What is norovirus?

By Michelle Forman, Senior Media Specialist, APHL

I can’t help but notice an overwhelming trend in my Facebook newsfeed these days: people all over the country are sick.  Stomach sick.  It does not sound pretty.  Despite being referred to as a variety of names – stomach flu (there is nothing “flu” about it, folks), food poisoning, or my personal fave, Horkfest 2012 – my friends and family are likely facing norovirus.

So what is norovirus?  And how does it spread so darn fast?


Noroviruses are actually a group of viruses that cause acute gastroenteritis (aka, angry tummy).  In fact, norovirus is the most common cause of gastroenteritis in the United States, leading to over 20 million cases every year.  The symptoms include diarrhea, vomiting, nausea… you know, overall tummy terribleness.  And while those symptoms are obviously no fun, the real danger comes when those symptoms lead to dehydration.

As if all of that isn’t bad enough, the scariest part is how quickly norovirus spreads.  Norovirus can spread without direct person-to-person contact which means you can catch it by touching the same surface as someone who has it. A person is contagious for *at least* three days after being sick even if they’re feeling better.  And it only takes a small number of viral particles to spread.  So you don’t need to have vomit on your hand – you just need to have a few microscopic particles lingering without your knowledge.

Here’s an example of how a person might spread norovirus:

Barney is a teacher.  One day he got home from work and felt awful.  Within a few hours Barney was vomiting. He was up all night feeling terrible, hugging his toilet and wishing for someone to put him out of his misery.  He called in sick to work the next day.  By that night he was feeling better and was finally able to keep down some fluids.  Assuming he was fine, he headed back to work the next morning.  As he helped the kids with their art projects and math worksheets, he touched desks, markers and notebooks along the way.  Barney didn’t know he was still contagious.  Uh oh.  Guess what happened next. Wouldn’t you know it?  Kids in his class started to get sick… and then their families too… and then their parents’ coworkers.

You frequently hear of norovirus outbreaks associated with food handling and this is why.  It isn’t that the food is bad, it is that a person handling the food – whether at a restaurant or a house party – is actually contaminating the food everyone is eating… with poop.  Yeah.

Here’s another interesting tidbit: Did you know that there is actually a season for norovirus?  Yep.  It is sometimes referred to as “Winter Vomiting Disease.”  (Creative, eh?)  Norovirus tends to be more common in colder months because that’s when people tend to gather indoors often in close quarters (offices, classrooms, house parties, etc.).

How can you avoid norovirus?

  • Wash your hands!  Wash them especially well after using the bathroom, changing diapers and before and after eating or preparing food.  (Proper hand washing tips from CDC here.  Yes, you can do it wrong.)
  • Wash fruit and vegetables before eating.  Lots of hands touch your produce before it gets to you – make sure it is clean before eating or feeding to your family.
  • Do not prepare or handle food for others within at least three days of having norovirus.  DON’T!
  • Wash and disinfect EVERYTHING.  If someone in your household is sick, pull out the bleach-based, heavy-duty cleaners to de-grossify the bathroom, kitchen and any other rooms where they may have gotten sick.  And don’t forget about disinfecting laundry!  Never tried that “sterilize” setting on your washer?  Now is the time to take it for a spin. Oh, and while you’re doing all of that, make sure you’re wearing rubber gloves.  Norovirus is frequently spread when one person is cleaning up another person’s noro-mess.
  • Don’t keep anything that goes in your mouth or touches your face near your toilet.  Where is your toothbrush?  Sitting in a cup on your bathroom counter?  Norovirus aerosolizes very easily. (This is about to get really disgusting, but you need to read it.  Press on.) If someone in your family is vomiting or has diarrhea, the particles from those bodily functions actually spray around your bathroom not only while they are getting sick but also when they flush.  So please.  Do yourself a favor.  Put your toothbrush, make-up, razor and anything else in a closed cabinet.
  • Finally, encourage your family members, friends, teachers, coworkers and anyone else to STAY HOME for at least three days after being sick with norovirus.  It is for the benefit of everyone around them.  Assure them that their boss would rather not have them in the office for a few days than to be curled up on the bathroom floor wishing that life would end.

Here’s the news that we’re reading on norovirus. Spoiler alert: It is not pretty.


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  2. Pingback: No Haven From Norovirus in Paradise | APHL Public Health LabLog

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