What is typhoid fever?
Typhoid fever is an acute illness associated
with fever caused by the Salmonella typhi bacteria. It can also be caused
by Salmonella paratyphi, a related bacterium that
usually causes a less severe illness. The bacteria are deposited in water or
food by a human carrier and are then spread to other people in the area.
The
incidence of typhoid fever in the United States has markedly decreased since
the early 1900s, when tens of thousands of cases were reported in the U.S.
Today, less than 400 cases are reported annually in the United States, mostly
in people who have recently traveled to Mexico and South America. This
improvement is the result of better environmental sanitation. India, Pakistan,
and Egypt are also known as high-risk areas for developing this disease.
Worldwide, typhoid fever affects more than 21 million people annually, with
about 200,000 people dying from the disease.
How Do People Get Typhoid Fever?
Typhoid
fever is contracted by drinking or eating the bacteria in contaminated food or
water. People with acute illness can contaminate the surrounding water supply
through stool, which contains a high concentration of the bacteria.
Contamination of the water supply can, in turn, taint the food supply. The
bacteria can survive for weeks in water or dried sewage.
About 3%-5%
of people become carriers of the bacteria after the acute illness. Others
suffer a very mild illness that goes unrecognized. These people may become
long-term carriers of the bacteria -- even though they have no symptoms -- and
be the source of new outbreaks of typhoid fever for many years.
How Is Typhoid Fever Diagnosed?
After the
ingestion of contaminated food or water, the Salmonella bacteria invade
the small intestine and enter the bloodstream temporarily. The bacteria are
carried by white blood cells in the liver, spleen, and bone marrow, where they
multiply and reenter the bloodstream. People develop symptoms, including fever,
at this point. Bacteria invade the gallbladder, biliary system, and the
lymphatic tissue of the bowel. Here, they multiply in high numbers. The
bacteria pass into the intestinal tract and can be identified in stool
samples. If a test result isn't clear, blood samples will be taken to make a
diagnosis.
What Are the Symptoms of Typhoid Fever?
The
incubation period is usually 1-2 weeks, and the duration of the illness is
about 3-4 weeks. Symptoms include:
- Poor appetite
- Headaches
- Generalized aches and pains
- Fever as high as 104 degrees Farenheit
- Lethargy
- Diarrhea
Chest
congestion develops in many people, and abdominal pain and discomfort are common. The
fever becomes constant. Improvement occurs in the third and fourth week in
those without complications. About 10% of people have recurrent symptoms after
feeling better for one to two weeks. Relapses are actually more common in
individuals treated with antibiotics.
How Is Typhoid Fever Treated?
Typhoid
fever is treated with antibiotics which kill the Salmonella
bacteria. Prior to the use of antibiotics, the fatality rate was 20%. Death
occurred from overwhelming infection, pneumonia, intestinal bleeding, or
intestinal perforation. With antibiotics and supportive care, mortality has
been reduced to 1%-2%. With appropriate antibiotic therapy, there is usually
improvement within one to two days and recovery within seven to 10 days.
Several
antibiotics are effective for the treatment of typhoid fever. Chloramphenicol
was the original drug of choice for many years. Because of rare serious side
effects, chloramphenicol has been replaced by other effective antibiotics. The
choice of antibiotics is guided by identifying the geographic region where the
infection was contracted (certain strains from South America show a significant
resistance to some antibiotics.) If relapses occur, patients are retreated with
antibiotics.
Those who
become chronically ill (about 3%-5% of those infected), can be treated with
prolonged antibiotics. Often, removal of the gallbladder, the site of chronic
infection, will provide a cure.
Typhoid Fever At A Glance
- Typhoid fever is caused by Salmonellae typhi bacteria.
- Typhoid fever is contracted by the ingestion of contaminated food or water.
- Diagnosis of typhoid fever is made when the Salmonella bacteria are detected with a stool culture.
- Typhoid fever is treated with antibiotics.
- Typhoid fever symptoms are poor appetite, headaches, generalized aches and pains, fever, and lethargy.
- Approximately 3%-5% of patients become carriers of the bacteria after the acute illness.
Reviewed by David
T. Derrer, MD on January 31, 2015
No comments:
Post a Comment