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Tuberculosis (the disease)




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What is Tuberculosis?

Tuberculosis (TB) is an infectious disease caused by the bacteria Mycobacterium tuberculosis. TB disease most often affects the lungs, but can occur anywhere in the body.

What is the difference between TB infection and TB disease?

In TB infection, the TB bacteria are in the body but are asleep or inactive. This means that a person with TB infection is not sick and cannot spread TB to other people. A person with TB infection usually has a positive TB skin test, a normal chest x-ray and no symptoms of TB disease.

TB infection can sometimes turn into TB disease. Many people (90%) who have TB infection never develop TB disease. However, about 10% of the people with TB infection develop TB disease.

In TB disease, the TB bacteria in the body awaken or become active. This means that a person with TB disease is sick and may spread TB to other people. A person with TB disease has a positive TB skin test, an abnormal chest x-ray (usually) and symptoms of TB disease (coughing for more than 3 weeks, fever, night sweats, fatigue, unexplained weight loss, and loss of appetite). A person with TB disease needs to take medication to become well.

Who can develop TB disease?

Persons most likely to develop TB disease are those who have recently become infected with TB through someone with whom they live or have close contact. TB disease usually develops within the first two years after getting infected with TB. After the two years is over, the risk of developing TB disease decreases. However, it may still be possible to develop TB disease if the immune system is weakened by another medical condition, drug abuse, malnutrition or old age.

How does TB spread?

TB spreads through the air. When a person with contagious TB coughs, laughs, sings, etc., the TB bacteria are released into the air. These TB bacteria can remain in the air for many hours. Anyone who breathes this air that contains TB bacteria may become infected.

To prevent spreading TB to another person, anyone with contagious TB disease should cover their mouth and nose when coughing or sneezing.

Fact: Persons with TB disease who have taken the correct TB medications for a specified period of time do not continue spreading TB to others.

Fact: TB bacteria do not spread by kissing or sharing drinking glasses, dishes, or other objects. TB bacteria must be inhaled in order for infection to occur.

What are the symptoms of contagious TB disease?

The most common symptom of contagious TB disease is a cough that lasts for more than a three weeks, sometimes producing mucous and/or blood. Other symptoms may include fatigue, loss of appetite, weight loss, fever, and night sweats. Chest pain may also occur.

For TB disease outside the lungs, the symptoms vary by where in the body the disease occurs.

People can have TB disease without having any symptoms.

What is the Treatment for TB disease?

Treating TB disease requires a minimum of 4 different medicines. Persons with TB disease who have taken the correct TB medications for a specified period of time do not continue spreading TB to others. However, it will take a minimum of 6 months to complete the treatment for TB disease. Sometimes, it may take longer.

Persons with TB disease must take every dose of medicine as prescribed, even if the symptoms of the disease disappear completely. Not taking the proper dosage of TB medications over a prescribed amount of time can result in the return of TB disease that does not respond to the TB drugs. Persons whose TB does not respond to the most commonly used TB drugs will need to take other medicines that may not work and have serious side effects.


Last Updated: 07-30-2011

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