San Diego County public health officials Thursday announced they are expanding an investigation into oyster-linked illnesses to include all oysters harvested from Mexico.
Health officials are recommending consumers and restaurants throw away any oysters imported from locations in Mexico until further notice.
According to the county Health and Human Services Agency, the local norovirus outbreak now includes 69 confirmed and probable cases, up from the 41 reported last week.
According to the county, 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 are now actively engaged in the investigation.
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 local health officials, a statement from the county read.
On Wednesday, the FDA then issued a second advisory for Laguna De Guerrero Negro and Laguna Manuela, both on the Pacific Coast of Baja California, Mexico, far from Sonora, linked by officials to the initial spate of illnesses.
The agency on Thursday also updated the earlier advisory on Sonora oysters to include a second harvest location, Estero Morua.
Local infections have remained mild, with no hospitalizations reported to date. The sickened patrons dined at the Fish Shop chain, with locations in Pacific Beach, Point Loma and Encinitas, and Carlsbad Aquafarm.
The new cases include 20 people who ate oysters at other food venues.
“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.”
She added that with the increasing number of cases, the chance for others at greater risk for more severe illness in the same home rises. Those in households with ailing people should wash their hands frequently to avoid spreading the infection.
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,” the county statement reads.
If you eat raw or undercooked oysters, germs that might be in the oyster can make you sick.
People infected with norovirus generally develop nausea, vomiting, diarrhea, stomach cramps, fever and body aches 12 to 48 hours after consuming contaminated foods. The illness typically lasts for 1-3 days.
The vomiting and diarrhea can lead to dehydration requiring medical attention, especially in young children, older adults and people with other illnesses.
HHSA is working with the California Department of Public Health, including the Shellfish Program, to continue investigating illnesses associated with oysters. To report illness, call 858-505-6814, or email fhdepi@sdcounty.ca.gov.
– City News Service