Untreated active TB disease can spread to other parts of the body, where it can lead to serious or life-threatening complications. TB that infects the bone, for example, can cause severe pain, abscesses, and joint destruction.
The most serious complication, however, is the recurrence of TB after the initial infection and the development of drug-resistant strains of the disease.
How it Spreads
TB germs are put into the air when a person with TB disease of the lungs or throat coughs, sneezes, speaks, or sings. These germs can stay in the air for several hours, depending on the environment. Persons who breathe in the air containing these TB germs can become infected; this is called latent TB infection.
Since TB is spread through the air, people cannot get infected with TB bacteria through handshakes, sitting on toilet seats, or sharing dishes and utensils with someone who has TB.