Listeriosis is a foodborne illness caused by the bacteria L. monocytogenes. Symptoms include fever, chills, and headache. Pregnant people and people with weakened immune systems are at the greatest risk of a severe infection. Treatment may include antibiotics. You can prevent a listeriosis infection by thoroughly washing and cooking your foods.
Listeriosis is a foodborne illness. The germ Listeria monocytogenes causes listeriosis. Listeria monocytogenes is commonly found in nature, especially in soil, groundwater, rotting vegetation and animal feces (poop).
Most people get listeriosis from eating contaminated foods. The listeriosis incubation period (the time when you first get infected and when you first show symptoms) varies. It usually takes one to two weeks, but it can be as short as a couple of days or as long as three months.
Other names for listeriosis include L. monocytogenes and listeria.
Contaminated foods are the most common cause of listeriosis infections. The most common foods that cause listeriosis include:
These foods have the highest risk of L. monocytogenes contamination. However, listeriosis can affect almost any improperly handled or prepared food.
The bacteria L. monocytogenes is unique from many other foodborne illnesses. It survives and even multiplies in low temperatures, including refrigerators and freezers. The bacteria can multiply to dangerous levels during storage.
Food that has spoiled breaks down and develops an unpleasant smell, taste or change in texture. When L. monocytogenes bacteria contaminate food, the smell, taste and texture don’t change.
Anyone can get listeriosis. However, it isn’t as dangerous for those with a healthy immune system. Those who are at the greatest risk of becoming very ill or dying include:
About 1,600 people get listeria in the United States each year.
Listeriosis symptoms include:
The most common symptoms of listeriosis in pregnant people are usually fever and other flu-like symptoms, especially fatigue and muscle aches.
Listeriosis symptoms in newborn babies include:
Most people contract listeriosis from contaminated food.
Pregnant people can transmit the L. monocytogenes bacteria to the fetus through the placenta. They can also transmit the bacteria to their babies in the birth canal.
You can’t pass listeriosis to another person unless a pregnant person passes it to the fetus.
Your healthcare provider can diagnose listeriosis after evaluating your symptoms and conducting medical tests. Tests may include checking the following for the presence of L. monocytogenes:
Your healthcare provider may order bacterial culture tests on your blood or placenta if you’re pregnant.
Yes, there is a cure for listeriosis. Your healthcare provider can prescribe antibiotics to rid your body of the infection.
Your healthcare provider is more likely to prescribe antibiotics to babies or if you’re pregnant, 65 or older or have a weakened immune system. Antibiotics commonly used to treat listeriosis include sulfamethoxazole (Bacter-Aid DS®) and ampicillin (Principen®).
Your provider may also prescribe medication to manage specific symptoms, including nausea and vomiting.
If you have mild symptoms, you may not need treatment.
If your baby is born with a listeriosis infection, your healthcare provider will give them antibiotics shortly after birth.
Side effects of antibiotics may include:
If you have listeriosis, the best way to manage your symptoms is to:
Not everyone can take NSAIDs. It’s a good idea to check with your healthcare provider before use.
Most people with a healthy immune system will feel better after a few days without treatment.
If you have a severe listeriosis infection, you should start to feel better three to five days after you start taking antibiotics.
It’s important to take your full course of antibiotics as prescribed by your healthcare provider, even if you start to feel better. If you don’t finish your full course of antibiotics, your listeriosis may come back and be more challenging to treat.
If you have a weak immune system or are pregnant, it’s a good idea to take precautions with what you eat and drink and how you store and prepare food.
If you have a healthy immune system and develop listeriosis, you’ll usually feel better without treatment in about two days.
If you have a weakened immune system, are pregnant or have a baby, listeriosis may cause serious illness or death. Contact your healthcare provider right away. With a quick diagnosis and proper treatment, your stand a better chance of a full recovery.
Call your healthcare provider if:
A note from Cleveland Clinic
Listeriosis is a relatively rare bacterial infection. It may have serious effects on pregnant people, fetuses, newborn babies, people 65 or older and people who have weakened immune symptoms. You’ll likely feel better after a few days without treatment if you have a healthy immune system. Talk to your healthcare provider right away if you notice any symptoms of listeriosis. Because listeriosis has an incubation period that may last up to a few months, it’s also a good idea to talk to your healthcare provider if you’ve consumed any recalled foods or drinks.
To help prevent a listeriosis infection, wash your hands, cook meats to a safe temperature and clean fruits and vegetables.
Last reviewed by a Cleveland Clinic medical professional on 06/06/2022.
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