What are Noroviruses?

by Jennifer Bunn, RN

The noroviruses are a group of viruses which commonly cause vomiting and diarrhea (gastrointestinal symptoms), usually during the winter months in the Northern Hemisphere. Noroviruses often cause outbreaks of illness among people who live in close proximity (i.e. nursing homes, cruise ships). Infection may be passed person-to-person or by the ingestion of contaminated food and water.


  • Sudden onset illness 24 to 48 hours after being exposed
  • Nausea/vomiting
  • Diarrhea
  • Abdominal pain/cramping
  • Malaise
  • Headache
  • Low-grade fever
  • Aching muscles

You can reduce your risk of contracting the virus by frequently washing your hands with soap and water or an alcohol-based product. Avoid spending prolonged periods of time in crowded areas during the winter months. Make sure all fruits and vegetables are washed well before eating. Cook all foods thoroughly before eating.

Should you become ill with a gastrointestinal virus (“stomach flu”), get plenty of rest. Try to take sips of fluids frequently, rather than large amounts of fluids less often. You may want to try oral replacement solutions (ORS) if the vomiting and diarrhea are prolonged. There can be purchased from a drugstore. If you become very weak or notice blood in your stool, or do not start to improve within 48 hours, consider a visit to the emergency room.

Source: Norwalk and Noroviruses

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