Facts About TB

What is tuberculosis?

Tuberculosis (TB) is a disease caused by TB bacteria that are spread through the air. TB usually affects the lungs, but can affect lymph nodes, bones, joints, and other parts of the body.


Symptoms of TB disease in the lungs include coughing, with or without blood, and chest pain. General symptoms of TB disease also include fever, night sweats, weight loss and tiredness. Symptoms of TB disease in other parts of the body depend on what area is affected. Some people with TB disease have no symptoms.

Who gets tuberculosis?

Tuberculosis can infect anyone. Certain people may be at increased risk for exposure to TB bacteria including:

  • Close contacts of someone who has infectious TB disease, People who are from, or frequently travel to, areas of the world where TB is more common.

People, infected with TB, may also have an increased risk of developing TB disease including:

  • People with weakened immune systems, including: young children, people with HIV/AIDS, and the elderly. Other medical risks include: diabetes mellitus, prolonged corticosteroid therapy or other immunosuppressive therapy, cancer, silicosis and being 10 percent or more below ideal body weight.
  • People who live or work in a setting where there is more possible exposure to TB (homeless shelters, correctional facilities, nursing homes, etc.).


How does TB spread to others?

TB is spread through the air when a person with TB disease of the lungs or throat coughs or sneezes. The TB bacteria may get into the air and be breathed in by others. Prolonged exposure is normally necessary for infection to occur. If infection does occur the person exposed will most likely not develop disease; only in rare cases does the person exposed quickly develop disease right after being infected.

The difference between latent TB infection and TB disease

Latent tuberculosis infection (LTBI) may result after being exposed to a person who has infectious TB disease in the lungs or throat. A person with LTBI does not feel sick or have symptoms of TB. They cannot spread TB to others. LTBI may last a lifetime without developing into TB disease. However, without preventive treatment, LTBI may develop into TB disease. A person with TB disease in the lungs or throat usually has symptoms and can infect others. Medications are given to the person to treat TB disease.

If you are around a person with TB

A person with LTBI is not contagious and cannot infect others. You do not need to be tested for TB if you have spent time with someone with LTBI. However, people with TB disease in the lungs or throat may be infectious. People with TB disease are most likely to infect people they spend time with every day, such as family members or coworkers. If you have been around someone with TB disease in the lungs or throat, you should contact your health care provider or local health department for more information on if you should get tested for TB.

Testing and diagnosis

A positive TB skin test or TB blood test only indicates that a person has been infected with TB bacteria; it cannot tell whether the person has LTBI or is sick with TB disease. A chest x-ray, a sample of sputum, and possibly other tests, are needed to diagnose TB disease.

Who should get tested for TB?

TB tests are generally not needed for people with no risk of infection from TB bacteria; however, some people should be tested because they are more likely to get TB disease. People who should be tested include:

  • People who have been in close contact with someone who has infectious TB disease.
  • People with HIV infection or another medical problem that weakens the immune system or before taking prescribed medication that intentionally suppresses the immune system.
  • People who have symptoms of TB disease (fever, night sweats, cough, and weight loss).
  • People who have lived or worked in a country where TB disease is common (includes any country other than the United States, Canada, Australia, New Zealand, or a country in western or northern Europe).


If you think you may need to get tested for TB, or want more information, talk to your health care provider or local health department, and find out where to get tested for TB.


If you have LTBI but not TB disease, your physician may want you to take medication to prevent you from developing TB disease. People with LTBI should be evaluated to determine the need for preventive therapy based on their individual risk of developing TB disease and other medical conditions.

If you have TB disease you must complete a course of treatment, which consists of taking several medications exactly as prescribed by a physician. Along with taking medications the physician may also perform follow-up laboratory tests to monitor treatment effectiveness. It is important for people being treated for TB disease to take all of their medication as prescribed to prevent sickness again or developing TB that is resistant to medication. Healthcare workers often watch patients take their medications. This is called directly observed therapy (DOT). DOT supports the patient through treatment completion and helps reduce complications associated with treatment.

How common is TB in Washington?

Since 2007, incidence rates of TB disease in Washington State have progressed downward. In 2018, the Washington TB case rate was 2.5 cases (per 100,000), which is significantly lower than the peak of 4.4 cases (per 100,000) seen in 2007. There were 183 cases of reported TB disease in Washington in 2018. However, an estimated 200,000 people in Washington have LTBI. Without treatment, many will develop TB disease in the future.

What is multidrug-resistant tuberculosis?

People exposed to drug-resistant TB disease, may develop multidrug-resistant tuberculosis (MDR TB). Drug resistance can also be acquired through inadequate TB treatment, like not taking medications as prescribed. How common is MDR TB? Although this is a serious threat that is causing problems in other parts of the world, it is not common in Washington State.

Treatment for multidrug-resistant tuberculosis

Advice from a TB specialist is necessary when treating MDR TB. Medication therapy can be as long as 24 months (much longer than treatment for LTBI or TB disease) and can have severe side effects, like a loss of hearing.

Preventing the spread of tuberculosis

Our public health system is responsible for stopping the spread of TB disease and identifying those exposed to TB. TB patients may need to avoid public places while they are infectious to prevent the spread of disease to others. Public health professionals conduct contact investigations to identify anyone who might have been exposed to TB disease to get them tested and treated. As a patient, the most important way to stop the spread of tuberculosis is to seek medical attention for symptoms of TB, avoid public place if you are sick, and take all medications as directed by your physician. Your local health department provides treatment for patients with TB disease through DOT of medications and monitoring of potential side effects. This ensures successful completion of treatment and prevents the spread of the disease to others.

For more information email or call the Tuberculosis Program.