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Norovirus - The "Cruise Ship Virus"


Updated October 29, 2012

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

What It Is:

Norovirus is the number one cause of gastroenteritis, or stomach flu, in the United States. It is a highly contagious virus that causes inflammation in the stomach and intestines. It is also the most common cause of "food poisoning" in the US, because it can easily contaminate and spread via food.

Norovirus is also known as norwalk virus, or "the cruise ship virus," because of the multiple outbreaks that have occurred on cruise ships.


Symptoms of norovirus are the same as symptoms of other types of stomach flu:

  • Vomiting
  • Diarrhea
  • Cramping/Stomach Pain
  • Nausea
  • Fever
  • Headache
  • Body Aches

When It Can Spread:

Norovirus can be contagious before you start showing symptoms, and for as long as two weeks after you start to feel better. But it's most contagious while you're sick, and during the first three days after your symptoms subside.

Who It Affects:

Norovirus sickens 21 million people a year and leads to approximately 800 deaths. Those at highest risk are young children and older adults. Both of these groups have immune systems that aren't as strong as those of older children or adults who are otherwise healthy, making it more difficult to recover from the symptoms, and leading to complications.

Possible Complications:

The most common complication from a stomach virus is dehydration. If not treated, dehydration can be very serious. If you are unable to keep even small amounts of fluid down, or have had very severe diarrhea (or both), you may be dehydrated. Severe dehydration may require medical treatment such as IV fluids or medications to help stop the vomiting. If you think you might be dehydrated due to vomiting or diarrhea, contact your health care provider.

Treatment Options:

Most people who get norovirus will not need any medical treatment. Typically, it's something that can be treated at home and will go away on its own.

If you are concerned about vomiting or you aren't sure what to do to treat it at home, this guide will take you through every step you need to take when you are vomiting.

Occasionally, a norovirus infection will be bad enough to require medical treatment. Although there is no medication that can kill or cure the infection, there are medications that can help stop or reduce vomiting so that you don't get dehydrated—or you can rehydrate if your body is already dehydrated. These medications are available only by prescription, so it's important to seek medical attention if you think it's something you need.


Because norovirus is so contagious, it can be hard to prevent. There is no vaccine to prevent it, and there is no medication to treat it. The best way we have to prevent norovirus is by good hand washing.

Always wash your hands after using the bathroom or changing diapers, before and after handling food, and before eating.

Norovirus can be found in the stool before you start showing any symptoms, and for as long as 2 weeks after you are feeling better.

Washing your hands well and frequently—especially if you think you could have been exposed to norovirus—is extremely important.

If you get sick, do not prepare food for others. This is important for people working in the food services industry, because they come into contact with the food of so many other people. If you have a stomach bug—even if you aren't sure it's norovirus—recommendations are that you not return to preparing food for others for at least 2 to 3 days after you are feeling better. Good hand washing and hygiene practices are even more important in these environments where outbreaks can occur so easily.


"Overview" Norovirus 12 Apr 12. Centers for Disease Control and Prevention. US Department of Health and Human Services. 17 Oct 12.

"Symptoms" Norovirus 12 Apr 12. Centers for Disease Control and Prevention. US Department of Health and Human Services. 17 Oct 12.

"Preventing Norovirus Infection" Norovirus 12 Apr 12. Centers for Disease Control and Prevention. US Department of Health and Human Services. 17 Oct 12.

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