Overview
Tuberculosis, also known as TB, is a contagious disease caused by Mycobacterium tuberculosis bacteria, affecting the lungs and other parts of the body. Most infections are latent, but a small proportion can progress to active disease, which can be fatal if left untreated. TB is spread through the air when people with active TB cough, spit, speak, or sneeze, and is more likely to become active in those with weakened immune systems.