Listeriosis

Listeriosis is a form of food poisoning you get from the bacteria Listeria monocytogenes. Many people refer to this bacterial infection as just “Listeria.”

For many people, a Listeria infection causes mild symptoms like a fever, headache, diarrhea or vomiting. But if you have a weakened immune system or are over 65, you’re at higher risk for life-threatening complications. If you’re pregnant, the infection can pass to the fetus during pregnancy or at birth (vertical transmission). This can cause pregnancy loss or serious, life-long health issues for your child.

Symptoms of Listeria infection

Listeriosis symptoms include:

• Fever
• Chills
• Headache
• Diarrhea
• Nausea and vomiting
• Muscle or joint pain
• Fatigue

You might not have all these symptoms. If Listeria spreads beyond your digestive system (invasive listeriosis), you might have additional, severe symptoms. These include:

• Confusion
• Loss of balance
• Stiff neck
• Seizures

How long after Listeria exposure do you get sick?

Symptoms of listeriosis can start a few days to two weeks after eating contaminated food. If you’re pregnant, you might have mild or no symptoms but can still pass the infection to the fetus.

Listeria causes

The bacteria Listeria monocytogenes causes listeriosis. You get it by eating or drinking something contaminated with the bacteria. If you’re pregnant and get a Listeria infection, you can transmit it to the fetus during pregnancy or childbirth.

What foods can contain Listeria?

Foods that are more likely to be contaminated with Listeria include:

• Deli meats, cold cuts and hot dogs
• Pâté (pureed meat) and meat spreads
• Cold-smoked fish, like lox
• Soft cheese, like Brie, Camembert and queso fresco
• Unpasteurized dairy products, like milk, cheese and ice cream (pasteurization kills germs)
• Unpasteurized fruit juices like apple cider
• Raw, unwashed fruits and vegetables (especially melon)
• Sprouts
• Raw sushi

Is Listeria contagious?

No, Listeria infections aren’t contagious — they don’t spread to people around you.

Risk factors

You have a higher risk of getting severely ill or dying from listeriosis if you’re:

• Pregnant
• 65 or older
• Have a weakened immune system due to illness or immunosuppressive medications

Complications of listeriosis

Listeria can spread from your digestive tract to other parts of your body. This can cause serious complications, including:

• Inflammation of your heart (endocarditis), bones (osteomyelitis) or the lining of your abdominal organs (peritonitis)
• Inflammation in your brain and spinal cord (encephalitis) or their lining (meningitis)
• Miscarriage, stillbirth or preterm birth
• Pneumonia
• Sepsis, a severe reaction to an infection that causes organ damage
• Septicemia, bacteria multiplying in your blood and spreading to other parts of your body
• Urinary tract infections
• Death

If you’re born with listeriosis or if you get an infection that spreads to your brain or causes sepsis, you could have long-lasting health conditions. These include:

• Developmental delays or differences
• Blindness
• Organ damage or failure
• Paralysis
• Seizures

How do you know if you have listeriosis?

You won’t know for sure if you have listeriosis unless you get tested. Many people don’t get tested if their symptoms are mild.

A healthcare provider might suspect you have listeriosis based on your symptoms and whether you’ve eaten something that could’ve been contaminated. They can confirm a diagnosis by testing your blood, fluid around your brain and spinal cord (cerebrospinal fluid), or amniotic fluid (if you’re pregnant) for signs of the bacteria.

Other tests might include:

• Blood culture
• Testing tissue from the placenta after birth (if you’re pregnant)
• CT scan or MRI of your brain if you have neurological symptoms

How is listeriosis treated?

Antibiotics like sulfamethoxazole and ampicillin treat listeriosis. Take your full course of medication as prescribed by your healthcare provider, even if you start to feel better. If you don’t take antibiotics as prescribed, the infection can come back.

If you have mild symptoms and aren’t pregnant or at risk for serious complications, you might not need treatment.

When should I see my healthcare provider?

Call your healthcare provider if:

• You’re pregnant, over 65 or have a weakened immune system and have symptoms of a Listeria infection
• Something you’ve eaten or drank recently has been recalled due to Listeria contamination, especially if you’re pregnant
• Your baby has listeriosis symptoms
• Your symptoms don’t get better a few days after starting antibiotics

Ask your provider how to take any medications they prescribe and what to do if you miss a dose.

Can Listeria be prevented?

You can reduce your risk of a Listeria infection by following food safety guidelines:

• Avoid unpasteurized dairy products and juices. This includes milk, cheese and ice cream.
• Wash your hands and any food surfaces before and after cooking,
• Use a scrub brush and clean, running water to clean raw fruits and vegetables.
• Cook hot dogs, egg dishes and seafood to an internal temperature of 165 degrees Fahrenheit (74 degrees Celsius).
• If you’re pregnant, don’t eat refrigerated pâté or meat spreads from the deli or the meat counter at a grocery store. Heat lunch meat until steaming hot.
• Clean up any spills in your refrigerator right away, especially meat juices.

Can Listeria be killed by cooking?

Yes, heating foods to the proper temperature kills Listeria.

Can Listeria go away on its own?

Yes, if you have a healthy immune system and aren’t pregnant, you’ll usually feel better in a couple of days without treatment. But if you’re pregnant or have risk factors for serious illness, talk to a healthcare provider right away. About 1 in 6 people with invasive listeriosis die.

Is there anything I can do to feel better?

You can manage the symptoms of listeriosis by resting and drinking lots of fluids. Avoid alcohol and caffeine, as they can make diarrhea worse. Over-the-counter medications might help relieve some symptoms. Talk to your child’s healthcare provider before giving them medications to make sure they’re safe.