Norovirus Fact Sheet (PDF)

What is Norovirus?

Norovirus is an illness caused by a group of viruses that cause gastroenteritis (inflammation of the stomach or intestines). It is often known as the stomach flu or stomach bug.

What are the symptoms of Norovirus?

Symptoms of norovirus include sudden nausea, vomiting, diarrhea and some stomach cramping. A low-grade fever can also occur. Symptoms usually last 24 to 72 hours.

How is Norovirus spread?

Norovirus is highly contagious. The illness is most commonly spread from person to person by hand-to-hand contact and by surfaces contaminated with feces or vomit. Outbreaks result from water or food contaminated with the virus.

How long after exposure do symptoms begin?

Symptoms usually appear 12 – 48 hours after exposure.

How long can a person be contagious with Norovirus?

Most people can spread the illness as soon as they feel ill, and up to 2 weeks after they feel better.

Is there treatment for Norovirus?

There is no specific treatment for norovirus. People ill with norovirus need to drink plenty of fluids to avoid dehydration. Most people recover after 72 hours.

How can Norovirus be prevented?

Hand washing is the most important thing to prevent norovirus infection.

• Wash your hands thoroughly and often with soap and warm water.
• Wash your hands before eating/preparing food and after using the bathroom or diapering/toileting a small child.
• Thoroughly clean contaminated surfaces such as toilets, doorknobs, countertops, and changing tables of any debris, then disinfect by using a bleach-based household cleaner.
• Make disinfectant using fresh, unscented bleach:
  • For stainless steel, food/mouth items and toys use 1 tablespoon of bleach in 1 gallon of water (1:250 dilution)
  • For non-porous surfaces, tile floors, countertops, sinks and toilets use 1/3 cup bleach in 1 gallon of water (1:50 dilution)
  • For porous surfaces and wood floors use 1½-cup bleach in 1 gallon of water (1:10 dilution)
  • Prepare a dilution of fresh bleach every day of use and discard unused portions
  • Standard bleach precautions should be followed according to the product label
• Wash clothing and linens in hot, soapy water to remove the virus.

Hand Washing Instructions

• Use soap and running water
• Rub your hands vigorously for 20 seconds
• Wash all surfaces, including:
  
  • Backs of hands
  • Wrists
  • Between fingers
  • Under fingernails
• Rinse well
• Dry hands with a paper towel
• Turn off the water using a paper towel instead of bare hands
• Alcohol-based hand sanitizer can be used in addition to hand washing, but not in place of hand washing. Hand sanitizer is not as effective at removing norovirus as hand washing.

For additional information about cleanliness and to avoid spreading illness, visit the Oakland County Health Division - Hand Washing web page.