Tuberculosis is an infectious disease, which generally affects the lungs but can also affect other parts of the body. The disease is usually caused by the bacterium Mycobacterium tuberculosis (MTB). It is spread as an aerosol by people with active TB when they cough, spit, speak or sneeze. The classic symptoms of TB are chronic cough with blood-containing sputum, night sweats, fever and weight loss. Most infections are only latent and do not have symptoms. About 10 % of the latent infections progress to active disease which, if left untreated, kills about half of those infected.
Today an estimate of one-third of the world´s population is infected with TB. In 2016 there were more than ten million cases of active TB, which resulted in 1.3 million deaths – more than 95% occurred in developing countries.