Understanding Tuberculosis

What is TB?

Tuberculosis (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 a person with TB in their lungs or throat coughs, laughs, sneezes, sings, or even talks, the germs that cause TB may spread through the air. If another person breathes in these germs there is a chance that they will become infected with tuberculosis. 

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 immune system is protecting them from the germs and they are not sick. This is referred to as latent TB.

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. This is referred to as active TB.

How Does Someone Become Infected with TB?

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. It is rare, but possible, for TB to be spread in an airplane. Over half of TB cases in the U.S. are among people born in countries with a high incidence of the disease.

How Does TB Disease Develop?

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 immune system protects them.

Many people who develop TB disease were infected with the TB germ in the past. Then their immune system becomes damaged and can no longer fight the germ so it develops into TB disease. The immune system may be damaged from AIDS or diabetes, drug or alcohol abuse, lack of medical care, or homelessness. 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.

How Serious is TB?

In some people, TB can cause cough, chest pain and bloody mucus. If it is not treated properly, TB can be fatal.

What is Multidrug- and Extensively Drug-Resistant TB?

Multidrug-resistant tuberculosis (MDR TB) is a very dangerous form of tuberculosis. Some TB germs become resistant to the effects of some TB drugs. This happens when TB disease is not properly treated. These resistant germs can then cause TB disease. The TB disease they cause is much harder to treat because the drugs do not kill the germs.

MDR TB can be spread to others, just like regular TB. If you have TB, it is important to follow your healthcare provider's instructions for taking your TB medicine so that you will not develop MDR TB.

Extensively drug-resistant TB (XDR TB) is an even more dangerous version of MDR TB. It is resistant to the same drugs as MDR TB, as well as more potent types used to treat MDR TB. Treatment for XDR TB is much more difficult, expensive, and last longer.