TB, or tuberculosis, is a disease caused by bacteria called Mycobacterium tuberculosis. The bacteria can attack any part of your body, but they usually attack the lungs. TB disease was once the leading cause of death in the United States.
In the 1940s, scientists discovered the first of several drugs now used to treat TB. As a result, TB slowly began to disappear in the United States. But TB has come back. After 1984, the number of TB cases reported in the United States began to increase. More than 25,000 cases were reported in 1993. But since then the number has steadily declined to about 14,500 cases in 2004.
TB is spread through the air from one person to another. The bacteria are put into the air when a person with TB disease of the lungs or throat coughs or sneezes. People nearby may breathe in these bacteria and become infected.
People who are infected with TB do not feel sick, do not have any symptoms, and cannot spread TB. But they may develop TB disease at some time in the future. People with TB disease can be treated and cured if they seek medical help. Even better, people who have Latent TB Infection(LTBI) but are not yet sick can take medicine so that they will never develop TB disease.
This short guide answers common questions about TB. Please ask your doctor or nurse if you have other questions about TB infection or TB disease.
更多的解釋在這裡 : Tuberculosis - wikipedia