What is Norovirus?

Norovirus (formerly known as Norwalk-like viruses) infection is a gastrointestinal illness that occurs at irregular intervals or in outbreaks. The illness only occurs in humans and the virus is found worldwide. Of all viruses, only the common cold is reported more often than viral gastroenteritis. Although the illness can occur at any time, it most commonly occurs in the period from October to April. Norovirus is also called viral gastroenteritis, winter vomiting disease and the stomach flu, although it is not caused by the influenza virus.


How is Norovirus Spread?

Norovirus is spread by exposure to infected individuals or contaminated food and water. The virus is passed in stool and vomit. It is usually spread from person-to-person by direct contact with fecally contaminated hands of an ill individual or by contact with fecally contaminated objects (e.g. door knobs) and then touching your mouth. Ill persons should not prepare or handle food of others, even for their family.


What are the symptoms of Norovirus?

Although the virus is easily spread, serious illness is rare. Symptoms of Norovirus infection may be more severe for older persons, young children and those with underlying medical conditions who are more vulnerable to dehydration because of vomiting and diarrhea. The most common symptoms include nausea, vomiting, stomach cramps or diarrhea. Fever is usually low grade or absent. If diarrhea is bloody and/or accompanied by a high fever, or if the symptoms last longer than 72 hours, seek medical attention. The illness may be due to something other than Norovirus.


How can Norovirus be prevented?

Immunity to Norovirus is short and reinfection can occur after a few weeks or months. The following actions may reduce the risk of acquiring or spreading the infection:

  • Perform hand hygiene frequently.  Make sure hands are properly washed, using soap and water for at least 15 seconds, after using the washroom, handling diapers and before and after preparing or serving food.
  • Infected health care workers should not attend work for a minimum of 48 hours after symptoms such as vomiting and diarrhea have resolved.
  • Patients with suspected Norovirus infection should be managed with Routine Practices with careful attention to proper hand hygiene practices. Contact precautions should be used when caring for individuals who are incontinent, during outbreaks in a facility and when caring for pediatric populations.
  • Individuals who experience nausea, vomiting or diarrhea should not attend school or work and should not prepare or touch food for others.
  • Avoid drinking untreated water.
  • Cook all shellfish thoroughly before eating.


Environmental cleaning, disinfection

  • General routine cleaning and disinfection practices should be continued daily with hospital-grade disinfectant – a hard surface disinfectant with DIN number and the following indication on the label: “for use in a health care facility.”
  • In health care settings, attention must be given to high touch surfaces such as bed rails, sinks, chairs, call bells, telephones, IV lines and poles, blood pressure cuffs, door handles, wall panel controls, thermostats and keyboards.
  • Processes for cleaning and disinfection should include sufficient contact time for disinfectants, appropriate strength of cleaning and disinfectant solutions, use of damp dusting, working from clean to dirty areas and eliminating the practice of dipping a cloth back into cleaning solution after use and re-using it on another surface.


This page provides basic information only. It must not take the place of medical advice, diagnosis or treatment. Always talk to a health care professional about any health concerns.


For Further Information

Call the Infectious Disease Program: (807) 625-5900

or toll-free 1-888-294-6630

Health Topic
Diseases & Infections