This information has been gathered from the Center for
What is TB?
TB is a disease caused by bacteria
This disease primarily affects the lungs, but can attack any
in the body. TB is spread through the air from one person to
another. The bacteria are put into the air when a person
disease of the lungs or throat coughs or sneezes. People
breathe in these bacteria and become infected. However, not
infected with TB bacteria becomes sick. As a result, two
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
In most people who breathe in TB bacteria and
infected, the body is able to fight the bacteria and stop
growing. The bacteria become inactive, but they remain alive
body and can become active later. This is called
There are an
estimated 10 to 15 million persons in the United States with
Many people who have latent TB infection
active TB disease.
In these people, the TB bacteria remain inactive for a
without causing disease. A person with
does not feel sick and cannot spread TB bacteria to others.
spread from person to person through the air. When a person
pulmonary or laryngeal TB coughs, sneezes, speaks, or sings,
are expelled into the air. Depending on the environment,
particles (1-5 microns in diameter) can remain suspended in
for several hours.
become infected, a person usually has to spend a relatively
time in a closed environment where the air was contaminated
person with untreated tuberculosis who was coughing and who
organisms (or tubercle bacilli) in secretions from the lungs
voice box (larynx). Infection is generally transmitted
air; therefore, there is virtually no danger of its being
dishes, linens, and items that are touched, or by most food
another person inhales air containing droplet nuclei,
may occur. The probability that TB will be transmitted
the infectiousness of the person with TB
number of organisms expelled into the air),
the environment in which exposure occurred,
the duration of exposure, and
the virulence of the organism.
best way to stop transmission is to isolate patients with
TB immediately and start effective TB therapy.
declines rapidly after adequate therapy is started, as long
patient adheres to the prescribed regimen.
Persons at the highest risk of becoming infected with
are those who had prolonged, frequent, or intense contact
person with infectious TB. These "case contacts" may be
members, roommates, friends, coworkers, or others. Data
CDC since 1987 show that infection rates have been
stable, ranging from 21% to 23% for the contacts of
have any questions about TB, please call your physician or
Health Service (832-1925). Phone calls will be returned in
the order they have
been received; we ask your patience.
scheduling an appointment for a skin test: Call 832-1926 (
Download the TB form: Click on