Listeriosis: Causes, Symptoms & Treatment

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

What is listeriosis?

Listeriosis is transmitted by so-called listeria. These are bacteria of the genus Listeria, which are very undemanding and therefore widespread. They occur predominantly in wild animals, but also in domestic animals. However, one species of Listeria can also affect humans: Listeria monocytogenes. This bacterial species is highly contagious and widespread throughout the world. Listeriosis was first discovered in guinea pigs and rabbits at an experimental animal farm in Cambridge in 1923. In 1929, the first human case of listeriosis was documented. 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, whether it occurs in humans or animals.

Causes

Listeriosis occurring in humans is caused by the bacteria of the species Listeria monocytogenes, which are found just about everywhere. These are rod-shaped, non-spore-forming bacteria that form flagella at temperatures above 25 degrees Celsius, making them motile. The insidious thing about this type of bacteria is that it can multiply at colder temperatures and thus survives even in the refrigerator. Listeriosis pathogens are found almost everywhere – on plants, in soil, in water. Thus, they also get into the feed of animals. The route of transmission to humans in the case of listeriosis can occur in various ways: Most commonly, Listeria monocytogenes enters the human body through contaminated food, but listeriosis infection can also occur through contact with infected animals or contaminated soil.

Symptoms, complaints, and signs

In most cases, listeriosis progresses without noticeable symptoms. Healthy adults often overcome the disease unnoticed. Occasionally, however, symptoms and serious complications may occur. Typical flu symptoms include fatigue, exhaustion or fever. If something irritating or spoiled is consumed, a severe gastrointestinal inflammation can occur. This is accompanied by symptoms such as vomiting, diarrhea and fever, which subside on their own after a few days. Infection via infected animals or contaminated soil can cause pustules on the hands and feet. Persons with a weakened immune system suffer from increasing discomfort in connection with listeriosis. At first, an increasing feeling of malaise sets in. After only a few hours, symptoms such as headache, nausea and vomiting, and increased body temperature may occur. In extreme cases, the disease can lead to blood poisoning, meningitis or encephalitis. These secondary diseases are life-threatening and are manifested by further symptoms accompanied by a growing feeling of illness. In pregnant women, listeriosis also leads to urinary tract infections and chills. Infants often suffer from apathy and a skin rash that can spread to the entire body. Seizures and respiratory distress may also occur.

Diagnosis and course

Diagnosis of listeriosis proves to be extremely difficult. It is difficult to detect without doubt in the human body. What can be detected clinically is a marked increase in white blood cells (leukocytes). Listeriosis cannot be clearly determined on the basis of symptoms alone. For an exact detection of the infectious disease, a pathogen detection is necessary. In this case, the listeria are detected either in the blood, in the spinal fluid or cerebrospinal fluid, or in other body fluids. However, the determination of antibodies is not meaningful in the case of listeriosis, since basically everyone has come into contact with listeria on several occasions and antibodies against listeria can therefore also be found in a healthy body. In healthy people, listeriosis usually goes completely unnoticed and without any noticeable symptoms. In immunocompromised people, as well as in pregnant women and newborns, signs of illness occur, such as high fever, severe headache, diarrhea, nausea and vomiting.Severe complications, such as blood poisoning, meningitis, or encephalitis, can accompany listeriosis.

Complications

Various complications or medical conditions may result from listeriosis. Those affected usually suffer from the usual symptoms of flu or a stomach infection. The main symptoms are fever and severe nausea. It is not uncommon for those affected to also suffer from vomiting and diarrhea. The quality of life is significantly reduced by the complaint. Due to the loss of fluids, the patient also suffers from fatigue and exhaustion. Furthermore, there is also pain in the head and joints. If listeriosis is not treated, it can also lead to inflammation of the brain or blood poisoning in the worst case. Both symptoms can be fatal and significantly reduce the life expectancy of the affected person. As a rule, listeriosis can be treated relatively easily with antibiotics if the treatment is carried out at an early stage. Complications usually do not occur. Those affected with a weak immune system may experience more severe symptoms. However, the 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’s death.

When should you go to the doctor?

If symptoms such as fatigue, tiredness, or exhaustion occur, a doctor should be consulted. If there are digestive problems, apathy or loss of appetite, a visit to the doctor is necessary. If the complaints increase or spread further, medical care for the affected person is necessary. If there are abnormalities in the appearance of the skin, the formation of pustules or discoloration on the skin, a doctor should be consulted. If fever, dizziness or nausea occurs, there is cause for concern. If vomiting, sweating, sleep disturbances or other flu-like symptoms occur, caution is advised. If the symptoms persist abruptly for several days, the affected person needs medical care. If headaches occur, there is increased irritability or a diffuse feeling of illness, a doctor should be consulted. Since the sequelae of listeriosis can lead to a life-threatening condition, a physician should be consulted at the first signs. A general feeling of malaise, internal 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, seizures or shortness of breath are warning signs of the organism. They should be followed up immediately to determine the cause and take necessary steps to improve the health condition.

Treatment and therapy

Listeriosis is treatable; however, the biggest problem here is timely detection of the disease. In most cases, the diagnosis of listeriosis is made much too late, so that treatment with antibiotics is no longer effective. If the diagnosis is made in time, common antibiotics such as amoxicillin, gentamicin, ampicillin or erythromycin are effective against the pathogen Listeria monocytogenes. Often an aminoglycoside is also used, alternatively cotrimoxazole. In the case of listeriosis, the risk of a relapse 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 all the listeria in the body. The biggest problem with listeriosis is that, especially when immunocompromised patients are to be treated, treatment with antibiotics is often very stressful for the body. Thus, support by the body’s own immune response is not always guaranteed and the therapy of listeriosis is more difficult than in immunocompromised people. Six weeks of antibiotic treatment is recommended for massive listeriosis associated with encephalitis or brain abscess, and four to six weeks for endocarditis (inflammation of the inner lining of the heart).

Outlook and prognosis

Listeriosis is one of the notifiable diseases with the highest number of deaths. About seven percent of those who contract the disease 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 pre-existing conditions such as immunodeficiency are present. In the case of immunodeficiency, 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, it can lead to premature birth, miscarriage or stillbirth. If transmitted to the child, 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 course of listeriosis, blood poisoning or meningitis may develop. A complicated course significantly worsens the prognosis. About 20 percent of all patients who suffer 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, sometimes even life-threatening.

Prevention

Listeriosis cannot be prevented by vaccination, as is the case with many other infectious diseases. To date, no effective vaccine against listeriosis exists. Therefore, the most important prophylactic measure is hygiene in food handling. People with an increased risk of disease should avoid foods such as raw meat and fish, raw milk and raw milk products. Adequate heating of food is considered the safest measure against listeriosis infection.

Follow-up

Infectious diseases often need good aftercare once they are cured. It is aimed at strengthening the immune system, regenerating those affected and, above all, preventing the disease from flaring up again. Depending on the degree of the disease, aftercare for listeriosis is somewhat different and is ideally discussed with the treating physician. Since this primarily affects the gastrointestinal tract, the body’s defenses can be strengthened by a number of measures that are in the patient’s own hands. These include a healthy diet, sufficient drinking and enough sleep. It is also important not to start sporting activities too early if those affected are not yet fit enough to do so. Often, the intestines are impaired in their function due to the medication given as part of the infection. This is especially true when antibiotics are given. In this case, a non-stressful diet consisting of light food helps in the aftercare. Natural yogurt, for example, is suitable for rebuilding a disturbed intestinal flora.

What you can do yourself

Listeriosis has been a notifiable disease since 2001. For this reason alone, if an infection with listeria is suspected, the doctor should be consulted immediately and the symptoms should not be self-treated. The best contribution to self-help that the patient can make is prevention as well as avoiding re-infection from the same source of danger. Listeriosis is caused in both humans and animals by contaminated food or feed. Because the disease can be transmitted from humans to animals and vice versa, farmers and animal caretakers who care for ruminants should be especially careful. Food contaminated with soil is particularly dangerous. Fruits and vegetables must therefore always be thoroughly washed and cleaned of residues. Animals must not be fed hay or grass contaminated with soil. In addition, certain foods such as raw milk cheese, soft cheese, butter and sausage, especially salami, teewurst and Mettwurst, are particular sources of danger for humans. Anyone who has contracted listeriosis should stop eating particularly risky foods and switch to other foods. For example, cooked cereal products such as rice or pasta are not dangerous. Listeria also does not persist on [[tomato]s, apples, and carrots, which is why these fruits and vegetables should be preferred. Because listeriosis particularly affects people with weakened immune systems, a healthy lifestyle can also help prevent the disease or speed up recovery.