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Listeriosis
Listeria Monocytogenes
(A Psychrophilic Bacterium)
What is Listeriosis?
Listeriosis is a serious infection caused by
eating foods contaminated with the
bacterium Listeria Monocytogenes.
 This disease affects primarily pregnant
women, newborn, and adults with weakened
immune systems.
 This bacterium is too small to be seen
without a microscope.
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Listeria monocytogenes is a rod-shaped aerobic and gram
positive pathogenic bacterium that invades the cytoplasm of
living cells. It develops a distinctive rocket tail structure to
help push through the cytoplasm. Eventually, these
"rockets" push bacteria into neighboring cells, propagating
the infection
Symptoms
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Fever
Muscle ache
GI Sx: Nausea, diarrhea
Pregnant women: mild
flu-like Sx, miscarriage,
still birth, premature
delivery, or infected
newborn.
Lethargy
irritability
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If infection spreads to the
nervous system: headache,
stiff neck, confusion, loss
of balance, or convulsions.
Listeria can cause
Pneumonia, Meningitis,
and Sepsis.
Contamination
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Listeria Monocytogenes 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.
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The bacterium has been
found in uncooked meats
and vegetables, soft
cheeses, deli cold-cuts, and
unpasteurized milk or
foods.
If acquired at birth, the
incubation period is 7 to
28 days.
The average incubation
period is 31 days; with a
range from 11 to 47 days.
How do you get Listeriosis?
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Eating food
contaminated with
Listeria.
Babies can be born
with Listeriosis if the
mother eats
contaminated food
during pregnancy.
Listeriosis is generally
not contagious from
person to person.
Diagnosis
There is no routine screening test for
susceptibility.
 If you have Sx of 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 Sx are due to
Listeriosis.
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Prevention
• Thoroughly cook raw food
from animal sources.
• Was raw vegetables
thoroughly before eating.
• Separate uncooked meats
from vegetables, cooked foods
and ready-to-eat foods.
• Avoid unpasteurized milk or
food.
• Wash hands, knives, and
cutting boards with hot soapy
water for at least 20 sec after
handling uncooked foods.
• Observe all expiration dates
on food items.
• Consume perishable and
ready-to-eat foods as soon as
possible.
• Do not eat soft cheeses: feta,
brier, camembert, blueveined, or Mexican-style etc.
• Do not east refrigerated meat
spreads, smoked salmon,
smoked seafood; canned or
shelf-stable smoked seafood
may be eaten.
• Listeria monocytogenes is
killed by cooking or by
heating methods, including
pasteurization.
Treatment
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Listeriosis is a serious disease requiring hospitilization.
A combination of antibiotics is given intravenously through
a small straw-like catheter.
When infection occurs during pregnancy, antibiotics must
be given promptly to the mother to prevent infection of the
fetus or newborn.
Babies with Listeriosis receive the same antibiotics as
adults.
The duration of antibiotic treatment is at least 2 weeks.
Even with prompt treatment, some infections result in
death.
Statistics
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About 2,500 people in the U.S develop Listeriosis each year.
5 out of every 100 people carry Listeria Monocytogenes in their
intestines.
About 20% of people die from the infection.
In 1989, there were 1,965 cases of Listeriosis with 481 deaths.
In 1993, there were 1,092 cases of Listeriosis with 248 deaths.
Listeria Monocytogenes reached the blood and cerebrospinal fluid in
89% of cases.
Listeriosis results is a higher number of hospitalizations than any other
food-born illness.
Pregnant women account for 27% of cases, people with
immunodeficiency disorders account for 70% of cases.
AIDS patients are 280 time more likely to contract Listeriosis than
others.
Government Intervention
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FDA( Food and Drug Administration) and (FSIS) U.S
Department of Agriculture monitor food regularly.
FSIS now requires plants that slaughter and process meat
and poultry to use a process called (HACCP) Pathogen
Reduction and Hazard Analysis and Control Point
When a processed food is found to be contaminated, food
monitoring and plant inspection are intensified, and if
necessary, the implicated food is recalled.
NCID( National Center for Infectious Disease is extensively
studying Listeriosis to help measure the impact of prevention
activities.
Early detection and reporting of outbreaks can help identify
sources of infection and prevent more cases of the disease.
The End