TB Basics | Vermont Department of Health
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TB Basics
Tuberculosis
TB Basics
TB Testing and Diagnosis
Treatment for LTBI and TB
Resources for Health Care Professionals and Partners
Tuberculosis (TB) is caused the bacterium
Mycobacterium tuberculosis
. It spreads from person to person through the air. The germs enter the air when a person with active TB disease of the lungs or throat coughs, sneezes, or sings. People who breathe in air containing the germs can become infected. A person is more likely to become infected with TB if they have had repeated or prolonged contact with a person with active TB disease.
The bacteria usually attack the lungs, but TB bacteria can attack any part of the body such as the kidneys, spine, lymph nodes, and brain. Not everyone infected with TB bacteria becomes sick. Many people with healthy immune systems can fight off TB germs and not get sick. As a result, two TB-related conditions exist:
latent TB infection (LTBI)
and
active TB disease
. If not treated properly, TB disease can be fatal. There are safe and effective treatments to cure both TB infection and TB disease.
Important Links
Testing and Diagnosis
Treatment
Preventing Exposure while Traveling Abroad
Tuberculosis (CDC)
Latent TB Infection and TB Disease
Not everyone infected with TB bacteria becomes sick.
People with
latent TB infection
(LTBI) have live TB bacteria in their body, but their immune system can fight the germs and prevent them from multiplying. The germs are considered inactive. People with LTBI do not feel ill and do not have symptoms of TB disease. They cannot spread the infection to others.
While some people can live their whole life with LTBI, others will develop TB disease if their body is no longer able to prevent the TB germs from multiplying. When this happens, the germs become active and make the person sick. This can occur months or years after infection. Treatment for LTBI is available. People can take medication to prevent them from ever progressing to TB disease.
Learn more about latent TB infections
People with
active
TB disease
have live bacteria in their body that are multiplying and causing disease. People with active TB disease are usually sick and have TB symptoms. The types of symptoms a person has depends on which part of their body is affected. TB disease of the lungs is the most common, but TB can affect any part of the body. People with TB disease in their lungs or throat can spread the infection to others. People with TB disease, regardless of the site of disease, require treatment. Without treatment, the condition can be fatal. With the appropriate treatment, TB disease can be cured.
Learn more about active TB disease (CDC)
Comparing LTBI and TB Disease
Latent TB Infection (LTBI)
Active TB Disease
A small amount of TB germs are in the person’s body that are alive but inactive
A large amount of active TB germs are in the person’s body
Does not feel sick, has no symptoms
Usually feels sick and has
symptoms
that may include:
•    a bad cough that lasts 3 weeks or longer
•    pain in the chest
•    coughing up blood or sputum (mucus from deep in the chest)
•    weakness or fatigue
•    no appetite
•    chills
•    fever
•    night sweats
•    other symptoms depending on the site of disease
Cannot spread the germs to others
Can spread the germs to others
Usually has a positive skin or blood test indicating TB infection
Usually has a positive skin or blood test indicating TB infection
Has a normal chest x-ray
May have an abnormal chest x-ray
Will have negative TB culture results from sputum (mucus from deep in the chest) or other sample from the body
May have positive TB culture result from sputum (mucus from deep in the chest) or other sample from the body
Should consider treatment for LTBI to prevent active TB disease
Needs treatment for active TB disease
Who is at higher risk for TB?
While anyone can develop a TB infection, some people have a higher risk for developing TB disease.
See a table
of indications that make someone at higher risk for developing TB.
Additional Resources
Tuberculosis: Get the Facts!
What Parents Should Know about Tuberculosis
Questions and Answers about Tuberculosis (CDC)
Topics:
Infectious Diseases
June 25, 2025