How Tubercle Bacilli Spread?

Infection spreads primarily by the respiratory route directly from an infected person who discharges live bacilli into the air. Minute droplets ejected by sneezing, coughing, and even talking can contain hundreds of tubercle bacilli that may be inhaled by a healthy person.

How is tubercle bacilli transmitted?

Infectious droplet nuclei are generated when persons who have pulmonary or laryngeal TB disease cough, sneeze, shout, or sing. TB is spread from person to person through the air. The dots in the air represent droplet nuclei containing tubercle bacilli.

How does tuberculosis multiply?

Persons become infected with TB when they inhale droplet nuclei that contain tubercle bacilli and the bacilli begin to multiply in the small air sacs of the lungs. A small number of bacilli enter the bloodstream and spread throughout the body.