• 10 - 15 million people in U.S. have TB germs and don't feel sick
• TB is not spread on dishes, drinking glasses or other objects
• TB germs get into the air through: sneezes, coughs, laughs, speaking
• TB germs are spread through the air by extended, confined contact in a poorly ventilated area

TB infection - a condition in which TB bacteria are alive but inactive in the body. People with TB infection have no symptoms, don't feel sick, can't spread TB to others, and usually have a positive skin test reaction. But they may develop TB disease later in life if they do not receive preventive therapy.

TB disease - an illness in which TB bacteria are multiplying and attacking different parts of the body. The symptoms of TB disease include weakness, weight loss, fever, no appetite, chills, and sweating at night. Other symptoms of TB disease depend on where in the body the bacteria are growing. If TB disease is in the lungs (pulmonary TB), the symptoms may include a bad cough, pain in the chest, and coughing up blood.

TB Basics

TB, or tuberculosis, is a disease caused by bacteria called Mycobacterium tuberculosis. The bacteria can attack any part of your body, but they usually attack the lungs. TB disease was once the leading cause of death in the United States.

In the 1940s, scientists discovered the first of several drugs now used to treat TB. As a result, TB slowly began to disappear in the United States. But TB has come back. After 1984, the number of TB cases reported in the United States began to increase. More than 25,000 cases were reported in 1993.

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

People who are infected with TB do not feel sick, do not have any symptoms, and cannot spread TB. But they may develop TB disease at some time in the future. People with TB disease can be treated and cured if they seek medical help. Even better, people who have TB infection but are not yet sick can take medicine so that they will never develop TB disease.

If I Have TB Infection, How Can I Keep from Developing TB Disease?

Many people who have TB infection never develop TB disease. But some people who have TB infection are more likely to develop TB disease than others. These people are at high risk for TB disease. They include

• people with HIV infection
• people in close contact with a person who has infectious TB
• people who became infected with TB bacteria in the last 2 years
• babies and young children
• people who inject drugs
• people who are sick with other diseases that weaken the immune system
• elderly people

Some persons are considered to be at high risk for TB disease because they belong to groups in which the prevalence of TB infection is higher than it is in the general population. These groups include foreign-born persons from areas with a high prevalence of TB; residents and employees of long-term institutional settings (such as nursing homes and correctional facilities); and medically underserved populations, including the poor, the homeless, high risk racial and ethnic minority groups, and injecting drug users (IDUs). Other persons include immunocompromised persons (especially those with HIV infection), persons with other medical risk factors (such as diabetes, end-stage renal disease, and being 10 percent or more below ideal body weight), and IDUs.

Sources: Centers for Disease Control and Prevention; American Lung Association; "About TB"