Human tuberculosis (TB) is a highly contagious bacterial infection that is passed from person to person through the air. It is usually spread through contact with an infected person who is actively coughing or talking. TB disease is caused when the bacteria multiply inside the body, causing tissue and organ damage. Without treatment, half of those with TB disease will die.
Most people know TB as a disease of the lungs. However, not all TB disease is pulmonary. Around 40% of TB disease occurs in another part of the body. This happens when the bacteria spread outside of the lungs. In these cases, TB is more difficult to diagnose since the patient does not have the normal signs and symptoms associated with pulmonary TB. TB disease can also occur in the lymph glands, brain, spine, kidneys, or other organs.
There are two forms of TB infection: Active and Latent.