Rotaviruses

The most common cause of acute, severe diarrhoea in infants and children is infection with rotavirus. This is a highly contagious virus that spreads rapidly, especially between February and April. Even contact with the smallest amounts of virus particles triggers an illness.

Infants between the ages of six months and two years are most affected by rotavirus infections. This is because the immune system is not yet fully developed at this age. However, older children and people over the age of 60 often also suffer from diarrhoea caused by rotaviruses. In adolescents and adults, a rotavirus infection usually causes only mild diarrhea - the more severe forms of gastrointestinal infections in this age group are usually due to infections with noroviruses.

The disease is contagious as long as the viruses are excreted in the stool. This infectious period usually lasts for about eight days from the onset of symptoms.

The name rotavirus is based on the wheel-shaped structure (Latin rota for wheel) of the viruses when magnified with an electron microscope. Seven different virus groups (serotypes A to G) are distinguished, each of which is again subdivided into different subgroups. Serotype A has the greatest clinical significance.

In Germany, infection with rotavirus is a notifiable disease, whereas this is not the case in Austria.

Infection with rotaviruses is usually transmitted faecal-orally from person to person by smear infection. In some countries, the infection can also be transmitted via contaminated food or drinking water. Because the viruses are extremely resistant, they can survive on infected objects or hands for up to two days. Even treatment with disinfectants makes it difficult to reliably kill all pathogens.

Since the immune system of children up to the age of two is not yet fully developed, they are particularly susceptible to rotavirus infection. From the second year onwards, the immune system is usually able to fight off the disease with antibodies. However, since there are numerous subtypes of rotaviruses, the diarrhoeal disease can recur even in later years of life.

The incubation period (time span from infection to the appearance of the first symptoms) is one to three days in the case of rotavirus disease. After that, the affected person usually suffers from stomach pain, vomiting, high fever and mild to severe, watery diarrhea.

In severe cases, the diarrhea can last up to five days, causing exsiccosis (dehydration of the body) due to the severe loss of water and electrolytes, which without treatment will lead to death within a short time. It is estimated that up to one million children worldwide die each year from rotavirus infection, mainly in developing countries.

Due to the characteristic symptoms in infants, the physician can quickly make a tentative diagnosis of an infection with rotaviruses. The ELISA method is suitable for reliable laboratory diagnosis. Antibodies against the virus are detected in a stool sample, which also allows the exact virus serotype to be determined.

Further possibilities for diagnosis would be the detection of the viruses by means of an electron microscope or other molecular biological methods. However, these are far more complex and are therefore not usually used.

A specific therapy against an infection with rotaviruses does not exist. It is particularly important to drink plenty of fluids, as diarrhoea can cause life-threatening fluid loss. When treating infants and small children, hospitalization may be necessary. In this case, sufficient fluid intake is achieved in the form of drinking solutions or via an infusion. In addition, the loss of electrolytes (loss of mineral salts) caused by the severe diarrhoea is also compensated.

Only a symptomatic therapy can be carried out - a direct fight against the pathogens through medication (called antiviral therapy) is not possible with rotaviruses.

The risk of death due to rotavirus disease is very low in the countries of Western Europe thanks to good medical care. However, almost 50% of cases in children under the age of five require hospitalisation. Of the cases of illness in adults after the age of 60, about one in three requires hospitalisation.

The only way to prevent infection with rotaviruses is to maintain strict hygiene and use special disinfectants if you come into contact with infectious people. Rotaviruses can be transmitted to other people as long as the sick person excretes viruses in their stool - this is usually the case for the period from the onset of symptoms to about eight days afterwards. Especially after changing the diapers of sick babies and toddlers, the hands and the changing mat should be well disinfected.

There are also two different vaccines available to prevent infection with rotaviruses, which have been approved since 2006. However, there is currently no general vaccination recommendation for protection against rotavirus infections. The benefit of a vaccination must be weighed against the risk on an individual basis.