SACRAMENTO – The California Department of Public Health (CDPH) today warned consumers to avoid eating raw oysters harvested from south and central Baynes Sound, in British Columbia, Canada. The raw oysters are linked to an outbreak of norovirus illnesses.

In California, as of April 27, approximately 100 individuals have reported illness after they consumed raw British Columbian oysters sold by restaurants and retailers throughout the state. Laboratory testing has confirmed norovirus infection in several patients from both California and Canada. Although the number of reported new illnesses has decreased during the last week, the investigation is ongoing.

Canada has reported 172 cases of gastrointestinal illness linked to consumption of raw oysters.

Four oyster farms in the south and central Baynes Sound area of British Columbia that were linked to illnesses were closed between March 23 and April 13, 2018, and remain closed at this time. Restaurants and retailers should not distribute or serve oysters from these farms, which can be recognized by the following landfile numbers located on the shellfish tags: CLF #1402060, CLF #1411206, CLF #1400483, and CLF #278757. Restaurants and retailers are encouraged to check Canada's above website for closure statuses and notices of re-opening.

Anyone who eats raw oysters should visit their doctors if they become ill, and should report the incident to the local health department.

"Avoid eating raw and undercooked shellfish, including oysters, to reduce your risk of illness," said CDPH Director and State Public Health Officer Dr. Karen Smith. "If you do eat shellfish, cook it until it reaches an internal temperature of at least 145°F. Quick steaming isn't sufficient to kill norovirus."

Norovirus is highly contagious and can 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 come in contact with 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. For more information on norovirus, please see CDPH's Norovirus Web page.

The most current information on shellfish advisories and quarantines are available at CDPH's toll-free Shellfish Information Line at (800) 553-4133. For additional information, please visit the CDPH Marine Biotoxin Monitoring Web page.