Norovirus, sometimes referred to as the winter vomiting bug, is the most common cause of gastroenteritis. Infection is characterized by non-bloody diarrhea, vomiting, and stomach pain. Fever or headaches may also occur. Complications are uncommon, but may include dehydration, especially in the young, the old, and those with other health problems.
It is common both in the developed and developing world. Norovirus infections occur more commonly during winter months and often in outbreaks.
Risk factors include unsanitary food preparation and person-to-person contact. It may also spread via contaminated surfaces or through air from the vomit of an infected person.
Norovirus results in about 685 million cases of disease and 200,000 deaths globally a year.