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Basic TB Facts

Tuberculosis (TB) is caused by a bacterium called Mycobacterium tuberculosis. The bacteria usually attack the lungs, but TB bacteria can attack any part of the body such as the kidney, spine, and brain. If not treated properly, TB disease can be fatal.  

Diagram of TB spread by sneezingHow TB Spreads

TB is spread through the air from one person to another. The TB bacteria are put into the air when a person with TB disease of the lungs or throat coughs, sneezes, speaks, or sings. People nearby may breathe in these bacteria and become infected.

TB is NOT spread by

  • shaking someone’s hand
  • sharing food or drink
  • touching bed linens or toilet seats
  • sharing toothbrushes
  • kissing

Latent TB Infection and TB Disease

Not everyone infected with TB bacteria becomes sick. As a result, two TB-related conditions exist: latent TB infection and TB disease.

Latent TB Infection

TB bacteria can live in the body without making you sick. This is called latent TB infection. In most people who breathe in TB bacteria and become infected, the body is able to fight the bacteria to stop them from growing. People with latent TB infection do not feel sick and do not have any symptoms. People with latent TB infection are not infectious and cannot spread TB bacteria to others. However, if TB bacteria become active in the body and multiply, the person will go from having latent TB infection to being sick with TB disease.

TB Disease

TB bacteria become active if the immune system can't stop them from growing. When TB bacteria are active (multiplying in your body), this is called TB disease. People with TB disease are sick. They may also be able to spread the bacteria to people they spend time with every day.

Many people who have latent TB infection never develop TB disease. Some people develop TB disease soon after becoming infected (within weeks) before their immune system can fight the TB bacteria. Other people may get sick years later when their immune system becomes weak for another reason.

For people whose immune systems are weak, especially those with HIV infection, the risk of developing TB disease is much higher than for people with normal immune systems. Learn more about the difference between LTBI and TB Disease.


TB Symptoms

Symptoms of TB disease include:

  • a bad cough that lasts 3 weeks or longer
  • pain in the chest
  • coughing up blood or sputum
  • weakness or fatigue
  • weight loss
  • no appetite
  • chills
  • fever
  • sweating at night
Man coughing

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TB Risk Factors

Once a person is infected with TB bacteria, the chance of developing TB disease is higher if the person:

  • Has HIV infection;
  • Has been recently infected with TB bacteria (in the last 2 years);
  • Has other health problems, like diabetes, that make it hard for the body to fight bacteria;
  • Abuses alcohol or uses illegal drugs; or
  • Was not treated correctly for TB infection in the past

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Testing for TB Infection

Woman receiving a skin testThere are two kinds of tests that are used to detect TB bacteria in the body: the TB skin test (TST) and TB blood tests. These tests can be given by a health care provider or local health department. If you have a positive reaction to either of the tests, you will be given other tests to see if you have latent TB infection or TB disease.

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Exposure to TB

If you think you have been exposed to someone with TB disease, contact your health care provider or local health department to see if you should be tested for TB infection. Be sure to tell the doctor or nurse when you spent time with the person who has TB disease.


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Treatment for Latent TB Infection and TB Disease

Treatment for Latent TB Infection

Male patient speaking with doctorIf you have latent TB infection but not TB disease, your health care provider may want you be treated to keep you from developing TB disease. Treatment of latent TB infection reduces the risk that TB infection will progress to TB disease. Treatment of latent TB infection is essential to controlling and eliminating TB in the United States. The decision about taking treatment for latent TB infection will be based on your chances of developing TB disease.

Treatment for TB Disease

TB disease can be treated by taking several drugs, usually for 6 to 9 months. It is very important to finish the medicine, and take the drugs exactly as prescribed. If you stop taking the drugs too soon, you can become sick again. If you do not take the drugs correctly, the germs that are still alive may become resistant to those drugs. TB that is resistant to drugs is harder and more expensive to treat.

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Related Links

For Patients
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    Division of Tuberculosis Elimination (DTBE)
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