Causative Agent

Tuberculosis is an infectious bacterial disease caused by Mycobacterium tuberculosis and less commonly by other organisms of the 'tuberculosis complex'.

The bacteria may remain dormant for many years (tuberculosis infection) before showing clinical manifestations (Tuberculosis). The most important source of infection is a pulmonary TB patient, especially smear-positive and who is coughing. Coughing produces tiny infectious droplet nuclei, usually less than 5 micron in size, containing tubercle bacilli, that avoid the defenses of the bronchi and penetrate into the terminal alveoli of the lungs where multiplication and infection begin. Droplets can also spread into the air when talking, sneezing and spitting.