Controlling the Spread of Norovirus

  • From Contra Costa Health Services
    Outbreaks of norovirus infection are more likely to occur during winter months within institutions such as residential facilities, hospitals, long-term care facilities, schools, and child care settings. The virus is easily spread from person-to-person through direct contact, contact with contaminated surfaces, and ingestion of contaminated food. This information is provided by Contra Costa County Communicable Disease Control to assist with the recognition and control of norovirus infections in schools and child care facilities.

    Norovirus Characteristics
    The typical symptoms of norovirus are nausea, vomiting, low-grade fever, abdominal cramps, and watery, non-bloody diarrhea. Vomiting is more common in children. Symptoms usually develop within 24 to 48 hours after exposure, but can appear as early as 12 hours. Illness typically lasts 12 to 60 hours and usually will resolve on its own.

    Norovirus is spread very easily from person to person, and people can become infected with the virus in several ways, including:
    • Eating food or drinking liquids that are contaminated with norovirus.
    • Touching surfaces or objects contaminated with norovirus, and then eating or placing their hand in their mouth.
    • Having direct contact with another person who has norovirus. Examples include, caring for someone with illness, or sharing foods or eating utensils with someone who is ill.
    The virus can persist on surfaces in the environment for weeks and is not destroyed by many disinfecting products. When an individual with norovirus handles or prepares food and drinks improperly, they can contaminate those items and can cause infections in people who consume those products; therefore, food workers with diarrhea or vomiting should not work until at least 48 hours after their symptoms have stopped.
    Re-infection can occur multiple times during a lifetime. An outbreak of norovirus infection is suspected when more than two students and/or staff in a facility or classroom have symptoms of this virus, starting within a 48 hour period. Report any suspected outbreaks to Communicable Disease Programs at 925-313-6740.
    Diagnosis and Treatment
    Individuals with diarrhea and vomiting should drink plenty of fluids and follow the control measures on the next page to prevent spread in their households. There is no vaccine or specific therapy for norovirus infection; treatment is supportive and focuses on preventing dehydration. If symptoms do not improve, individuals should contact their primary care physician. Confirmatory laboratory testing for norovirus during an outbreak can be arranged through the Contra Costa Public Health Laboratory by contacting the Communicable Disease Program. During community-wide outbreaks or periods of high norovirus transmission, laboratory diagnosis may not be necessary.
    Control Measures
    Strict infection control practices are necessary to control norovirus spread. These are:
    • Hands should be washed vigorously with soap and warm water for> 20 seconds:

    Wash Hands AFTER:

    • Toilet visits
    • Cleaning up vomit or diarrhea
    • Changing diapers
    • Handling soiled clothing or linens
    • Contact with a symptomatic person
    • Sneezing, coughing

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