• Tuberculosis (TB) disease is caused by a bacterium called Mycobacterium tuberculosis. The bacteria usually attack the lungs, but TB bacteria can attack any part of the body such as the kidney, spine, and brain.
• TB is spread through the air from one person to another. The TB bacteria are sent into the air when a person with active TB disease of the lungs or throat coughs, sneezes or speaks. People nearby may breathe in these bacteria and become infected.
• Not everyone infected with TB bacteria becomes sick. As a result, two TB-related conditions exist: latent TB infection and active TB disease.
• With latent TB, tuberculosis bacteria can live in your body without making you sick.
• 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 infection do not feel sick and do not have any symptoms. The only sign of TB infection is a positive reaction to the tuberculin skin test or special TB blood test.
• People with latent TB infection are not infectious and cannot spread TB bacteria to others. However, if TB bacteria become active in the body and multiply, the person will get sick with TB disease.
• Only about 5 to 10 percent of infected persons will develop active TB disease at some time in their lives. About half of those people who develop active TB will do so within the first two years of infection.
• TB bacteria become active (multiplying in your body) if the immune system can’t stop them from growing.
• Active TB symptoms may include:
- a bad cough that lasts three weeks or longer
- pain in the chest
- coughing up blood or sputum
- weakness or fatigue
- weight loss
- no appetite
- sweating at night
• The risk of transmission increases with longer and closer contact to the person with the active disease.
• Some people develop TB disease soon after becoming infected (within weeks) before their immune system can fight the TB bacteria. Other people may get sick years later, when their immune system becomes weak for another reason.
• Even though active TB disease can be very serious, there are effective treatments, and most individuals can recover completely.
Testing for TB
• There are two kinds of tests that can be used to help detect TB infection – the TB skin test (TST) and special TB blood tests.
• The TB skin test is performed by injecting a small amount of fluid (called tuberculin) into the skin in the lower part of the arm. A person given the tuberculin skin test must return within 48 to 72 hours to have a trained health care worker look for a reaction on the arm.
• The special blood tests measure how the immune system reacts to the bacteria that cause TB. Only one visit is required to draw blood for the test. The QuantiFERON®-TB Gold test (QFT-G) and T-SPOT®.TB test are two examples of special TB blood tests.
• A positive TB skin test or TB blood test only indicates that a person has been infected with TB bacteria. It does not tell whether or not the person has progressed to TB disease.
• Other tests, such as a chest X-ray, are needed to see whether the person has TB disease.
Who should get tested for TB
• Persons can get tested for TB by visiting their doctor or local health department.
• Persons should get tested if they have spent time with a person known or suspected to have active TB; have an HIV infection that weakens their immune system; have symptoms of active TB disease; are from a country where active TB disease is very common (most countries in Latin America and the Caribbean, Africa, Asia, Eastern Europe, and Russia); or live somewhere in the United States where active TB disease is more common, such as a homeless shelter, migrant farm camp, prison or jail, or some nursing homes.
Treatment for Latent TB
• People with latent TB infection have TB germs in their bodies, but they are not sick because the germs are not active. They are often prescribed treatment to prevent them from developing TB disease.
• Usually, only one drug is needed to treat latent TB infection. The medicine usually taken for the treatment of latent TB infection is called isoniazid (INH).
• Taking INH for nine months is the preferred regimen. INH kills the TB bacteria that are in the body.
Treatment for Active TB
• A person with active TB disease can be treated by taking several drugs for six to 12 months.
• There are 10 drugs currently approved by the U.S. Food and Drug Administration (FDA) for treating TB.
• Of the approved drugs, the first-line anti-TB agents that form the core of treatment regimens include:
• isoniazid (INH)
• rifampin (RIF)
• ethambutol (EMB)
• pyrazinamide (PZA)
• BCG (bacille Calmette-Guerin) is a vaccine for TB disease.
• This vaccine is not widely used in the United States, but it is often given to infants and small children in other countries where TB is common.
• The BCG vaccination may cause a false-positive reaction to the tuberculosis skin test, which may complicate decisions about prescribing treatment.
• Blood tests to detect TB infection, unlike the tuberculosis skin test, are not affected by prior BCG vaccination and are much less likely to give a false-positive result.
• The BCG vaccine does not always protect people from getting TB.
Global TB Statistics
• One-third of the world’s population is infected with TB.
• Each year, nearly nine million people around the world become sick with TB.
• Each year, there are almost two million TB-related deaths worldwide.
• Nearly 14,000 active TB cases were reported in the United States in 2006.
• There were 646 deaths from TB in the United States in 2005