Tuberculosis FactsWhat
is TB?
TB, or tuberculosis, is a disease caused by bacteria called Mycobacterium
tuberculosis. The bacteria can attack any part of your body, but they
usually attack the lungs.
What
are the symptoms of TB disease?
Symptoms
of TB depend on where in the body the TB bacteria are growing.
TB bacteria usually grow in the lungs. TB in the lungs
may cause
- a bad cough that lasts longer
than 2 weeks
- pain in the chest
- coughing up blood or sputum
(phlegm from deep inside the lungs)
- weakness or fatigue
- weight loss
- no appetite
- chills and fever
- sweating at night
How
is TB spread?
The
bacteria are put into the air when a person with TB disease
of the lungs coughs or sneezes. People nearby may breathe in
these bacteria and become infected. People with TB disease
are most likely to spread it to people they spend time with
every day. This includes family members, friends, and coworkers.
In most people who breathe in TB bacteria and become
infected, the body is able to fight the bacteria to stop them
from growing. The bacteria become inactive, but they remain alive
in the body and can become active later. This is called latent
TB infection. People with latent TB infection:
- have no symptoms
- don't feel sick
- can't spread TB to
others
- usually have a positive skin
test reaction
- can develop TB disease later
in life if they do not receive treatment for latent TB infection
Ninety-five
percent of
people who have latent TB infection never develop TB disease.
In these people, the TB bacteria remain inactive for a
lifetime without causing disease. Other people may get
sick later, when their immune system becomes weak for some
reason, especially
people with any of these conditions:
- substance abuse
- diabetes mellitus
- silicosis
- cancer of the head or neck
- leukemia or Hodgkin's disease
- severe kidney disease
- low body weight
- certain medical treatments
(such as corticosteroid treatment or organ transplants)
- HIV
infection
How
do I know if I have been infected with the TB bacteria?
A
TB skin test is the only way to find out if you have latent
TB infection. If you have a positive reaction to the skin
test, other tests will be done to see if you have TB disease.
These tests usually include a chest x-ray.
If you have
a negative reaction to the skin test, you may need a second
skin test 10 to 12 weeks after the last time you spent
time with the infectious person. This is because it can
take several weeks after infection for your immune system
to be able to react to the TB skin test. If your reaction
to the second test is negative, it is very unlikely that
you have latent TB infection.
Difference
Between Latent TB Infection and TB Disease
|
Latent
TB Infection
|
TB
Disease
|
| • Have no symptoms: |
• Symptoms include: |
| • Do not feel sick |
- a bad cough that lasts longer than 2 weeks
- pain in the chest
- coughing up blood or sputum
- weakness or fatigue
- weight loss
- no appetite
- chills
- fever
- sweating at night
|
| • Cannot spread TB to others |
| • Usually have a positive skin test |
| • Chest x-ray and sputum test normal |
| |
• May spread
TB to others |
| • Usually have a positive
skin test |
| • May have abnormal
chest x-ray, and/or positive sputum smear or culture |
Are
people with latent TB treated?
The
medicine usually used for the treatment of latent TB infection
is a drug called isoniazid, or INH. INH kills the TB bacteria
that may be in the body and prevents active TB from developing
later in life. Treatment will keep almost everyone with latent
TB from ever developing TB disease.