Calicivirus Laboratory

Norovirus

Norovirus infections result in gastroenteritis (inflammation of the stomach and intestines) with symptoms characterized by vomiting, diarrhea, abdominal cramps, and nausea. Low grade fever and headaches may also occur. An individual may not exhibit all symptoms. The symptoms usually occur 24 to 48 hours, but as early as 12 hours, after infection and last for 24 to 60 hours. Severe dehydration may occur in children and the elderly, and rehydration therapy can sometimes be required. Recovery is usually complete with no long term problems. It is important to note that gastroenteritis can be caused by other viruses, bacteria, and parasites.

The transmission of noroviruses occurs by the fecal-oral route, which means that infections can occur by consumption of food or water that has been contaminated by feces. Virus infections can also occur by contact with contaminated surfaces (soiled clothing from another person who is infected, contaminated eating utensils or surfaces) and contact with people's mouths. Noroviruses may be shed from infected persons for a few weeks after recovery from symptoms and the viruses are relatively stable in the environment.

The transmission capabilities of noroviruses are reasons for practicing good hygiene. Hand washing should be performed after restroom use and before preparation of food and before eating. Care should be taken when handling clothing from ill individuals because of the possibility of virus contamination. A 10% dilution of household bleach (e.g. 1 cup of liquid bleach plus 9 cups of water) has been one method used for disinfection of noroviruses on bleach-tolerant surfaces. Other products have also been shown to be helpful in disinfection.