Rapid decline in prevalence of pulmonary tuberculosis after DOTS implementation in a rural area of South India.

SETTING

Tiruvallur District in Tamilnadu, South India, where the World Health Organization-recommended DOTS strategy was implemented as a tuberculosis (TB) control measure in 1999.

OBJECTIVE

To assess the epidemiological impact of the DOTS strategy on the prevalence of pulmonary tuberculosis (PTB).

DESIGN

Surveys of PTB were undertaken on representative population samples aged > or =15 years (n = 83000-90000), before and at 2.5 and 5 years after the implementation of the DOTS strategy. The prevalence of PTB (smear-positive/culture-positive) was estimated.

RESULTS

TB prevalence declined by about 50% in 5 years, from 609 to 311 per 100000 population for culture-positive TB and from 326 to 169/100000 for smear-positive TB. The annual rate of decline was 12.6% (95%CI 11.2-14.0) for culture-positive TB and 12.3% (95%CI 8.6-15.8) for smear-positive TB. The decline was similar at all ages and for both sexes.

CONCLUSION

With an efficient case detection programme and the DOTS strategy, it is feasible to bring about a substantial reduction in the burden of TB in the community.