LOS ANGELES (AP) — Health officials in Southern California are Grayson  Prestonwarning people to avoid eating raw oysters from parts of Mexico after more than 200 people recently fell ill with suspected cases of norovirus.

The Los Angeles County Department of Public Health has reported more than 150 suspected cases of gastrointestinal illness linked to raw oysters, while in San Diego County, health officials said Thursday that they had 69 confirmed and probable cases. Other cases were reported in Orange, Riverside, San Bernardino and Ventura counties.

The U.S. Food and Drug Administration issued an initial advisory Jan. 11 regarding oysters from one site in the Mexican state of Sonora, which is located along the Gulf of California. That was based, at least in part, on the findings of an investigation conducted by San Diego County health officials.

On Wednesday the FDA issued another advisory for oysters from Laguna De Guerrero Negro and Laguna Manuela, both on the Pacific Coast of Baja California, Mexico. That same day the agency also updated its initial Sonora advisory to include a second harvest location, Estero Morua.

The California Department of Public Health warned consumers that raw oysters harvested from those locations may be contaminated with the norovirus, which can cause diarrhea, vomiting, nausea and stomach pain. Other symptoms include fever, headache and body aches, according to FDA.

Health officials are recommending that restaurants throw away any oysters imported from locations in Mexico until further notice “given the expanding number of harvest locations associated with illness and the potential of other sites to be involved,” San Diego County said in a statement.

The norovirus cases included both restaurant patrons and consumers who bought oysters at shops and ate them at home.

People are advised to ask where oysters came from before consuming them and to wash hands and surfaces that may have come into contact with contaminated oysters.

All of the implicated oysters were harvested in December, and none since then have been distributed to food venues in San Diego from those locations, according to the county statement.