Norovirus (Stomach Bug)

Norovirus Infection

Norovirus infection causes inflammation in the stomach and intestines (gastroenteritis) and food poisoning. It is caused by exposure to a virus in a group of similar viruses called noroviruses.

Norovirus spreads very easily from person to person (is very contagious). It often occurs in places where people are in close contact, such as schools, nursing homes, and cruise ships. You can get it from food, water, surfaces, or other people who have the virus (are contaminated). Norovirus is also found in the stool (feces) or vomit of infected people. You can spread the infection as soon as you feel sick, and you may continue to be contagious after you recover.

What are the causes?

This condition is caused by contact with norovirus. You can catch norovirus if you:

• Eat or drink something that is contaminated with norovirus.
• Touch surfaces or objects that are contaminated with norovirus and then put your hand in or around your mouth or nose.
• Have direct contact with an infected person who has symptoms.
• Share food, drink, or utensils with someone who is sick with norovirus.

What are the signs or symptoms?

Symptoms usually begin within 12 hours to 2 days after you become infected. Most norovirus symptoms affect the digestive system. Symptoms may include:

• Nausea.
• Vomiting.
• Diarrhea.
• Stomach cramps.
• Fever.
• Chills.
• Headache.
• Muscle aches.
• Tiredness.

How is this diagnosed?

This condition may be diagnosed based on:

• Your symptoms.
• A physical exam.
• A stool test.

How is this treated?

There is no specific treatment for norovirus. Most people get better without treatment in about 2 days. Young children, the elderly, and people who are already sick may take up to 6 days to recover.

Follow these instructions at home:

Eating and drinking

• Drink plenty of water to replace fluids that are lost through diarrhea and vomiting. This prevents dehydration. Drink enough fluids to keep your urine clear or pale yellow.
• Drink clear fluids in small amounts as you are able. Clear fluids include water, ice chips, fruit juice with water added (diluted fruit juice), and low-calorie sports drinks.

-Avoid fluids that contain a lot of sugar or caffeine, such as energy drinks, sports drinks, and soda.
-Avoid alcohol.

• If instructed by your health care provider, drink an oral rehydration solution (ORS). This is a drink that is sold at pharmacies and retail stores. An ORS contains minerals (electrolytes) that you can lose through diarrhea and vomiting.
• Eat bland, easy-to-digest foods in small amounts as you are able. These foods include bananas, applesauce, rice, lean meats, toast, and crackers.

-Avoid spicy or fatty foods.

General instructions

• Rest at home while you recover.
Do not prepare food for others while you are infected. Wait at least 3 days after you recover from the illness to do this.
• Take over-the-counter and prescription medicines only as told by your health care provider.
• Wash your hands frequently with soap and water. If soap and water are not available, use hand sanitizer.
• Make sure that all people in your household wash their hands well and often.
• Keep all follow-up visits as told by your health care provider. This is important.

How is this prevented?

To help prevent the spread of norovirus:

• Stay at home if you are feeling sick. This will reduce the risk of spreading the virus to others.
• Wash your hands often with soap and water for at least 20 seconds, especially after using the toilet or changing a diaper.
• Wash fruits and vegetables thoroughly before peeling, preparing, or serving them.
• Throw out any food that a sick person may have touched.
• Disinfect contaminated surfaces immediately after someone in the household has been sick. Use a bleach-based household cleaner.
• Immediately remove and wash soiled clothes or sheets.

Contact a health care provider if:

• You have vomiting, diarrhea, or stomach pain that gets worse.
• You have symptoms that do not go away after 2 to 6 days.
• You have a fever.
• You cannot drink without vomiting.
• You feel light-headed or dizzy.
• Your symptoms get worse.

Get help right away if:

You develop symptoms of dehydration that do not improve with fluid replacement, such as:

• Excessive sleepiness.
• Lack of tears.
• Very little urine production.
• Dry mouth.
• Muscle cramps.
• Weak pulse.
• Confusion.


• Norovirus infection is common and often occurs in places where people are in close contact, such as schools, nursing homes, and cruise ships.
• To help prevent the spread of this infection, wash hands with soap and water for at least 20 seconds before handling food or after having contact with stool or body fluids.
• There is no specific treatment for norovirus, but most people get better without treatment in about 2 days. People who are healthy when infected often recover sooner than those who are elderly, young, or already sick.
• Replace lost fluids by drinking plenty of water, or by drinking oral rehydration solution (ORS), which contains important minerals called electrolytes. This prevents dehydration.

This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.

Document Released: 03/09/2004
Document Revised: 01/24/2018
Document Reviewed: 01/24/2018
Elsevier Interactive Patient Education © 2019 Elsevier Inc.

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