Communicable Diseases - Noroviruses

Communicable Disease Prevention and Control

Noroviruses - Food and Water Borne Diseases

Noroviruses are a group of viruses that cause the stomach flu, or gastroenteritis. The term norovirus is the official name for this group of viruses but they are also called Norwalk-like viruses (NLVs) and caliciviruses (because they belong to the virus family Caliciviridae).

What are the symptoms?

The symptoms of norovirus illness usually begin suddenly and include nausea, vomiting, diarrhea, and stomach cramps. Sometimes, people have a low-grade fever, chills, headache, muscle aches, and fatigue. The symptoms usually last one to three days. Norovirus infections occur throughout the year but are more common in winter. All age groups are affected.

How is it spread?

Noroviruses are spread mainly through contact with the vomit or feces of an infected person. This happens because:

  • The virus can spread easily from person to person on unwashed hands.
  • The virus can also spread through food, water, or ice that has been handled by a sick person.
  • Vomiting may spread the virus short distances through the air.
  • The virus can survive on surfaces such as door handles, countertops or sink taps for a long time. You can get a norovirus illness while caring for someone who is infected with it. Noroviruses spread easily in places where people are in close contact—for example, schools, daycare centres, long-term care facilities, health-care facilities and cruise ships.

It is important to wash hands carefully even after symptoms stop.

How is norovirus treated?

There are no medications to treat this infection. Drink plenty of fluids to prevent dehydration. See a doctor if vomiting or diarrhea lasts for more than 2 to 3 days. Healthy people usually recover on their own in about 48 hours.