Prevalence of pulmonary tuberculosis among adults in selected slums of Delhi city.

Background: A survey was carried out to estimate the point prevalence of bacteriologically positive pulmonary tuberculosis (PTB) among persons ≥15 years of age residing in Jhuggi-Jhopri (JJ) colonies - urban slums in Delhi, India implementing Directly Observed Treatment strategy since 1998.

Methods: Among 12 JJ colonies selected by simple random sampling, persons having persistent cough for ≥2 weeks at the time of the survey or cough of any duration along with history of contact/currently on ant-TB treatment/known HIV positive were subjected to sputum examination - 2 specimens, by smear microscopy for Acid Fast Bacilli and culture for Mycobacterium tuberculosis. Persons with at least one specimen positive were labelled as bacteriologically confirmed PTB. Prevalence was estimated after imputing missing values to correct bias introduced by incompleteness of data and corrected for non-screening by X-ray by a multiplication factor derived from recently conducted surveys.

Results: Of 40,756 persons registered, 40,529 (99.4%) were screened. Of them, 691 (2%) were eligible for sputum examination. Spot specimens were collected from 659 (99.2%) and early morning sputum specimens from 647 (98.1%). Using screening by interview alone, prevalence of bacteriologically positive PTB in persons ≥15 years of age was estimated at 160.4 (123.7-197.1) per 100,000 populations and210.0 (CI: 162.5-258.2) after correcting for non-screening by X-ray.

Conclusion: Observed prevalence suggests further strengthening of TB control program in urban slums.