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Tuberculosis (TB) - Topic Overview

Tuberculosis (TB) is an infection caused by slow-growing bacteria that grow best in areas of the body that have lots of blood and oxygen. That's why it is most often found in the lungs. This is called pulmonary TB. But TB can also spread to other parts of the body, which is called extrapulmonary TB. Treatment is often a success, but it is a long process. It usually takes about 6 to 9 months to treat TB. But some TB infections need to be treated for up to 2 years.

Tuberculosis is either latent or active.

  • Latent TB means that you have the TB bacteria in your body, but your body's defenses (immune system) are keeping it from turning into active TB. This means that you don't have any symptoms of TB right now and can't spread the disease to others. If you have latent TB, it can become active TB.
  • Active TB means that the TB bacteria are growing and causing symptoms. If your lungs are infected with active TB, it is easy to spread the disease to others.

Pulmonary TB (in the lungs) is contagious. It spreads when a person who has active TB breathes out air that has the TB bacteria in it and then another person breathes in the bacteria from the air. An infected person releases even more bacteria when he or she does things like cough or laugh.

If TB is only in other parts of the body (extrapulmonary TB), it does not spread easily to others.

Some people are more likely than others to get TB. This includes people who:

  • Have HIV or another illness that weakens the immune system.
  • Have close contact with someone who has active TB, such as living in the same house as someone who is infected with TB.
  • Care for a patient who has active TB, such as doctors or nurses.
  • Live or work in crowded places, such as prisons, nursing homes, or homeless shelters, where other people may have active TB.
  • Have poor access to health care, such as homeless people and migrant farm workers.
  • Abuse drugs or alcohol.
  • Travel to or were born in places where untreated TB is common, such as Latin America, Africa, Asia, Eastern Europe, and Russia.

It is important for people who are at a high risk for getting TB to get tested once or twice every year.

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