Listeriosis (Listeria Infection)

What is listeriosis?

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 persons of advanced age, pregnant women, newborns, and adults with weakened immune systems. However, persons without these risk factors can also rarely be affected. The risk may be reduced by following a few simple recommendations.

What are the symptoms of listeriosis?

A person with listeriosis has fever, muscle aches, and sometimes gastrointestinal 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 miscarriage 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.