Noroviruses are a group of viruses that cause acute gastroenteritis in humans. Noroviruses belongs to the group of viruses that
include rotavirus, astrovirus, and enteric adenoviruses. These noroviruses belong to one of four norovirus genogroups (GI, GII,
GIII, GIV). Because of the diversity of noroviruses, infection may not provide long-term immunity and persons may be infected
multiple times. Noroviruses are highly contagious, with as few as 10 particles sufficient to cause infection. Noroviruses are
transmitted through the fecal-oral route and people can be infected by eating food, touching surfaces or contaminated objects,
or having direct contact with another person infected with norovirus. Studies have speculated that norovirus can persist on
surfaces for up to 48 hours if not disinfected. The incubation period is about 24 to 48 hours after exposure to the virus, but can
be as short as 12 hours with symptoms lasting one to two days. People who have recovered can continue shedding virus for up
to 14 days.
Infection Control Recommendations:
· Isolation Precautions:
· Sporadic cases of suspected norovirus infection should be managed with standard precautions with careful
attention to hand-hygiene practices.
· Contact precautions should be used with diapered or incontinent persons or in outbreak situations.
· During outbreaks, cohort symptomatic patients or isolate them to their rooms.
· During outbreaks, exclude patients from group activities and common rooms (including the dining room)
while symptomatic and for an additional 72 hours after their symptoms resolve without the use of
· Masks should be worn by persons while cleaning areas heavily contaminated with feces or vomit.
· Instruct visitors regarding hand hygiene and other infection control precautions.
· Environmental Disinfection:
· Chlorine bleach with a minimum concentration of 1000 ppm (1 part household bleach to 50 parts water) is the
disinfectant of choice for norovirus. Surfaces should be vigorously wiped for at least 10 seconds and allowed to air
dry to achieve disinfection on visibly soiled surfaces.
· Check the product label regarding effectiveness of the product against norovirus.
· A list of cleaning products recommended by the Environmental Protection Agency (EPA) as effective
against norovirus is available at www.epa.gov/oppad001/list_g_norovirus.pdf.
· Laundry Concerns
· Soiled linens should be handled as little as possible. Do not shake soiled linens and laundry. Soiled
linens should be placed directly into a designated bag at the point of removal.
· Ensure proper segregation of clean and soiled laundry.
· Do not overfill washers or dryers: this prevents adequate cleaning.
· Wash with an approved detergent in hot water ≥160°F for ≥25 minutes. Dry in hot dryer if fabric allows.
· Prevent Contamination of Ice Machines
· Do not handle ice directly by hand, which may lead to contamination.
· Wash hands before obtaining ice.
· Do not allow the ice scoop to remain in the ice bin.
· Limit access to ice-storage chests, and keep container doors closed except when removing ice.
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Norovirus Infection Control Recommendations for
Healthcare, Long-Term Care, and Residential Care Settings Public Health
· Hand hygiene:
· All employees should wash hands frequently with warm running water and soap for at least 20 seconds, especially
after performing patient-care duties, using the toilet, changing diapers, and before eating or preparing food.
· Alcohol-based hand gels may be used in addition to hand washing with soap and water, however are not
recommended as the sole form of hand hygiene.
· Emphasize thorough and frequent hand hygiene to those recovering from diarrheal illness since they can continue
to be contagious for several days after symptoms resolve.
· Exclude staff members who are currently symptomatic with vomiting and/or diarrhea. All staff members
who provide direct care or who prepare food should be excluded from all duties while symptomatic and for
an additional 72 hours after their symptoms resolve without the use of medications.
· Cohort staff members early in an outbreak to limit spread in a healthcare or long term-care facility.
· Perform thorough and frequent hand hygiene after returning to work because the virus can continue to be
shed for several days after symptoms resolve.
· Patients or residents who are symptomatic should be excluded from group activities, dining halls, and
common areas until all symptoms of diarrhea, nausea, or vomiting have subsided.
· In outbreak situations, maintain contact precautions for at least 72 hours after symptoms resolve without
the use of medications.
For further information call or visit us on the World Wide Web
Acute Disease Service
Oklahoma State Department of Health
Phone (405) 271-4060
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