What is tuberculosis?

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Tuberculosis, also called TB, is an infectious disease caused by a bacterium named Mycobacterium tuberculosis. TB usually involves the lungs (pulmonary TB) but can infect almost any organ in the body. TB is almost always curable with antibiotics that are readily available in countries such as the U.S.

What are the symptoms?

These symptoms usually come on gradually over a period of weeks. The most common symptoms are:

- cough, (usually for more than 3 weeks)
- coughing up blood or sputum (phlegm from deep inside the lungs)
- pain in the chest
- fatique
- weight loss
- fever
- night sweats

How is it spread?

TB spreads when someone who has pulmonary TB coughs. TB bacteria from that person's lungs are then expelled into the air, and may be inhaled into the lungs of another person. TB is not very infectious; it's much harder to catch than the common cold. Usually a lot of time needs to be spent with a person with pulmonary TB for someone to catch TB. It's not possible to get TB from sharing a glass with a person with TB or touching a doorknob after someone with TB has used it. Also, once a person with TB is on medication he or she quickly becomes non-contagious. People on medication can quickly resume their normal patterns of life without fear of spreading TB to others.

How is TB treated?

To treat TB several antibiotics need to be taken together over a period of usually 6 months to a year. For the treatment to work it's vital that these medicines be taken regularly and that the treatment be completed. Lengthy treatment is necessary because it is difficult to eradicate TB bacteria from the body.

What is TB infection and how is it treated?

TB infection means someone has bacteria sleeping in their body. They're not sick or contagious because the bacteria are dormant. TB infection is detected when someone has a positive skin test but a normal chest x-ray and no other sign of tuberculosis disease. To kill these sleeping bacteria and to prevent the development of active disease, persons with TB infection are often advised to take several months of treatment, usually with only one or two medications.

What is the difference between TB infection and TB disease?

People with TB disease are made sick by germs that are active in their bodies. Often they have several symptoms of TB, such as persistent cough, fever and weight loss. If the disease is in their lungs they can give the disease to other people. Permanent damage and death can result from this disease. Medications to cure TB are almost always effective.

People who have TB infection have the germ that can cause TB inside their bodies. However, they are not sick because the germ is inactive inside their bodies. They cannot make other people sick. These people may develop TB in the future. Medication is often given to these people to prevent them from developing TB disease.

Who's at risk?

Anyone can get TB. However, some groups are at higher risk to get active TB disease. The groups that are at high risk include:

- People with HIV infection (the AIDS virus)
- People in close contact with those known to be infectious with TB 
- People with medical conditions that make the body less able to protect itself from disease (for example: diabetes, the dust disease silicosis, or people undergoing treatment with drugs that can suppress the immune system, such as long-term use of corticosteroids)
- Foreign-born people from countries with high TB rates
- Some racial or ethnic minorities
- People who work in or are residents of long-term care facilities (nursing homes, prisons, some hospitals)
- Health care workers and others such as prison guards
- People who are malnourished
- Alcoholics, IV drug users and people who are homeless

Tuberculosis kills more people today than any other infectious disease. About 2 million people a year die from TB worldwide. However, death from TB is rare in the United States. King County reports 120-150 cases of people with active TB per year and of these people the cure rate is almost one hundred percent.

There is continued concern about  drug-resistant strains and newly-arrived immigrants  from countries where TB is on the rise.

Information from King County - Seattle & King County, American Lung Assoc.