Tuberculosis, or TB, is a disease spread through the air from 1 person to another. To contract TB, a person must be exposed to someone with the disease in an enclosed space for a prolonged period of time. TB germs are spread when someone with TB disease of the lung coughs, speaks, laughs, sings or sneezes.
TB germs can live in your body without making you sick; this is called a latent TB infection (LTBI). Someone with a latent TB infection may have been exposed to the disease at some point, but has not yet developed TB disease. Patients with latent tuberculosis are not contagious - it is not possible to get TB from someone with latent tuberculosis infection. TB disease is usually in the lungs but can also attack other parts of the body such as the kidneys, brain or spine. When TB disease is in the lungs patients are contagious to other people. Many years can pass from the time of exposure to the development of active TB.
Although anyone can be exposed to this disease, certain individuals are at higher risk for exposure including health care professionals, the homeless and people who were born in countries with high TB rates. Children younger than age 4, elderly people and individuals with HIV or AIDS are also more likely to develop TB disease because their bodies are less able to fight off infections.