The noroviruses are highly contagious. Minimal amounts of 10-100 viral particles are sufficient to allow an infection. The transmission of Norovirus is from person to person through different infection routes. Main infection source is faeces, vomit and vomiting when the resulting aerosol. Especially in the chair is the virus in large quantities. For comparison, in one gram of faeces are about 10 million virus particles.

This shows the importance of professional hygiene.

Outbreaks are often contaminated by food or beverages. Examples are: salad, fish and shellfish, and unclean water. As the virus particle is very tough, also play contaminated objects like toys in the nursery, clothing, door handles an important role. This explains the, often in schools, hospitals, other communities, emerging high propagation speed of infection. Explained so that even the high infection rate. The high concentration of virus in stool or vomit of sick and by the low infectious dose required for infection is needed.

The incubation period is short and is only up to 3 days. The risk of infection during the acute illness, and usually more than 2 days after symptoms. After the illness, the virus particle is about two weeks to pass. Norovirus infection can occur throughout the year, but the focus is in the winter months.

The duration of acute symptoms is usually 12 to 72 hours. After expired Norovirus infection leads to a short lasting immunity.

In the case of infection with the norovirus antibodies are rarely formed. If you ever had noroviruses, one is in front of the virus in the future but not sure.