Global Burden and Epidemiology of Tuberculosis
Section snippets
Incidence
The number of new TB cases per capita each year (incidence) is the central measure of progress toward the ultimate goal of eliminating TB as a public health problem (see Box 1).13 It is not feasible to measure incidence by counting cases arising in cohorts under continuous observation because such studies would require cohorts of hundreds of thousands of people. Surveys of infection using tuberculin skin testing have been used in the past to derive estimates of incidence of TB disease, but the
Incidence
The WHO estimates that 9.27 million new cases of TB occurred in 2007 (139/100,000 population), compared with 9.24 million new cases (140/100,000 population) in 2006.2 Of these 9.27 million new cases, an estimated 44% or 4.1 million (61/100,000 population) were new smear-positive cases. India, China, Indonesia, Nigeria, and South Africa rank first to fifth in the total number of incident cases (Fig. 2). Among the 15 countries with the highest estimated TB incidence rates, 13 are in Africa, a
Trends in TB case notifications and rates of case detection and treatment success
The 196 countries reporting to the WHO in 2008 notified 5.6 million new and relapse cases in 2007, of which 2.6 million (46%) were new smear-positive cases. Notifications disaggregated by sex were reported for new pulmonary smear-positive TB cases by 170 countries. Of 2.55 million notifications, 1.65 million were male and 0.9 million were female, giving a male/female ratio of 1.8 for those aged 14 years and older. One of the factors associated with the male/female ratio in smear-positive TB
Can TB be eliminated by 2050?
TB can be controlled by preventing infection, stopping progression from infection to active disease, and rapid detection and treatment of active disease.52, 53 To date, only bacille Calmette-Guérin (BCG) vaccination (provided to more than 80% of the annual birth cohort) and treatment of active TB using first-line drugs have been implemented on a large scale.54 With these interventions, global targets set for 2015 will be met in some regions, but on current trends, elimination (defined as an
Summary
Despite progress in our understanding of TB epidemiology and the availability of effective treatments, the number of new TB cases that occur each year is still rising, particularly in poor and otherwise disadvantaged populations.75 To reverse this trend and achieve global targets set for 2015 and 2050, major and urgent scaling up of the interventions and approaches included in the Stop TB Strategy is needed in most countries, combined with the successful development and application of new
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