TB is caused by a bacterium called Mycobacterium tuberculosis. Most people who develop TB will have it in their lungs, but the TB bacteria can attack any part of the body.
A person must spend a lot of time or have close contact with a person with TB to become infected. TB bacteria spreads from one person to another through the air when a person with active TB:
Others nearby may then breathe in these bacteria and become infected.
All people infected with TB will experience latent TB infection, but only some people infected with TB will develop active TB disease. People are at highest risk of developing active TB disease when they:
A person with latent TB infection:
Active TB occurs when a person’s immune system is unable to prevent the development of the disease. A person with active TB disease:
Special thanks to Tacoma-Pierce County Health Department for adaptation of materials.