Oyster associated norovirus cases are also being reported in Orange, Riverside, San Bernardino, Ventura, and Los Angeles counties. Both the California Department of Public Health and U.S. Food and Drug Administration (FDA) are now actively engaged in the investigation.  

The investigation of oyster-linked illnesses by County of San Diego health officials has expanded to include additional oyster harvest locations in Mexico. Health officials are recommending consumers and restaurants throw away any oysters imported from locations in Mexico until further notice. 

The local norovirus outbreak now includes 69 confirmed and probable cases. The severity of the infections in San Diego County has remained mild, with no hospitalizations reported to date. The initial investigations identified 41 probable and confirmed norovirus cases linked to oysters harvested in Sonora, Mexico. The sickened patrons dined at the Fish Shop chain and Carlsbad Aquafarm. Twenty-eight more cases have been added including 20 who ate oysters from other food venues.  

The FDA, which has jurisdiction over oysters imported into the country, issued an initial advisory on Jan. 11, based, at least in part, on the findings of the investigation conducted by County health officials.  

On Jan. 17th, the FDA issued a second advisory for Laguna De Guerrero Negro and Laguna Manuela, both on the Pacific Coast of Baja California, Mexico but locations geographically distant from Sonora. Today, FDA updated the initial advisory on Sonora oysters to include a second harvest location, Estero Morua. 

The new FDA recommendations advise restaurants and retailers to dispose of any oysters they still have or contact their distributor to coordinate return or destruction. People who have them in their homes should do the same. 

All of the implicated oysters were harvested in December 2023 and no oysters since then have been distributed to food venues in San Diego from those locations.  

Given the expanding number of harvest locations associated with illness and the potential of other sites to be involved, County Public Health is recommending against the use of all oysters imported from Mexico at this time. 

“The County recommends that people ask where oysters were harvested when eating out or getting food from wholesale locations to avoid consuming oysters imported from Mexico,” said Dr. Ankita Kadakia, Deputy County Public Health Officer. “Norovirus is typically a mild illness but can cause dehydration especially for the very young and very old. Given the increasing number of cases, the chance for others at greater risk for more severe illness in the same home is also increased. I want to remind people who become ill, and those that live with them, to wash their hands frequently to avoid contaminating surfaces and foods that could further spread the infection.”  

Eating raw oysters has been linked to outbreaks with other germs including Vibrio, Shigella, and E. coli, in addition to norovirus. If you eat raw or undercooked oysters, germs that might be in the oyster can make you sick.  

People who have or develop symptoms should reach out to their healthcare provider. To report illness to the County after dining out or purchasing from wholesale food locations call (858) 505-6814, or email fhdepi@sdcounty.ca.gov.  

More information on seafood and shellfish safety is available here, general information on norovirus is here, and prevention of norovirus spread in the home information is here. 

Audience

Restaurants and food retailers that have received shipments of oysters harvested between January 16, 2023 and February 17, 2023, from Deep Bay subarea 14-8 landfiles #0278744, #0278742, #0278741, #0278740, #1414396, #0319716, #1414456, #1414457, #1400483, #1411206, #1407063, #1408485, #0278739, #0278737, #1403139, #0278734, #1411153 and #1411195 in British Columbia, Canada.

Product

• Oysters harvested between January 16, 2023, and February 17, 2023, from Deep Bay subarea 14-8 landfiles #0278744, #0278742, #0278741, #0278740, #1414396, #0319716, #1414456, #1414457, #1400483, #1411206, #1407063, #1408485, #0278739, #0278737, #1403139, #0278734, #1411153 and #1411195 in British Columbia, Canada.
• Packaged oysters include the harvest area information on their packaging.

Purpose

The FDA is advising consumers not to eat, and restaurants and food retailers not to sell, and to dispose of oysters that were harvested between January 16, 2023 and February 17, 2023, from Deep Bay subarea 14-8 landfiles #0278744, #0278742, #0278741, #0278740, #1414396, #0319716, #1414456, #1414457, #1400483, #1411206, #1407063, #1408485, #0278739, #0278737, #1403139, #0278734, #1411153, and #1411195 in British Columbia, Canada. Consumers who purchased oysters after January 16, 2023 should check the packaging to see if they were harvested in Deep Bay from the affected landfiles of subarea 14-8, landfiles #0278744, #0278742, #0278741, #0278740, #1414396, #0319716, #1414456, #1414457, #1400483, #1411206, #1407063, #1408485, #0278739, #0278737, #1403139, #0278734, #1411153, and #1411195. Contaminated shellfish can cause illness if eaten raw, particularly in people with compromised immune systems. Food contaminated with norovirus may look, smell, and taste normal. Consumers of these products who are experiencing symptoms of norovirus illness should contact their healthcare provider, who should report their symptoms to their local Health Department.

Summary of Problem and Scope

The U.S. Food and Drug Administration (FDA) is working with federal, state, and local officials, and with Canadian public health authorities on a norovirus outbreakExternal Link Disclaimer linked to raw oysters from British Columbia, Canada. Currently, illnesses have only been reported in Canada with no known cases of norovirus associated with these oysters reported in the U.S. The FDA is alerting restaurants, retailers and consumers because it is possible that states received these oysters through distribution to the U.S.

Retailers should not sell or serve raw oysters harvested from BC 14-8 landfiles #0278744, #0278742, #0278741, #0278740, #1414396, #0319716, #1414456, #1414457, #1400483, #1411206, #1407063, #1408485, #0278739, #0278737, #1403139, #0278734, #1411153 and #1411195, with harvest dates starting as early as January 16, 2023, which will be printed on product tags.

Shellfish can cause illness if eaten raw, particularly in people with compromised immune systems. Food contaminated with norovirus may look, smell, and taste normal.

FDA Actions

The FDA is issuing this alert advising consumers to not eat, and restaurants and food retailers to not sell, oysters harvested between January 16, 2023 and February 17, 2023, from BC 14-8 landfiles #0278744, #0278742, #0278741, #0278740, #1414396, #0319716, #1414456, #1414457, #1400483, #1411206, #1407063, #1408485, #0278739, #0278737, #1403139, #0278734, #1411153 and #1411195, British Columbia, Canada due to possible norovirus contamination. The FDA is awaiting information on distribution of the oysters and will continue to monitor the investigation and provide assistance to state authorities as needed.

Symptoms of Norovirus

People of all ages can get infected and sick with norovirus. The most common symptoms of norovirus are diarrhea, vomiting, nausea, and stomach pain. Other symptoms include fever, headache, and body ache.

A person usually develops symptoms 12 to 48 hours after being exposed to norovirus. Most people with norovirus illness get better within 1 to 3 days.

If you have norovirus illness, you can feel extremely ill, and vomit or have diarrhea many times a day. This can lead to dehydration, especially in young children, older adults, and people with other illnesses. Symptoms of dehydration include decrease in urination, dry mouth and throat, and feeling dizzy when standing up. Children who are dehydrated may cry with few or no tears and be unusually sleepy or fussy. 

If you think you or someone you are caring for is severely dehydrated, call your healthcare provider.

Recommendations for Restaurants and Retailers

Restaurants and retailers should not sell/serve the potentially contaminated oysters. Restaurants and retailers should dispose of any products by throwing them in the garbage or returning to their distributor for destruction.

Restaurants and retailers should also be aware that shellfish may be a source of pathogens and should control the potential for cross-contamination of food processing equipment and the food processing environment. They should follow the steps below:

• Wash hands with warm water and soap following the cleaning and sanitation process.
• Retailers, restaurants, and other food service operators who have processed and packaged any potentially contaminated products need to be concerned about cross-contamination of cutting surfaces and utensils through contact with the potentially contaminated products.
• Retailers that have sold bulk product should clean and sanitize the containers used to hold the product.
• Regular frequent cleaning and sanitizing of food contact surfaces and utensils used in food preparation may help to minimize the likelihood of cross-contamination.