Understanding Norovirus

Norovirus is a very contagious virus that can infect the stomach and intestines. It causes diarrhea and vomiting. Norovirus is the most common cause of illness from contaminated food in the U.S. The virus spreads easily through contaminated foods and surfaces. Norovirus is not related to the influenza (flu) virus.

What causes norovirus infection?

You can be infected with norovirus by coming into contact with a person who has the virus. Or you can get it by touching a contaminated surface or eating contaminated food. Washing your hands well can lower your risk of getting the virus. You can also get it by consuming food and water contaminated with the virus. Foods most likely to become tainted include:

• Shellfish

• Ready-to-eat salads and sandwiches

• Produce, such as celery, melons, and leafy vegetables

Follow these tips to prevent infection:

• Wash your hands for at least 20 seconds with soap and water after going to the bathroom, after changing a diaper, and before touching any food. Don't prepare food for others when sick and for 2 days after symptoms stop.

• If someone in the house has norovirus, disinfect all surfaces that might be contaminated. Use a bleach-based cleaner. Wash clothes or linens right away that may be contaminated.

• Don't eat food or drink water in areas with warnings of contamination.

What are the symptoms of norovirus?

Some people may have no symptoms. In people who do, symptoms show up suddenly, often within a day of being exposed. The illness lasts 1 to 3 days. Symptoms include:

• Fever

• Nonbloody diarrhea

• Nausea

• Nonbloody vomiting

• Headache

• Achiness

• Stomach cramping

More severe cases are often seen in infants, older adults, and people with other health problems. Symptoms may last longer and be more severe in these groups.

How is norovirus treated?

There is no medicine to cure norovirus, but some may be used to ease symptoms. Treatment includes:

• Rest. You may feel better faster if you get plenty of rest.

• Fluids. Drinking lots of fluids will help you stay hydrated. Don’t drink alcohol or beverages with caffeine. They can make your symptoms worse.

• Medicine. Over-the-counter medicines for diarrhea may ease symptoms. These should be used only by adults. Pain relievers, such as acetaminophen or ibuprofen, can help with headaches and body aches. Antibiotics are not effective in treating norovirus.

What are the possible complications of norovirus?

Dehydration is the main concern with norovirus infection. Severe dehydration may need to be treated in the hospital. You may need to get fluids through an IV (intravenous line) in your vein.

When should I call my healthcare provider?

Call your healthcare provider right away if any of the following occur:

• Fever of 100.4°F (38°C) or higher, or as directed by your healthcare provider

• Belly (abdominal) pain that gets worse

• Severe dizziness, especially when getting up from bed

• Vomiting so severe that you can’t keep fluids down