Listeriosis is an infectious disease mainly caused by contaminated food. Listeriosis is relatively harmless for healthy people, but the infection can be dangerous for pregnant women, weakened or old people.


What is listeriosis?

According to Bestitude, listeriosis is transmitted by something called listeria. These are bacteria of the Listeria genus, which are very undemanding and therefore widespread. They are mostly found in wild animals, but also in domestic animals.

However, one species of Listeria can also affect humans: Listeria monocytogenes. This type of bacteria is highly contagious and distributed throughout the world. Listeriosis was first discovered in 1923 in guinea pigs and rabbits on an experimental animal farm in Cambridge.

The first human case of listeriosis was documented in 1929. Listeriosis was named after the British surgeon Joseph Baron Lister (1827-1912). According to the Infection Protection Act, listeriosis has been a notifiable disease since 2001, regardless of whether it occurs in humans or animals.


Listeriosis, which occurs in humans, is caused by the almost ubiquitous bacteria of the species Listeria monocytogenes. These are rod-shaped, non-spore-forming bacteria that form flagella at a temperature of over 25 degrees Celsius and are therefore mobile.

The insidious thing about this type of bacteria is that it can also multiply in colder temperatures and thus survive in the refrigerator. The listeriosis pathogens can be found almost everywhere – on plants, in the soil, in water. This is how they get into the animal feed.

Listeriosis can be transmitted to humans in various ways: Listeria monocytogenes most commonly enters the human body through contaminated food, but listeriosis infection can also occur through contact with infected animals or contaminated soil.

Symptoms, Ailments & Signs

In most cases, listeriosis runs its course without recognizable symptoms. Healthy adults often overcome the disease unnoticed. Occasionally, however, discomfort and serious complications can occur. Flu symptoms are typical, for example tiredness, exhaustion or fever. If something irritating or spoiled is eaten, severe gastroenteritis can occur.

This is accompanied by symptoms such as vomiting, diarrhea and fever, which disappear by themselves after a few days. Infection via infected animals or contaminated soil can cause pustules on the hands and feet. People with a weakened immune system suffer from increasing symptoms in connection with listeriosis. First, there is increasing discomfort.

Symptoms such as headaches, nausea and vomiting and increased body temperature can occur after just a few hours. In extreme cases, the disease can lead to blood poisoning, meningitis or encephalitis. These secondary diseases are life-threatening and are expressed by further symptoms that are accompanied by a growing feeling of illness.

In pregnant women, listeriosis also causes urinary tract infections and chills. Infants often suffer from apathy and a rash that can spread to the entire body. Seizures and shortness of breath can also occur.

Diagnosis & History

Diagnosing listeriosis is extremely difficult. It is difficult to determine beyond doubt in the human body. What can be clinically proven is a significant increase in white blood cells (leukocytes).

Listeriosis cannot be clearly identified from the symptoms alone. Exact detection of the infectious disease requires detection of the pathogen. Listeria are detected either in the blood, in the spinal cord or brain fluid or in other body fluids. However, an antibody determination is not meaningful in the case of listeriosis, since basically everyone has come into contact with listeria several times and therefore antibodies against listeria can also be found in a healthy body.

In healthy people, listeriosis usually goes completely unnoticed and without recognizable symptoms. Symptoms such as high fever, severe headache, diarrhea, nausea and vomiting occur in people with a weakened immune system, as well as in pregnant women and newborns. Severe complications such as blood poisoning, meningitis or encephalitis can be associated with listeriosis.


Listeriosis can cause various complications or symptoms. Those affected usually suffer from the usual symptoms of flu or a stomach infection. The main symptoms are fever and severe nausea. Not infrequently, those affected also suffer from vomiting and diarrhea.

The quality of life is significantly reduced by the complaint. The loss of fluid also leads to fatigue and exhaustion in the patient. There is also pain in the head and joints. If listeriosis is not treated, in the worst case it can lead to inflammation in the brain or blood poisoning.

Both symptoms can be fatal and significantly reduce the life expectancy of those affected. As a rule, listeriosis can be treated relatively easily with antibiotics if treatment is started early. Complications usually do not arise.

Symptoms can be more severe in people with a weak immune system. However, life expectancy itself is not limited by listeriosis. In the case of inflammation of the brain or meninges, serious therapy is necessary to prevent the patient from dying.

When should you go to the doctor?

A doctor should be consulted in the event of symptoms such as exhaustion, tiredness or exhaustion. If there are digestive problems, apathy or loss of appetite, a doctor’s visit is necessary. If the symptoms increase or spread further, medical care for the person concerned is necessary.

A doctor should be consulted in the event of abnormalities in the complexion, the formation of pustules or discolouration on the skin. If you experience fever, dizziness or nausea, there is cause for concern. Caution should be exercised in the event of vomiting, sweating, trouble sleeping, or other flu-like symptoms. If the symptoms persist for several days, the person concerned needs medical care.

If headaches occur, if there is increased irritability or a diffuse feeling of illness, a doctor should be consulted. Since the secondary diseases of listeriosis can lead to a life-threatening condition, a doctor should be consulted at the first sign. A general malaise, an inner weakness or a decrease in the usual level of performance are considered unusual. They should be clarified by a doctor so that treatment to alleviate the symptoms can be initiated at an early stage. Chills, seizure disorders or shortness of breath are warning signs of the organism. They should be promptly followed up to determine the cause and take necessary steps to improve health.

Treatment & Therapy

Although listeriosis can be treated, the biggest problem here is the timely detection of the disease. Listeriosis is usually diagnosed too late, so that treatment with antibiotics is no longer effective.

Common antibiotics such as amoxicillin, gentamicin, ampicillin or erythromycin help against the pathogen Listeria monocytogenes for a timely diagnosis. An aminoglycoside is often used in addition, alternatively cotrimoxazole. With listeriosis, the risk of a recurrence is relatively high, so it is particularly important to take the antibiotic for at least three weeks at a time. This is the only way to really kill off all Listeria in the body.

The biggest problem with listeriosis is that treatment with antibiotics is often very stressful for the body, especially if patients with a weak immune system are to be treated. This means that support from the body’s own immune reaction is not always guaranteed and the treatment of listeriosis is more difficult than in people with a strong immune system.

Six weeks of antibiotic treatment is recommended for severe listeriosis associated with encephalitis or a brain abscess, and four to six weeks for endocarditis (inflammation of the lining of the heart).

Outlook & Forecast

Listeriosis is one of the notifiable diseases with the highest number of deaths. Around seven percent of those infected die as a result of listeriosis. If the patient is healthy, listeriosis usually progresses without long-lasting symptoms. The disease often heals completely unnoticed. The prognosis is worse if there are previous illnesses such as an immune deficiency. In the case of an immune deficiency, listeriosis can lead to disorders of the immune system. In immunocompromised individuals, the mortality rate is 20 to 30 percent.

If listeriosis occurs during pregnancy, this can lead to premature birth, miscarriage or stillbirth. In the case of transmission to the child, the so-called neonatal listeriosis can also occur. Affected infants suffer mental and physical damage and die from the disease in 30 to 50 percent of cases.

In the context of listeriosis, blood poisoning or meningitis can develop. A complicated course significantly worsens the prognosis. About 20 percent of all patients who suffer from sepsis die from blood poisoning. Meningitis leads to death in around 13 percent of cases. Chronic diseases such as tumors or AIDS also have a poorer prognosis. Likewise after organ transplants or during drug treatment with glucocorticoids. In seniors, listeriosis can cause serious complications that can even be life-threatening.


Unlike many other infectious diseases, listeriosis cannot be prevented by vaccination. To date, there is no effective vaccine against listeriosis. Therefore, the most important prophylactic measure is hygiene when handling food. People with an increased risk of illness should avoid foods such as raw meat and fish, raw milk and raw milk products. The safest measure against listeriosis infection is sufficient heating of the food.


Infectious diseases often need good follow-up care after they have healed. It aims to strengthen the immune system, regenerate those affected and, above all, to prevent the disease from flaring up again. Depending on the degree of illness, the follow-up care for listeriosis looks a little different and is ideally discussed with the doctor treating you.

Since this mainly affects the gastrointestinal area, the immune system can be strengthened by a number of measures that are in the hands of the patient. This includes a healthy diet, drinking enough water and getting enough sleep. It is also important not to start sporting activities too early if the person concerned is not fit enough for it.

The function of the intestine is often impaired by the medication given as part of the infection. This applies in particular to the administration of antibiotics. A non-stressful diet consisting of light food helps with aftercare. Natural yoghurt is suitable, for example, for rebuilding a disturbed intestinal flora.

You can do that yourself

Listeriosis has been a notifiable disease since 2001. For this reason alone, if you suspect an infection with listeria, you should consult your doctor immediately and not treat the symptoms yourself. The best contribution to self-help that the patient can make is prevention and avoiding re-infection from the same source of danger.

Listeriosis is triggered in both humans and animals by contaminated food or feed. Since the disease can be transmitted from humans to animals and vice versa, farmers and animal keepers who care for ruminants should be particularly cautious. Food that is soiled with soil is particularly dangerous. Fruit and vegetables must therefore always be washed thoroughly and freed from residues. Animals must not be fed hay or grass contaminated with soil. Certain foodstuffs such as raw milk cheese, soft cheese, butter and sausage, especially salami, Teewurst and Mettwurst, are also sources of particular danger for humans. Anyone suffering from listeriosis should stop eating particularly risky foods and switch to other foods. Cooked cereal products such as rice or pasta are harmless. Listeria also do not stick to [[tomato]n,Apples and carrots, why these fruits and vegetables should be preferred.

Since listeriosis particularly affects people with a weakened immune system, a healthy lifestyle can also help to prevent disease or speed up healing.