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Notorious Virus – Norovirus

Do you remember the last time you had the “stomach flu”?

Most likely, it came on very quickly, and you probably blamed it on the last meal you ate or someone who was sick. Chances are the real culprit was a bug called norovirus. 

Food safety has been in the news a lot this year, mostly in a less-than-positive light (remember Chipotle’s crisis over foodborne illnesses tied to its restaurants?). Which makes this year’s National Food Safety Month (NFSM) theme even more relevant: “Notorious Virus”— how to protect against the leading causes of foodborne illness.”


The virus is highly contagious and commonly spread through food or water that is contaminated by fecal matter during preparation.

Noroviruses are a group of viruses that cause inflammation of the stomach and large intestine lining; they are the leading cause of gastroenteritis in the U.S. Noroviruses are highly contagious, and they can be transmitted through food or water that’s been contaminated by fecal matter during preparation. You can also be infected through close contact with an infected person.

This infection is often mistakenly referred to as the “stomach flu”- it is not related to the flu (influenza), which is a respiratory illness caused by influenza virus that goes around in the winter, which is a respiratory illness caused by a different type of virus.


  • Vomiting
  • Diarrhea
  • Stomach ache or cramps
  • Low-grade fever and chills
  • Headache or muscle aches
  • General sense of tiredness

These symptoms often come on suddenly, usually within one or two days after exposure, and you may quickly become very sick. Even though you might feel like you want to die, norovirus symptoms last one to three days, and most people recover completely without treatment.

Greater Risk

However, some people, such as the very young, elderly, and immune-compromised, are at greater risk if they are unable to drink enough liquids to replace those lost due to vomiting and diarrhea. These people can suffer from dehydration and should seek medical attention.

Lurking Near

People become infected with noroviruses when they eat food or drink liquids that have been contaminated; raw or undercooked oysters and raw fruits and vegetables have been implicated in some outbreaks. You can also get infected if you share food, by shaking hands, or touch an object or surface that has been infected with the virus and then touch your nose, mouth, or eyes. You also may get it through direct contact with someone who is infected.

Sometimes referred to as “the cruise ship virus,” norovirus infection occurs most frequently in closed and crowded environments such as hospitals, nursing homes, daycare centers, schools, cruise ships and other close quarters. Noroviruses are difficult to wipe out because they can withstand hot and cold temperatures as well as most disinfectants.

Always Susceptible

It’s important to remember that you (or others) are contagious from the moment you first start to feel ill to at least 24 hours after you recover. Some people may be infectious for as long as two weeks after they recover, potentially spreading the virus to many people they encounter at work, school, and other public places. Since there are many different kinds of noroviruses, being infected once does not prevent becoming infected again later from another kind of norovirus. There is no vaccine to prevent norovirus, and no drug to treat people who get sick. Antibiotics do not work, as they fight bacteria and not viruses.


Now that your memory has been “refreshed” about how awful norovirus is, you’re probably wondering how you can prevent ever getting it again. To help prevent its spread:

  • Wash your hands and forearms frequently and thoroughly using warm water and soap. This is particularly important after using the toilet, changing diapers and before preparing or eating food.
  • Wash fruits and vegetables before cooking or eating them. Cook seafood thoroughly.
  • Disinfect virus-contaminated areas with a chlorine bleach solution. Wear gloves.
  • Dispose of vomit and fecal matter carefully, to avoid spreading norovirus by air. Soak up material with disposable towels, using minimal agitation, and place them in plastic disposal bags. Wear disposable gloves when handling soiled items and wash your hands afterwards.
  • If you are sick, stay home! You may be contagious as long as three days after your symptoms end. Children should stay home from school or day care.


Animated Flu Germ

Contact Our Expert!


Extension Educator:
Vicki Hayman – (307) 746-3531

University of Wyoming Extension

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Extension Educator:
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University of Wyoming Extension

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Issued in furtherance of extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kelly Crane, Director, University of Wyoming Extension, College of Agriculture and Natural Resources, University of Wyoming Extension, University of Wyoming, Laramie, Wyoming 82071.

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