What is listeriosis?
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.
In what foods is listeria found?
Contaminated foods are the most common cause of listeriosis infections. The most common foods that cause listeriosis include:
- Hot dogs.
- Deli meats.
- Fresh vegetables.
- Fresh fruits, especially melons.
- Unpasteurized dairy products (sterilized to kill bacteria).
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.
Who does listeriosis affect?
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:
- Pregnant people.
- Unborn babies.
- People 65 or older.
- People with a weakened immune system, usually from another condition (like AIDS or cancer) or taking prescribed immunosuppressive medications.
How common is listeria?
About 1,600 people get listeria in the United States each year.
Symptoms and Causes
What are the symptoms of listeriosis?
Listeriosis symptoms include:
- Upset stomach.
- Nausea and vomiting.
- Muscle aches.
- Loss of balance.
- Convulsions (muscle contractions that you can’t control).
What are the symptoms of listeriosis in pregnant people?
The most common symptoms of listeriosis in pregnant people are usually fever and other flu-like symptoms, especially fatigue and muscle aches.
What are the symptoms of listeriosis in newborn babies?
Listeriosis symptoms in newborn babies include:
- Constant crying.
- Trouble breathing (rapid breathing, short breaths and wheezing).
- No interest in eating.
How do you get listeriosis?
Most people contract listeriosis from contaminated food.
Pregnant people can transmit the L. monocytogenes bacteria to their unborn babies through their placenta. They can also transmit the bacteria to their babies in the birth canal.
Is listeriosis contagious?
You can’t pass listeriosis to another person unless a pregnant person passes it to their unborn child.
Diagnosis and Tests
How do you know if you have listeriosis?
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:
- Cerebrospinal fluid (a clear fluid in your brain and spinal cord).
- Meconium (your baby’s first poop; it’s dark green and thicker and stickier than normal poop).
- Animal feed.
Your healthcare provider may order bacterial culture tests on your blood or placenta if you’re pregnant.
Management and Treatment
Can listeriosis be cured?
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.
What are the side effects of antibiotics?
Side effects of antibiotics may include:
- Allergic reactions. Allergic reactions may range from mild rashes and itching to skin blisters, swelling in your face and throat and difficulty breathing. Talk to your healthcare provider about any past drug reactions or allergies.
- Clostridioides difficile. Clostridioides difficile (C. difficile or C. diff) is a bacteria that causes diarrhea.
- Antibiotic resistance. Antibiotic resistance occurs when bacteria change and get stronger so that antibiotic medicines can’t kill them or stop their growth. Bacterial infections then become difficult to treat with medications.
How do I manage my symptoms?
If you have listeriosis, the best way to manage your symptoms is to:
- Take prescription medications as directed by your healthcare provider.
- Drink lots of fluids.
- Eat a light diet.
- Take nonsteroidal anti-inflammatory drugs (NSAIDs) to manage fever and relieve muscle aches.
Not everyone can take NSAIDs. It’s a good idea to check with your healthcare provider before use.
How soon after treatment will I feel better?
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.
How can I reduce my risk of contracting listeria?
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.
- Check product labels to ensure that any dairy products or juices are pasteurized. Avoid unpasteurized dairy products and juices.
- Wash your hands and any food surfaces before and after cooking.
- Use a scrub brush, clean running water and a fruit and vegetable wash to clean raw fruits and vegetables.
- Cook hot dogs, egg dishes, seafood and deli meats to an internal temperature of 165 degrees F (74 degrees C). If you can’t, you should avoid them.
- Don’t eat refrigerated pâté (pureed meat) or meat spreads from a deli or the meat counter at a grocery store. Foods that don’t require refrigeration, like canned or shelf-stable pâté and meat spreads, are safe to eat. Refrigerate these items after opening.
- Heat your leftovers until they are steaming hot. Don’t eat any leftovers if they are several days old.
- Wrap food in plastic wrap or foil, or place it in plastic bags or clean, covered containers before you place them in your refrigerator. Ensure that foods such as raw meat don’t leak juices onto other foods.
- Clean up any spills in your refrigerator right away, especially meat juices.
Outlook / Prognosis
What can I expect if I have listeriosis?
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.
When should I see my healthcare provider?
Call your healthcare provider if:
- You’re pregnant, over 65 or have a weakened immune system and display listeriosis symptoms.
- The U.S. Food and Drug Administration (FDA) has recalled a food or drink that you’ve recently consumed because of a listeriosis outbreak.
- You have a baby who displays listeriosis symptoms.
- Your symptoms don’t go away a few days after starting antibiotics.
What questions should I ask my healthcare provider?
- How do you know that I have listeriosis?
- If I don’t have listeriosis, what other condition might I have?
- How did I get listeriosis?
- Do I need antibiotics or any other medications?
- For how long and at what times of the day should I take my medications?
- How should I store my medications?
- Is my unborn baby at risk of having listeriosis?
- How can I protect my unborn baby?
- How do you know that my newborn baby has listeriosis?
- What medications will you prescribe my newborn baby?
- Will my newborn baby have any long-term effects from listeriosis?
A note from Cleveland Clinic
Listeriosis is a relatively rare bacterial infection. It may have serious effects on pregnant people, unborn babies, 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.
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