Common Places Norovirus Outbreaks Tend to Occur


The Centers for Disease Control and Prevention (CDC) estimates that noroviruses cause nearly 21 million cases of acute gastroenteritis annually, making noroviruses the leading cause of gastroenteritis in adults in the United States.

Humans are the only host of norovirus, and norovirus has several mechanisms that allow it to spread quickly and easily.

Norovirus causes nearly 60% of all foodborne illness outbreaks. Norovirus is transmitted primarily through the fecal-oral route, with fewer than 100 norovirus particles needed to cause infection.

Infected individuals shed the virus in large numbers in their vomit and stool, shedding the highest number of viral particles while they are ill.

Aerosolized vomit has also been implicated as a mode of norovirus transmission.

When food is the vehicle of transmission, contamination occurs most often through a food handler improperly handling a food directly before it is eaten.

Common settings for norovirus outbreaks include restaurants and events with catered meals, nursing homes, schools, vacation settings or cruise ships, Shellfish (oysters, clams, mussels) pose the greatest risk and any serving may be contaminated with norovirus.