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Department of Health and Human Services > Epidemiology
and Disease Reporting > Epidemiology
Corner > Norovirus
Epidemiology
Corner
September
23, 2005
Norovirus
Noroviruses are
single-stranded RNA viruses that cause “stomach flu,”
or gastroenteritis, in humans. These viruses occur worldwide
and are common, affecting all age groups. Norwalk is a commonly
known Norovirus.
Norovirus illness
may begin suddenly with an incubation period of 24 to 48 hours.
Symptoms include nausea, vomiting, diarrhea and stomach cramping.
There may be low-grade fever, chills, headache, muscle aches
and a general sense of tiredness. People may become dehydrated
and need medical attention because of fluid loss from the vomiting
and diarrhea.
The illness is
usually self limiting and most people feel better in one or
two days. When people are ill with vomiting and diarrhea, they
should drink plenty of fluids to prevent dehydration. Currently,
there is no antiviral medication that works against norovirus
and there is no vaccine to prevent infection. Norovirus infection
cannot be treated with antibiotics.
Noroviruses are
contagious and can spread easily from person to person. Both
stool and vomit from infected persons are infectious. People
are infectious from when they begin to feel ill up to three
days after the diarrhea and vomiting stops.
Transmission
can occur through:
- Eating food
or drinking liquids that are contaminated with stool and vomit
of infected people; this occurs commonly with people using
the restroom and not washing their hands thoroughly with soap
and water before touching food and water. It can also occur
if people do not wash properly after attending to people with
diarrhea and vomiting.
- Touching
surfaces or objects contaminated, with stool and vomit of
infected person and then placing hand in mouth;
- Having direct
contact with an infected person who is showing symptoms, for
example, when caring for someone, or sharing foods or eating
utensils.
Norovirus
infection can be prevented by:
- Frequent
washing of hands, especially after toilet visits and changing
diapers and before eating or preparing food.
- Carefully
wash fruits and vegetables and steam oysters before eating
them.
- Thoroughly
clean and disinfect contaminated surfaces immediately after
an episode of illness by using a bleach-based household cleaner.
- Immediately
remove and wash clothing or linens that may be contaminated
with virus after an episode of illness (use hot water and
soap).
- Flush or
discard any vomitus and/or stool in the toilet and make sure
that the surrounding area is kept clean.
- Food that
may have been contaminated by an ill person should be disposed
of properly.
- People who
are infected with norovirus should not prepare food while
they have symptoms and for three days after they recover from
their illness.
For more
information: www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-qa.htm
or the City of Houston health department, Bureau of Epidemiology
at 713-794-9181.
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