Can you eat raw oysters? It depends. What you should know about ‘flesh-eating bacteria’

At least eight people in Florida have died so far this year from the so-called “flesh-eating” bacteria.

Vibrio vulnificusa is fatal bacterial infection found in warm coastal waters.  

While the bacteria can be found in warm saltwater and brackish water — entering the body through fresh cuts or scrapes — most people get infected by eating raw or undercooked shellfish, particularly oysters, according to the Centers for Disease Control.

The agency issued a health alert earlier in September about the bacteria.

Vibrio vulnificusa: What CDC health alert had to say about bacteria

The CDC health advisory was issued to:

• Notify healthcare providers, laboratories, and public health departments about recent reports of fatal Vibrio vulnificus infections, including wound and foodborne infections.
• Urge healthcare professionals to consider V. vulnificus as a possible cause of infected wounds that were exposed to coastal waters, particularly near the Gulf of Mexico or East Coast, and during periods with warmer coastal sea surface temperatures.
• Share important guidance for managing V. vulnificus wound infections.

 How do most people get infected by the ‘flesh-eating’ bacteria?

Most people get infected with Vibrio by eating raw or undercooked shellfish, particularly oysters, according to the CDC. 

While millions of people enjoy eating raw oysters, some with certain medical conditions risk serious illness or even death. The U.S. Food and Drug Administration advises high-risk individuals not to eat raw oysters, and consume only oysters that have been thoroughly cooked.

Who is considered high risk and shouldn’t eat raw oysters?

Vibrio vulnificus infections in high-risk individuals have a 50 percent fatality rate, according to the FDA.

These conditions include:

• Liver disease (from hepatitis, cirrhosis, alcoholism, or cancer).
• Iron overload disease (hemochromatosis).
• Diabetes.
• Cancer (including lymphomas, leukemia, Hodgkin’s disease).
• Stomach disorders.
• Any illness or medical treatment that weakens the body’s immune system, including HIV infection.

Information about the potential dangers of raw oyster consumption is available 24 hours a day from the FDA’s Seafood Hotline: 1-800-332-4010.

Can you tell if an oyster is infected with Vibrio?

No. An oyster that contains Vibrio doesn’t look, smell, or taste different from any other oyster, said the CDC.

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Can you kill the bacteria in an oyster?

Yes. You can kill Vibrio in oysters and other shellfish by cooking them properly.

Eating raw oysters with hot sauce or while drinking alcohol does not kill the bacteria, the FDA warned. Only heat can destroy the bacteria.

Here are suggestions from the CDC to safely consume oysters. Discard any shellfish with open shells.

For shellfish in the shell, either:

• Boil until the shells open and continue boiling another 3 to 5 minutes, or
• Add to a steamer when water is already steaming and cook for 4 to 9 minutes.

Only eat shellfish that open during cooking. Throw out any shellfish that do not open fully after cooking.

For shucked oysters, either:

• Boil for at least 3 minutes,
• Fry in oil for at least 3 minutes at 375 degrees,
• Broil 3 inches from heat for 3 minutes, or
• Bake at 450 degrees for 10 minutes.

How many people have been infected with Vibrio in the Florida and the US?

The CDC estimated about 80,000 people get infected with the bacteria in the United States every year. About 100 people die from the infection.

In Florida, 41 people have been infected so far this year; eight have died, according to the Florida Department of Health.

Infected in restaurant:Man dies after contracting Vibrio vulnificus bacteria from fresh oysters in Texas restaurant

What Florida counties have seen the most cases and deaths from the ‘flesh-eating’ bacteria?

Counties with the most cases — four each — so far this year include: Escambia, Hillsborough, Lee, Okaloosa and Sarasota.

Deaths connected to Vibrio in 2023 occurred in the following counties:

• Broward: 1
• Hillsborough: 2
• Manatee: 1
• Pasco: 1
• Polk: 1
• Sarasota: 2

Hurricane Ian contributed to spike in Vibrio cases

The Florida Department of Health reported 74 cases and 17 deaths of Vibrio in 2022.

Officials attributed the increase in the number of cases to waters left behind by Hurricane Ian.

Can Vibrio be treated?

If Vibrio vulnificus is suspected, treatment should be started immediately since antibiotics improve survival, according to the Florida Department of Health.

Aggressive attention should be given to the wound site. For patients with wound infections, amputation of the infected limb is sometimes necessary.

For more information on care and treatment, visit the CDC’s website.

Symptoms of Vibrio infection

Ingestion of Vibrio vulnificus can cause vomiting, diarrhea and abdominal pain. 

If the bacteria enters the body through an open wound, an infection could lead to skin breakdown and ulcers.

Healthy individuals typically develop a mild disease; however Vibrio vulnificus infections can be a serious concern for people who have weakened immune systems, particularly those with chronic liver disease.

The bacteria can invade the bloodstream, causing a severe and life-threatening illness with symptoms like fever, chills, decreased blood pressure (septic shock) and blistering skin lesions. 

Vibrio vulnificus bloodstream infections are fatal about 50 percent of the time, according to the Florida Department of Health.