Tuberculosis is a bacterium that typically affects the lungs, but can affect any part of the body such as the kidney, spine, and brain. Not everyone infected with TB bacteria becomes sick. These conditions are known as latent TB and TB disease. If not treated properly, TB disease can be fatal. 


The bacteria spreads through the air from one person to another. TB bacteria is dispersed in the air when people with TB disease of the lungs or throat cough, speaks, or sing. Individuals 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

People with TB disease are most likely to spread it to people they spend time with every day. This includes:

  • Family members
  • Friends
  • Coworkers
  • Schoolmates

Difference between Latent TB Infection and TB Disease

Latent TB infection is when the bacteria lives in the body, but it does not make you sick. Typically, people with latent TB infection do not have symptoms, can’t spread TB bacteria to others, will usually have a positive TB skin test or positive TB blood test, and may possibly develop TB disease if they do not receive treatment.

TB disease becomes active if the immune system cannot stop the bacteria from multiplying. People with TB disease are sick. People with the infection may be able to spread the bacteria to others.

Signs & Symptoms 

Symptoms of TB disease can vary depending on where in the body the TB bacteria are growing. TB bacteria typically grows in the lungs. Here are some signs and symptoms of TB disease in the lungs

  • A bad cough that lasts 3 weeks or longer
  • Pain in the chest
  • Coughing up blood or sputum (phlegm)

Other symptoms include

  • Weakness or fatigue
  • Weight loss
  • No appetite
  • Chills
  • Fever
  • Sweating at night

Symptoms in other parts of the body depend on the area affected.

TB Risk Factors

Some people develop TB disease soon after becoming infected (within weeks). Other people may get sick years later. Usually, people at high risk for developing TB disease have recently been infected with TB bacteria or have medical conditions that weaken the immune system.


In many countries, TB is more prevalent than in the United States. If traveling outside of the U.S., travelers should avoid prolong contact with known TB patients in crowded, poorly ventilated enclosed environments such as clinics, hospitals, prisons, or homeless shelters.


If you believe you have symptoms of TB, please seek medical care immediately.