Listeriosis, a serious infection caused by eating food
contaminated with the bacterium
recently been recognized as an important public health problem in
the United States. The disease affects primarily pregnant women,
newborns, and adults with weakened immune systems. It can be
avoided by following a few simple recommendations.
What are the symptoms of listeriosis?
A person with listeriosis has:
Sometimes gastrointestinal symptoms such as nausea or
If infection spreads to the nervous system, symptoms such
Possibly, loss of balance
Infected pregnant women may experience only a mild, flu-like
illness. However, infections during pregnancy can lead to:
Infection of the newborn
How great is the risk for listeriosis?
In the United States, an estimated 2,500 persons become
seriously ill with listeriosis each year. Of these, 500 die. At
increased risk are:
Pregnant women - about 20 times more likely than other healthy
adults to get listeriosis (About one-third of listeriosis cases
happen during pregnancy)
Newborns - suffer the serious effects of infection in
Persons with weakened immune systems
Persons with cancer, diabetes, or kidney disease
Persons with AIDS - almost 300 times more likely to get
listeriosis than people with normal immune systems
Persons who take glucocorticosteroid medications
Healthy adults and children occasionally get infected with
, but they rarely become seriously ill.
get into food?
is found in soil and water.
Vegetables can become contaminated from the soil or from manure
used as fertilizer. Animals can carry the bacterium without
appearing ill and can contaminate foods of animal origin such as
meats and dairy products. The bacterium has been found in a variety
of raw foods, such as
as well as in
that become contaminated after
processing, such as
Unpasteurized (raw) milk
or foods made from
unpasteurized milk may contain the bacterium.
killed by pasteurization, and heating procedures used to prepare
ready-to-eat processed meats should be sufficient to kill the
bacterium. However, unless good manufacturing practices are
followed, contamination can occur after processing.
How do you get listeriosis?
You get listeriosis by eating food contaminated with
. Babies can be born with listeriosis if their
mothers eat contaminated food during pregnancy. Although healthy
persons may consume contaminated foods without becoming ill, those
at increased risk for infection can probably get listeriosis after
eating food contaminated with even a few bacteria. Persons at risk
infection by avoiding certain high-risk
foods and by handling food properly.
Can listeriosis be prevented?
The general guidelines recommended for the prevention of
listeriosis are similar to those used to help prevent other
foodborne illnesses, such as salmonellosis.
How can you reduce your risk for listeriosis?
Thoroughly cook raw food from animal sources, such as beef,
pork, or poultry.
Wash raw vegetables thoroughly before eating.
Keep uncooked meats separate from vegetables and from cooked
foods and ready-to-eat foods.
Avoid raw (unpasteurized) milk or foods made from raw
Wash hands, knives, and cutting boards after handling uncooked
Recommendations for persons at high risk, such as pregnant women
and persons with weakened immune systems, in addition to the
recommendations listed above:
Avoid soft cheeses such as feta, Brie, Camembert, blue-veined,
and Mexican-style cheese. (Hard cheese, processed cheeses, cream
cheese, cottage cheese, or yogurt need not be avoided.)
Leftover foods or ready-to-eat foods, such as hot dogs, should
be cooked until steaming hot before eating.
Although the risk of listeriosis associated with foods from
deli counters is relatively low, pregnant women and immunosupressed
persons may choose to avoid these foods or thoroughly reheat cold
cuts before eating.
How do you know if you have listeriosis?
There is no routine screening test for susceptibility to
listeriosis during pregnancy, as there is for rubella and some
other congenital infections. If you have symptoms such as fever or
stiff neck, consult your doctor. A blood or spinal fluid test (to
cultivate the bacteria) will show if you have listeriosis. During
pregnancy, a blood test is the most reliable way to find out if
your symptoms are due to listeriosis.
What should you do if you've eaten a food recalled because of
The risk of an individual person developing
infection after consumption of a contaminated product is very
small. If you have eaten a contaminated product and do not have any
symptoms, we do not recommend that you have any tests or treatment,
even if you are in a high-risk group. However, if you are in a
high-risk group, have eaten the contaminated product, and within
two months become ill with fever or signs of serious illness, you
should contact your physician and inform him or her about this
Can listeriosis be treated?
When infection occurs during pregnancy, antibiotics given
promptly to the pregnant woman can often prevent infection of the
fetus or newborn. Babies with listeriosis receive the same
antibiotics as adults, although a combination of antibiotics is
often used until physicians are certain of the diagnosis. Even with
prompt treatment, some infections result in death. This is
particularly likely in the elderly and in persons with other
serious medical problems.
Centers for Disease Control and
Prevention, October 2002
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a