Norovirus: What it is and how you can prevent it

Guide I-116

Sonja Koukel

College of Agricultural, Consumer and Environmental Sciences, New Mexico State University

Professor/Extension Community and Environmental Health Specialist, Department of Extension Family and Consumer Sciences, New Mexico State University. (Print Friendly PDF)

What is norovirus?

Norovirus is a group of viruses that cause gastroenteritis (GAS-tro-en-ter-I-tis) in people. Gastroenteritis is an inflammation (swelling) of the lining of the stomach and intestines. The term “norovirus” is the official name for this group of viruses. Other names are “Norwalk virus” and “Norwalk-like viruses,” named after the original strain of norovirus that caused an outbreak of gastroenteritis in a school in Norwalk, Ohio, in 1968.

Photograph of a person covering their mouth and holding their abdomen.

© Xalanx |

What illness is caused by norovirus?

Illness caused by norovirus infection has several names:

  • Stomach flu; this “stomach flu” is not the same as the flu (influenza). Influenza is caused by the influenza virus. Influenza affects the respiratory system (your nose, throat, and lungs).
  • Viral gastroenteritis; this is the most common name for illness caused by norovirus.
  • Food poisoning (there are other causes of food poisoning)
  • Acute gastroenteritis
  • Non-bacterial gastroenteritis
  • Calicivirus infection; calicivirus infections cause inflammation (swelling) of the stomach and intestines.

What are the symptoms of illness caused by norovirus?

Symptoms include:

  • Feeling sick to your stomach (nausea)
  • Vomiting (throwing up; more common in adults)
  • Diarrhea (loose, watery poop; more common in children)
  • Stomach cramping (pains)

Sometimes people may have:

  • Low-grade fever. This is an oral temperature (taken by mouth) above the normal 98.6°F, but lower than 100.4°F, over 24 hours.
  • Chills
  • Headache
  • Muscle aches/pains
  • Feeling tired

How serious is norovirus?

The illness can start suddenly. Signs of illness can show up anywhere between 12 to 48 hours after swallowing or breathing in the virus. The infected person may feel very sick, often throwing up many times a day. In most people, the illness is self-limiting (gets better on its own without medical treatment) and mild, with symptoms lasting for about 1 or 2 days.

Throwing up and diarrhea can result in dehydration (loss of water in the body). For some people, this may require medical attention. Generally, dehydration happens to very young children, the elderly, and people who have other illnesses.

How do people get norovirus?

Norovirus is an oral-fecal transmitted disease. This means the germs are in the stool (poop or poo) and vomit of people who have the disease. Norovirus is very contagious (can make other people sick). Getting sick with norovirus can happen in many ways:

  • Food: Eating food or drinking liquids that hold the virus.
  • Water: Removing the virus from water is difficult. The virus can be in water from city and town supplies, wells, lakes, swimming pools, and water stored aboard cruise ships. Ice can contain the virus and make you sick. Freezing does not kill the virus.
  • Hands: The virus can live up to 2 weeks on surfaces or objects (such as carpets, toilets, doors, and countertops). You can get sick when you touch surfaces or objects and then place your hands around or in your mouth.
  • Person to person: Having direct contact with a person who is infected. You can get sick from someone who has norovirus when you care for them, or share foods or eating utensils.
  • Airborne: The germs can be spread in the air. For example, when a sick person throws up, the germs can float in the air.

People who work in daycare centers or nursing homes should pay special attention to anyone who has norovirus illness. The virus can spread very fast in these places. Take extra care with young children in diapers who may have diarrhea.

How long do people carry the virus?

People who get infected with norovirus are contagious (can spread the disease to other people) from the moment they begin feeling ill to at least 3 days after the vomiting and diarrhea stop.

Who can get norovirus?

Anyone can get sick with norovirus. There are many different types of germs (strains of virus) that cause norovirus illness. This makes it difficult for a person’s body to develop long-lasting protection (immunity). So, norovirus illness can happen more than once over a person’s lifetime.

How often is norovirus reported?

Only the common cold is reported more often than norovirus as a cause of illness in the U.S.

Can noroviruses be prevented?

There is no vaccine (shot) to prevent the virus from making people sick. There is no medicine for people who get sick. Antibiotic drugs do not work because they fight against bacteria, not viruses.

Protect yourself from getting sick with norovirus by following these steps

  • Wash your hands often! Especially after using the toilet, changing diapers, playing with pets, sneezing, coughing, blowing your nose, and before eating or preparing foods.

    • Use soap and water.
    • Alcohol-based hand sanitizers do not kill the virus.

  • Clean and disinfect (destroy the germs) all surfaces.

    • Wear rubber gloves and use bleach water. Mix anywhere from 5 to 25 tablespoons of household bleach in one gallon of water. The amount of bleach depends on the surface to be cleaned.

    • You can use less bleach for hard surfaces, such as metals, glass, hard plastic, counters, doorknobs, and light switches.

    • Use more bleach for soft or porous surfaces, such as fabrics, carpets, and brick or concrete flooring.

    • Upholstered furniture can be steam cleaned.

  • Clean and disinfect the bathroom. Use bleach water to clean the toilet, sink, floor, walls, and all surrounding areas.

  • Wash clothing or linens immediately. Use very hot water and soap. Bleach can be used for whites. Machine dry the laundry.

  • Wash fresh fruits and vegetables before eating (FDA, 2018).

    • Use clean running water only. Washing fruits and vegetables with soap, detergent, bleach, or commercial produce wash is not recommended.

    • Firm vegetables, such as melons and cucumbers, can be cleaned with a produce brush.

    • Dry the washed fruits and vegetables with a clean cloth towel or paper towel to remove any germs that may remain on the surface.
Photograph of a caution sign. Caution: People who are sick with norovirus should not prepare food while they have symptoms and for at least 2 to 3 days after they recover from their illness. Throw out all foods if you think an ill person may have prepared them.


Centers for Disease Control and Prevention. 2019, April 5. Norovirus.

Cleveland Clinic. 2014, June 13. How to clean up after norovirus: 5 tips to prevent spreading this tough virus.

Food and Drug Administration (FDA). 2018, March 14. Selecting and serving produce safely.

New Mexico State University. n.d. Multimedia educational resources about norovirus.

For Further Reading

I-102: West Nile Virus: Information for New Mexico

I-108: Recommended Vaccinations for Adults

I-113: Measles: Protecting Yourself and Your Family

Photo of Sonja Koukel.

Sonja Koukel
is a Professor and Extension Community and Environmental Health Specialist in the Department of Extension Family and Consumer Sciences. She earned her B.S. at NMSU and her M.S. and Ph.D. at Texas Tech University. Her Extension programs focus on health and wellness—physical, mental, spiritual, and environmental.

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April 2020 Las Cruces, NM