Tuberculosis (TB) is caused by a bacterium called Mycobacterium tuberculosis. The bacteria usually attack the lungs, but TB bacteria can attack any part of the body such as the kidney, spine and brain. Not everyone infected with TB bacteria becomes sick. As a result, two TB-related conditions exist: latent TB infection (LTBI) and TB disease. If not treated properly, TB disease can be fatal.
 

TB bacteria spread through the air from one person to another. When a person with TB disease of the lungs or throat coughs, speaks or sings. TB bacteria can get into the air. People nearby may breathe in these bacteria and become infected.
 

Symptoms of TB disease depend on where in the body the TB bacteria are growing. TB bacteria usually grow in the lungs (pulmonary TB). TB disease in the lungs may cause symptoms such as

• a bad cough that lasts 3 weeks or longer

• pain in the chest

• coughing up blood or sputum (phlegm from deep inside the lungs) Other symptoms of TB disease are

• weakness or fatigue

• weight loss

• no appetite

• chills

• fever

• sweating at night
 

Symptoms of TB disease in other parts of the body depend on the area affected.