Patients with strongly suspected or confirmed tuberculosis undergo an initial treatment period that lasts two months and consists of combination therapy with isoniazid, rifampicin, ethambutol, and pyrazinamide. These drugs may be given daily or two times per week.

How is tubercle bacilli transmitted?

M. tuberculosis is transmitted through the air, not by surface contact. Transmission occurs when a person inhales droplet nuclei containing M. tuberculosis, and the droplet nuclei traverse the mouth or nasal passages, upper respiratory tract, and bronchi to reach the alveoli of the lungs (Figure 2.2).

How long can tubercle bacilli survive outside the body?

Once coughed out by a person with TB, the bacilli can survive up to six months outside the body if they are protected from direct sunlight. Often they settle in dusty, dark areas.