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This information has been gathered from the Center for Disease
Control Website
www.cdc.gov
What is TB?
TB is a disease caused by bacteria called
Mycobacterium
tuberculosis.
This disease primarily affects the lungs, but can attack any organ
in the body. TB is spread through the air from one person to
another. The bacteria are put into the air when a person with TB
disease of the lungs or throat coughs or sneezes. People nearby may
breathe in these bacteria and become infected. However, not everyone
infected with TB bacteria becomes sick. As a result, two TB-related
conditions exist: latent TB infection and active TB disease.
Both of these conditions are treatable and curable.
What is the difference between latent TB infection and active TB
disease?
In most people who breathe in TB bacteria and become
infected, the body is able to fight the bacteria and 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.
There are an
estimated 10 to 15 million persons in the United States with latent
TB infection.
Many people who have latent TB infection
never develop
active TB disease.
In these people, the TB bacteria remain inactive for a lifetime
without causing disease. A person with
latent TB infection
does not feel sick and cannot spread TB bacteria to others.
TB is
spread from person to person through the air. When a person with
pulmonary or laryngeal TB coughs, sneezes, speaks, or sings, droplet
nuclei containing
M. tuberculosis
are expelled into the air. Depending on the environment, these tiny
particles (1-5 microns in diameter) can remain suspended in the air
for several hours.
To
become infected, a person usually has to spend a relatively long
time in a closed environment where the air was contaminated by a
person with untreated tuberculosis who was coughing and who had
numerous
M. tuberculosis
organisms (or tubercle bacilli) in secretions from the lungs or
voice box (larynx). Infection is generally transmitted through the
air; therefore, there is virtually no danger of its being spread by
dishes, linens, and items that are touched, or by most food
products.
If
another person inhales air containing droplet nuclei, transmission
may occur. The probability that TB will be transmitted depends on
four factors:
-
the infectiousness of the person with TB (the
number of organisms expelled into the air),
-
the environment in which exposure occurred,
-
the duration of exposure, and
-
the virulence of the organism.
The
best way to stop transmission is to isolate patients with infectious
TB immediately and start effective TB therapy. Infectiousness
declines rapidly after adequate therapy is started, as long as the
patient adheres to the prescribed regimen.
Persons at the highest risk of becoming infected with
M.
tuberculosis
are those who had prolonged, frequent, or intense contact with a
person with infectious TB. These "case contacts" may be family
members, roommates, friends, coworkers, or others. Data collected by
CDC since 1987 show that infection rates have been relatively
stable, ranging from 21% to 23% for the contacts of infectious TB
patients.
If you
have any questions about TB, please call your physician or our
Health Service (832-1925). Phone calls will be returned in the order they have
been received; we ask your patience.
For
scheduling an appointment for a skin test: Call 832-1926 (
appointment line)
Download the TB form: Click on
Tuberculosis
Screening Form |
