Norovirus Illness: Key Facts

Norovirus—the stomach bug

• Norovirus is a highly contagious illness caused by infection with a virus called norovirus. It is often called by other names, such as viral gastroenteritis, stomach flu, and food poisoning.
• Norovirus infection causes acute gastroenteritis (inflammation of the stomach and intestines); the most common symptoms are diarrhea, vomiting, and stomach pain.
• Anyone can get norovirus, and they can have the illness multiple times during their lifetime.
• Norovirus is the most common cause of acute gastroenteritis in the United States.

Norovirus illness can be serious

• Norovirus can make people feel extremely ill and vomit or have diarrhea many times a day.
• Most people get better within 1 to 2 days.
• Dehydration can be a problem among some people with norovirus infection, especially the very young, the elderly, and people with other illnesses.

Norovirus is highly contagious and spreads rapidly

• Noroviruses are highly contagious, and outbreaks are common due to the ease of transmission.
• People with norovirus are contagious from the moment they begin feeling ill to at least 3 days and perhaps for as long as 2 weeks after recovery, making control of this disease even more difficult.
• Norovirus can spread rapidly in closed environments like daycare centers and nursing homes

Many sources for norovirus infection

Noroviruses are found in the stool and vomit of infected people. People can become infected by

• Eating food or drinking liquids that are contaminated with norovirus.
• Touching surfaces or objects that are contaminated with norovirus, and then placing their hand in their mouth.
• Having direct contact with an infected person; for example, by exposure to the virus when caring for or when sharing food, drinks, or eating utensils with an infected person.

Tips to prevent the spread of norovirus

Practice proper hand hygiene: Wash your hands carefully with soap and water, especially after using the toilet and changing diapers and always before eating or preparing food. Alcohol-based hand sanitizers (containing at least 62% ethanol) may be a helpful addition to hand washing, but they are not a substitute for washing with soap and water. See “Handwashing: Clean Hands Save Lives.”

Take care in the kitchen: Carefully wash fruits and vegetables, and cook oysters and other shellfish thoroughly before eating them.

Do not prepare food while infected: People who are infected with norovirus should not prepare food for others while they have symptoms and for 3 days after they recover from their illness.

Clean and disinfect contaminated surfaces: After an episode of illness, such as vomiting or diarrhea, immediately clean and disinfect contaminated surfaces by using a bleach-based household cleaner as directed on the product label or a solution made by adding 5–25 tablespoons of household bleach to 1 gallon of water.

Wash laundry thoroughly: Immediately remove and wash clothing or linens that may be contaminated with vomit or fecal matter. Handle soiled items carefully—without agitating them—to avoid spreading virus. They should be laundered with detergent at the maximum available cycle length and then machine dried.

No specific treatment or vaccine for norovirus infection

• There is no vaccine to prevent norovirus infection, although this is an area of active research.
• There is no specific drug to treat people with norovirus illness.
• Rehydration is important for infected people—they must drink plenty of liquids to replace fluid lost through vomiting and diarrhea. In some cases, fluid may need to be given intravenously.

orovirus Illness: Key Facts