22/05/19: Illnesses prompt new warning against certain raw oysters from Mexico

Importers shipped the oysters to California, Nevada, New York, and Arizona, according to this afternoon’s public alert from the Food and Drug Administration. The implicated oysters were sold to wholesale distributors that sell directly to restaurants and not to grocery retail outlets. The estuary where the oysters were harvested is about 600 miles south of San Diego on the Baja Peninsula.

As of May 10, there had been 16 people across five states confirmed with infections, according to the most recent update from the Centers for Disease Control and Prevention. Twelve confirmed patients have tested positive for specific foodborne infections from various pathogens. Of those 12 patients, five tested positive for Shigella flexneri. Two patients have been admitted to hospitals.

Anyone who has eaten raw oysters, especially in California and experienced symptoms of foodborne illness should contact their healthcare providers and tell them about their possible exposure, according to FDA and CDC alerts. Public health investigators say raw oysters harvested from Estero El Cardon are a likely source of this outbreak, the CDC and FDA have reported.

“Restaurants and retailers should not serve oysters from the Estero El Cardon harvest area in Baja California Sur, Mexico. Restaurants and retailers should dispose of any products with harvest tags that indicate a growing area of Estero El Cardon by throwing them away,” today’s FDA notice says.

“. . . Laboratory analyses were used to confirm that reported clinical illnesses matched pathogens found in product samples and traceback information indicated the implicated shellfish were harvested from Estero El Cardon, in Baja California Sur, Mexico.”

Officials from the FDA are working with state investigators in U.S. states and officials in Mexico. On May 7 the Mexican government suspended oyster harvests in the implicated area.

The FDA is also working with Mexico’s health authorities, and state and local partners to verify the implicated oysters have been successfully removed from commerce and to ensure that the raw oysters were not further distributed.

Initial outbreak information
The CDC first reported on May 10 that the confirmed patients were from Alaska, California, Nevada, Illinois, and New Hampshire. The New Hampshire patient reported eating raw oysters in California. 

In that initial outbreak announcement, the CDC also reported All 15 people who were interviewed reported eating raw oysters from different restaurants in California and Nevada. State health officials collected traceback information for 15 cases and found that oysters were shipped by Sol Azul, S.A. De C.V. (MX 01 SS) and harvested from the Estero El Cardon estuary.

Illnesses started on dates ranging from Dec. 16, 2018, to April 17 this year. Among 15 people with information available, ages range from 26 to 80 years. Additional confirmed patients could be identified because of the lag time, which can take four or more weeks, between when a person becomes sick and when confirmed laboratory test results are provided to the CDC.

Symptoms of Shigella infection
Shigella is a bacterium that often spreads through unclean water that an infected person has been in. Food can become contaminated when handled by an infected person who did not use proper hand hygiene after going to the bathroom, or if contaminated water is used in the process of growing or preparing the food.

Symptoms of shigellosis generally develop within 8 hours to 2 days after exposure. It can become very serious in some cases. Severe cases can be treated with certain antibiotics. Symptoms of shigellosis may include watery stool that may have blood, pus, or mucus in it, vomiting, cramping, and fever. Young children, the elderly, and people with a weak immune system are more likely than others to develop severe illness.

Recommendations for retailers
The CDC and FDA have posted information for consumers and restaurant operators who have been in contact with the oysters in question. In the event that retailers and/or other foodservice operators are found to have handled recalled or other potentially contaminated food in their facilities, the CDC says they should:

  • Contact their local health department and communicate with their customers regarding possible exposure to Shigella.
  • Wash the inside walls and shelves of the refrigerator, cutting boards and countertops, and utensils that may have contacted contaminated foods; then sanitize them with a solution of one tablespoon of chlorine bleach to one gallon of hot water; then dry with a clean cloth or paper towel that has not been previously used.
  • Wash and sanitize display cases and surfaces used to potentially store, serve, or prepare potentially contaminated foods.
  • Retailers that have sold a bulk product should clean and sanitize the containers used to hold the product.
  • Wash hands with warm water and soap following the cleaning and sanitation process.

The FDA notice says consumers who have experienced symptoms of illness after eating or handling raw oysters should consider reporting their illnesses to MedWatch: FDA’s Safety Information and Adverse Event Reporting Program. The FDA encourages consumers with questions about product safety to submit an inquiry or to visit www.fda.gov/fcic for additional information.