Noroviruses (Norwalk)

Be a germ stopper!
What are Noroviruses and who is most susceptible?
What are the symptoms associated with this virus?
How do people get Norovirus infection?
When can someone get sick and how long will they be contagious?
How are these viruses controlled?

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Prevent the spread of Noroviruses

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What are Noroviruses and who is most susceptible?

  • Noroviruses cause stomach and intestinal illness which often occurs in outbreaks. Most people are susceptible to the virus since there is no vaccine to prevent it and previous infections do not provide long-term immunity in most cases.
  • Only humans get the disease. Outbreak settings include child care facilities, schools, health care facilities, cruise ships, banquets, parties and restaurants.

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What are the symptoms associated with this virus?

  • Most people have nausea and/or vomiting and/or diarrhea. They may also have abdominal cramps, headache, low grade fever, chills and muscle pain. Vomiting occurs more frequently in children, while adults tend to have more diarrhea. Diarrhea due to this virus should not have blood or mucous in it as a rule. If it does, see a physician right away and ask for a stool test to check for a bacterial infection as the cause of the diarrhea.
  • Infected persons usually recover in 2 hours to several days, (average 24 to 48 hours), without serious or long-term health effects. It is important to continue fluid intake to replace liquids lost with vomiting and diarrhea.

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How do people get Norovirus infection?

  • Contaminated water drunk 4 to 77 hours (usually 24 to 48) hours before illness begins. City of Ottawa water and commercial bottled water are considered safe. Untreated water (or ice made from it) may be the source of the infection.
  • Contaminated food eaten 4 to 77 hours (usually 24 to 48) hours before illness begins. Raw and undercooked clams and oysters may be contaminated if they have been in contact with raw sewage. Salad ingredients, fruit and other uncooked foods may be contaminated by infected food handlers.
  • Touching a hard surface contaminated with stool or vomit from an infected person and then putting your fingers to your mouth before washing your hands.

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When can someone get sick and how long will they be contagious?

The incubation period (time between contracting the virus and having the first symptom) is usually 24 to 48 hours with a range of 4 to 77 hours. A person may be contagious until 72 hours after the last episode of vomiting or diarrhea.

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How are these viruses controlled?

  • The ill person should not enter a child care facility, school or health care facility or handle food to be eaten by others until 48 hours after the last episode of vomiting or diarrhea.
  • Hand washing with soap and water is essential after using the toilet, and before preparing food, eating, smoking or any other hand to mouth activity. Waterless alcohol-based hand sanitzers, available at pharmacies and many other stores, can also be used if the hands are not visibly dirty. If they are, use soap and water.
  • Ensure safe food handling at all times.
  • When someone at home is ill, disinfect the bathroom and hard surfaces that may be contaminated with the virus at least daily.
  • Those who live in the same household as an ill person may attend a child care facility, school, health care facility or handle food to be eaten by others as long as they immediately go home if they develop nausea, vomiting, diarrhea or abdominal cramps.

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For further information, call Ottawa Public Health at 613-580-6744.
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