Patient education: Listeria infection (The Basics)

What is Listeria infection? — Listeria is a type of bacteria. It can cause fever, stomach upset, and other symptoms. People can get it from eating certain foods.

Listeria infection can be mild or severe. It is not usually serious in healthy people. But it can be more dangerous for pregnant people. A pregnant person can also pass Listeria to their baby. This can cause serious health problems or even death.

Certain other people are also at risk of getting very sick from Listeria infection. They include:

●Newborn babies

●Older people

●People who have HIV, cancer, diabetes, or another serious medical condition

●People who had an organ transplant or stem cell transplant

●People who take medicines that weaken the immune system

These people are more likely to get Listeria infections in the blood or brain.

What are the symptoms of Listeria infection? — The symptoms are different depending on which part of the body is affected.

People with Listeria infection in the brain and spinal cord can have:

●Fever

●Headache

●Nausea and vomiting

●Stiff neck

●Confusion or trouble thinking

●Weak muscles on 1 side of the body, trouble walking, or shaky hands

●Seizures – Seizures are waves of abnormal electrical activity in the brain. They can make people pass out or move or behave strangely.

People with Listeria infection in the blood can have:

●Fever

●Chills

●Dizziness

●Low blood pressure

●Fast heart rate

●Pain in joints and muscles

People with Listeria infection in the digestive system (figure 1) can have:

●Fever

●Watery diarrhea

●Nausea and vomiting

●Headache

●Pain in joints and muscles

Should I see a doctor or nurse? — Call a doctor or nurse if you have any of the symptoms listed above and you:

●Are pregnant

●Are older than 50

●Have a serious medical condition

●Take medicines that weaken your immune system

Call a doctor or nurse if your newborn baby:

●Gets sick with a fever or any of the other symptoms listed above

●Acts differently from normal, such as feeding less than usual, breathing faster than usual, or looking sleepier than usual

Is there a test for Listeria infection? — Yes, there are a few different tests. Which tests you need depends on your symptoms, whether you are pregnant, and if you have other medical conditions.

Tests include:

●Blood tests

●Lumbar puncture (sometimes called a "spinal tap") – To do this test, a doctor puts a thin needle into your lower back. Then, they take out a small amount of spinal fluid. Spinal fluid is the fluid around the brain and spinal cord. They do tests on the fluid to look for Listeria.

●Tests on a sample of your bowel movement (if you could have Listeria that affects the digestive system)

●Imaging tests of the brain – These tests create pictures of the inside of the body. They can include an MRI or CT scan.

How is Listeria infection treated? — This depends on your symptoms and any other health conditions you have. For example:

●Pregnant people, newborn babies, and people with serious Listeria infections are treated with antibiotics. These are usually given through a thin tube that goes into a vein, called an "IV." People who are very sick might need treatment in the hospital.

●Healthy people with Listeria in their digestive system don't usually need treatment. The infection usually goes away on its own in about 2 days.

Can Listeria infection be prevented? — You can lower your chances of getting Listeria with good food safety. Tips include:

●Avoid milk and cheese that is "unpasteurized," or foods made with them.

●Wash fruits and vegetables well before eating them.

●Keep the refrigerator colder than 40°F (4.4°C) and the freezer colder than 0°F (-18°C).

●Cook meat and seafood until well done.

●Cook eggs until the yolk is firm.

●Wash hands, knives, and cutting boards after they touch raw food.

For more tips on food safety, see the table (table 1).

People with weakened immune systems or people who are pregnant should be extra careful. They should also avoid foods such as:

●Raw milk

●Soft cheeses (including Mexican-style cheeses like queso blanco)

●Hot dogs

●Deli meats

●Refrigerated pâtés or meat spreads

●Smoked seafood (such as lox)

Your doctor or nurse can talk to you about which foods to avoid. You can also check the Centers for Disease Control and Prevention website at www.cdc.gov/listeria/prevention.html. This page includes information about Listeria outbreaks and foods to avoid or be careful about eating.

More on this topic

Patient education: Avoiding infections in pregnancy (The Basics)
Patient education: Bacterial meningitis (The Basics)
Patient education: Food poisoning (The Basics)
Patient education: Sepsis in newborn babies (The Basics)

Patient education: Acute diarrhea in adults (Beyond the Basics)
Patient education: Foodborne illness (food poisoning) (Beyond the Basics)