Tuberculosis (also known as TB) is a serious and chronic condition that affects the lungs. It can also affect other areas such as the spine, brain, kidneys, and intestines. It is caused by a bacteria called Mycobacterium tuberculosis. About 11,500 people in the United States get TB every year. How does TB spread? TB spreads when an infected person coughs, sneezes, speaks and infected droplets are released into the air which other people are exposed to. Once a person has been infected, they will usually experience chest pain, chills, fever, coughing which may have blood in it, and fatigue.