Home > Health Library > Noroviruses (Norwalk Viruses)
Noroviruses are also called
Norwalk-like viruses and caliciviruses. Noroviruses cause gastroenteritis, food infection,
food poisoning, and acute nonbacterial
typically spread through contaminated water and foods, although they can also
pass from person to person. Water becomes contaminated if human waste enters drinking water because of flooding or from a sewage system that isn't working properly. You may become infected by:
Persons working in day care centers or nursing homes
should pay special attention to children or residents who have norovirus
illnesses. This virus is very contagious and can spread rapidly throughout
The symptoms of
gastroenteritis caused by the noroviruses include nausea, vomiting, diarrhea,
and abdominal (belly) pain. Diarrhea and vomiting can cause
dehydration. You may have a headache and a fever. A mild and
brief illness usually develops 24 to 48 hours after you eat or drink the
contaminated food or water and lasts for 24 to 60 hours. Only in rare cases does a person get very sick or have to go to the hospital.
Most norovirus infections are mild and pass in a few days. So most people do not
go to their doctors for a diagnosis. You can often diagnosis food
poisoning yourself if others who ate the same food as you also become ill.
If you do go to your doctor, he or she will make the
diagnosis based on your symptoms, a medical history, and a physical exam. Your
doctor will ask where you have been eating and whether anyone who
ate the same foods has the same symptoms. A stool test is sometimes done.
treat gastroenteritis caused by noroviruses by managing complications until
Dehydration caused by diarrhea and vomiting is the
most common complication. Do not use medicines, including antibiotics and other
treatments, unless your doctor recommends them.
To prevent dehydration, take
frequent sips of a rehydration drink (such as Pedialyte). Try to drink a cup of water or rehydration drink for each large,
loose stool you have. Soda
and fruit juices have too much sugar and not enough of the important
electrolytes that are lost during diarrhea, and they
should not be used to rehydrate. In cases of severe dehydration, fluids may
need to be replaced through an IV (intravenously).
Try to stay with your normal diet as much as possible. Eating your
usual diet will help you to get enough nutrition. Doctors believe that eating a
normal diet will also help you feel better faster. But try to avoid foods that
are high in fat and sugar. Also avoid spicy foods, alcohol, and coffee for 2
days after all symptoms have disappeared.
If you had diarrhea caused by norovirus, you should stay home for 2 to 3 days after your symptoms end before going back to work or school. This will help prevent spread of the virus.
can help prevent infection by doing the following:
Current as of:
June 4, 2014
E. Gregory Thompson, MD - Internal Medicine & W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
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