TB Infection

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

TB bacteria can live in the body without making you sick. This is called 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 TB infection:

• Have no symptoms
• Don’t feel sick
• Can’t spread TB bacteria to others
• Usually have a positive TB skin test reaction or positive TB blood test
• May develop TB disease if they do not receive treatment for latent TB infection

Many people who have TB infection never develop TB disease. In these people, the TB bacteria remain inactive for a lifetime without causing disease. But in other people, especially people who have a weak immune system, the bacteria become active, multiply, and cause TB disease.