Norwalk Virus: Your A-to-Z Guide from Diagnosis to Treatment to Prevention

Young boy in a cap. Norwalk virus.What is norwalk virus?

Norwalk virus was first identified as the cause of an outbreak of gastroenteritis among children at a school in Norwalk, Ohio – and among their teachers and their families.
Norwalk virus is a significant cause of gastroenteritis outbreaks in schools, day-cares, summer camps, restaurants, and cruise ships. It is also a significant cause of gastroenteritis in the absence of an outbreak. In addition, Norwalk virus is a significant cause of food poisoning.

Who gets it?

Anyone can get Norwalk virus, from the nursery to the nursing home, but those at highest risk are children under 4. Outbreaks often occur in settings where there is close contact between many children. The virus is found in stool and on hands and surfaces that have had contact with stool. Norwalk food poisoning has most often been associated with contaminated ice, water, raw shellfish, salads, sandwiches, and cookies.

The virus is destroyed by cooking, but not by freezing

What are the symptoms?

Diarrhea and vomiting are the hallmark symptoms of Norwalk virus infection. These may be accompanied by fever, headache, muscle aches, abdominal cramps, and generally feeling crummy.

Is it contagious?

Norwalk virus is quite contagious, and may be spread via the fecal-oral route, through direct contact,through infected fomites, or through contaminated food or water.

How long does it last?

Symptoms usually begin 12 hours to 4 days after having been exposed. The illness may last for as little as a day, or as long as 2 weeks.

How is it diagnosed?

The diagnosis is usually based on history and physical examination. Stool tests are available that can detect the virus.

How is it treated?

Usually, the only treatment is to prevent or treat dehydration by drinking plenty of fluids. Oral rehydration solutions such as Pedialyte may be used. In more severe cases, intravenous fluids may be needed.

Antibiotics usually make the situation worse.

How can it be prevented?

Wash hands before preparing or serving foods. Have someone else prepare the food if you have cramps, nausea, vomiting, or diarrhea, or have sores on your hands. Children, and those who care for them, should wash thoroughly before eating and after toileting.

For further prevention ideas, see the articles on fecal-oral transmission, contact transmission, and fomites.

Related concepts:

Calciviruses, Tummy flu, Stomach flu.

Dr. Alan Greene

As a father of four himself, Dr. Greene has devoted himself to freely giving real answers to parents' real questions -- from questions about those all too common childhood conditions to those that address the most recent and rare pediatric illnesses. His answers combine cutting edge science, practical wisdom, warm empathy, and a deep respect for parents, children, and the environment. He is also an electrifying public speaker, and has personally touched many during his talks in North America, Europe, Asia, and the Middle East.

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Dr. Greene is the Founding President of the Society for Participatory Medicine and has served as both President and Board Chair of Hi-Ethics (Health Internet Ethics. He is on the Board of Directors for Healthy Child Healthy World, The Lunchbox Project, and The Society for Participatory Medicine. He has also served as an advisor to URAC for both their inaugural and their updated health web site accreditation program. He is a founding member of the e-Patient Scholars Working Group, and a founding board member of the Center for Information Therapy.

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Dr. Greene is the author of Feeding Baby Green (Wiley, 2009), Raising Baby Green (Wiley, 2007), From First Kicks to First Steps (McGraw-Hill, 2004), The Parent's Complete Guide to Ear Infections (People's Medical Society, 1997), and a co-author of The A.D.A.M. Illustrated Family Health Guide (A.D.A.M., Inc., 2004). He is the medical expert for three additional books, The Parent's Soup A-to-Z Guide to Your New Baby, (Contemporary Books, 1998) The Parent's Soup A-to-Z Guide to Your Toddler, (Contemporary Books, 1999), and The Mother of All Baby Books, (Hungry Minds, Inc., 2002).

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