Norovirus fact sheet

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, or sharing foods or utensils with someone who is infected.
• Inhaling virus released when an infected person vomits.
• Coming into direct contact with or taking care of an infected person.

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 48 hours after symptoms end.

• Diagnosis is usually made based on the person's symptoms.
• Laboratory testing 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:

• Avoid eating undercooked or raw oysters.
• 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. See complete list of EPA approved disinfectants against norovirus.
• Immediately remove and wash clothing or linens if they become soiled with stool or vomitus. Use hot water and soap to launder.
• Avoid preparing food for others for at least 48 hours after symptoms have ended.