Norovirus
Fact Sheet
1. What are noroviruses? - Noroviruses are a group of viruses that
cause gastroenteritis, sometimes called the “stomach flu,” in people. Like all
viral infections, noroviruses are not affected by treatment with antibiotics,
and cannot grow outside of a person’s body. The term norovirus was recently
approved as the official name for this group of viruses.
2. What are the symptoms
of illness caused by noroviruses?
- The symptoms of norovirus illness usually include nausea, vomiting, diarrhea,
and some stomach cramping. Sometimes people also have a low-grade fever,
chills, headache, muscle aches, and a general sense of tiredness. The illness
often begins suddenly, and the infected person may feel very sick. In most
people the illness is self-limiting with symptoms lasting for about 1 or 2
days. Most people with norovirus illness have both vomiting and diarrhea.
3. What is the name of the
illness caused by noroviruses?
- Illness caused by norovirus infection has several names, including:
a. Stomach
flu – this “stomach flu” is not related to the flu (or influenza), which is a
respiratory illness caused by influenza virus.
b. Viral
gastroenteritis – the most common name for illness caused by norovirus. Gastroenteritis
refers to an inflammation of the stomach and intestines.
c. Acute
gastroenteritis.
d.
Non-bacterial gastroenteritis.
e. Food
poisoning (although there are other causes of food poisoning and many norovirus
infections are not foodborne).
f. Calicivirus
infection.
4. How serious is
norovirus disease? -
People may feel very sick and vomit many times a day, but most people get
better within 1 or 2 days, and they have no long-term health effects related to
their illness. However, sometimes people are unable to drink enough liquids to
replace the liquids they lose due to vomiting and diarrhea. These persons can
become dehydrated and may need special medical attention. Dehydration is
usually only seen among the very young, the elderly, and persons with underlying
conditions.
5. How do people become
infected with noroviruses?
- Noroviruses are found in the stool or vomit of infected people. Persons
working in child care centers or nursing homes should pay special attention to
children or residents who have norovirus illness. This virus is very contagious
and can spread rapidly throughout such environments. People can become infected
with the virus in several ways, including:
a. Eating food or drinking
liquids that are contaminated with norovirus.
b. Touching surfaces or
objects contaminated with norovirus, and then placing their hand in their
mouth.
c. Having direct contact with
another person who is infected and showing symptoms (for example, when caring
for someone with illness, or sharing foods or eating utensils with someone who
is ill).
6. When do symptoms appear? - Symptoms of norovirus illness usually
begin about 24 to 48 hours after ingestion of the virus, but they can appear as
early as 12 hours after exposure.
7. Are noroviruses
contagious? - Noroviruses
are very contagious and can spread easily from person to person. Both stool and
vomit are infectious. Particular care should be taken with young children in
diapers who have diarrhea.
8. How long are people
contagious? - People
infected with norovirus are contagious from the moment they begin feeling ill
until at least 3 days after recovery. Some people may be contagious for as long
as 2 weeks after recovery. Therefore, it is particularly important for people
to use good hand washing and other hygienic practices even after recovering
from norovirus illness.
9. Who gets norovirus
infection? - Anyone can
become infected with these viruses. There are many different strains of
norovirus, which makes it difficult for a person’s body to develop long-lasting
immunity. Therefore, norovirus illness can recur throughout a person’s
lifetime. In addition, because of differences in genetic factors, some people
are more likely to become infected and develop more severe illness than others.
Because norovirus is highly contagious, it is a common cause of outbreaks in
schools, child care settings, cruise ships, and institutional settings.
10. How is norovirus
diagnosed? – Norovirus is
usually diagnosed clinically. Laboratory diagnosis requires examination of
stool or vomitus from ill individuals by a specialized laboratory.
11. What treatment is
available for people with norovirus infection? - 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. This is
because antibiotics work to fight bacteria and not viruses. Norovirus illness
is usually brief in healthy individuals. When people are ill with vomiting and
diarrhea, they should drink plenty of fluids to prevent dehydration.
Dehydration among young children, the elderly, and those with underlying
conditions can be common, and it is the most serious health effect that can
result from norovirus infection. By drinking juice, water, or oral rehydration
fluids (ORF) people can reduce their chance of becoming dehydrated. Sports
drinks do not replace the nutrients and minerals lost during this illness.
12. Can norovirus
infections be prevented? -
You can decrease your chance of coming in contact with noroviruses by following
these preventive steps:
a.
Frequently wash your hands, especially after toilet visits and changing diapers
and before eating or preparing food.
b. Carefully
wash fruits and vegetables, and steam oysters before eating them.
c.
Thoroughly clean and disinfect contaminated surfaces immediately after an
episode of illness by using a bleach-based household cleaner.
d.
Immediately remove and wash clothing or linens that may be contaminated with
virus after an episode of illness (use hot water and soap).
e. Flush or
discard any vomitus and/or stool in the toilet and make sure that the
surrounding area is kept clean.
f. Persons
who are infected with norovirus should not prepare food while they have
symptoms and for 3 days after they recover from their illness. Food that may
have been contaminated by an ill person should be disposed of properly.
13. For more information
about Noroviruses: http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-keyfacts.htm
This fact sheet provides
general information. Please contact your physician for specific clinical
information.
Information obtained from
Pennsylvania Department of Health at: http://www.health.pa.gov/My%20Health/Diseases%20and%20Conditions/M-P/Documents/Norovirus%20Fact%20Sheet.pdf