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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 gastroenteritis.
Noroviruses 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 these environments.
Keep your child at home while they are sick and for a few days after feeling better. That's when the virus most likely can be spread to others. The virus can stay in your child's stool for weeks after the symptoms are gone.
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 48 to 72 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, they 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.
You treat gastroenteritis caused by noroviruses by managing complications until it passes. 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, drink plenty of fluids. Choose water and other clear liquids until you feel better. You can take frequent sips of a rehydration drink (such as Pedialyte). Soda, fruit juices, and sports drinks have too much sugar and not enough of the important electrolytes that are lost during diarrhea. These kinds of drinks should not be used to rehydrate. In cases of severe dehydration, fluids may need to be replaced through an IV (intravenously).
When you feel like eating again, start with small amounts of food.
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.
You can help prevent infection by doing the following:
Current as of:
July 1, 2021
Author: Healthwise StaffMedical Review: E. Gregory Thompson MD - Internal MedicineAdam Husney MD - Family MedicineElizabeth T. Russo MD - Internal Medicine
Current as of: July 1, 2021
Author: Healthwise Staff
Medical Review:E. Gregory Thompson MD - Internal Medicine & Adam Husney MD - Family Medicine & Elizabeth T. Russo MD - Internal Medicine
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