Salmonellosis is an infection with a bacteria
called Salmonella. Most persons infected with Salmonella
develop diarrhea, fever, and abdominal cramps 12 to 72 hours after infection.
The illness usually lasts 4 to 7 days, and most persons recover without
treatment. However, in some persons the diarrhea may be so severe
that the patient needs to be hospitalized. In these patients, the
Salmonella infection may spread from the intestines to the blood
stream, and then to other body sites and can cause death unless the person
is treated promptly with antibiotics. The elderly, infants, and those
with impaired immune systems are more likely to have a severe illness.
What sort of
germ is Salmonella?
The Salmonella germ is actually
a group of bacteria that can cause diarrheal illness in humans. They
are microscopic living creatures that pass from the feces of people or
animals, to other people or other animals. There are many different
kinds of Salmonella bacteria. Salmonella serotype Typhimurium
and Salmonella serotype Enteritidis are the most common in the United
States. Salmonella has been known to cause illness for over
100 years. They were discovered by a American scientist named Salmon,
for whom they are named.
How can Salmonella
infections be diagnosed?
Many different kinds of illnesses can cause
diarrhea, fever, or abdominal cramps. Determining that Salmonella
is the cause of the illness depends on laboratory tests that identify Salmonella
in the stools of an infected person. These tests are sometimes not
performed unless the laboratory is instructed specifically to look for
the organism. Once Salmonella has been identified, further
testing can determine its specific type, and which antibiotics could be
used to treat it.
How can Salmonella
infections be treated?
Salmonella infections usually resolve
in 5-7 days and often do not require treatment unless the patient becomes
severely dehydrated or the infection spreads from the intestines.
Persons with severe diarrhea may require rehydration, often with intravenous
fluids. Antibiotics are not usually necessary unless the infection
spreads from the intestines, then it can be treated with ampicillin, gentamicin,
trimethoprim/sulfamethoxazole, or ciprofloxacin. Unfortunately,
some Salmonella bacteria have become resistant to antibiotics, largely
as a result of the use of antibiotics to promote the growth of feed animals.
Are there long
term consequences to a Salmonella infection?
Persons with diarrhea usually recover completely,
although it may be several months before their bowel habits are entirely
normal. A small number of persons who are infected with Salmonella,
will go on to develop pains in their joints, irritation of the eyes, and
painful urination. This is called Reiter's syndrome. It can
last for months or years, and can lead to chronic arthritis which is difficult
to treat. Antibiotic treatment does not make a difference in whether
or not the person later develops arthritis.
How do people
catch Salmonella?
Salmonella live in the intestinal tracts of humans and other animals, including birds. Salmonella are usually transmitted to humans by eating foods contaminated with animal feces. Contaminated foods usually look and smell normal. Contaminated foods are often of animal origin, such as beef, poultry, milk, or eggs, but all foods, including vegetables may become contaminated. Many raw foods of animal origin are frequently contaminated, but fortunately, thorough cooking kills Salmonella. Food may also become contaminated by the unwashed hands of an infected food handler, who forgot to wash his or her hands with soap after using the bathroom.
Salmonella may also be found in
the feces of some pets, especially those with diarrhea, and people can
become infected if they do not wash their hands after contact with these
feces. Reptiles are particularly likely to harbor Salmonella
and people should always wash their hands immediately after handling a
reptile, even if the reptile is healthy. Adults should also be careful
that children wash their hands after handling a reptile.
What can a person
do to prevent this illness?
There is no vaccine to prevent salmonellosis. Since foods of animal origin may be contaminated with Salmonella, people should not eat raw or undercooked eggs, poultry, or meat. Raw eggs may be unrecognized in some foods such as homemade hollandaise sauce, caesar and other salad dressings, tiramisu, homemade ice cream, homemade mayonnaise, cookie dough, and frostings. Poultry and meat, including hamburgers, should be well-cooked, not pink in the middle. Persons also should not consume raw or unpasteurized milk or other dairy products. Produce should be thoroughly washed before consuming.
Cross-contamination of foods should be avoided. Uncooked meats should be keep separate from produce, cooked foods, and ready-to-eat foods. Hands, cutting boards, counters, knives, and other utensils should be washed thoroughly after handling uncooked foods. Hand should be washed before handling any food, and between handling different food items.
People who have salmonellosis should not prepare food or pour water for others until they have been shown to no longer be carrying the Salmonella bacterium.
People should wash their hands after contact
with animal feces. Since reptiles are particularly likely to have
Salmonella, everyone should immediately wash their hands after handling
reptiles. Reptiles (including turtles) are not appropriate pets for
small children and should not be in the same house as an infant.
How common is
salmonellosis?
Every year, approximately
40,000 cases of salmonellosis are reported in the United States.
Because many milder cases are not diagnosed or reported, the actual number
of infections may be twenty or more times greater. Salmonellosis
is more common in the summer than winter. Children are the
most likely to get salmonellosis. Young children, the elderly, and
the immunocompromised are the most likely to have severe infections.
It is estimated that approximately 1,000 persons die each year with acute
salmonellosis.
What else can
be done to prevent salmonellosis?
It is important for the public health department to know about cases of salmonellosis. It is important for clinical laboratories to send isolates of Salmonella to the City, County, or State Public Health Laboratories so the specific type can be determined and compared with other Salmonella in the community. If many cases occur at the same time, it may mean that a restaurant, food or water supply has a problem which needs correction by the public health department.
Some prevention steps occur everyday without
you thinking about it. Pasteurization of milk and treating municipal
water supplies are highly effective prevention measures that have been
in place for many years. In the 1970s, small pet turtles were a common
source of salmonellosis in the United States, and in 1975, the sale of
small turtles was halted in this country. Improvements in farm animal
hygiene, in slaughter plant practices, and in vegetable and fruit harvesting
and packing operations may help prevent salmonellosis caused by contaminated
foods. Better education of food industry workers in basic food safety
and restaurant inspection procedures, may prevent cross-contamination and
other food handling errors that can lead to outbreaks. Wider use
of pasteurized egg in restaurants, hospitals, and nursing homes is an important
prevention measure. In the future, irradiation or other treatments
may greatly reduce contamination of raw meat.
What is the government
doing about salmonellosis?
The Centers
for Disease Control and Prevention (CDC) monitors the frequency of
Salmonella infections in the country and assists the local and State
Health Departments to investigate outbreaks and devise control measures.
CDC also conducts research to better identify specific types of Salmonella.
The Food and Drug Administration inspects
imported foods, milk pasteurization plants, promotes better food preparation
techniques in restaurants and food processing plants, and regulates the
sale of turtles. The FDA also regulates the use of specific antibiotics
as growth promotants in food animals. The US
Department of Agriculture monitors the health of food animals, inspects
egg pasteurization plants, and is responsible for the quality of slaughtered
and processed meat. The US Environmental
Protection Agency regulates and monitors the safety of our drinking
water supplies.
How can I learn
more about this and other public health problems?
You can discuss any medical concerns you
may have with your doctor or other heath care provider. Your local
City or County Health Department can provide more information about this
and other public health problems that are occurring in your area.
General information about the public health of the nation is published
every week in the "Morbidity
and Mortality Weekly Report", by the CDC in Atlanta, GA. Epidemiologists
in your local and State Health Departments are tracking a number of important
public health problems, investigating special problems that arise, and
helping to prevent them from occurring in the first place, or from spreading
if they do occur.
What can I do
to prevent salmonellosis?