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 Southeast 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.

State of the Pandemic
There were more than 9 million new cases of TB, and approximately 1.7 million deaths from the disease in 2006, the most recent year for which data are available. The World Health Organization estimates that there are more than 14 million people living with TB. In 2006, out of an estimated 9.2 million new TB cases worldwide, 4.1 million were diagnosed by laboratory testing, 710,000 were among people living with HIV and there were 500,000 cases of multi-drug resistant TB (MDR-TB). Of the estimated 1.7 million people who died of TB in 2006, 14% 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 Southeast Asia and Africa. One-third of the number of new TB cases occurs in Southeast Asia, but the estimated incidence per capita is highest in Africa. In addition, Africa has the highest number of estimated deaths due to TB and 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 an inexpensive and highly effective means of detecting TB cases and treating patients already infected with TB. DOTS aims to decrease TB-related morbidity and prevent new infections, the development of drug resistance, and TB deaths. Worldwide, 184 countries were implementing the DOTS strategy in 2006, and 93% of the world’s population was living in areas where DOTS was in place. DOTS programs reported 2.5 million new TB cases through lab testing in 2006, a case detection rate of 61%, and the average success rate for DOTS treatment was nearly 85% in 2005. DOTS is a major component of the WHO’s "Stop TB Strategy" announced in 2006.

Sources:

• WHO, Global Tuberculosis Control: Surveillance, Planning, Financing, March 2008
• WHO, Frequently Asked Questions About TB and HIV