Tuberculosis (often called TB) is an infectious disease that usually attacks the lungs, but can attack almost any part of the body. Tuberculosis is spread from person to person through the air.

When people with TB in their lungs or throat cough, laugh, sneeze, sing, or even talk, the germs that cause TB may be spread into the air. If another person breathes in these germs there is a chance that they will become infected with tuberculosis. Repeated contact is usually required for infection.

It is important to understand that there is a difference between being infected with TB and having TB disease. Someone who is infected with TB has the TB germs, or bacteria, in their body. The body's defenses are protecting them from the germs and they are not sick.

Someone with TB disease is sick and can spread the disease to other people. A person with TB disease needs to see a doctor as soon as possible.

It is not easy to become infected with tuberculosis. Usually a person has to be close to someone with TB disease for a long period of time. TB is usually spread between family members, close friends, and people who work or live together. TB is spread most easily in closed spaces over a long period of time. However, transmission in an airplane, although rare, has been documented.

Even if someone becomes infected with tuberculosis, that does not mean they will get TB disease. Most people who become infected do not develop TB disease because their body's defenses protect them.

TB is an increasing and major world wide problem, especially in Africa where the spread is facilitated by AIDS. It is estimated that nearly 1 billion people will become newly infected, over 150 million will become sick, and 36 million will die worldwide between now and 2020 if control is not further strengthened. Each year there are more than 8.7 million cases and close to 2 million deaths attributed to TB; 100,000 of those 2 million deaths occur among children.

Anyone can get TB. People of all races and nationalities. The rich and poor. And at any age. But for many reasons, some groups of people 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 mal-nourished

Alcoholics and IV drug users

A person with TB infection will have no symptoms. A person with TB disease may have any, all or none of the following symptoms:

• cough that will not go away
  Feeling tired all the time
  Weight loss
  Loss of appetite
  Fever
  Coughing up blood
  Night sweats

These symptoms can also occur with other types of lung disease so it is important to see a doctor and to let the doctor determine if you have TB.

It is also important to remember that a person with TB disease may feel perfectly healthy or may only have a cough from time to time. If you think you have been exposed to TB, get a TB skin test.

There are two possible ways a person can become sick with TB disease:

The first applies to a person who may have been infected with TB for years and has been perfectly healthy. The time may come when this person suffers a change in health. The cause of this change in health may be another disease like AIDS or diabetes. Or it may be drug or alcohol abuse or a lack of health care because of homelessness.

Whatever the cause, when the body's ability to protect itself is damaged, the TB infection can become TB disease. In this way, a person may become sick with TB disease months or even years after they first breathed in the TB germs.

The other way TB disease develops happens much more quickly. Sometimes when a person first breathes in the TB germs the body is unable to protect itself against the disease. The germs then develop into active TB disease within weeks.

Treatment for TB depends on whether a person has TB disease or only TB infection.

A person who has become infected with TB, but does not have TB disease, may be given preventive therapy. Preventive therapy aims to kill germs that are not doing any damage right now, but could break out later.

If a doctor decides a person should have preventive therapy, the usual prescription is a daily dose of isoniazid (also called "INH"), an inexpensive TB medicine. The person takes INH for six to nine months (up to a year for some patients), with periodic checkups to make sure the medicine is being taken as prescribed.

What if the person has TB disease? Then treatment is needed.

Years ago a patient with TB disease was placed in a special hospital for months, maybe even years, and would often have surgery. Today, TB can be treated with very effective drugs.

Often the patient will only have to stay a short time in the hospital and can then continue taking medication at home. Sometimes the patient will not have to stay in the hospital at all. After a few weeks a person can probably even return to normal activities and not have to worry about infecting others.

The patient usually gets a combination of several drugs (most frequently INH plus two to three others), usually for nine months. The patient will probably begin to feel better only a few weeks after starting to take the drugs.

It is very important, however, that the patient continue to take the medicine correctly for the full length of treatment.

If the medicine is taken incorrectly or stopped the patient may become sick again and will be able to infect others

with TB. As a result many public health authorities recommend Directly Observed Therapy (DOT), in which a health care worker insures that the patient takes his/her medicine.

If the medicine is taken incorrectly and the patient becomes sick with TB a second time, the TB may be harder to treat because it has become drug resistant. This means that the TB germs in the body are unaffected by some drugs used to treat TB.

Multi-drug resistant TB is very dangerous, so patients should be sure that they take all of their medicine correctly.

Regular checkups are needed to see how treatment is progressing. Sometimes the drugs used to treat TB can cause side effects. It is important both for people undergoing preventive therapy and people being treated for TB disease to immediately let a doctor know if they begin having any unusual symptoms.

Yes, if they have TB disease and it is not being treated. Once treatment begins, a patient ordinarily quickly becomes noninfectious; that is, they cannot spread the disease to others.

There is little danger from the TB patient who is being treated, is taking his or her medication continuously, and is responding well. The drugs usually make the patient noninfectious within weeks.

TB is spread by germs in the air, germs put there by coughing or sneezing. Handling a patient's bed sheets, books, furniture or eating utensils does not spread the infection.

Brief exposure to a source of TB rarely infects a person. It's day-after-day close contact that usually does it.