Global burden of tuberculosis - Estimated incidence, prevalence, and mortality by country

Objective To estimate the risk and prevalence of Mycobacterium tuberculosis (MTB) infection and tuberculosis (TB) incidence, prevalence, and mortality , including disease attributable to human immunodeficiency virus (HIV), for 212 countries in 1997. Participants A panel of 86 TB experts and epidemiologists from more than 40 countries was chosen by the World Health Organization (WHO), with final ag reement being reached between country experts and WHO staff. Evidence Incidence of TB and mortality in each country was determined by (1 ) case notification to the WHO, (2) annual risk of infection data from tube rculin surveys, and (3) data on prevalence of smear-positive pulmonary dise ase from prevalence surveys, Estimates derived from relatively poor data we re strongly influenced by panel member opinion. Objective estimates were de rived from high-quality data collected recently by approved procedures, Consensus Process Agreement was reached by (1) participants reviewing metho ds and data and making provisional estimates in dosed workshops held at WHO 's 6 regional offices, (2) principal authors refining estimates using stand ard methods and all available data, and (3) country experts reviewing and a djusting these estimates and reaching final agreement with WHO staff. Conclusions In 1997, new cases of TB totaled an estimated 7.96 million (ran ge, 6.3 million-11.1 million), including 3.52 million (2.8 million-4.9 mill ion) cases (44%) of infectious pulmonary disease (smear-positive), and ther e were 16.2 million (12.1 million-22.5 million) existing cases of disease. An estimated 1.87 million (1.4 million-2.8 million) people died of TB and t he global case fatality rate was 23% but exceeded 50% in some African count ries with high HIV rates, Global prevalence of MTB infection was 32% (1.86 billion people). Eighty percent of all incident TB cases were found in 22 c ountries, with more than half the cases occurring in 5 Southeast Asian coun tries, Nine of 10 countries with the highest incidence rates per capita wer e in Africa. Prevalence of MTB/HIV coinfection worldwide was 0.18% and 640 000 incident TB cases (8%) had HIV infection. The global burden of tubercul osis remains enormous, mainly because of poor control in Southeast Asia, su b-Saharan Africa, and eastern Europe, and because of high rates of M tuberc ulosis and HIV coinfection in some African countries.