Dear Doctor: My wife and I love raw oysters. Whenever they're on the menu, we always order a dozen or even two. But I recently read that someone died from some kind of bacterial infection after eating them. Just how risky are they?
Dear Reader: We are aware of at least two instances in 2018 when someone died after eating raw oysters. The cause was infection with a bacterium known as Vibrio vulnificus, which lives in the same marine environments that support oysters. One of the deaths occurred in Florida in July, a time of year that warmer waters can encourage bacterial growth. In fact, there's an old saying that oysters should only be eaten during months that contain the letter "r," which excludes the late spring and summer months.
However, that bit of folklore is far from infallible. In warmer waters, the bacterium can be present throughout the year. And since oysters consume nutrients by filtering the water they live in, if Vibrio vulnificus is present, chances are the oysters will contain it. A state legislator from North Dakota, who ate raw oysters during a visit last year to New Orleans in the "r" month of October, ingested the bacterium and died.
Infection with Vibrio vulnificus is the leading cause of death in the United States associated with eating seafood. Symptoms typically begin between 24 and 48 hours after eating something contaminated with the bacterium. These symptoms include nausea, vomiting, fever, chills, diarrhea, skin lesions and shock. If anyone who has eaten raw shellfish experiences any of these symptoms, he or she should seek immediate medical care. Be sure to tell the physician or health care professional what was eaten and when.
The bacterium can attack on two fronts. Most common among individuals who ingest it in raw shellfish is a systemic blood infection known as primary septicemia. This infection can be life-threatening and must be treated in a hospital as quickly as possible.
Also, Vibrio vulnificus is a so-called "flesh eating" bacterium that can cause necrotizing fasciitis if it enters an open wound. This is a fast-moving infection that causes widespread tissue death. Treatment includes antibiotics and supportive care. For those who develop necrotizing fasciitis, aggressive wound therapy may include amputation. People with weakened immune systems are at greater risk from Vibrio vulnificus infection.
If you want to protect yourself, don't eat raw oysters or raw or undercooked seafood from coastal waters or estuaries. Lemon juice and hot sauce have no effect on Vibrio vulnificus.
For those cooking seafood at home, always throw away any oysters, clams or mussels with shells that have opened prior to cooking or shucking. In addition:
-- Boil in the shell for at least three minutes in order to kill the bacterium.
-- When steaming, cook for at least four minutes. Any oysters that do not open during cooking should go into the trash.
-- When frying or broiling, set the timer for at least three minutes. Broiled oysters need to be no more than three inches away from the heat source.
-- Baked oysters need at least 10 minutes in a 450-degree oven.
Always keep cooked and raw seafood separate to avoid cross-contamination. And, as with all cooking, wash your hands often.
(Send your questions to email@example.com, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)