The CDC reported last week that a new strain of norovirus — the most common cause of viral gastroenteritis (vomiting, diarrhea, dehydration) in the United States — has arrived from Australia:

Compared with other norovirus genotypes, GII.4 noroviruses have been associated with increased rates of hospitalizations and deaths during outbreaks.


Elizabeth Weise at USA Today has more about norovirus and the illness it causes:

The norovirus season typically runs from November through March and peaks in January.

“This year, that unfortunately coincides with an early increase in flu season,” Hall said. Some people mistakenly call norovirus “stomach flu,” but aside from timing, “there’s no connection between them at all,” he said.

Norovirus typically begins very suddenly and lasts one to three days. Most people recover without treatment, but some require rehydration with liquids or intravenous fluids. The disease is most severe in the elderly and can also hit young children hard. Every year, more than 21 million Americans become infected with acute stomach bugs, called gastroenteritis by doctors, and approximately 800 die, according to the CDC. Much of that is probably from norovirus, Hall said.


The reasons why there is so much concern: 

  • Since this is a new strain, humans have no prior immune system memory to fight an infection.  Without these immune defenses, more severe symptoms are predictable.
  • We’re still in the middle of a severe influenza season.  Getting one infection (influenza or norovirus) lowers your immune resistance, allowing a sick individual to more easily get the other infection.  Fighting both at the same time could be brutal for a lot of people.  It’s still not too late to get a flu vaccine!
  • Because norovirus is often food-borne, you can protect yourself and your family by good hand-washing and clean kitchen techniques.  Having others prepare your food (when eating out at a restaurant, for example) provides no certainty that your food won’t be contaminated.


So be careful out there!  Wash your hands (and insist that others do the same).  If you are sick, stay at home until you are well.  Let’s keep our germs to ourselves!