Overview
In 1993, the World Health Organization (WHO) declared tuberculosis (TB) to be a global health emergency. Today, TB remains one of the world's major causes of illness and death. About one-third of the world's population, or two billion people, carry the TB bacteria, although most never develop active TB disease. An infectious disease, TB has been on the rise since the 1980s, with its spread concentrated in Asia and Africa. Much of TB's resurgence is directly connected to the HIV/AIDS pandemic -- especially in Africa where HIV is the most important factor determining the increased incidence of TB. Global access to TB treatment is improving but remains low and the emergence of drug-resistant TB, particularly in settings where many TB patients are also infected with HIV, poses a serious threat to TB control, and confirms the need to strengthen prevention and treatment efforts.
Frequently asked questions
State of the Pandemic
There were more than 9 million new cases of TB, and approximately 1.8 million deaths from the disease in 2007, the most recent year for which data are available. The World Health Organization estimates that there are 13.7 million people living with TB. In 2007, out of an estimated 9.3 million new TB cases worldwide, 1.4 million were among people living with HIV and there were 500,000 cases of multi-drug resistant TB (MDR-TB). Of the estimated 1.8 million people who died of TB in 2007, 26% were co-infected with HIV. The U.N. Millennium Development Goals include targets to halve the 1990 TB prevalence and death rates by 2015.
Most TB cases occur in Asia and Africa. More than half of the estimated number of new TB cases in 2007 occured in Asia, but the estimated incidence per capita is highest in Africa. In addition, Africa has the highest mortality per capita, with HIV leading to rapid increases in TB incidence in the region.
TB and HIV/AIDS form a lethal combination, each speeding the other's progress. Because HIV weakens the immune system, people with HIV are more likely to become infected with TB and someone who is HIV/TB co-infected is many times more likely to become sick with TB than someone infected with TB who is HIV-negative. TB is a leading cause of death among people who are HIV-positive. In Africa, HIV is the single most important factor determining the increased incidence of TB over the past 10 years.
Directly observed treatment, short course, or DOTS, has been the internationally recommended strategy to control TB. DOTS is a means of detecting TB cases and treating patients already infected with TB, and aims to decrease TB-related morbidity and prevent new infections, the development of drug resistance, and TB deaths. Worldwide, DOTS programs reported 2.6 million new TB cases through lab testing in 2007, a case detection rate of 63%, and the success rate for DOTS treatment was 85% in 2006, which was the global target for treatment success first set in 1991. DOTS is a major component of the WHO’s "Stop TB Strategy" announced in 2006.
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