Tuberculosis (TB) is an infection caused by bacteria that can infect the lungs, bones, and other body parts. The TB bacteria are spread through the air on tiny drops of fluid that spread when a person with active TB coughs or sneezes. Generally, it takes a significant amount of close contact for TB to spread from one person with active TB to another. TB can be prevented, treated, and cured.
Latent TB
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 do not have any symptoms and cannot spread TB. If they do not get treatment, however, they may develop active TB disease in the future, spread the disease to others, and feel quite ill.
Active TB
Active TB disease means the TB bacteria are actively multiplying in your body making you sick. TB can occur anywhere in the body, but for most people, it will infect the lungs. People with active TB disease in the lungs can spread the infection to others.
Symptoms and Testing
People with active TB disease in the lungs may have:
- A bad cough lasting 3 weeks or longer
- Chest pain
- Cough up blood or sputum
- Weakness or fatigue
- Weight loss
- No appetite
- Chills
- Fever
- Sweating at night
A positive TB skin test or TB blood test only tells that a person has been infected with TB bacteria. It does not tell whether the person has latent or active TB. Other tests, such as a chest X-ray and a sputum sample, are needed to determine if a person has active TB.
Frequently asked questions
This is an accordion element with a series of buttons that open and close related content panels.
What do I do next if I was exposed to active TB?
If you were exposed to someone with active TB, you should get a TB skin test or special TB blood test.
If you test positive for TB, follow the advice of your health care provider on next steps.
One threshold referenced by the CDC for estimating risk of TB exposure includes more than 120 hours of exposure per month without a mask to be considered a contact.
Will I be able to travel if I was exposed to active TB?
If you test negative for active TB, you may travel. Those who are infectious with active TB should postpone all travel by commercial airplane until they are no longer ill. A person with latent TB cannot spread the bacteria to others right away. Only those who develop active TB can spread the bacteria to others.
Does wearing a mask help prevent the spread of TB?
Yes. Because TB bacteria are spread through the air by tiny droplets of fluid, mask wearing helps prevent the spread of TB. The respiratory droplets from an infected person are trapped within their mask. Masks also act as a barrier to protect the wearer from inhaling droplets released by other people.
Do I need to quarantine if I was exposed to active TB?
No. If you have been exposed to someone with active TB, you should get a TB skin test or special TB blood test. If you test positive for TB, follow the advice of your health care provider on next steps.
Where can I find out more?
Learn more about tuberculosis: