Tuberculosis (TB) is an infectious disease caused by the bacillus Mycobacterium tuberculosis.
The bacteria are spread via airborne droplets when individuals with active pulmonary TB disease cough and expel the bacteria into the air. There are two types of TB conditions: latent TB infection and TB disease. Individuals with latent TB are infected, but have no clinical or radiographic evidence of active disease. Latently infected individuals do not transmit the bacteria. TB disease occurs when manifestations of pulmonary or extrapulmonary TB become apparent, either clinically or on x-ray .
Only 10% of untreated latent infected individuals will develop TB disease . The most important risk factor for developing TB disease is immunosuppression (e.g. HIV, cancers, poor nutrition, alcoholism, ageing) [1, 2, 3].
TB typically affects the lungs, although it may also affect other sites of the body (extrapulmonary TB) .