Tuberculosis epidemiology in India: a review.

High prevalence and incidence of disease and a high rate of transmission of infection characterise the tuberculosis (TB) situation in India. Disease surveys conducted in different parts of the country since the 1950s have reported prevalences of smear-positive pulmonary TB (PTB) of 0.6-7.6 per 1000 population, culture-positive TB of 1.7-9.8 and culture and/or smear-positive TB of 1.8-12.7. The incidence of smear-positive PTB has been observed in the range of 1.0-1.6/1000 and that of culture-positive PTB 1.0-2.5/1000 in the limited number of studies carried out. The annual risk of tuberculous infection (ARTI) had been estimated at 1-2% for most of the tuberculin surveys carried out in different areas over different time periods. During a nationwide study in 2000-2003, the average ARTI in the country was estimated at 1.5%. An increasing trend has been observed in human immunodeficiency virus (HIV) seropositivity among TB cases, which has been found to vary between 0.4% and 28.8% in different studies conducted mostly at tertiary health care centres. The proportion of new cases with multidrug resistance (MDR) was relatively low, at 0.5-5.3%. However, the proportion of MDR cases among previously treated cases varied between 8% and 67%.