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What are noroviruses?
Noroviruses are a group of viruses that cause the “stomach flu” in people. Noroviruses have also been called Norwalk –like viruses.

What are the symptoms of illness caused by noroviruses?
The symptoms of this illness usually include nausea, vomiting, diarrhea, and some stomach cramping. Sometimes people also have a low-grade fever, chills, headache, muscle aches and a general sense of tiredness. The illness is usually brief, begins suddenly and the person recovers within 1 to 2 days. In general, children may vomit more than adults.

How serious is norovirus disease?
Norovirus disease is usually not serious, although people may feel very sick and vomit many times a day. Most people get better within 1 to 2 days and have no long–term health effects related to their sickness. The sickness can cause a loss of fluids within the body, which may lead to very serious conditions for the young, the elderly, and already sick persons. Proper water and juice intake may help prevent a serious condition.

How do people become sick with noroviruses?

Noroviruses are found in the stool or vomit of sick people. People can become sick with the virus in several ways, including:

• Eating food or drinking liquids that are infected with norovirus
• Touching surfaces or objects infected with noroviruses, and then placing their hand in their mouth
• Having direct contact with another person who is sick, caring for a sick person, or sharing foods/eating utensils with someone who is sick.

When do symptoms appear?
Symptoms usually begin about 24 to 48 hours after contact. Sometimes the symptoms can appear as early as 12 hours after contact.

Are noroviruses spread person-to-person?

Yes, noroviruses can spread quickly from person-to-person.

How long do people carry the virus?

Sick persons can spread the virus from the moment they begin feeling ill to at least 3 days after recovery. Some people can spread the virus for as long as 2 weeks after recovery.

What treatment is available for people with norovirus illness?

Currently, there is no vaccine or medication that exists to prevent infection. Antibiotics do not treat viruses.

Can norovirus illness be prevented?
Yes. The following steps will help prevent the spread of norovirus:

• Frequently wash your hands, especially after using the bathroom and eating/preparing food.
• Carefully wash fruits and vegetables, and steam oysters before eating them.
• Thoroughly clean and disinfect surfaces immediately after an episode of illness by using a bleach-based household cleaner.
• Immediately remove and wash clothing/linens that may be dirty after an episode of illness (use hot water and soap).
• Flush or discard vomit/stool in the toilet and make sure the surrounding area is kept clean.

Sick persons should not prepare food while they are sick and for 3 days after they recover from their illness. Any food that may be exposed to the virus should be disposed of properly.

Links to Additional Information

Report Food Poisoning

Guidelines for Cleaning & Disinfection of Norovirus (MDCH & MDA)

Norovirus Infection (CDC)

Norovirus Q & A (CDC)

Norovirus Technical Fact Sheet (CDC)

Norovirus & Foodhandlers (CDC)

Norovirus in Healthcare Facilities (CDC)