What are noroviruses?

Noroviruses are a group of germs that cause an inflammation (swelling) of the stomach and intestines (gastroenteritis).  It can also be called “stomach flu (this is not related to the flu or influenza, which is an infection of the nose, throat and lungs caused by influenza virus), or food poisoning.  Norovirus can be spread very easily.  Viruses are different from bacteria and parasites.  Some bacteria and parasites can cause illnesses that are like norovirus infection.  Viruses are much smaller, cannot be treated with antibiotics and cannot grow outside of a person’s body.

What are the symptoms of illness caused by noroviruses?

Symptoms usually happen 1 to 2 days after exposure to the virus, but they can also happen as early as 12 hours after exposure.  Symptoms are:

• Upset stomach, vomiting, diarrhea, stomach pain.
• Sometimes people have a fever, chills, headache, muscle aches, and tiredness.
• Norovirus illness often begins suddenly and the infected person may feel very sick.  Symptoms normally last 1 or 2 days.
• Children normally have more vomiting than adults.

People who have norovirus can spread it from the time they begin feeling sick until at least 3 days after they get better.  Some people can spread norovirus illness for as long as 2 weeks after they get better.  It is very important to use good hand washing after you have gotten better from a norovirus illness.

How do you get norovirus illness?

Noroviruses are found in the stool or vomit of infected people.  You can get norovirus illness by:

• Eating food or drinking liquids that are contaminated with norovirus;
• Touching objects contaminated with norovirus and then placing your hand or something you touched to your mouth;
• Having direct contact with another person who is infected and has symptoms of norovirus.  This includes taking care of someone with norovirus illness or sharing foods or eating utensils with someone who has norovirus illness.
• People working in day-care centers or nursing homes should pay special attention to children or residents who have norovirus illness.  Norovirus can spread quickly in day cares and nursing homes.

How serious is norovirus illness?

Norovirus illness is usually not serious, though people may feel very sick and vomit many times a day.  Most people get better within 1 or 2 days.  Sometimes, people cannot drink enough liquids and become dehydrated, which may cause them to need more medical care by a doctor.  Dehydration is common in the very young, the elderly and people with weakened immune systems who have norovirus illness.  There are no known long-term health problems from norovirus illness.

How is norovirus illness diagnosed?

Norovirus illness is diagnosed by laboratory tests ordered by a doctor.

What is the treatment for norovirus illness?

There is no medicine for norovirus and there is no vaccine against norovirus infection.  Antibiotics do not cure norovirus.

What can I do if I have norovirus illness?

Follow your doctor’s orders.  Drink plenty of liquids so you do not become dehydrated, including water, clear juice, and oral rehydration fluids (ORF).  Sports drinks do not replace the nutrients and minerals lost during this illness.

How can I prevent norovirus infection?

• Wash your hands often, especially after using the toilet and changing diapers, and before eating or preparing food.
• Carefully wash fruits and vegetables.  Steam oysters before eating them.
• Thoroughly clean and disinfect contaminated objects immediately after having norovirus illness by using a household cleaner that has bleach in it.
• Immediately take off and wash clothing or bedding that may be contaminated with norovirus.  Use hot water and soap.
• Flush or throw away any vomit and/or stool in the toilet and make sure the surrounding area is kept clean.

People who have norovirus should not prepare food while they have symptoms and for 3 days after they get better from their illness.  Food that may be contaminated by an ill person should be disposed of properly.

Can I get norovirus illness more than once?

Yes.  There are many different types of norovirus; so it is difficult for the body to build long-lasting immunity (defense).  People may get norovirus illness many times in their lifetime.