Norovirus is the name of a group of viruses that is a common cause of viral gastroenteritis (“stomach flu”) outbreaks. Although people who have norovirus infection may feel very sick for several days, the illness is seldom serious.
Symptoms often begin suddenly within 12 to 48 hours after exposure to norovirus. Most people get better within one or two days and have no long-term health effects from the illness, though dehydration (loss of fluids) may occur and may result in hospitalization.
Symptoms include:
- Nausea and vomiting
- Watery diarrhea
- Stomach cramps
- Fever, chills, headache, muscle aches
Norovirus is found in the stool and vomit of infected people. It is very contagious and usually spread person-to-person, or by contaminated food. People can become infected with the virus by:
- Eating food or drinking liquids that are contaminated with norovirus.
- Touching surfaces or objects contaminated with norovirus and then putting their hands in their mouth.
- Direct contact with a person who is infected and showing symptoms, such as caring for someone with the illness, or sharing foods or eating utensils with someone who is ill.
Norovirus can spread quickly in places with close living quarters, such as childcare centers, long-term care facilities, and cruise ships. People who work in these types of facilities should carefully follow steps to prevent the spread of infection when caring for children or residents who may have a norovirus infection. People infected with norovirus are contagious from the moment they begin feeling ill to, at least, 3 days after symptoms end.
- Diagnosis is usually made based on the person’s symptoms.
- Laboratory diagnosis for norovirus is usually only done to help determine the cause of an outbreak. Public Health may request samples of stool or vomit to look for norovirus in the laboratory.
- Treatment consists of drinking plenty of fluids and adequate rest. Antibiotics are not effective against norovirus.
You can decrease your chance of becoming ill with norovirus, or of spreading norovirus to others by following these recommendations:
- Wash your hands, especially after using the toilet, changing diapers, before eating, and before preparing food.
- Flush or discard any vomit and stool down the toilet. Clean and disinfect the surrounding area as necessary.
- Clean and disinfect hard, non-porous surfaces (i.e. countertops, toilets, floors) contaminated with vomit or stool quickly. Wipe up as much of the matter as possible, clean with soap and water, then disinfect with a solution of 1/3 cup household bleach mixed with one gallon of water. Leave on the surface for 10 minutes, rinse with water, then air dry. Carpets can be disinfected by steam cleaning.
- Immediately remove and wash clothing or linens contaminated with norovirus after an episode of diarrhea or vomiting. Use hot water and soap to launder.
- Avoid food preparation or contact with healthy people for at least three days after the last symptoms have occurred.
- Wash raw fruits and vegetables, and cook oysters before eating them.
