Shigellosis Attributed to Oysters from Mexico


In a May 21st release the FDA has advised consumers not to eat raw oysters harvested from Estero el Cardon in Baja California Sur in Mexico.  The affected product was distributed in California, Nevada, New York and Arizona through wholesale distributors selling to restaurants.


On May 7th the Shellfish Sanitation Program of Mexico voluntarily closed the oyster beds of Estero el Cardon and halted harvesting as a result of illnesses in the U.S. and presumably in Mexico.  Due to short shelf-life of raw oysters, the action by authorities should have ended the outbreak of Shigella flexneri.  The outbreak in the U.S. was limited to five patients with the last illness on April 17th.


This case emphasizes the ability of state health laboratories and the FDA through databases to identify multistate outbreaks involving only a few patients.  Laboratories assays including whole genome sequencing can match isolates from patients with product harvested from affected sources or areas.