In 2012, more than one and a quarter million people died from a condition often considered a relic of the past: tuberculosis. Tuberculosis infections reached a low at the later part of the last century, but rose again with the spread of AIDS—it is one of the most common opportunistic infections—and the development of drug resistant strains of the bacterium.
Researchers estimate that one in three people in the world has the TB bacterium but does not have the disease; these people have what is known as latent TB, which is not contagious. Even when it is contagious, catching it, especially from brief contact with a stranger, is difficult. long term close contact is needed for it to spread. HIV is the biggest risk factor, with one in eight TB sufferers being HIV-positive. Smokers, malnourished people, and alcoholics are also at risk. TB susceptibility is also a side effect of certain medications.
People with tuberculosis cough up mucus or blood, get chills and fever, poor appetite and weight loss, fatigue, and night sweats Left untreated, tuberculosis can cause major complications, whether or not it ends up being fatal itself. The disease can get into the brain, resulting in meningitis, or it can spread to other organs ans disrupt their functioning. Tuberculosis that spreads from the lungs to the heart can result in a fatal condition known as cardiac tamponade, in which fluid accumulates in the area around the heart, compressing it.
Recent research has found that tuberculosis survives and spreads by taking advantage of the very mechanisms intended to shut it down and destroy it. The initial immune response to a tuberculosis infection is to isolate the bacteria in what are called granulomas. The body then extends blood vessels into these granulomas. The bacteria use these blood vessels, first, to get enough oxygen to survive, and then to escape the granulomas holding them and spread within the body. This may be what causes TB to go from latent to active. A medical approach based on preventing this blood vessel growth is being explored as a potential treatment for tuberculosis.