Tuberculosis (TB) is a contagious bacterial infection caused by Mycobacterium tuberculosis that primarily affects the lungs and is spread through the air from person to person by droplets. You can become infected by inhaling these droplets when an infected person coughs, sneezes, speaks, sings, or laughs.
Nearly one-third of the world's population is infected with tuberculosis. In 2013, 9 million people worldwide became sick with TB disease. In the United States, 9,582 cases were reported with the highest rates among people with HIV and those born in countries were tuberculosis is common. Overall, the number of cases in the U.S. is decreasing. Anyone can get tuberculosis, but your risk increases if you have close or prolonged contact with a person with active TB disease or if you have a health problem that weakens your immune system.
Tuberculosis can remain inactive in your body, a condition known as latent tuberculosis infection (LTBI). You are not sick or contagious with latent tuberculosis. However, without treatment about 5% to 10% of people with latent TB will develop active TB disease. With active TB disease you become very sick, contagious and you must be isolated. Students with active TB disease put at risk their grades, enrollment, friends and classmates.
Symptoms of active tuberculosis disease include:
- Fever for several weeks (temperature over 100°F or 37.7°C)
- A bad cough that lasts 3 weeks or longer
- Chest pain
- Coughing up blood
- Unexplained weight loss and wasting
- Night sweats (soaking nightclothes and bedding and not related to room heat or blankets)
- Weakness and unusual tiredness
Tuberculosis can be diagnosed two ways. The first is a blood test called interferon gamma release assay, for example the QuantiFERON-TB Gold. Results are generally available within several days. The second is the tuberculin skin test, which takes 48-72 hours and a return visit for the reading. If either of these tests indicate TB infection, a chest x-ray is the next step.
To prevent TB, avoid contact with people who have active TB disease. Persons with active TB disease must be isolated and treated with specific antibiotics. Healthcare workers must follow TB control plans. Bacille Calmette-Guèrin (BCG) is a vaccine for tuberculosis, but it is not used in the United States because it does not completely prevent tuberculosis. In countries where TB is common, BCG is often given to infants and small children.
If you discover you have latent tuberculosis, you can treat the infection with several months of antibiotics. It's important to stay in touch with your health care provider during treatment to make sure your blood and liver function remains normal.
Active tuberculosis disease is also treated with antibiotics, based on the culture and sensitivity of the bacteria. Often, more than one drug is needed. You must take them according to a strict schedule for several months. You will be isolated from other people for several weeks until you are no longer contagious. Throughout all the contagious time, the person with tuberculosis disease must not attend class or social events.
If you have active or latent tuberculosis, keep your medical appointments and take medications exactly as prescribed. Also, remember that you can be infected with tuberculosis more than once in your life so pay attention to symptoms.