Five residents of Louisiana have died this year after contracting infections from Vibrio vulnificus, a flesh-eating bacterium that thrives in warm, brackish coastal waters, state health officials reported. In addition to the fatalities, four other individuals in Louisiana were hospitalized with the illness, which has been linked exclusively to wounds exposed to seawater.

Vibrio bacteria naturally occur in coastal environments and can infect people through open wounds that come into contact with contaminated water or by consuming undercooked shellfish, particularly oysters. The risk of infection tends to increase during warmer months, typically from May through October, when sea temperatures rise.

The Centers for Disease Control and Prevention (CDC) estimates that approximately 80,000 cases of vibriosis occur annually across the United States, with about 20% of those infected by Vibrio vulnificus dying from the illness, often within days of symptom onset. Common symptoms include diarrhea, stomach cramps, nausea, vomiting, and fever, while severe infections can lead to bloodstream involvement, low blood pressure, and blistering skin lesions.

All the Louisiana patients who contracted Vibrio vulnificus had pre-existing health conditions, which are known to increase vulnerability to serious complications. Similar cases have also been reported in Florida, where state health authorities confirmed two deaths and a total of 14 infections in 2024. Florida officials noted that exposure risks rise following severe weather events such as hurricanes and storms, which can drive brackish water further inland. This year, Florida reported 19 deaths attributed to the bacteria amid the impacts of Hurricanes Helene and Milton.

In April, researchers identified Vibrio vulnificus in several coastal waters off Long Island, New York, illustrating the expanding geographic range of the bacterium—an extension scientists attribute in part to climate change. Warmer sea temperatures have enabled Vibrio bacteria to establish themselves in areas previously considered too cold to support them.

U.S. Department of Agriculture and Environmental Protection Agency studies project a 50% increase in Vibrio infections in the United States by 2090 compared with 1995 levels, a trend driven by rising ocean temperatures.

Health officials in Louisiana have advised the public to avoid saltwater or brackish water if they have open wounds and to clean any such wounds promptly with soap and water after exposure. They also recommended thorough cooking of seafood and separating cooked seafood from raw items to prevent contamination.