Norovirus makes its way into the marine environment through untreated human sewage (poop) and vomit. This may come from leaky septic systems, faulty waste water treatment plants, boaters, or beach-goers. Shellfish are filter feeders, which means they filter seawater through their bodies to get food floating in the water. When norovirus particles are in the water, shellfish can accumulate the virus in their bodies. For a bit of history: A Baker’s Dozen of years of Oyster Norovirus Outbreaks.
California: The California Department of Public Health (CDPH) warned consumers April 2, 2022, not to eat raw oysters from British Columbia, Canada because they may be linked to an outbreak of norovirus illnesses in California. In California, at least 34 persons have become ill following the consumption of oysters at nine restaurants located throughout the state. Illness has been reported from March 11 through 19, 2022.
Minnesota: On April 1, 2022, the Minnesota Department of Health, Hennepin County Public Health, and the Minnesota Department of Agriculture are working with federal officials and public health agencies in other states and Canada to investigate norovirus illnesses associated with oysters harvested from Bay 14-8 in British Columbia. 29 Minnesotans have been sickened in this outbreak. They became ill with confirmed or suspected norovirus gastroenteritis after eating raw oysters at Travail Kitchen in Robbinsdale on March 20.
Washington: On April 1, 2022, officials at the Washington State Department of Health (DOH) advise Washington residents to not serve or eat raw oysters harvested from an area of British Columbia (BC), Canada until further notice. 18 Washington residents have reported norovirus-like illness after eating BC oysters from harvest area BC 14-8 since March 7, 2022.
Canada: As of March 31, 2022, there have been 279 cases of norovirus and gastrointestinal illness linked to consumption of B.C. oysters reported in the following provinces: B.C. (262), Alberta (1), Saskatchewan (1), and Ontario (15). Individuals became sick between mid-January and late March 2022, and no deaths have been reported. Although not all cases of illness have been tested, testing of several cases has confirmed the presence of a norovirus infection. In mid-March Canada had announced 50 sick with norovirus – B.C. Oysters have Norovirus – 50 sickened.
Recall Information: Some oyster harvest areas in B.C. that have been associated with illnesses in this outbreak have been closed as a part of the investigation. Food recalls were conducted on February 18, March 20, March 23, and March 27, 2022, for oysters from B.C.
About Norovirus: Norovirus is a highly contagious virus and can be spread easily from person-to-person, through contaminated surfaces, and by eating contaminated food, including raw or undercooked oysters. Symptoms of norovirus usually begin 12 to 48 hours after a person has encounter the virus and can last for 1 to 3 days. Common symptoms include vomiting, diarrhea, nausea, and stomach cramps. People who develop symptoms of norovirus infection should consult their health care providers. Also, see: What do you need to know about Norovirus and Raw Oysters.