What to Know About Flesh-Eating Vibrio

Most reported infections in the U.S. have been from the Gulf Coast region. Since 2007, Florida has averaged 37 infections and nine deaths annually.

Why is vibriosis called a flesh-eating disease?

V. vulnificus infections can be severe, causing the flesh around an open wound to die. Such a condition, known as necrotizing fasciitis, can require intensive care or limb amputations, and about 1 in 5 people with this infection die, sometimes within a day or two of becoming ill, according to the Centers for Disease Control and Prevention (CDC).

The bacteria can invade the bloodstream of immunocompromised individuals, causing a severe and life-threatening illness with symptoms including fever, chills, decreased blood pressure (septic shock) and blistering skin lesions, according to the Florida Department of Health.

If swallowed, the bacteria can cause diarrhea, often accompanied by abdominal cramping, nausea, vomiting, fever and chills. These symptoms usually begin within a day and can last about three days, according to the CDC.

Healthy individuals typically develop a mild disease. Severe illness is rare and typically occurs in people with a weakened immune system.

What is the treatment?

People with less severe stomach infections usually recover on their own. If you experience diarrhea, drinking plenty of liquids is recommended. For severe cases, a doctor can prescribe antibiotics. Wound infections should be treated by a doctor, according to the New York State Department of Health.

What can you do to guard against a vibrio infection?

1. If you have an open wound — including scrapes, cuts, recent tattoos or piercings — avoid swimming, wading or walking in warm marine waters such as the Atlantic Ocean, Gulf of Mexico, Long Island Sound or Chesapeake Bay.

2. If you do go in the water, keep any wound covered with a waterproof bandage and wear proper foot protection to prevent cuts or scrapes from rocks or shells.

3. Health officials suggest avoiding direct contact with sargassum, also referred to as the seaweed blob, the floating algae that’s washed ashore in places such as the Florida Keys, because it can contain the pathogen.

4. Don’t consume raw oysters or other raw shellfish taken from warm coastal waters during the summer months. Instead, cook shellfish (oysters, clams, mussels) thoroughly. Boil shucked oysters at least three minutes, or fry them in oil at least 10 minutes at 375°F, according to the Florida Health Department.

5. Wear gloves when handling raw shellfish, and thoroughly wash your hands with soap and water when finished.

Is there government regulation of shellfish?

States do monitor commercial shellfish for vibrio, and some require commercial harvesters to take measures to reduce the risk of selling contaminated shellfish. In Connecticut, where oysters are harvested from Long Island Sound, the Department of Agriculture has conducted routine monitoring for Vibrio parahaemolyticus, a different species of vibrio, since 2013 and for V. vulnificus since 2022. (Thus far, V. vulnificus has not been present in any shellfish.)

From July through September, when vibrio are more prevalent in the waters, commercial harvesters in Connecticut are required to rapidly cool shellfish taken aboard their boats as well as take other steps to control the pathogen, according to the agency.

What’s the connection between hurricanes and vibriosis?

Health officials have observed spikes in vibriosis cases during and after flooding from hurricanes in the Gulf region. In 2022, there were 38 cases (and 11 deaths) attributed to Hurricane Ian despite public health messages on the importance of avoiding contact with floodwaters, particularly for those with open wounds. Spikes in vibriosis cases also occurred after Hurricane Katrina in 2005 and Hurricane Irma in 2017, according to the CDC.

Are there other types of vibrio bacteria to worry about?

Yes. About a dozen species of vibrio can cause illness. In the U.S., the most common of these rare pathogens are V. parahaemolyticus, which can cause diarrhea. Another is V. alginolyticus, which can cause gastroenteritis, ear infections and sepsis.

Is cholera the same as vibriosis?

No. Cholera is a distinct diarrheal illness caused by infection of the intestine with a different species of vibrio, V. cholerae bacteria. Modern water and sewage treatment systems have largely wiped out the disease in the U.S. Nearly all domestic cholera cases involve people who were infected in parts of Africa, Southeast Asia or Haiti where the disease persists.

Editor's note: This story, originally published August 25, 2023, has been updated to reflect new information.