Brief overview
- Symptoms: Nausea, gushing vomiting, diarrhea, headache, abdominal pain, aching limbs, low-grade fever, fatigue.
- Course and Prognosis: Generally, norovirus heals without problems in otherwise healthy adults. Young children and the elderly are more susceptible to complications due to severe fluid and electrolyte loss.
- Causes and risk factors: Infection usually person-to-person (fecal-oral), sometimes smear or droplet infection.
- Treatment: Symptomatic therapy by compensation of fluid and electrolyte loss; possibly anti-vomiting agent (antiemetic); inpatient therapy in hospital and infusion in severe cases
What is norovirus?
Many disinfectants are not sufficiently effective against noroviruses. Only preparations with proven efficacy against viruses (“virucidal efficacy”) are suitable.
According to the Robert Koch Institute, noroviruses are responsible for a large proportion of non-bacterial gastroenteritis. In children, they cause around 30 percent and in adults up to 50 percent of all gastroenteritis illnesses.
What are the symptoms?
Norovirus symptoms usually begin very suddenly and manifest themselves in an acute “stomach flu” (gastroenteritis). In most cases, signs such as gushing vomiting and diarrhea appear just a few hours after infection with the norovirus. The combination of vomiting and diarrhea is called vomiting diarrhea.
Vomiting diarrhea is potentially dangerous because it deprives the body of a lot of fluid and salts (electrolytes). In infants, young children and the elderly, this can be life-threatening. Possible consequences include circulatory problems, seizures and even kidney failure.
In most cases, diarrhea and vomiting last one to three days, possibly up to five days. Accompanying symptoms such as fatigue often persist for several days beyond that.
Norovirus infections are manifested in most cases not only in diarrhea and vomiting. Often, norovirus is accompanied by signs such as:
- Nausea
- Abdominal pain
- headache
- Pain in the limbs
- General feeling of illness
- Mild fever
- Fatigue
In children, only an elevated temperature is often observed with norovirus. However, fever rarely occurs here. This distinguishes norovirus from bacterial gastroenteritis, in which fever is a typical sign.
The norovirus incubation period (infection period) is the time between infection and the onset of the first symptoms. It varies somewhat from person to person. In most infected people, the first symptoms appear just a few hours after infection. In others, one to two days pass between infection and the outbreak of the disease. Overall, the norovirus incubation period is between six and 50 hours.
Course of the disease and prognosis
Infection with norovirus is usually short and severe. Symptoms usually last one to three days, rarely longer. If no complications occur and the fluid and electrolyte balance is conscientiously balanced, norovirus usually heals without problems.
Especially in people who are already older or weakened by other diseases (such as HIV), the severity and duration of the symptoms are often more severe. This also applies to infants and young children. Here, treatment in hospital may be necessary. This is especially true if the loss of fluids and electrolytes is very great. There is then a risk of damage to internal organs. Only in very rare cases does norovirus lead to death.
Pregnant women are often very worried when they become infected with norovirus. However, the noroviruses themselves do not pose a threat to the unborn child. However, the severe vomiting and/or diarrhea may build up so much pressure in the body that labor starts early. It is also particularly important for expectant mothers to ensure that they are always adequately supplied with fluids, electrolytes and nutrients.
If an older child or adult in a household becomes ill with norovirus, it is important to be especially careful about hygiene when handling the baby or young child. It is advisable to isolate the sick person from the infant and other family members as much as possible.
If an infant shows signs of norovirus infection, notify a doctor as soon as possible as a precaution!
How does the infection occur?
Norovirus is transmitted directly from person to person: the vomit and stool of a sick person contain a great deal of virus. Tiny remnants of excretions containing noroviruses are sufficient to 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 viruses easily enter his body via the mucous membranes. This is known as the fecal-oral route of infection.
In addition, infection with norovirus is possible when fine droplets form during vomiting and enter the mouth or nose of another person through the air. This is known as droplet infection.
According to current knowledge, norovirus is only transmitted between humans, but not between humans and animals.
How long is one contagious?
Very often in winter and in communal facilities
During the cold season, the immune system is often battered. The mucous membranes are also often drier and then less protected against pathogens. This is why norovirus outbreaks are particularly frequent during the winter months. However, cases of illness are also possible throughout the rest of the year.
How to protect yourself from infection
There is no specific way to prevent infection with norovirus: there is no norovirus vaccine yet. However, you can reduce the risk of contracting norovirus by taking the following measures:
- Careful hygiene: Wash your hands regularly and thoroughly, especially before eating and after going to the toilet.
- Washing: Make sure that laundry that the affected person has used is always washed immediately. Choose a wash temperature of 90 degrees Celsius to kill any noroviruses that may be present on it.
- Avoid contact: It is advisable that affected persons stay at home for two days even after symptoms have subsided so as not to infect other persons.
Maintain hygiene measures for at least one week after symptoms have subsided. This applies especially to the conscientious washing and disinfecting of hands.
The high number of subtypes is also the reason why pharmaceutical companies do not bother with the development of a vaccine: It is almost impossible to cover all subtypes by vaccination.
After surviving the disease, one is not immune to the norovirus! The viruses are too versatile for that. Therefore, it is possible to become infected again after having been infected with norovirus.
Examinations and diagnosis
Taking the medical history
During the so-called medical history, the physician inquires about the exact symptoms and other important parameters. Possible questions are:
- Do you suffer from diarrhea and vomiting?
- Do you feel listless and tired?
- What did you eat in the last few hours before the onset of symptoms?
- Have you had any recent contact with people who have had similar symptoms?
Even the typical symptoms often provide a strong indication of infection with norovirus.
After taking a medical history, the physician performs a physical examination. The focus is on the abdomen: He first checks with a stethoscope whether normal bowel sounds are audible. He then carefully palpates the abdomen. He looks for tension (“defensive tension”) and any painful areas in the abdomen.
With the physical examination, he primarily rules out other causes for the diarrhea and vomiting.
Detection of noroviruses
There are various ways to detect noroviruses. Either the laboratory physicians look for characteristic components of the viruses, such as nucleic acids or proteins, in the patient samples. Or they try to detect virus particles directly – with the aid of an electron microscope.
Norovirus: Obligation to report
According to the German Infection Protection Act (IfSG), detection of norovirus is reportable. The data are transmitted with the patient’s name to the responsible public health department.
Treatment
There is no specific drug therapy for norovirus infection and it is usually not necessary. Instead, one tries to alleviate the symptoms as much as possible (symptomatic therapy).
In general, it is best for patients with norovirus to take it easy. Bed rest is recommended. Further measures depend on the severity of the symptoms and the patient’s general state of health.
Norovirus treatment for mild to moderate symptoms
Make sure infants and young children drink more breast milk or a suitable replacement food.
Shifts in electrolyte levels are potentially dangerous: they trigger drowsiness, circulatory problems and cardiac arrhythmias, for example.
The home remedies “cola and salt sticks” are not suitable for vomiting and diarrhea: The caffeine in cola may increase fluid loss. Therefore, cola is not advisable, especially for children. Salt sticks are not problematic in themselves. They mainly provide sodium as electrolytes, but not the potassium that is also needed. This can be found in bananas, for example.
Norovirus treatment for more severe symptoms
The substitution solution is also called oral rehydration solution (ORL) or WHO solution (after the World Health Organization WHO). It contains glucose and electrolytes dissolved in water, such as table salt or potassium chloride. It is available in pharmacies, usually in powder form to be dissolved in liquid.
For more severe vomiting, an anti-nausea and anti-vomiting agent (antiemetic) can be administered in consultation with the doctor.
Norovirus treatment for severe symptoms
Children and the elderly are usually particularly sensitive to the high loss of fluids and electrolytes. For them, norovirus therapy therefore usually takes place in hospital.
