Tuberculosis is an infectious disease caused by a type of bacteria called Mycobacterium
tuberculosis. Tuberculosis (often called "TB") mainly infects the lungs,
but can affect other organs.
Tuberculosis (too-bur-kyuh-LOW-sis) was one of the worst diseases of the 19th century.
It became much rarer as living conditions and medical care got better in the United
States. But it's making a comeback today, particularly among the homeless, those in
prison, and people whose immune systems
are weakened (for instance, from HIV
Is Tuberculosis Contagious?
Yes. When someone with untreated TB coughs or sneezes, it sends droplets with the
bacteria into the air. Inhaling these infected droplets is the usual way a person
But not everyone who inhales infected droplets will get sick. That's why doctors
categorize TB as either:
latent TB infection: This is when people have the M. tuberculosis
bacteria in their bodies, but they don't feel sick or have symptoms. They also cannot
pass TB to others. or
TB disease: This is when people with M. tuberculosis
bacteria become sick and have symptoms. Sometimes it can happen if a latent TB infection
was not treated. They can spread TB to others.
What Are the Signs & Symptoms of Tuberculosis?
Someone with TB disease might have these symptoms:
coughing for 3 weeks or
longer (and might cough up blood)
How Is Tuberculosis Diagnosed?
A latent tuberculosis infection causes no signs or symptoms, and a chest
X-ray won't show any signs of infection. Doctors can diagnose both latent TB infections
and TB disease by doing a:
Tuberculin skin test (TST): This is how doctors usually test
kids for TB. It's done in two steps. First, the health care provider injects a small
amount of fluid (called tuberculin) into the skin on the lower part of the arm. Then,
the person returns 48–72 hours later, when the provider checks the skin for
a reaction. A raised, hard area or swelling means the person has TB bacteria in the
Blood test: The health care provider will take a blood sample
to be checked in a lab for TB bacteria. This option doesn't need a second step.
Someone with a positive tuberculin test (PPD) will need more testing to see whether
they have a latent TB infection or TB disease.
Who Should Get Tested for TB?
Health experts recommend TB testing for people at higher risk for TB disease, such
as those who:
have symptoms of TB disease
were around someone with TB disease
have HIV or another condition that weakens the immune system
use illegal drugs
live in areas where the disease is common (including some countries in Asia, Latin
America, Eastern Europe, and Africa)
live or work in settings where TB disease is more common (such as homeless shelters
How Is Tuberculosis Treated?
Most people with tuberculosis don't need treatment in a hospital and can be cared
for at home. Doctors usually treat TB with oral (taken by mouth) antibiotics. Killing
all the TB bacteria takes time, though, so most people need to take medicine for 6–9
months. Sometimes doctors use a combination of bacteria-killing medicines to treat
It's important to take the antibiotics for as long as the doctor prescribed, even
if someone feels better in a few weeks. That is the best way to kill the harmful bacteria.
Stopping treatment too soon or skipping doses can give the remaining bacteria a chance
to become resistant to the antibiotic. Drug resistance can lead to more dangerous
types of tuberculosis that are harder to treat.
Doctors also might treat people with a latent infection and no symptoms. This is
called preventive therapy. It kills the bacteria so they can't cause
health problems later. The most common preventive therapy is a daily dose of an antibiotic
called isoniazid taken for 6–9 months. Doctors also sometimes give isoniazid
to people at risk for getting TB again.
Can Tuberculosis Be Prevented?
The prevention of TB depends on:
avoiding contact with people who have the active disease
using medicines as a preventive measure in high-risk cases
maintaining good living standards
To prevent the spread of germs that cause TB and other infections, encourage everyone
in your family to: