

Abstract

Setting: Mass miniature radiography (MMR) is the usual tool for population screening in tuberculosis case prevalence surveys. However, this facility is not available at most centres in India. Objective: The feasibility of conducting a survey without MMR screening was therefore investigated. Design: The study was carried out in Bangalore rural district during 1984–1986. The area was the same as for six earlier prevalence surveys conducted since 1961. The population aged up to 44 years was tuberculin tested. Persons with test induration size of ⩾ 10 mm were eligible for sputum examination, besides all those aged over 45 years who were eligible without discrimination. Results: Reduction of workload was not adequately achieved through screening, as 78.4% of the registered population (29 400) was still eligible for sputum examination. The changed screening procedure in this survey also made comparison with earlier data difficult. In spite of more liberal and comprehensive screening, the observed prevalence rate of cases ( 438 100 000 population aged 10+ years) was similar to earlier surveys. The prevalence rate of smear-positive cases, however, was much lower ( 68 100 000 population aged 10+ years). Conclusion: In conclusion, the candidate screening procedure was not suitable. The findings nevertheless conformed to the overall declining trend for the area, as reported earlier.