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salmonella infections Alternative Namessamonellosis, Salmonella food poisoning
Definition
Salmonella infections are caused by one of more than 2,000 strains of a
bacterium known as Salmonella.
What is going on in the body?
Salmonella infections occur worldwide. People acquire Salmonella bacteria
from one another or from animals. Once the person swallows the bacteria, he or
she may develop an infection of the gastrointestinal system known as
gastroenteritis.
This inflammation of the stomach and intestines commonly
causes stomach upset, vomiting, and diarrhea.
Many animals may carry Salmonella bacteria. These include cats, dogs,
livestock, fish, birds, rodents, reptiles, and amphibians.
What are the signs and symptoms of the infection?
Most people who develop a Salmonella infection will not have any symptoms. If
symptoms do occur, they usually start 12 to 72 hours after contact. Most
symptoms last from 4 to 7 days. Diarrhea may last up to 2 weeks. Someone
who has a Salmonella infection may have the following symptoms:
Sometimes the bacteria can enter the bloodstream. The bloodstream infection can
cause very high fever and low blood pressure. From the bloodstream, the
bacteria may spread to other parts of the body. The brain, bones, and
other organs may be infected. This often happens in infants with the infection.
Typhoid fever, caused by a specific type of Salmonella known as
Salmonella typhi, has a slow onset of symptoms including:
What are the causes and risks of the infection?
Salmonella infections are caused by one of the more than 2,000 strains of the
Salmonella bacteria. Salmonella infections are transmitted from animals to
people, or from person to person, in the following ways:
- coming into contact with the feces of infected animals, especially
livestock, poultry, turtles, iguanas, and other reptiles
- coming into contact with the feces of infected people
- drinking contaminated water
- eating any kind of food that is contaminated with animal feces, including
fruits and vegetables
- eating food contaminated by a food handler with a Salmonella infection
- eating raw poultry, eggs, unpasteurized milk, cheese products, and meat
that hasn't been properly handled or cooked
The risk of acquiring this infection is increased by the following:
- being under 5 years of age or over 70 years of age
- having a weakened immune system, including people with HIV or cancer
- having liver disease
- having stomach surgery
- using antacids
What can be done to prevent the infection?
There are a few ways to help prevent this infection.
- Certain pets, such as turtles and other reptiles, should not be kept in
homes with young children.
- Hands should be washed with soap after changing diapers or using the
toilet.
- Hands should be washed with soap after touching animals and animal
products, such as eggs.
- Meat, poultry, and eggs should be cooked thoroughly before they are
eaten.
- People are advised to get the Salmonella typhi vaccine
before traveling to certain areas. These areas include parts of Latin America,
Asia, and Africa.
Public health measures are important in food processing plants. Outbreaks
affecting thousands of people have occurred from a single dirty machine.
How is the infection diagnosed?
The diagnosis of Salmonella infection starts with a medical history and
physical
examination. Salmonella organisms can be identified in the stool, blood, urine,
or pus of an infected person. In severe cases, they may be found in the
cerebrospinal fluid. This is the clear
fluid surrounding the brain and spinal cord.
What are the long-term effects of the infection?
Salmonella infections usually have no long-term effects. Recovery takes less
than a week in most cases. More severe infections are seen in the very young
and the very old. People with weak immune systems may also develop more serious
infections. In these cases, infections may
involve the brain or heart. This can result in death or serious organ damage.
Those who have recovered from an attack of typhoid will
have
lifelong immunity. Complications of typhoid fever may include:
- cholecystitis, or an
inflammation of the gallbladder
- formation of abscesses, or pus pockets, in soft tissues
- gastrointestinal
bleeding or a hole in the intestines
- infections involving the heart
- infections involving the reproductive organs in males and females
- kidney and bladder infections
- osteomyelitis, or an
infection within a bone
- pneumonia and other
respiratory infections
- septic arthritis, or
an infection within a joint
Some people develop a condition called Reiter syndrome following a Salmonella
infection. Reiter syndrome causes
joint pain, eye irritation, and painful urination.What are the risks to others?
A Salmonella infection can easily be spread to others. People caring for
children or preparing food should follow the rules of good hygiene.
What are the treatments for the infection?
Healthcare providers suggest that people with mild cases allow the disease to
run its course. The main treatment in this case is
drinking fluids to prevent
dehydration. Some people are not able to keep any liquids down.
Such people may need fluids given to them through an IV tube in their arm.
Antibiotics such as trimethoprim-sulfamethoxazole,
ciprofloxacin, ampicillin, or gentamicin may be given to certain persons. These
include:
- individuals diagnosed with typhoid fever
- people with immunodeficiency disorders, such as HIV
- people with severe infections
- young children
What are the side effects of the treatments?
Antibiotics may cause allergic reactions, stomach upset, and
rash.
What happens after treatment for the infection?
After a Salmonella infection, people often shed the bacteria in their stools
for more than a month. Good hygiene is important to avoid giving the infection
to others. Children may be excluded from day care until their stool is clear of
the bacteria. Food handlers may be kept off the job until they are no longer
carriers.
Three percent of people infected with the
Salmonella typhi organism are chronic carriers. This means the
organism is in their stool 1 year or more after treatment. They can infect
others while having no symptoms themselves. Most
carriers are women over the age of 50. How is the infection monitored?
Any new or worsening symptoms should be reported to the healthcare provider.
| Author: Danielle Zerr, MD Date Written: 12/09/99 Reviewer: Eileen McLaughlin, RN, BSN Date Reviewed: 09/04/01
Potential conflict of interest information for reviewers available on request
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