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What is Norovirus?

Tricia Christensen
Tricia Christensen
Tricia Christensen
Tricia Christensen

Norovirus, sometimes also called the Norwalk virus, causes the intestinal flu. People infected with a norovirus, generally experience stomach cramps, diarrhea, vomiting, and slight fever. This virus often occurs in outbreaks. It is a common cause of high numbers of people being ill on cruise ships. It can also sweep through a convalescent home or school with ease.

Failure to properly wash the hands after using the bathroom usually transmits norovirus to others. Coming into contact with hands or food that is prepared by hands that are contaminated with molecules of infected stool can cause outbreaks. Sometimes exposure to raw sewage may also cause outbreaks of norovirus. Most commonly however, an outbreak begins with a person who is infected preparing food for others without thoroughly washing the hands.

The norovirus causes cramps and an upset stomach.
The norovirus causes cramps and an upset stomach.

For example, on a cruise ship, a person who has not washed his hands and then cut fruit for a large fruit salad could infect high numbers of people. Incubation for the illness is usually about one to two days. This means people exposed to the Norwalk virus get sick quite rapidly after exposure.

In healthy populations, norovirus is uncomfortable, inconvenient, and miserable. However, usually no interventions are needed as healthy people normally recover in about 24-48 hours. The course of the virus in the elderly, the very young, or in those with serious illnesses may be more complicated.

A slight fever is a common symptom of norovirus.
A slight fever is a common symptom of norovirus.

In young children, constant vomiting and diarrhea can quite easily lead to dehydration. If you believe a child has been exposed to the Norwalk virus, it may be best to visit a doctor, particularly if symptoms do not resolve within the first 24 hours. With the elderly and medically fragile, dehydration may also be a factor. Norovirus can also complicate other illnesses.

Bleach disinfects surfaces that have been contaminated by diarrhea and vomit attributed to norovirus.
Bleach disinfects surfaces that have been contaminated by diarrhea and vomit attributed to norovirus.

Some people may require hospitalization and intravenous fluids in order to recover from norovirus without risking serious dehydration. Dehydration can also prolong symptoms of vomiting, and severe dehydration can lead to organ shutdown. If one’s symptoms fail to resolve in a day or so, one should see a physician.

In order to prevent transmission, people should always thoroughly wash the hands with warm, soapy water after using the bathroom, and before eating. If one is ill with the stomach flu, he or she should try to stay away from others. Children should be kept home from school until symptoms have resolved. Workers in the food industry especially should not attend work when they have the stomach flu.

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

Learn more...

Discussion Comments

anon953082

You're contagious for at least 72 hours after you feel better, and very likely even longer.

anon91801

I am a medical epidemiologist and infectious disease specialist and one of my areas of expertise is management of the challenge of norovirus. I’ll apologize now for the length of my response.

In Ireland where I work, we see many outbreaks caused by norovirus. It is too costly to test the bowel motions of everyone to see if they are shedding the virus so we test a sample and go on the clinical picture (symptoms) of the remainder of the cases but experiments show us that people who have norovirus will continue to shed it for many days (and in some for up to two weeks after) after their symptoms subside. You are much less likely to spread norovirus; if you do you have diarrhea (normally formed stools are much less prone to accidental sailing of hands when cleaning your perineal area at toilet).

All the evidence suggests that within 48 hours of symptoms subsiding, your risk of passing on is very high but this falls rapidly over the next few days. However, after five days of normal stool it is still quite possible to pass on the virus.

Forty-eight hours has been chosen as an arbitrary cut off point. Return after more than 48 hours and your risk of passing it on are present but wit good personal hygiene the risk is acceptable. But within 48 hours the chance of passing it on is high, and the risk is unacceptable.

People returning to work too soon can (say in a hotel or in a hospital) pass illness on to other staff and prolong the outbreak.

Moreover, if the infection is passed on to guests (in a hotel) or to a patient (in a hospital) this makes a difficult legal problem. Hotels and hospitals have a “duty-of-care” to their patients/guests and failing to ensure that the risk of norovirus to clients is low then the owner of the hotel/hospital can be legally liable since they put the client in harm's way. Statutory facilities such as hospitals pay their staff for being ill, but many private sector facilities such as hotel staff do not and if ill they have to forgo pay. It is only natural that they will want to get back to work as soon as possible and often overlook telling their supervisor that they are within 28 hours of symptoms.

But I have seen at first hand how likely such a course of action is to introduce a second wave of infection, which is a bad investment for the hotel. It would pay for itself many times over that, during a norovirus outbreak in a hotel, that sick days would be paid to ensure people stay off in the manner that all guidance says they should.

anon57367

it is true that it IS illegal for someone to work in any environment with this illness. i work at a convalescent center, and i currently have the virus. i am not allowed to even step one foot onto my work premises.

anon32336

i have had norovirus since tuesday the 12th may until today, i have had d+v throughout, but its unusual, because i feel OK, then i feel ill again. i proven positive on sunday 17th still even though i starved myself for 48 hours. should i attend work, i'm not directly in contact with food, but i am working on a kitchen, i serve customers, and they don't wash their hands after i hand them cash. i also believe it is illegal for me to work in any kitchen with a virus like this or similar.

how true is this?

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    • The norovirus causes cramps and an upset stomach.
      By: Dessie
      The norovirus causes cramps and an upset stomach.
    • A slight fever is a common symptom of norovirus.
      By: evgenyatamanenko
      A slight fever is a common symptom of norovirus.
    • Bleach disinfects surfaces that have been contaminated by diarrhea and vomit attributed to norovirus.
      By: design56
      Bleach disinfects surfaces that have been contaminated by diarrhea and vomit attributed to norovirus.
    • If a child is thought to have been exposed to norovirus, they should visit a doctor.
      By: Marcin Sadlowski
      If a child is thought to have been exposed to norovirus, they should visit a doctor.
    • Cruise ships have had large outbreaks of norovirus.
      By: Rawpixel
      Cruise ships have had large outbreaks of norovirus.
    • Some people may need hospitalization and intravenous fluids to recover from norovirus.
      By: ShpilbergStudios
      Some people may need hospitalization and intravenous fluids to recover from norovirus.
    • Children infected with norovirus should not attend school until symptoms have resolved.
      By: Zsolt Biczó
      Children infected with norovirus should not attend school until symptoms have resolved.