Listeriosis is a serious infection caused by eating
food contaminated with bacteria called Listeria
Persons with listeriosis usually have:
Sometimes nausea or
If the infection spreads to the nervous
system, the following symptoms may occur:
Loss of balance
Who gets listeriosis?
Although listeriosis is uncommon in the United
States, anyone can get listeriosis if they eat food
contaminated with Listeria bacteria.
Although healthy people may consume contaminated food
without becoming ill, certain persons at high risk for
infection may get listeriosis after eating food contaminated with even a few bacteria.
high risk for infection include:
About one third of listeriosis
cases happen during pregnancy.
Newborns are very likely to suffer
the serious effects of infection during their
Infants may be stillborn, born with
septicemia (bacteria in their blood), or develop
meningitis (inflammation of the covering of the
brain or spinal cord) very early in life, even if the
mother does not have any symptoms.
People with weakened immune
systems e.g., people with:
People who are taking glucocorticoids
How is listeriosis spread?
You get listeriosis by eating food contaminated with
Babies can be born with listeriosis if
their mothers eat contaminated food during their pregnancy.
L. monocytogenes is found in soil and water.
Vegetables can become contaminated from the soil
or from manure used as fertilizer.
Animals can carry
the bacteria without appearing ill and can
contaminate foods of animal origin, such as meats
and dairy products.
Listeria has been found in raw
foods, such as meat and vegetables, and in processed
foods that become contaminated after processing,
such as soft cheeses and cold cuts.
(raw) milk or foods made from unpasteurized milk
may contain the bacteria.
How soon after exposure do symptoms
Symptoms have been noted to occur within as few as
3 to as many as 70 days after consumption of a
contaminated food, and most commonly within 3 weeks.
How is listeriosis diagnosed?
Listeriosis is diagnosed by a test of the blood or
What is the treatment for listeriosis?
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.
Even with prompt treatment, some infections result
in death. This is particularly likely in the elderly and
in persons with other serious medical problems.
How can listeriosis be prevented?
Listeriosis can be prevented by following guidelines
used to prevent other foodborne illnesses:
Cook thoroughly raw food from animals, 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 milk.
Wash hands, knives, and cutting boards after
handling uncooked foods.
If you are in one of the high-risk categories, the
following guidelines are also suggested:
Avoid soft cheeses such as feta, Brie, Camembert,
blue-veined, and Mexican-style cheese.
cheeses, processed cheeses, cream cheese, cottage
cheese, or yogurt need not be avoided.
Cook until steaming hot all leftover foods or
ready-to-eat foods (i.e., hot dogs) before eating.
Although the risk of listeriosis associated with
foods from deli counters is low, persons at high
risk may choose to avoid these foods or
thoroughly reheat cold cuts before eating.
Where can I get more information?
Contact your physician or the Southern Nevada Health District, Office of Epidemiology at (702) 759-1300.