What is Norwalk Virus?
Norwalk virus is a very common source of non-bacterial
diarrhea and vomiting in humans. Symptoms usually have a sudden
onset and include watery diarrhea, vomiting, cramps, headache,
fever, chills and sore throat. The illness usually last 24 to 48
There are several different viruses that make up the Norwalk and
Norwalk-like viruses. The virus is very small and often
difficult to detect.
Norwalk viruses are more commonly associated with outbreaks in
nursing homes, homes for the aged and other adult institutions
due to the close proximity of the residents. Outbreaks have also
been linked to banquets, cruise ships, swimming pools, schools
How is The Norwalk Virus
Man is the only known reservoir for the Norwalk virus. It is
probably spread by the "fecal-oral" route,although
direct contact or airborne transmission has been suggested to
explain the rapid spread in institutions. The virus is very
contagious and only a few are needed to cause illness.
Contaminated water is the most common source for outbreaks other
than in institutions. Shellfish and salad ingredients are the
foods most often implicated in Norwalk outbreaks.
Immunity against the virus is
about 14 days. The incidence
of illness can occur year round
however, it is higher in the fall and
How Do You Prevent Norwalk
. Thorough hand washing is the best
prevention. Make sure hands
are properly washed after using
the toilet, changing diapers and
. People ill with diarrhea and Norwalk
like symptoms should be
isolated from others.
. Dispose of feces and fecally contaminated
. Clean and sanitize washrooms and
all hand contact surfaces once
daily or as needed.
. In institutions, isolate ill residents
from group activities until
they are symptom-free for 48
hours. Ill staff should remain off
work until symptom-free for 48
. Encourage visitors to wash their hands
before and after visiting the
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