What is tuberculosis (TB)?
Tuberculosis, or TB, is primarily an airborne disease caused by the bacteria, M. tuberculosis. The bacteria are spread through the air and usually infect the lungs, but can also infect other parts of the body as well.
One-third of the world’s population, nearly 2 billion people, is infected with M. tuberculosis, the TB bacterium. Although TB was once the leading cause of death in the United States, cases of TB declined rapidly in the 1940s and 1950s, once scientists discovered the first of several drugs used to treat the disease. Today, the incidence of TB in the U.S. is the lowest ever. However, case rates among foreign born persons living in the U.S. now accounts for most of the reported cases.
TB can be spread when a person with active pulmonary TB disease coughs, sneezes, talks, sings or laughs. Only people with an active pulmonary infection are contagious. Most people who breathe in TB bacteria are able to fight the bacteria and stop it from growing. The bacterium becomes inactive in these individuals, and is referred to as a latent TB infection. Approximately 10% of the U.S. population has latent infection.
Although the bacteria are inactive, they still remain alive in the body, and can become active later. Some people can have a latent TB infection for a lifetime, without it ever becoming active and developing into TB disease. However, TB can become active if the immune system becomes weakened and cannot stop them from growing. This is when the latent TB infection becomes a TB disease.
How do I know if I should get tested for tuberculosis (TB)?
If you feel that you should be tested, a skin test will determine if you have a latent TB infection. There is also a blood test available to determine infection with TB. You should consider a skin test or blood test if:
- You are a resident or employee in group settings where the risk is high (i.e. correctional facilities, hospices, skilled nursing facilities and other healthcare facilities).
- You work in a mycobacteriology laboratory.
- You have been in contact with a person known or suspected to have TB disease.
- Your body’s resistance to illness is low, due to aging, malnutrition, HIV or other conditions that weaken the immune system.
- You think you might already have TB disease and are experiencing symptoms that are characteristic of TB disease.
- You are from a country or lived in a country where TB disease is prevalent, such as Africa, Asia, Eastern Europe, Russia, the Caribbean, and most countries in Latin America.
- You live or have been present in a facility where TB is common, such as in a crowded shelter, prison, and/or long-term care facility.
- You have used injected illicit drugs.
What are the symptoms of tuberculosis (TB)?
Those people with inactive TB do not exhibit symptoms; however, they may have a positive skin reaction test. The tuberculin skin test has low specificity but three are newer tests that are more specific for M. tuberculosis. The CDC has recently established guidelines for these new blood tests.
Those with TB disease, however, can exhibit any of the following symptoms: