Norovirus is easily transmitted from a patient, patient secretions, or spread by surfaces, food and drinking water infected by the virus. The symptoms are characterized by rapid onset, abundant vomiting or diarrhoeal disease. The duration of symptoms varies from half a day to five days. In hospitals the epidemic spreads effectively to others in the room, to other patients within the ward and to the staff. In suspected cases of patient infection caused by norovirus, new patients should not be admitted to the same room, and a separate WC and shower room should be reserved for the patients.