Vibrio vulnificus, a flesh-eating bacteria in the same family as cholera, is becoming more common along the East Coast of the United States as ocean temperatures rise, according to research published Thursday in Scientific Reports.
Vibrio vulnificus is a bacteria that lives in warm, salty water and can cause infections by coming into contact with wounds, bites, or cuts. It can also infect oysters, mussels, clams, and scallops — however the foodborne form of Vibrio vulnificus is typically only caused by oysters, since they're not cooked before eating.
The bacteria kills roughly 20% of its victims — sometimes within just a day or two of a person getting sick — and those who get infected can require intensive care, with around 10% needing surgical tissue removal or limb amputations. The bacteria is also capable of causing necrotizing fasciitis, a medical term describing a "flesh-eating" infection.
Symptoms of an infected wound can include swelling, pain, redness, warmth, fever, discoloration, and discharge.
According to the report, infections of Vibrio vulnificus remain rare but have been steadily increasing along the East Coast between 1988 and 2018, jumping from around 10 per year to around 80 per year.
Infections used to be localized to the Gulf of Medico and the southern Atlantic coast of the United States and were previously rare north of Georgia. However, the researchers' analysis of CDC data has found infections are being reported as far north as Philadelphia. As ocean temperatures have risen, the researchers said Vibrio vulnificus has spread northwards up the East Coast at a rate of around 30 miles per year.
"It's not that it's shifting north, it's expanding," said Elizabeth Archer, the report's first author and a postgraduate researcher at the University of East Anglia. "We're still seeing cases in Texas but we're also seeing them in Pennsylvania, which we weren't seeing 20 years ago."
Accounting for warming temperatures, the researchers predicted Vibrio vulnificus could expand as far as New York within the next 20 years. Using climate models where carbon emissions are even worse, they predicted the bacteria could spread to every East Coast state and infections could be as high as 140 to 200 a year by the end of the century. People over 60, who are more susceptible to infections, could see infections from the bacteria double by 2041-2060 or triple by 2081-2100, the researchers projected.
The report's findings point to the wider impact that climate change is having on the environment, Archer said. Given how sensitive Vibrio vulnificus is to temperature, it's "sort of a microbial barometer of climate change," she said.
Archer added that the bacteria is a natural part of the coastal ecosystem and eradicating it isn't possible or reasonable. "We can't just eradicate them from the environment they naturally occur in," she said.
Jim Oliver, an emeritus professor of biology at the University of North Carolina and an author on the report, said the take-away message is not to avoid going to the beach but to be aware of the bacteria and its symptoms.
Young and healthy people are less at risk while older people and the immunocompromised are at higher risk, Oliver said.
"We don't want to make people afraid to go to the beach," he said. "Just be aware."
"This kind of wound contamination is usually sustained by people working in seawater such as fishermen," said William Schaffner, an infectious disease expert at Vanderbilt University. He added that it's essential to immediately seek medical care if you have a wound that's been infected.
"The infection can proceed incredibly fast," Schaffner said. "I worked with one woman whose husband was infected and it went from looking like a spider bite to necrotizing fasciitis within four hours."
"It's very important not to tough it out," Schaffner added. "If you sustained an injury and you think you have a wound infection, have it attended to as quickly as possible. That's key." (Hart, Forbes, 3/23; Weise, USA Today, 3/26; O'Kane, CBS News, 3/23)
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