Listeria infection (listeriosis) - Symptoms and causes
Listeria infection is a foodborne bacterial illness that can be very serious for pregnant women, people older than 65 and people with weakened immune systems. It's most commonly caused by eating improperly processed deli meats and unpasteurized milk products.
Healthy people rarely become ill from listeria infection, but the disease can be fatal to unborn babies, newborns and people with weakened immune systems. Prompt antibiotic treatment can help curb the effects of listeria infection.
Listeria bacteria can survive refrigeration and even freezing. So people who are at higher risk of serious infections should avoid eating the types of food most likely to contain listeria bacteria.
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If you develop a listeria infection, you might have:
Symptoms might begin a few days after you've eaten contaminated food, but it can take 30 days or more before the first signs and symptoms of infection begin.
If the listeria infection spreads to your nervous system, signs and symptoms can include:
Confusion or changes in alertness
Loss of balance
Symptoms during pregnancy and in newborns
During pregnancy, a listeria infection is likely to cause only mild signs and symptoms in the mother. The consequences for the baby, however, can be devastating — the baby can die in the womb or have a life-threatening infection within a few days of being born.
Signs and symptoms of a listeria infection in a newborn can be subtle, but can include:
Little interest in feeding
When to see a doctor
If you've eaten a food that's been recalled because of a listeria outbreak, watch for signs or symptoms of illness. If you have a fever, muscle aches, nausea or diarrhea, contact your doctor. The same goes for illness after eating a potentially contaminated product, such as foods made with unpasteurized milk or poorly heated hot dogs or deli meats.
If you have a high fever, severe headache, stiff neck, confusion or sensitivity to light, seek emergency care. These signs and symptoms can indicate bacterial meningitis, a life-threatening complication of a listeria infection.
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Listeria bacteria can be found in soil, water and animal feces. People can get infected by eating the following:
Raw vegetables that have been contaminated from the soil or from contaminated manure used as fertilizer
Unpasteurized milk or foods made with unpasteurized milk
Certain processed foods — such as soft cheeses, hot dogs and deli meats that have been contaminated after processing
Unborn babies can contract a listeria infection from the mother.
Pregnant women and people who have weak immune systems are at highest risk of contracting a listeria infection.
Pregnant women and their babies
Pregnant women are much more susceptible to listeria infections than are other healthy adults. Although a listeria infection might cause only a mild illness in pregnant women, consequences for their babies can include:
A potentially fatal infection after birth
People who have weak immune systems
This category includes people who:
Are older than 65
Are receiving chemotherapy
Have diabetes or kidney disease
Take high-dose prednisone or certain rheumatoid arthritis drugs
Take medications to block rejection of a transplanted organ
Most listeria infections are so mild they can go unnoticed. However, in some cases, a listeria infection can lead to life-threatening complications, including:
Generalized blood infection
Inflammation of the membranes and fluid surrounding the brain (meningitis)
To prevent a listeria infection, follow simple food safety guidelines:
Keep things clean. Wash your hands thoroughly with warm, soapy water before and after handling or preparing food. After cooking, use hot, soapy water to wash the utensils, cutting boards and other food preparation surfaces.
Scrub raw vegetables. Clean raw vegetables with a scrub brush or vegetable brush under plenty of running water.
Cook your food thoroughly. Use a food thermometer to make sure your meat, poultry and egg dishes are cooked to a safe temperature.
Precautions for people particularly at risk
If you're pregnant or you have a weak immune system, be particularly cautious about listeria. Take additional precautions with these types of foods:
Soft cheeses and Mexican-style cheeses. Don't eat soft cheeses such, as feta, brie, Camembert or blue cheese, or Mexican-style cheeses such as queso blanco and queso fresco, unless it's clear from the packaging that the product was made using pasteurized milk.
Hot dogs and deli meats. Avoid these unless they're reheated until steaming hot. Keep fluid from hot dog packages away from other foods, utensils and food preparation surfaces. Wash your hands after handling these products.
Meat spreads. Don't eat refrigerated meat spreads. Canned or shelf-stable — meaning they can be safely stored at room temperature — meat spreads are acceptable. Refrigerate after opening.
Smoked seafood. These products can be labeled as nova style, lox, kippered or jerky. It's OK to eat them in cooked dishes. Canned or shelf-stable smoked seafood is acceptable.
Raw or lightly cooked sprouts. Cook sprouts of any kind thoroughly.
By Mayo Clinic Staff
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Causes, Symptoms, Treatment & Prevention
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:
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:
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
Flu-like symptoms are common signs of listeriosis.
What are the symptoms of listeriosis?
Listeriosis symptoms include:
Nausea and vomiting.
Loss of balance.
Convulsions (muscle contractions that you can’t control).
A severe listeriosis infection may spread to your bloodstream or brain. Severe infections may cause sepsis, meningitis or encephalitis.
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.
Listeriosis may quickly cause miscarriage, stillbirth, premature birth and death in newborn babies without timely treatment.
What are the symptoms of listeriosis in newborn babies?
Listeriosis symptoms in newborn babies include:
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 the fetus through the 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 the fetus.
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).
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
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 fetus at risk of having listeriosis?
How can I protect my fetus?
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, 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.
Listeria as a causative agent of food poisoning
For many centuries, mankind has known that eating poor-quality products can provoke human poisoning. When microorganisms enter food, toxins accumulate in the latter, which can cause food poisoning.
They are characterized by sudden onset, bouts of nausea and repeated vomiting, diarrhoea, cramping abdominal pain, fever and symptoms of intoxication.
Foodborne infections can be caused by various microorganisms, including Listeria. There are several types of Listeria, but only Listeria monocytogenes causes food poisoning in humans. Listeriosis is a foodborne infection caused by a specific bacterial species, Listeria monocytogenes.
Where does listeriosis come from? Who is at risk for this disease? And how to prevent it? Galina Vyacheslavovna Safroshina, head of the food microbiology and veterinary and sanitary examination sector of the testing laboratory of the Bryansk MVL, will give us answers to these questions.
— Galina Vyacheslavovna, how does listeriosis occur?
- Listeria monocytogenes is actually everywhere. They can be found in soil, dirty water, the gastrointestinal tract, and animal feces.
Listeria has a peculiarity: unlike many other pathogens, they thrive at low temperatures. Therefore, they actively multiply, for example, in refrigerators. Listeria has another insidious property: the ability to multiply in salty foods of plant and animal origin. If most microbes die under these conditions, then Listeria can withstand a concentration of table salt up to 6-20%.
Listeria die at boiling temperature, and under the influence of sunlight, the causative agent of the disease will live no more than 15 days.
The risk of catching listeriosis increases if you consume:
• raw vegetables and fruits that have not been washed well;
• uncooked meat;
• raw foods that have been stored in the refrigerator for a long time;
• unpasteurized milk;
• Prepared foods such as soft cheese, hot dogs, deli meats, salads that have been contaminated with Listeria (eg from someone else's dirty hands).
— Who is at risk for listeriosis?
— Most often, pregnant women, newborn children, elderly people over 65 years of age, that is, those who have a weakened immune system, face severe complications of the course of listeriosis.
— Galina Vyacheslavovna, is it possible to prevent listeriosis, if so, how?
- Listeriosis can be prevented in the same way as other foodborne infections, namely by following the rules of prevention:
• Wash your hands regularly with warm water and soap. Especially before meals, as well as before and after cooking.
• If you have cut or otherwise cooked raw foods, wash anything that has come into contact with them in hot water and detergent: cutting boards, knives, plates.
• Wash raw vegetables and fruits thoroughly before eating. It is best to do this with a brush under running water.
• Fry meat, poultry, and bring eggs to full readiness. Listeria die when cooked. If you are at risk, take extra precautions. In particular, avoid unpasteurized milk, soft cheeses, and convenience foods (hot dogs, cold cuts) unless they are heated to steam.
In Russia, the incidence of listeriosis in recent years has been at the level of single cases (less than 0.05 per 100,000 population), which is 15 times lower than similar indicators in European countries. But doctors take it very seriously. The fact is that in some people the infection spreads to the central nervous system and can provoke a serious complication - bacterial meningitis. Every fifth person infected in this case dies.
Specialists of the sector of food microbiology and veterinary and sanitary examination of the testing center of the Federal State Budgetary Institution "Bryansk MVL" conduct tests of food products for the "Listeria monocytogenes" indicator in accordance with the scope of accreditation, using the microbiological method of research. The use of modern measuring instruments and equipment, as well as the introduction of new research methods, make it possible to ensure a high level of reliability of tests carried out on the basis of the institution. Laboratory tests are carried out by qualified specialists of the Federal State Budgetary Institution "Bryansk MVL", who regularly improve their professional skills and qualifications.
Food poisoning: symptoms, treatment and prevention
What is food poisoning and what to do about it?
Almost every person at least once in his life experienced the severity of food poisoning. Especially often such a negative phenomenon occurs in children. Therefore, it is important to know what to do and what to fear in case of trouble. And of course - how to avoid poisoning in the future.
Food poisoning (food poisoning, PTI, or in foreign terminology - food sickness) occurs when a person eats any food contaminated with pathogenic bacteria. The list of pathogenic microorganisms is very wide, and many of them, if they enter the digestive system, can lead to very serious consequences.
The problem is exacerbated by the fact that pathogenic microorganisms, being in food, produce toxins. These substances cause symptoms of poisoning even when the food is sufficiently thermally processed and there are no living microbial bodies in it.
Which foods pose a risk of food poisoning?
There are a lot of such products. The most dangerous are those that should be stored in a cool place, in refrigerators and freezers. In the hot season, it is not always possible to provide such conditions, especially when a company or family goes on a picnic in nature.
Food poisoning hazards include:
raw or undercooked meat or poultry;
unpasteurized dairy products;
raw shellfish, fish, seafood;
unwashed fruits and vegetables.
Poisoning by fish products is especially dangerous.
Symptoms of food poisoning
They can appear both after a few hours and 2-5 days after eating poor-quality food or drink. The duration of the asymptomatic (it is not entirely correct to call it incubation) period is determined by the massive intake of toxins into the body. The more contaminated food eaten / drunk, the shorter the prosperous period.
Symptoms for most food poisoning are:
repeated loose stools, diarrhea;
loss of appetite;
vomiting, often relieved;
weakness and fatigue.
One or more people can get poisoned by toxins from contaminated food. Of course, if they used the same products. Family poisoning is very common.
When should you see a doctor about poisoning?
Most patients (or victims) from food poisoning do not go to the doctors, since the symptoms described above are mild and ignored. And they pass within 1-3 days.
However, there are symptoms when medical attention should not be delayed. Call your doctor if:
Severe diarrhea lasts more than 3 days.
Frequent vomiting lasts more than 2 days.
There is blood in the stool.
Body temperature above 38 degrees Celsius
Seek emergency care if:
maroon or black stools or significant blood in the stool;
feeling of strong palpitations or interruptions in the work of the heart;
The cause of food poisoning is most likely fish or seafood.
A very serious disorder which, when poisoned, causes vomiting and diarrhea.
Symptoms of dehydration include:
reduced urine output (less than 2-3 times a day), urine darker than usual;
headache and confusion;
dizziness, sensation of intoxication.
Another symptom is the absence of tears when a person cries. It may be relevant if a small child is sick.
To correct mild dehydration, it is necessary to drink clean water in small sips, in small portions (so as not to provoke vomiting), but often every 20-30 minutes. You can juice with water, carbonated drinks without dyes.
Sugary soda, coffee and tea can aggravate the lack of moisture in the body.
A good alternative are oral rehydration solutions (Regidron), which contain salts and electrolytes in the amount necessary for a person.
Treatment of food poisoning
Most cases of food poisoning are mild and resolve spontaneously in a few days. For this period, the most important thing is to support the body and compensate for the loss of fluid, electrolytes, which the body loses with frequent loose stools and vomiting.
Dairy products and solid, heavy foods should be avoided until the diarrhea is gone. With the onset of improvement, you can gradually return to your usual diet. Starting with soft foods: bananas, white bread toast, crackers, light porridge.
Avoid spicy, fried foods and dairy products for a few more weeks.
It is important to drink plenty of fluids, but it should not be milk or caffeinated drinks: just pure water, natural juices.
Do not drink fitness drinks: they do not provide the necessary balance of electrolytes and minerals.
In case of severe intoxication, gastric and intestinal lavage should be done. If necessary (uncontrollable vomiting, frequent loose stools), intravenous infusions are prescribed to eliminate dehydration. Such activities are carried out in stationary conditions.
Is food poisoning a serious illness?
Yes. The main negative factor is dehydration. However, the danger, in addition to it, is also the bacteria themselves.
For example, Listeria food poisoning can be very dangerous for the unborn children of pregnant women. The infection is easily tolerated by the mother, but can lead to miscarriage, premature birth, stillbirth, and developmental problems in their children. People with weakened immune systems are also at risk of developing listeriosis complications.
Escherichia coli (E. coli) food poisoning can cause hemolytic uremic syndrome (HUS). HUS can cause kidney failure, especially in people with weakened immune systems.
Can food poisoning be prevented or avoided?
The best way to prevent food poisoning is to always know what you are eating. The best way to always know what you are eating is to eat at home. You have more control over the storage and preparation of food at home. Care should be taken when snacking at lunchtime: the heat leads to the rapid multiplication of pathogenic microorganisms in products and the accumulation of toxins in them.
Tips for preventing food poisoning:
wash fruits and vegetables thoroughly;
Wash countertops, cutting boards, knives and utensils thoroughly before using them for cooking;
wash your hands and dishes frequently;
do not put raw and cooked meat on the same plate;
if the knives were used for butchering raw chicken, do not use them for other foods that will not be cooked;
cook meat thoroughly, if necessary use a meat thermometer: make sure beef is cooked to at least 70°C, chicken and other poultry to 80°C, and fish from 60°C;
do not use prepackaged products that are past their expiration date;
discard preserves from bulging or deformed cans;
if the food is not eaten within the next 4 hours, put it in the cold;
do not eat mushrooms;
do not eat soft cheeses (especially imported ones) during pregnancy or in case of weak immunity;
when abroad, pour boiling water over all fruits and vegetables (try to do this at home as well).