A flesh-eating bacteria found in warm coastal waters is responsible for at least five deaths so far this year in Louisiana, state health officials reported Thursday.

There have been at least nine total cases of Vibrio vulnificus in the state in 2026, according to the Louisiana Department of Health. All nine patients were hospitalized.

The nine patients all contracted Vibrio vulnificus through wounds that were exposed to seawater, the health department said, and all of them had underlying health conditions.

Over the past 10 years, Louisiana has averaged seven cases of Vibrio vulnificus per year and one fatality, the health department said. In 2025, however, there were at least 26 cases and five fatalities recorded in the state. 

The Florida Department of Health has also recorded two deaths from Vibrio vulnificus so far this year. In 2024, it reported 19 deaths, and another five in 2025. The agency said Florida saw higher rates of infection after major storms, such as Hurricane Helene in 2024, that brought deluges of floodwater and standing water to communities.

Rising water temperatures caused by climate change are also contributing to the risk of Vibrio vulnificus infections in new regions, experts say.

This spring, Vibrio vulnificus was discovered in water samples taken in coastal areas of New York’s Long Island. 

There are about a dozen Vibrio species that can cause the illness known as vibriosis, but Vibrio vulnificus is the most serious and life-threatening. About one in five people who contract Vibrio vulnificus will die from it, per data from the U.S. Centers for Disease Control and Prevention. It can also lead to amputations.

Vibrio infections are most commonly contracted between May and October, when ocean water temperatures are warmest, according to the CDC.

They can be contracted when an open wound is exposed to seawater, or through the consumption of raw or undercooked shellfish, specifically oysters, the CDC said.

Those with preexisting conditions are most susceptible to serious illness from Vibrio vulnificus, the Louisiana Health Department said. Those conditions include cancer, liver disease, HIV, thalassemia and those receiving immune-suppression treatments.  

Symptoms of a Vibrio wound infection can include fever, skin discoloration, drainage or discharge, or pain and swelling around the wound. Symptoms of a Vibrio bloodstream infection can include fever, chills, dangerously low blood pressure and skin lesions.

Gastrointestinal symptoms of Vibrio can include diarrhea, stomach cramps, nausea and vomiting.

To avoid infection, the Louisiana Health Department advises the public to stay out of salt or brackish water, which are areas where saltwater and freshwater mix. After a possible exposure, wash wounds with soap. When preparing seafood, cook it thoroughly and keep cooked seafood separate from raw seafood.