Listeriosis: Facts and Details

What is listeriosis?

Listeriosis is a serious infection usually caused by eating food contaminated with the bacterium Listeria monocytogenes. The disease primarily affects older adults, pregnant women, newborns and adults with weakened immune systems. Although rare, persons without these risk factors can also be affected.

What are the symptoms of listeriosis?

A person with listeriosis usually has fever and muscle aches; sometimes diarrhea occurs first. Other symptoms can include headache, stiff neck, confusion, loss of balance and convulsions.

Pregnant women typically only have a mild, flu-like illness. However, infections during pregnancy can lead to miscarriage, stillbirth, premature delivery, or life-threatening infection of the newborn.

How do you get listeriosis?

People can get listeriosis by eating food contaminated with Listeria bacteria. Babies can be born with listeriosis if their mothers eat contaminated food during pregnancy.

How soon after exposure do symptoms appear?

The time from infection to when symptoms appear varies. Symptoms usually appear about one month after exposure, although the incubation period can range from three to seventy days.

Can listeriosis be treated?

Antibiotics given promptly can cure the illness and in pregnant women, prevent infection of the fetus. Even with prompt treatment, some Listeria infections result in death. This is particularly likely in older adults and in persons with other serious medical problems.

How can you reduce your risk for listeriosis?

General recommendations to prevent an infection from Listeria include:

• Thoroughly cook raw food from animal sources, such as beef, pork or poultry to a safe internal temperature.
• Rinse raw fruits and vegetables thoroughly under running tap water before eating.
• Keep uncooked meats and poultry separate from vegetables, and from cooked foods and ready-to-eat foods.
• Do not drink raw (unpasteurized) milk, and do not eat foods that have unpasteurized milk in them.
• Wash hands, utensils, countertops and cutting boards after handling and preparing uncooked foods.
• Consume perishable and ready-to-eat foods as soon as possible.
• If you are in a high-risk group (e.g., pregnant woman, older adult, person with weakened immune system):
• Do not eat hot dogs, luncheon meats, cold cuts, etc. unless they are heated to an internal temperature of 165 degrees Fahrenheit.
• Do not eat refrigerated pate or meat spreads from a deli or meat counter.
• Do not eat soft cheese such as feta, queso blanco, queso fresco, brie, etc. Make sure the label says, “Made with pasteurized milk.” Be aware that some Mexican-style cheeses made from pasteurized milk, such as queso fresco, can be contaminated during cheese-making.
• Do not eat refrigerated smoked seafood unless it is contained in a cooked dish

For more information contact the Sedgwick County Health Department Epidemiology Program at 316-660-7300