Encyclopedia of Health and Medicine

360 Infectious Diseases
Doing so is hazardous both for the person, who
then remains infected with tuberculosis, and in
the context of public health because it fosters DRUG
resistance. It is essential to take the medications as
directed for the full course of treatment. When
compliance is a significant concern, doctors may
use a protocol called directly observed treatment
(DOT), in which the person comes to a clinic and
takes his or her medication under direct observation
of a health-care provider. Such treatment
cures the tuberculosis. Any damage to the lungs or
the kidneys (granulomas) remains, however, and
is permanent.
Risk Factors and Preventive Measures
Crowded, unsanitary living conditions present the
greatest risk for tuberculosis infection. Active
tuberculosis is contagious through contact with
sputum (material coughed up from the lungs),
which contains M. tuberculosis. Latent tuberculosis
is not contagious, though may emerge as active
disease and become contagious. Tuberculosis is a
common OPPORTUNISTIC INFECTION in people who
have HIV/AIDS. Prevention efforts focus on routine
testing of people at risk for exposure. In the
United States, such testing takes place through
public health programs, school-based programs,
institutional programs (such as in the military and
in prisons), and employer-based programs. People
who have positive skin tuberculin tests should
receive further evaluation from a doctor and may
require a course of prophylactic treatment with
anti-tuberculosis medications.
See also BONE; COMMUNITY SANITATION; PATHOGEN.
typhoid fever An illness resulting from INFECTION
with the bacterium Salmonella typhi. Typhoid FEVER
is rare in the United States, and most people who
have the illness acquire the infection while traveling
in regions of the world where typhoid fever is
endemic. Substandard COMMUNITY SANITATION is the
key risk for the spread of typhoid fever. The BACTE-
RIA infect the SMALL INTESTINE. Infection spreads
through fecal–oral contamination, primarily
through consumption of contaminated water and
foods. Some people are carriers of typhoid fever;
they are infected with S. typhi but do not develop
symptoms or illness.
Symptoms of typhoid fever include
• high fever
• NAUSEA, VOMITING, and DIARRHEA
• RASH
• ABDOMINAL PAIN
• extreme fatigue and weakness
Cultures of BLOOD and stool samples reveal the
presence of S. typhi, which is conclusive for diagnosis.
Treatment is ANTIBIOTIC MEDICATIONS, commonly
ampicillin, trimethoprim-sulfamethoxazole
(TMP-SMZ), or ciprofloxacin. Most people feel
much improved within three days of starting
antibiotic therapy, though the bacteria may
remain in their bodies for six weeks or longer,
during which time they remain contagious (capable
of passing the infection to others). People who
work in food service, health care, and other public
contact jobs may require a doctor’s statement of
health, verifying negative blood and stool cultures,
before they can return to work. People who are
planning to travel to regions of the world where
typhoid fever is common should receive typhoid
fever VACCINE to prevent infection.
See also FOODBORNE ILLNESSES; WATERBORNE ILL-
NESSES.