Color enhanced thin section transmission electron micrograph (TEM) depicts the ultrastructural details displayed by a number of Gram-positive Mycobacterium tuberculosis bacilli, the causative agent for tuberculosis. These bacteria usually attack the lungs; however, tuberculosis can attack any part of the body such as the kidneys, spine, and brain. If not treated properly, TB disease can be fatal, and was once the leading cause of death in the United States. TB is spread through the air from one person to another. The bacteria are put into the air when a person with active TB disease of the lungs, or throat, coughs or sneezes. People nearby may breathe in these bacteria and become infected, but not everyone infected with TB bacteria becomes sick. People who are not sick have what is called 'latent TB infection'. People who have latent TB infection do not feel sick, do not have any symptoms, and cannot spread TB to others, but some people with latent TB infection go on to get TB disease. People with active TB disease can be treated and cured if they seek medical help. Even better, people with latent TB infection can take medicine so that they will not develop active TB disease.