Norovirus and other viral gastroenteritis
What is viral gastroenteritis?
Often referred to as “stomach flu” (a misnomer, as it is not caused by the influenza virus) these viruses include adenovirus, calicivirus, astrovirus, and norovirus and are the leading cause of foodborne illness in the United States. Nororvirus is the most common cause of gastroenteritis in child care and school settings and therefore used to determine guidelines when there is no testing done in outbreak settings. Viral gastroenteritis is common year-round, but it is seen more often in the winter months (November — April). Animals do not carry or spread this type of pathogen.
Signs and symptoms
- Low-grade fever
- Abdominal cramps
- Diarrhea
- Vomiting
- Nausea
- Headache
- Body aches
Incubation period
Varies depending on the specific virus. However, one to three days (usually two) is the incubation period for norovirus and therefore used when the specific type of infection is not known.
Contagious period and spread
Norovirus and other viral gastroenteritis pathogens are highly contagious and spread mainly through the fecal→oral route, either by consumption of fecally-contaminated food or water, or by direct person-to-person spread. It may also be spread by touching contaminated surfaces or objects and then touching your mouth, placing contaminated objects in your mouth (pacifier, toys, cigarettes, etc.), or inhaling virus particles that have been released into the air when a person with infection vomits.
People infected with norovirus and other viral gastroenteritis are most contagious while symptomatic and for several days after symptoms resolve. However, studies have shown that you can still spread these viruses for several weeks after symptoms have resolved.
Public health reporting requirements
- Single cases of illness do not need to be reported to public health.
- Outbreaks must be reported immediately (within four hours) to the state or local public health agency. An outbreak is defined as the occurrence of more illness than expected in a given area, or among a specific group of people, over a period of time. This could be as few as two individuals from separate households experiencing similar symptoms. Outbreak reporting should not be delayed due to lack of diagnostic testing.
Control of spread
- Consult with local or state public health on implementation of control measures.
- Immediately throw away any food handled or prepared by an ill person.
- Encourage and teach the importance of frequent handwashing with soap and water, especially after using the toilet, changing diapers, and before eating. Sample signs showing when and how to wash hands are included on the department’s child care health regulations webpage under “Preventing illness” and in the hand hygiene section of this document. Post them or similar signs throughout the child care center or school to remind people to wash their hands.
- Ensure all handwashing facilities have soap and paper towels.
- Hand sanitizing gels or wipes are not as good at cleaning the hands as proper handwashing. Some are ineffective against norovirus.
- Immediately clear the room or area after a public display of vomiting.
- People cleaning up vomit/fecal material are encouraged to wear disposable gloves, mask, and gown/coverall to avoid direct contact with vomit/fecal material. Review the Cleaning and disinfection of fecal and vomit accidents guidance.
- Noroviruses are resistant to many commonly used disinfectants. If norovirus is suspected, it is important to use at least 5,000 parts per million (ppm) bleach solution (one cup bleach and 10 cups of water) or a disinfectant approved by the EPA with specific claims for activity against norovirus. Read the product labels to ensure norovirus is listed as a pathogen affected by the product and follow the instructions on the bottle. A list of EPA-registered disinfectants effective against norovirus is available on the EPA’s website under “List G: EPA’s Registered Antimicrobial Products Effective Against Norovirus.” For help mixing disinfectants, refer to the Bleach Dilution Calculator Tool.
- Most commercial disinfection products are not intended for use on heavily soiled surfaces. Safely remove the bulk of organic material, then wash with detergent and rinse with water prior to disinfection. Refer to Disease Prevention: The Facility Environment for disinfection guidance.
- Food contact surfaces and items that may be placed in the mouth must be washed with detergent, rinsed with water, and sanitized following the use of strong disinfectants.
- Items that can be laundered (towels, sheets, clothes, toys, etc.) that are contaminated during a fecal or vomit accident should be washed in hot water (>140o F) with detergent and bleach (or a laundry disinfectant product effective against norovirus) and dried in a hot dryer (> 140o F).
- People with severe or prolonged diarrhea (lasting longer than two to three days) or who have a high fever or bloody diarrhea should be referred to a health care provider.
- Alert possibly exposed family and staff members to watch for symptoms and provide them with prevention tips. See recommendations for caregivers and family section below.
Treatment
Most people with healthy immune systems will recover without treatment in one to three days. There is no specific treatment for viral gastroenteritis although fluids are important to prevent dehydration. No immunization is available.
Exclusion
- EXCLUDE all infected children and/or staff until at least 48 hours after diarrhea and vomiting symptoms have resolved, without the use of anti-diarrheal or antiemetic (anti-vomiting) medications.
- Infected students or staff who handle food must not prepare food for others until they have been symptom-free for at least 48 hours.
- During an outbreak, exclusion may be extended to 72 hours after symptom resolution.
Role of teachers, caregivers, and family
- If your child or a child you care for is infected with norovirus or other viral gastroenteritis, follow the advice of the child’s health care provider.
- Norovirus is HIGHLY contagious. Good handwashing using warm water, soap, and paper towels is one of the best ways to prevent the spread of gastrointestinal illness, especially after changing diapers, going to the bathroom or helping a child go to the bathroom, or handling food. Most hand sanitizers don’t work against norovirus and should not be used instead of proper handwashing with soap and hot water.