TAG 2010 Pipeline Report
the TB bacilli enter the lung, the immune system sends cells to contain the bacteria and trap it in immunological prisons called granuloma. When this happens, TB does something that science has yet to fully understand–it changes its diet and stops and/ or significantly slows down replication. At this point, TB is in latency. Most people latently infected with TB are able to maintain this state for the rest of their lives. Despite the ease of transmission and the fact that one third of the world’s population—2 billion people—is latently infected with TB, the disease is a disproportionately low priority on the global health agenda, as manifested by the lack of political will, meager funding, and inadequate progress against the disease. The majority of people infected with latent TB infection (LTBI) are able to contain the bacilli from causing symptoms and pose no risk of infecting others. However, annually, approximately 10% of those with LTBI go on to develop active TB disease. In 2008, an estimated 9.4 million people developed active TB disease (WHO 2009). Little is known about what triggers LTBI to progress to active TB disease but once TB is able to break out of its immunological prison, it is considered to have progressed to active TB disease. Children under the age of five, and people who are malnourished and/or immune-compromised are at increased risk of disease progression. In most cases, active TB disease develops in the lungs, but it can also manifest in other parts of the body (extrapulmonary TB)—which is much more common in infants, young children and people with HIV. TB is a preventable and curable disease. Yet it is a killer, especially for pregnant women, children, people with HIV, and others who are malnourished or suffer from immune suppression. In 2008, TB claimed the lives of 1.82 million people, of which 500,000 occurred among people infected with HIV, making it the leading cause of death for people with HIV (WHO 2009). These data reveal TB control efforts are failing, and that the Millennium Development Goal (MDG) to halt and reverse the incidence of TB by 2015, and eliminate it as a public health threat by 2050 will not be met. In 2008, the case detection rate for all forms of TB was only 61%, and the treatment success rate for reported TB cases in 2007 reached 86%—the first time this indicator has met the 85% target set by the World Health Assembly in 1991 (WHO 2009). Despite the availability of drugs to treat and cure up to 95% of drug-susceptible TB cases—control efforts are weakened by concurrent HIV in Africa, soaring multidrugresistant (MDR) TB rates in the former Soviet Union, and weak health systems almost everywhere.
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