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Norovirus: duration, course, treatment, incubation period

by Josephine Andrews
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norovirus infection is an acute gastrointestinal disease with severe vomiting and diarrhea. It is caused by the norovirus. Infection occurs easily through contact with sick people, contaminated objects or (raw) food. The infection usually lasts only a few days and subsides without permanent damage. For small children and older people, however, the high loss of fluids caused by norovirus can be dangerous. Read everything you need to know about Norovirus!

ICD codes for this disease:

ICD codes are internationally valid codes for medical diagnoses. They can be found, for example, in doctor’s letters or on certificates of incapacity for work.


Norovirus is highly contagious. Pay attention to particularly careful hygiene and disinfection in order not to infect your relatives.

Quick Reference: Norovirus

  • Description: A highly contagious gastrointestinal disease caused by norovirus.
  • High risk of infection: Norovirus is transmitted directly from person to person, via contaminated objects or food, and via droplet infection.
  • Symptoms: Nausea, violent vomiting, diarrhea , headache, abdominal pain and body aches, slight fever , exhaustion
  • Treatment: symptomatic therapy by compensating for fluid and electrolyte loss; possibly anti-vomiting medication (antiemetic); inpatient therapy in the hospital and infusion in severe cases
  • Prognosis: Norovirus usually heals without any problems in otherwise healthy adults. Young children and the elderly are more prone to complications from excessive fluid and electrolyte depletion.
  • Obligation to report: Proven infections must be reported. Suspicion of norovirus must also be reported for people who work with food or in public facilities.

What is norovirus?

Norovirus is a type of virus that is spread worldwide. It is very resistant to adverse environmental influences: the pathogen survives on food (also refrigerated) and on surfaces such as doorknobs, water taps, banisters or toilet seats. It even withstands temperatures of up to 60 degrees for several minutes.

Attention: Many disinfectants are not sufficiently effective against noroviruses. Only preparations with proven effectiveness against viruses (virucidal effectiveness) are suitable.

According to the Robert Koch Institute, noroviruses are responsible for the majority of non-bacterial gastrointestinal inflammations (medical gastroenteritis). In children they cause around 30 percent and in adults up to 50 percent of all gastroenteritis diseases.

In principle, there is a risk of infection with norovirus all year round. The duration and course of the infection depend on the general health of the patient. Nothing is known about residual damage after infection with norovirus.

Norovirus: routes of infection and protection

Norovirus is very contagious. Even the smallest amounts of ten to 100 virus particles are sufficient for a person to contract the norovirus. Even a single infected person can be enough to trigger a local epidemic!

Norovirus – how to prevent it

The norovirus can be transmitted directly from person to person : the vomit and the stool of a sick person contain a lot of viruses. Tiny remnants of the excretions with norovirus can be transmitted to other people via the hands, for example when shaking hands. If the healthy person then unconsciously grabs his mouth or nose with the hand in question , the virus can easily penetrate his body via the mucous membranes. This is called the fecal-oral route of transmission .

A so-called smear infection via contaminated objects such as doorknobs or cutlery is also possible with norovirus infections. The viruses can even survive for some time on food and in liquids. In the past, there were some local norovirus epidemics that were triggered by contaminated food or drinks (salads, mussels, water, etc.).

You can also become infected with norovirus if fine droplets form when you vomit and get into someone else’s mouth or nose through the air. This is referred to as droplet infection .

Note: According to the current state of knowledge, the norovirus is only transmitted between humans, but not between humans and animals.

Norovirus: how long are you contagious?

There is a risk of infection immediately after infection with norovirus (see below: incubation period). It is particularly great as soon as symptoms appear. However, patients are still contagious up to 48 hours after the symptoms have subsided. The viruses can even be detected in the tool for up to 14 days, in some cases even longer. You should therefore pay attention to careful hygiene during this whole time.

Norovirus: Very common in winter and in community facilities

During the cold season, the immune system is often weak. The mucous membranes are then also less protected against pathogens. This is why there are frequent norovirus outbreaks, especially during the winter months. Cases of illness are also possible during the rest of the year.

The viruses spread particularly quickly where many people are together in a manageable space. For example, hospitals , community facilities such as old people’s homes or care facilities and schools can become true “Norovirus breeding grounds”. Such outbreaks are usually due to inadequate hygiene measures.

Norovirus: How to protect yourself

You cannot specifically prevent an infection with the norovirus: there is still no norovirus vaccination. However, you can reduce the risk of contracting norovirus by taking the following measures:

  • Meticulous hygiene. Above all, you should wash your hands regularly and thoroughly, especially before eating and after going to the toilet.
  • Disinfect. You can also use a norovirus-effective disinfectant to wash your hands, which is available in pharmacies. The disinfectant must act for 30 seconds to prevent norovirus transmission. All objects that a sick person touches in the household should also be disinfected if possible. These include, for example, door handles, light switches and cutlery. It is best to wear gloves when doing this, since surface disinfectants are usually skin-damaging. A face mask is also recommended to avoid inhaling virus particles.
  • washing Make sure that laundry that the victim has used is always washed immediately. Choose a washing temperature of 90 degrees Celsius to kill any norovirus that may be present on it.
  • avoid contact. Affected people should stay at home for up to two days after infection so as not to infect other people.

Note: Hygiene measures should be maintained for at least a week after the symptoms have subsided. This applies in particular to the conscientious washing and disinfecting of hands.

Many sufferers believe that they are immune after being infected with the norovirus and are therefore protected from further diseases. But that only applies to the exact same virus. However, there are a large number of different subtypes of noroviruses, which are also constantly changing. Therefore there is no immunity against norovirus after surviving the infection. The large number of subtypes is also the reason why the pharmaceutical industry is not involved in the development of a vaccine: it is almost impossible to cover all subtypes with a vaccine.

Attention: After surviving the disease you are not immune to norovirus! Viruses are too versatile for that. An infection with the norovirus can therefore occur again at any time, even after an infection has been experienced once.

Norovirus: Symptoms

Norovirus infection is usually rapid and severe. Most patients experience severe vomiting and diarrhea , usually accompanied by headaches, stomach aches and body aches as well as a slight fever . These acute signs usually last one to three days. However, symptoms such as lethargy and a general feeling of illness can persist for a few days longer.

In some patients, norovirus infection causes only diarrhea without vomiting or vomiting without diarrhea . There are also infections that go completely without symptoms .

The body may lose a lot of fluid and salts (electrolytes) through diarrhea and vomiting. This can be particularly dangerous for small children and older people: circulatory problems, seizures and even kidney failure can occur.

You can read everything you need to know about the typical signs of a norovirus infection in the article Norovirus – Symptoms .

Norovirus: incubation period

The norovirus incubation period (infection period) is the period of time between norovirus infection and the onset of the first symptoms. It differs a bit from person to person. In most patients, the first symptoms appear just a few hours after infection. For others, one to two days elapse between infection and the onset of the disease. Overall, the norovirus incubation period can be six to 50 hours.
Attention: Anyone who has been infected with noroviruses is already contagious to others during the incubation period – ie before the first symptoms appear. The risk of infection becomes even greater when the symptoms begin.

Norovirus: investigations and diagnosis

If a norovirus infection is suspected, the family doctor is the right person to contact. In order to detect the norovirus, three diagnostic steps are usually necessary: ​​taking the medical history, physical examination and detection of the norovirus.

Medical history collection

In the so-called anamnesis , the doctor inquires about the exact symptoms and other important parameters. Possible questions are:

  • Do you suffer from diarrhea and vomiting?
  • Do you feel weak and tired?
  • What have you eaten in the last few hours before the onset of symptoms?
  • Have you recently been in contact with people who had similar symptoms?

Even the typical symptoms can be a very strong indication of an infection with noroviruses.

Physical examination

After taking the medical history, the doctor performs a physical exam. In doing so, he focuses on the stomach: First, he uses the stethoscope to check whether normal bowel sounds can be heard. Then he carefully feels the abdomen. He pays attention to tension (“defensive tension”) and any painful areas in the abdomen.

The physical examination primarily excludes other causes of diarrhea and vomiting.

Detection of noroviruses

There are several diseases out there that cause symptoms similar to norovirus infection. A reliable diagnosis is therefore only possible by detecting the pathogen. For this purpose, a sample of the stool or vomit is examined in the laboratory. So far, this has only been possible in special laboratories.

There are various ways to detect noroviruses. One can either look for characteristic components of the virus such as nucleic acids or proteins in the patient samples. Or one tries to detect virus particles directly – with the help of an electron microscope.

Virus detection is important when there are large numbers of cases of vomiting and diarrhea in a particular area or community facility over a short period of time. If noroviruses are identified as the cause of the disease, appropriate measures can be taken quickly to prevent the pathogen from spreading further.

Norovirus: obligation to report

According to the German Infection Protection Act (IfSG), detection of the norovirus is notifiable . The data is transmitted to the responsible health authority with the name of the patient.

The mere suspicion of a norovirus infection must be reported if the person concerned handles food or works in communal catering facilities. The aim of the obligation to report is to identify local norovirus epidemics at an early stage and thus prevent further diseases.

Norovirus: treatment

There is no specific drug therapy for norovirus infection and it is usually not necessary. Instead, one tries to alleviate the symptoms as best as possible ( symptomatic therapy ).

In general, patients with norovirus should take it easy. Bed rest is recommended. Further measures depend on the severity of the symptoms and the general health of the patient.

Norovirus treatment for mild to moderate symptoms

If an infection only has mild to moderate symptoms, the patient can be cared for at home. The loss of fluid and electrolytes ( sodium , chloride , potassium , etc.) from vomiting and diarrhea should be compensated. For this purpose, the patient should drink plenty of fluids with sufficient salt. This can be water or tea with a little salt and sugar, broth and diluted juices. Breast milk or an equivalent substitute must be increasingly supplied to small children and infants.

Attention: Shifts in the electrolyte values ​​can be dangerous. For example, they can cause drowsiness, circulatory problems and cardiac arrhythmia.

Despite the diarrhea, you should try to eat a little. This helps the intestinal mucosa to recover. Rusks, butter biscuits and crispbread, for example, are easily digestible. Even after an infection has been overcome, you should initially only eat easily digestible food and avoid heavy, high-fat food.

Note: The home remedy “Coke and pretzel sticks” are not suitable for vomiting and diarrhea: the caffeine in the cola can increase the loss of fluids. That’s why cola is not advisable, especially for children. Pretzel sticks are not a problem in themselves. They supply mainly sodium to electrolytes, but not the potassium that is also required. This is found in bananas, for example.

Norovirus treatment for more severe symptoms

If there are pronounced signs of norovirus, it can make sense to compensate for the loss of fluid and electrolytes with a so-called substitution solution from the pharmacy. This is especially true if the patient cannot or does not want to take in enough fluids and electrolytes. This often happens in children and the elderly.

The substitution solution is also known as oral rehydration solution (ORL) or WHO solution (after the World Health Organization WHO). It contains glucose and electrolytes dissolved in water, such as common salt or potassium chloride. They are available in pharmacies, usually in powder form to be dissolved in liquid.

In consultation with the doctor, a remedy for nausea and vomiting (antiemetic) can be administered to prevent stronger vomiting.

Norovirus treatment for severe symptoms

In the case of severe and long-lasting symptoms, a norovirus infection should definitely be treated in the hospital . There, the doctors can compensate for the fluid loss with an infusion into the vein. Necessary nutrients and electrolytes can also be administered quickly in this way. Often the patient also receives a remedy for the severe vomiting (antiemetic).

Note: Children and the elderly are usually particularly sensitive to the high loss of fluid and electrolytes. For them, norovirus therapy is therefore usually carried out in the hospital.

Norovirus: pregnancy and young children

Pregnant women are often very worried when they contract the norovirus. The unborn child is not threatened by the noroviruses themselves. However, the violent vomiting and/or diarrhea can build up so much pressure in the body that labor begins early. It is also particularly important for expectant mothers that they are always adequately supplied with liquids, electrolytes and nutrients.

When a newborn or infant gets norovirus, it can be very dangerous. Babies and young children are sensitive to the virus, and dehydration can quickly become life-threatening. That is why treatment is often carried out in hospital.

If an older child or adult in a household falls ill with norovirus, special care should be taken with hygiene when dealing with the young child. The sick person should be isolated from the infant and other family members as much as possible.

Attention: If infants show signs of a norovirus infection, a doctor should be informed immediately as a precaution.

Norovirus: disease course and prognosis

An infection with the norovirus is usually violent and short. Symptoms usually last one to three days. If no complications occur and the fluid and electrolyte balance is consciously balanced, norovirus usually heals without any problems.

Children under the age of six should not return to a community facility (such as a kindergarten) for at least two days after the (suspected) norovirus infection has subsided. Hygiene must be carefully observed.

The course of the norovirus and the duration of the symptoms can be more severe, especially in people who are older or weakened by other diseases (such as HIV). This often applies to infants and young children as well. Hospital treatment may be necessary. This is especially true if the loss of fluid and electrolytes is very large. Then there is a risk of damage to internal organs. Only in very rare cases does norovirus lead to death.

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