Raw oysters from certain parts of Mexico could be contaminated after norovirus outbreak in San Diego, FDA warns

Raw oysters from certain parts of Mexico could be a source of norovirus, the U.S. Food and Drug Administration (FDA) is warning.

The agency has advised restaurants and retailers to stop selling and to dispose of oysters harvested from Bahia Salina, Sonora, Mexico — which were shipped by freight carrier Sociedad Acuicola GolPac on Dec. 18, Dec. 19 and Dec. 27, 2023. 

Consumers are also advised against eating these oysters and to seek medical attention for any symptoms of norovirus.

The alert is geared primarily toward California restaurants, retailers, and consumers, although the FDA noted that the potentially contaminated oysters may have also been shipped to other states.

The FDA was first alerted to an outbreak of norovirus in San Diego County on Jan. 10, which was linked to oysters shipped from Mexico.

“An investigation is ongoing and the number of illnesses is being tracked,” the FDA’s alert said 

“Mexican shellfish authorities have initiated an investigation into the source of the illnesses and have closed the Bahia Salina growing area to harvest on Jan. 12, 2024.”

The contaminated oysters may “look, smell and taste normal,” but can cause illness if eaten raw, particularly among those with compromised immune systems, the agency said.

Dr. Edward Liu, chief of infectious diseases at Hackensack Meridian Jersey Shore University Medical Center in New Jersey, told Fox News Digital that it is likely the oysters grew in contaminated water.  

“This virus is more common in colder months and can infect large groups of people due to its highly contagious nature,” he said.

Dr. Marc Siegel, clinical professor of medicine at NYU Langone Medical Center and a Fox News medical contributor, pointed out that the biggest problem is that people tend to eat oysters raw, which leads to the highest amount of norovirus if contaminated.

“I would pay very careful attention to these alerts and avoid all oysters coming from these areas in Mexico,” he told Fox News Digital.

What is norovirus?

Norovirus is a highly contagious virus that causes inflammation of the stomach or intestines, per the Centers for Disease Control and Prevention (CDC). 

While it is often referred to as a “stomach flu” or “stomach bug,” it is not related to influenza.

Primary symptoms of the virus include vomiting, diarrhea, nausea, and stomach pain.

Some people may also experience fever, headache, and body aches.

Frequent vomiting and diarrhea can lead to dehydration for some patients.

“The treatment is supportive with hydration until the symptoms improve,” said Liu of New Jersey. “The most vulnerable people are the very young or old or immunocompromised, who can’t tolerate dehydration.”

Symptoms typically develop within 12 to 48 hours of exposure and tend to subside within one to three days, the CDC stated.

Newer stool tests (PCR-based tests) can detect the virus and may be available in hospital emergency rooms and some physician offices, Liu noted, but older stool cultures will not detect the virus. 

“Outbreaks have happened due to contaminated food and are more common in certain settings, like cruise ships and patient facilities,” he said.

To prevent the spread of the disease, Lui stressed the importance of good hand hygiene and disinfecting of high-touch surfaces. 

“Careful handwashing and use of gloves can help food handlers from catching it or passing it along,” Siegel added.

People who experience symptoms of illness after consuming oysters should seek medical attention and report their symptoms to their local health department, the FDA advised.