• Vibrio vulnificus, known as the flesh-eating bacteria, has killed 5 people in Florida this year, according to the state's health department.
• Overall, at least a dozen people have died from the infection across the U.S. so far in 2023.
• The bacteria, which thrives in warm water where river and ocean waters mix, can enter the body through a cut, scrape or wound. Raw seafood can also cause infections.

Five people in the Tampa, Florida, area have died from a rare flesh-eating bacteria, which is also the recent cause of death for three others in Connecticut and New York.

The Vibrio vulnificus bacteria, which can be found in raw or undercooked seafood, saltwater, and brackish water, led to the death of two people since January in Hillsborough County, home of Tampa, according to the Florida Department of Health. An additional person died in each of the surrounding Pasco, Polk and Sarasota counties. Florida has recorded a total of 26 cases statewide this year.

The bacteria has led to other recent deaths in the Northeast, where New York Gov. Kathy Hochul announced the virus was detected in a person who died in Long Island.

“While rare, the vibrio bacteria has unfortunately made it to this region and can be extraordinarily dangerous,” Hochul said Wednesday in a statement. New York health officials are still investigating how the Long Island victim was infected.

In Connecticut, three people, aged between 60 and 80 years old, were infected with the bacteria in July, the state's Department of Public Health said. Two of those patients have since died.

How flesh-eating bacteria infections happen

One of the Connecticut patients reported eating raw oysters from an out-of-state establishment, while the other two reported exposure to salt or brackish water in the Long Island Sound.

Brackish water is created when fresh water from a river or lake meets seawater, which has salt in it. The Florida health department warns people not to get into warm, brackish water if they have fresh cuts or scrapes, because the bacteria can enter the body through a cut or wound and cause an infection.

The department did not list the cause of the infection in the five 2023 cases and officials did not immediately respond to a request for comment from USA TODAY.

“Whenever you have a break in the skin and you’re in a marine environment then theoretically you’re at risk,” Dr. Eric Shamas, an emergency medicine physician at Bayfront Health St. Petersburg, told WFLA News Channel 8 in Tampa.

“It’s very important to keep in mind these severe infections are very rare,” Shamas added.

Why is Vibrio vulnifus called the 'flesh-eating" bacteria?

Technically, it's inaccurate to call Vibrio vulnifus the “flesh-eating bacteria” because it kills, but does not eat tissue. The bacteria cannot penetrate intact skin, but must enter through an existing break in the skin. If the bacteria enters the body through a cut or wound it can cause necrotizing fasciitis, in which the flesh around the infection site dies. Vulnificus means "to wound" in Latin.  

Some Vibrio vulnificus infections can lead to life-threatening wound infections in which the flesh around an open wound dies, according to the Centers for Disease Control and Prevention. Many who are infected may need intensive care or limb amputations; about 1 in 5 who get the infection die, sometimes within a day or two of becoming ill, the CDC says.

About 80,000 people get vibrio infections each year and about 100 people die from the infection annually in the U.S, the CDC says.

Flesh-eating bacteria is 'always in the water' and heading north

Because of climate change and warming ocean waters, Vibrio vulnificus is migrating north, studies have found. "The warmer water is, the more bacteria can reproduce faster," said researcher Gabby Barbarite at Florida Atlantic University's Harbor Branch Oceanographic Institute in Fort Pierce, Florida.

Infections have increased eight-fold between 1988 and 2018 in the U.S., as climate change has warmed the coastal waters where the bacteria live, according to research published in March in the journal Nature Portfolio. The bacteria and infections are spreading northwards up the East Coast at a rate of about 30 miles a year, researchers said.

Cases used to be concentrated almost exclusively in the Gulf of Mexico in the southern United States," Dr. William Schaffner, an infectious disease expert at Vanderbilt University, told USA TODAY earlier this year.

Vibrio vulnificus is "actually always in water," Manisha Juthani, the commissioner of the Connecticut Department of Public Health, said during a news conference Monday.

"What happens in the summertime is that bacteria like this tend to overgrow, and if you have an open wound, you should never be getting into water because there are any number of bacteria that are in the water," she said.

Particularly at risk are persons who are immunocompromised – have chronic liver disease, kidney disease, or a weakened immune system, for example. They should wear proper foot protection to prevent cuts and injury caused by rocks and shells on the beach, Florida health officials say.

How can I prevent getting infected with Vibrio vulnificus?

According to the CDC, you can reduce your chance of getting infected with the bacteria by following these tips:

• If you have a wound (including from a recent surgery, piercing, or tattoo), stay out of saltwater or brackish water, if possible. This includes wading at the beach.
• Cover your wound with a waterproof bandage if it could come into contact with saltwater, brackish water, or raw or undercooked seafood and its juices. This contact can happen during everyday activities, such as swimming, fishing or walking on the beach. It could also happen when a hurricane or storm surge causes flooding.
• Wash wounds and cuts thoroughly with soap and water if they come into contact with saltwater, brackish water, raw seafood or its juices.
• Avoid eating raw or undercooked seafood, particularly oysters. You also can get an infection if an open wound comes into contact with raw or undercooked seafood or its juices.

What are signs and symptoms of a Vibrio vulnificus infection?

Some common signs and symptoms of infection can include:

• Watery diarrhea, often accompanied by stomach cramping, nausea, vomiting, and fever.
• For bloodstream infection: fever, chills, dangerously low blood pressure, and blistering skin lesions.
• For wound infection, which may spread to the rest of the body: fever, redness, pain, swelling, warmth, discoloration, and discharge (leaking fluids).

Other recent Vibrio vulnificus cases in the United States

Three North Carolina residents died from the infection last month, according to The Virginian-Pilot. Two of the three deaths followed scratches exposed to brackish water.

The third case also had brackish water exposure and that person also consumed personally caught seafood, according to a news release from the North Carolina Department of Health and Human Services.

In June, a 54-year-old Missouri man died after he contracted the bacteria while eating raw oysters, according to NBC News.

Contributing: Elizabeth Weise

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