Tuberculosis (TB) FAQs

What is TB?

Tuberculosis, or TB, is a preventable infectious disease caused by a bacterium called Mycobacterium tuberculosis. TB can attack any part of the body, but primarily attacks the lungs.

TB disease was once a leading cause of death in the United States. Worldwide, TB still causes more deaths than any other infectious disease.

HISTORY: During the 1940s, scientists discovered the first of many drugs used to treat TB. As a result, TB slowly began to disappear in the U.S. Unfortunately, TB infection has made a comeback in recent decades. After 1984, the number of TB cases reported in the U.S. began to increase. More than 25,000 cases were reported in 1993.

How are people tested for TB?

A healthcare provider can offer you a TB skin test if you are considered to be at high risk for getting TB. If you have a positive reaction to the skin test, your doctor or nurse may do other tests to see if you have TB disease. These tests usually include a chest x-ray and a test of the phlegm you cough up.

Because the TB bacteria may be found elsewhere besides the lungs, a doctor or nurse may check your blood or urine, or do other tests. If you are found to have TB disease, you will need to take medicine to cure it.

How is TB spread?

TB is spread through the air from one person to another. The bacteria are spread when a person with active TB disease of the lungs or throat coughs or sneezes. People nearby can breathe in the TB germs that are in the air and may become infected.

You CANNOT get TB from sharing a drinking glass with a person who has TB or touching a doorknob after someone with TB has used it. Also, once a person with TB is taking medication for treatment, he or she quickly becomes non-contagious. Additionally, once treatment has begun, he or she can quickly resume their normal life without fear of spreading TB to others.

What is active TB disease?

The presence of TB bacteria in the body can lead to active TB disease if an infected person's immune system can't stop the bacteria from multiplying. Some people develop active TB disease soon after becoming infected, before their immune system can fight the TB bacteria. Other people that carry the bacteria may become sick later in life.

Symptoms of active TB disease depend on where in the body the TB bacteria are growing and may include:

  • Bad cough lasting more than 3 weeks
  • Pain in the chest
  • Coughing up blood or sputum
  • Weakness/fatigue
  • Weight loss
  • No appetite
  • Chills, fever, night sweats
  • Usually have a positive skin test
  • May have abnormal chest x-ray and/or positive sputum smear or culture 

What is Latent TB Infection (LTBI)?

In most people who breathe in TB bacteria and become infected, the person's body is able to fight the infection and keep them from growing. The TB bacteria become dormant, and this is called latent TB infection. People with latent TB infection:

  •   Have no symptoms
  •   Don't feel sick
  •   Can't spread TB to others
  •   Usually have a positive skin screening test reaction

Many people who have latent TB infection never develop active TB disease. In these people, the TB bacteria remain in the body for a lifetime without causing disease. But, in others, especially those who have weak immune systems, the bacteria can become active and cause TB disease.

Who is at the highest risk for getting TB?

Those at highest risk for TB infection (recommended for testing) include the following populations:

  • Close personal contacts of active TB patients
  • Foreign-born individuals who have been in the U. S. less than 5 years
  • Residents and employees of prisons, hospitals, nursing homes, long-term care facilities, homeless shelters
  • HIV-positive persons
  • Patients with organ transplants and others who are immuno-suppressed (have weak immune systems)
  • Persons whose chest X-rays are consistent with TB disease
  • Injection drug users
  • Persons with clinical conditions that place them at a higher risk, including those with diabetes and chronic renal failure