Norovirus is a very contagious illness.  You may hear norovirus illness called "winter vomiting disease" or "stomach flu.”   You can get norovirus from an infected person, contaminated food or water, or by touching contaminated surfaces.

Norovirus Symptoms

Norovirus causes inflammation of the stomach or intestines or both. The most common symptoms are:

• diarrhea,
• vomiting (throwing up),
• nausea, and
• stomach pain.

Other symptoms include:

• fever,
• headache, or
• body aches.

A person usually develops symptoms 12 to 48 hours after being exposed to norovirus. Most people with norovirus illness get better within 1 to 3 days.

If you have norovirus illness, you can feel extremely ill and vomit or have diarrhea many times a day. This can lead to dehydration, especially in young children, older adults, and people with other illnesses.

Symptoms of dehydration are decrease in urination, dry mouth and throat, and feeling dizzy when standing up.  Children who are dehydrated may cry with few or no tears and be unusually sleepy or fussy.

Norovirus Prevention

There is no vaccine to prevent norovirus infection.  Steps you can take to prevention norovirus infection include:

1. Wash your hands carefully with soap and water:

• especially after using the toilet and changing diapers, and
• always before eating, preparing, or handling food.

2. Wash fruits and vegetables and cook seafood thoroughly.

Carefully wash fruits and vegetables before preparing and eating them. Cook oysters and other shellfish thoroughly before eating them. 

3. When you are sick, do not prepare food or care for others who are sick.

You should not prepare food for others or provide healthcare while you are sick and for at least 2 days after symptoms stop. This also applies to sick workers in settings such as schools and daycares where they may expose people to norovirus.  Many local and state health departments require that food workers and preparers with norovirus illness not work until at least 48 hours after symptoms stop. If you were recently sick, you can be given different duties in the restaurant, such as working at a cash register or hosting.

4. Clean and disinfect contaminated surfaces.

After vomiting or having diarrhea, immediately clean and disinfect contaminated surfaces. Use a chlorine bleach solution with a concentration of 1000–5000 ppm (5–25 tablespoons of household bleach [5.25%] per gallon of water) or other disinfectant registered as effective against norovirus by the Environmental Protection Agency (EPA).

5. Wash laundry thoroughly.

Immediately remove and wash clothes or linens that may be contaminated with vomit or stool (feces).  You should:

• handle soiled items carefully without agitating them,
• wear rubber or disposable gloves while handling soiled items and wash your hands after, and
• wash the items with detergent at the maximum available cycle length then machine dry them.

Norovirus Testing and Treatment

Your medical provider may diagnosis norovirus based on symptoms alone (acute onset of vomiting and diarrhea).  A laboratory test called “PCR” (polymerase chain reaction) is very accurate at detecting norovirus.  Your medical provider will ask for a sample of your feces.  The sample will be sent to a laboratory, where a test is run to look for norovirus DNA.

There is no specific medicine to treat people with norovirus illness.  Norovirus infection cannot be treated with antibiotics because it is a viral (not a bacterial) infection.

If you have norovirus illness, you should drink plenty of liquids to replace fluid lost from throwing up and diarrhea.  This will help prevent dehydration.  Sports drinks and other drinks without caffeine or alcohol can help with mild dehydration.  However, these drinks may not replace important nutrients and minerals.  Oral rehydration fluids that you can get over the counter are most helpful for mild dehydration. Dehydration can lead to serious problems.  Severe dehydration may require hospitalization for treatment with fluids given through your vein (intravenous or IV fluids).  If you think you or someone you are caring for is severely dehydrated, call their medical provider.

Norovirus can spread quickly in school and daycare settings.  Early reporting of potential outbreaks, enhanced environmental cleaning, good hand hygiene, and exclusion of symptomatic individuals until they are symptom-free for at least 24 hours are critical to controlling the spread of disease.  

Outbreak Reporting Form

Guidelines for Norovirus in the Classroom or Daycare Setting

Norovirus Information for Parents (CDC) - English

Norovirus Information for Parents (CDC) - Spanish

For more information about norovirus, please call the Monterey County Health Department's Communicable Disease Unit at 831-755-4521.

To report a suspected outbreak, please call the Monterey County Health Department's Epidemiology & Surveillance Unit at 831-755-4698.

Please click to view the Communicable Disease dashboard with local norovirus data available in English and Spanish.

For More Information

California Department of Public Health Norovirus Website

For Healthcare Providers

Individual cases of norovirus are not reportable in the state of California.  However, suspected outbreaks should be immediately reported to the Epidemiology & Surveillance Unit at 831-755-4698.  Click here for more information about reporting requirements in Monterey County.  

The Monterey County Health Department recommends polymerase chain reaction (PCR) for confirming norovirus diagnosis, if specimens can be collected within 10 days of symptom onset.  PCR is available at the Monterey County Public Health Laboratory and any many commercial laboratories.  For more information about norovirus testing at the Monterey County Public Health Laboratory, call 831-755-4516.

For questions about norovirus or reporting, please contact the Monterey County Health Department's Communicable Disease Unit at 831-755-4521.

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