Listeria Symptoms in Adults

By Temma Ehrenfeld @temmaehrenfeld
August 28, 2018

When listeria, a foodbourne germ, spreads beyond your intestines, it can be dangerous. Listeria symptoms in adults range from headaches to miscarriages.

Eat food contaminated with listeria and you may get a fever, muscle aches, and diarrhea. But when the germ spreads beyond your gut, it is more dangerous.

About 1,600 Americans get sick from listeria every year, and about 260 die, according to the Centers for Disease Control and Prevention. Half of all infections occur in seniors, who may have weakened immunity or less stomach acid, which helps kill unfriendly bacteria.

You’re also more likely to get an infection if you are using steroids or receiving chemotherapy or have less immunity because of another condition like cancer, diabetes, alcoholism, or HIV. People with cancer are 10 times more likely to get a Listeria infection than other people. Pregnant women are also at risk.


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What is listeria monocytogenes?

It is the scientific name for the germ is Listeria monocytogenes, or L. monocytogenes.

What are the main listeria symptoms in adults?

Listeria symptoms in adults may include a fever, muscle aches, nausea, or diarrhea. The symptoms of listeria monocytogenes usually start within a few days but can strike up to two months after you eat contaminated food. Most people with severe symptoms require hospital care. Usually, the bacteria have spread from their intestines to their blood, or their central nervous system, where it can cause headaches, stiff necks, confusion, loss of balance, or even confusion. A listeria infection is not contagious from person to person except during pregnancy.

A blood or spinal fluid test can confirm the diagnosis. The standard treatment is 14 days of antibiotics.

In pregnant women, the symptoms are often mild, suggesting a flu. But the infection can pass to the unborn child, and lead to a miscarriage, stillbirth, or preterm labor. Antibiotics can often prevent infection of the fetus or newborn. Babies who have listeriosis receive the same antibiotics as adults.

Where does listeria come from?

Listeria lives in soil and water. It can contaminate vegetables through the soil or fertilizer and animals, reaching people through contaminated meat and dairy, including processed products. In the 1990s, deli meats and hot dogs caused outbreaks of infections. More recently, investigators have traced outbreaks to soft cheeses, celery, sprouts, cantaloupe, and ice cream.

How to avoid listeria

  • Don’t eat any dairy product, including soft cheese — such as queso fresco, queso blanco, panela (queso panela), brie, Camembert, blue-veined cheese, and feta — unless it is made from pasteurized milk. Pasteurization kills listeria, but cheese from unsanitary facilities still may be contaminated.
  • Keep all milk and milk products refrigerated.
  • If you are at risk, don’t eat raw sprouts.
  • Eat cut melon immediately or refrigerate it. Throw away cut melons left at room temperature for more than four hours.
  • Wash your hands after handling any deli meats. Once a sealed package is open, refrigerate and eat any meat that isn’t factory sealed within five days.

People at risk should stay away from smoked seafood (lox) unless it is cooked.


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March 26, 2020

Reviewed By:  

Janet O’Dell, RN