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Noroviruses are a group of very contagious viruses that cause stomach illness. People of all ages can get sick with norovirus by accidentally consuming small amounts of poop or vomit from an infected person. Common symptoms of norovirus include vomiting, diarrhea, and stomach cramps. Norovirus is also called gastroenteritis or the “stomach flu.” Although it is commonly called the stomach flu, norovirus is not related to the flu (influenza). Norovirus is the leading cause of foodborne illness outbreaks in Wisconsin.

Norovirus 101

Norovirus spreads very easily from person to person. The viruses that cause norovirus are found in the poop or vomit of people who are sick. Someone can get sick if they accidentally consume small amounts of infected poop or vomit. People can become infected with norovirus by:

  • Eating or drinking food or water contaminated with norovirus.
  • Touching surfaces or objects contaminated with norovirus and then touching their mouth or eating without washing their hands.
  • Having direct contact with someone who is sick with norovirus.

Norovirus can easily contaminate food or water because it only takes a very small amount of virus to make someone sick.

People with norovirus can start to have symptoms one or two days after being exposed. The most common symptoms are vomiting, diarrhea, and stomach pain. Other symptoms of norovirus include:

  • Nausea
  • Fever
  • Chills
  • Aches
  • Tiredness

People who are sick with norovirus, especially young children, older adults, and people with other illnesses, may be at an increased risk of dehydration.

There is no specific medicine to treat people who are sick with norovirus. If you have norovirus, drink plenty of fluids so you don’t become dehydrated. Most people will get better within one to three days.

People can protect themselves and others from norovirus by taking simple prevention steps.

  • Wash your hands with soap and water after using the bathroom, after changing diapers, before preparing foods, and before eating.
  • Handle and prepare food safely. Carefully wash fruits and vegetables and cook oysters and other shellfish thoroughly.
  • Do not prepare food or take care of others if you are sick and for at least two days after symptoms stop.
  • Clean and disinfect surfaces with a household bleach solution immediately after someone vomits or has diarrhea.
  • Wash soiled clothes and linens thoroughly.

Information for providers

Questions about Norovirus? Contact us!
Phone: 608-267-9003 | Fax: 608-261-4976

Wisconsin Local Health DepartmentsRegional officesTribal agencies

Last revised February 21, 2023