Pulmonary tuberculosis. Coloured frontal 3D computed tomography (CT) scan of the lungs of a patient with tuberculosis (TB), showing scarring and granuloma in the lung apices due to chronic pulmonary tuberculosis infection. The pleura in the right lung (left) have been digitally removed. TB is caused by infection with Mycobacterium tuberculosis bacteria. It is spread by the inhalation of droplets coughed or sneezed by an infected person. Symptoms of tuberculosis include blood-containing sputum, fever, night sweats and weight loss.