Tuberculosis (TB) is a serious infectious disease that mainly affects the lungs and it is caused by bacteria (Mycobacterium tuberculosis). The bacteria responsible for tuberculosis is spread from one person to another through tiny droplets released into the air via cough and sneeze. Tuberculosis can be fatal when it is untreated. Untreated active disease typically affects the lungs, and it can spread to other parts of the body through the blood stream. Complications of tuberculosis include spinal pain, joint damage, swelling of the membranes that cover the brain, liver or kidney problems and heart disorders. People diagnosed with active TB disease generally have to take a combination of medications for six to nine months. A significant number of TB patients develop post tubercular airway disease or TB-associated COPD.