Listeriosis

by CDC

Listeriosis, a serious infection caused by eating food contaminated with the bacterium Listeria monocytogenes, has 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 fever, muscle aches, and sometimes gastrintestinal symptoms such as nausea or diarrhea. If infection spreads to the nervous system, symptoms such as headache, stiff neck, confusion, loss of balance, or convulsions can occur.

Infected pregnant women may experience only a mild, flu-like illness; however, infections during pregnancy can lead to miscarraige or stillbirth, premature delivery, or 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 - They are about 20 times more likely than other healthy adults to get listeriosis. About one-third of listeriosis cases happen during pregnancy.
• Newborns - Newborns rather than the pregnant women themselves suffer the serious effects of infection in pregnancy.
• Persons with weakened immune systems
• Persons with cancer, diabetes, or kidney disease
• Persons with AIDS - They are almost 300 times more likely to get listeriosis than people with normal immune systems.
• Persons who take glucocorticosteroid medications
• The elderly

Healthy adults and children occasionally get infected with Listeria, but they rarely become seriously ill.

How does Listeria get into food?

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. The bacterium has been found in a variety of raw foods, such as uncooked meats and vegetables, as well as in processed foods that become contaminated after processing, such as soft cheeses and cold cuts at the deli counter. Unpasteurized (raw) milk or foods made from unpasteurized milk may contain the bacterium.

Listeria is killed by pasteurization and cooking; however, in certain ready-to-eat foods such as hot dogs and deli meats, contamination may occur after cooking but before packaging.

How do you get listeriosis?

You get listeriosis by eating food contaminated with Listeria. 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 can prevent Listeria 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?

General recommendations:

• 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 unpasteurized (raw) milk or foods made from unpasteurized milk.
• Wash hands, knives, and cutting boards after handling uncooked foods.
• Consume perishable and ready-to-eat foods as soon as possible.

Recommendations for persons at high risk, such as pregnant women and persons with weakened immune systems, in addition to the recommendations listed above:

Do not eat hot dogs, luncheon meats, or deli meats, unless they are reheated until steaming hot.

About the Author

www.cdc.gov
The Centers for Disease Control and Prevention (CDC) is one of the 13 major operating components of the Department of Health and Human Services (HHS), which is the principal agency in the United States government for protecting the health and safety of all Americans and for providing essential human services, especially for those people who are least able to help themselves.