Fact Sheets
Tuberculosis: General Information
Last Updated: August 5, 1999
Tuberculosis (TB) is a disease that is spread from
person to person through the air. TB usually affects the lungs,
but it can also affect other parts of the body, such as the brain,
the kidneys, or the spine. TB germs are put into the air when a
person with TB disease of the lungs or throat coughs or sneezes.
When a person inhales air that contains TB germs, he or she may
become infected. People with TB infection do not feel sick and do
not have any symptoms. However, they may develop TB disease at some
time in the future.
The general symptoms of TB disease include feeling
sick or weak, weight loss, fever, and night sweats. The symptoms
of TB of the lungs include coughing, chest pain, and coughing up
blood. Other symptoms depend on the part of the body that is affected.
The Difference Between Latent TB Infection and
TB Disease
People with latent TB infection but not TB disease
have the germ that causes TB in their bodies. They are not sick
because the germs are inactive in their bodies. They cannot spread
the germs to others. However, these people may develop TB disease
in the future. They are often prescribed treatment to prevent them
from developing the disease.
People with TB disease are sick from germs that are
active in their body. They usually have symptoms of TB, such as
feeling sick, coughing, weight loss, fever, or night sweats. Usually,
people with TB disease of the lungs or throat are capable of spreading
the disease to others. They are prescribed drugs that can cure TB.
How is TB Spread?
TB is spread from person to person through the air.
When people with TB disease of the lungs or throat cough or sneeze,
they can put TB germs into the air. Then other people who breathe
in the air containing these germs can become infected.
People with TB disease are most likely to spread it
to people they spend time with every day, such as family members
or coworkers. If you think you have been around someone who has
TB disease, you should go to your doctor or the local health department
for tests. It is important to remember that people who have TB infection
but not TB disease cannot spread the germs to others.
What is a Tuberculin Skin Test?
The tuberculin skin test is used for finding out whether
a person is infected with the TB germs. It does not tell whether
a person has TB disease. For the skin test, a small amount of fluid
called tuberculin is injected under the skin in the lower part of
the arm. Two or three days later, a health care worker looks for
a reaction on the arm.
What Does a Positive Reaction Mean?
A positive reaction to the tuberculin skin test usually
means that the person has been infected with the TB germ. It does
not necessarily mean that the person has TB disease. Other tests,
such as a chest x-ray and a sample of phlegm, are needed to see
whether the person has TB disease. People who have a positive reaction
to the skin test but who do not have TB disease cannot spread the
germs to others. They may be given a drug to treat the infection
and prevent them from developing TB disease. People who have TB
disease must take several drugs to cure the disease.
Skin Testing for Persons
Who Have Been Vaccinated with BCG
BCG, or bacille Calmette-Guérin,
is a vaccine for TB disease. BCG is used in many countries, but
it is not generally recommended in the United States. BCG vaccination
does not completely prevent people from getting TB. People who have
been vaccinated with BCG can be given a tuberculin skin test.
Treatment of Latent TB Infection
If you have latent TB infection
but not TB disease, your doctor may want you to take a drug to treat
the infection and prevent you from developing the disease. The decision
about taking treatment for latent infection will be based on your
age and on the chances that you will develop the disease. Some people
are more likely than others to develop TB disease once they have
TB infection; this includes: people with HIV infection, people who
were recently exposed to someone with TB disease, and people with
certain medical conditions.
Treatment for TB Disease
TB disease can be cured by taking
several drugs for 6 to 12 months. It is very important that people
who have TB disease take the drugs exactly as prescribed. If they
stop taking the drugs too soon or if they do not take the drugs
correctly, the germs that are still alive may become resistant to
those drugs. TB that is resistant to drugs is harder to treat.
In some situations, staff of
the local health department meet regularly with patients who have
TB to help them remember to take their medications. This is called
directly observed therapy (DOT).
For More Information
To find out more about TB, you
may call CDCs Voice and Fax Information System at 1-888-CDC-FACT
(232-3228) or you may visit the Division of TB Eliminations
Web site at http://www.cdc.gov/nchstp/tb.
To order Questions
and Answers About TB, call the CDCs Voice and Fax
Information System (recording) toll free at (888) 232-3228, then
press options 2, 5, 1, 2, 2 (Note: You may select these options
at any time without listening to the complete message). Request
the publication number of the document you would like to order.
You may also visit the Division of TB Eliminations Web site
at http://www.cdc.gov/nchstp/tb.
Publication # 00-6469. Questions
and Answers About TB. Atlanta: CDC;1994.
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