What is tuberculosis?
Tuberculosis (TB) is a lung disease caused by bacteria called mycobacterium tuberculosis. TB is highly contagious and can be spread through the air when people cough, sneeze or even talk. The lungs are the major site for this bacterial infection. Just because people are infected by TB does not mean they will become sick. In people with healthy immune systems, the bacteria will be walled off in the lungs and be inactive for years. People can get reactivation TB when their immune systems become weak as they age or get sick.

Even though tuberculosis (TB) can be caused by three different bacteria, the term almost always refers to the contagious, potentially fatal infection that is caused by the bacterium Mycobacterium tuberculosis. In the United States, TB usually is acquired by inhaling air that contains bacteria coughed into the air by a person with active TB. The bacteria can remain in the air for several hours.

During the course of most TB infections, the bacteria are destroyed. In fact, almost all TB infections heal without ever being noticed; there's only a slight chance of developing an active infection within 1 to 2 years. However, the bacteria can remain dormant for years. About 80% of TB infections occur after dormant bacteria become active -- for example, when the immune system is weakened, in which case the infection can be life threatening. Active TB usually begins in the lungs, and, if spread through the blood, can damage other parts of the body.

Discovery Health

Tuberculosis (TB) has ravaged human populations since ancient times. There has even been DNA evidence found of the disease in Egyptian mummies.

The European TB epidemic, which began in the 1600 and was known as the Great White Plague, rampaged for 200 years, killing an estimated one of every seven people it infected.

TB was continually a problem in colonial America. Even as late as the close of the 19th century, approximately 10 percent of all U.S. deaths were attributed to TB.

Continue Learning about Tuberculosis (TB)

Tuberculosis (TB)

Tuberculosis (TB)

Tuberculosis is a highly contagious bacterial infection of the lungs that can be spread through the air when a person speaks, coughs or sneezes. Also known as TB, symptoms of tuberculosis include fever, fatigue, chest pain and a s...

evere, chronic cough. There are different types of TB, including active tuberculosis, and meningeal and milary TB, and doctors can screen for each of these types using the tuberculin skin test or the Mantoux test. Treatment of tuberculosis usually involves several types of antibiotics, and in rare cases, surgery.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.