A flesh-eating bacteria that kills roughly 20% of its victims and lives in coastal waters is expanding far beyond its original Gulf Coast home, working its way up the East Coast at about 30 miles per year.
While still rare, infections from Vibrio vulnificus have increased eight-fold between 1988 and 2018, as climate change has warmed the brackish coastal waters where the bacteria live, a paper published Thursday found.
The bacterial infection, which eats away at the flesh and sometimes requires amputation to stop it, used to occur mostly in brackish waters along shores and inlets from Texas to Florida. Now cases are showing up as far north as Massachusettes.
“Vibrio has been talked about as a barometer of climate change because it is so sensitive to environmental conditions, it gives us some indications of what the impacts of climate change are,” said Iain Lake, lead author on the paper and a professor of environmental sciences at the University of East Anglia in the United Kingdom.
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Here’s what to know about Vibrio vulnificus:
What is Vibrio vulnificus?
Vibrio vulnificus is one of several forms of the Vibrio bacteria. The best known is Vibrio cholerae, a waterborne disease that causes an acute diarrheal illness that can kill within hours if untreated. It is rare in the United States but common in areas without modern sewage treatment.
The flesh-eating variety is called Vibrio vulnificus and lives in warm, brackish water, especially in bays, estuaries and areas where rivers and streams meet the sea. It can also occur after heavy rains that cause flooding and storm surges.
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Is Vibrio vulnificus spreading?
As ocean temperatures rise due to climate change, the bacteria that cause these infections is spreading northwards up the East Coast at a rate of about 30 miles a year, according to the paper published Thursday in the journal Nature Portfolio.
“Cases used to be concentrated almost exclusively in the Gulf of Mexico in the southern United States,” said Dr. William Schaffner, an infectious disease expert at Vanderbilt University.
U.S. cases increased eightfold between 1988 and 2018, the researchers found. Between 1988 and 2016, there were more than 1,100 found infections with the bacteria and 159 deaths.
Cases also underwent “a profound geographical expansion” in the words of the paper. In the late 1980s infections further north than Georgia were rare. By 2018 they were being regularly reported as far north as Philadelphia.
“It’s not that it’s shifting north, it’s expanding. We’re still seeing cases in Texas but we’re also seeing them in Pennsylvania, which we weren’t seeing 20 years ago,” said Elizabeth Archer, the paper’s first author and a postgraduate researcher at the University of East Anglia.
The bacteria prefer warm water above 64.4 degrees
If waters continue to warm and the bacteria makes it to New York state in coming decades, cases could double again.
How can you protect yourself?
The open ocean is too salty for Vicbrio vulnificus, which prefers the slightly less salty, brackish waters found in bays, inlets and estuaries.
The take-away from the study is not to avoid the beach but to be aware, said Jim Oliver, an emeritus professor of biology at the University of North Carolina who’s been studying the bacteria for decades and who is one of the paper’s authors.
Young and healthy people are less at risk while older people, especially men, and those who are immunocompromised, are at higher risk, he said.
“We don’t want to make people afraid to go to the beach. Just be aware,” he said.
“This kind of wound contamination is usually sustained by people working in seawater such as fishermen,” said Schaffner. People who are older and have compromised immune systems are at special risk.”
What should you do if you think you’ve been exposed to the bacteria?
Wash wounds and cuts thoroughly with soap and water if they have come into contact with saltwater and also if they come into contact with raw seafood, the CDC suggests.
The most important thing is that if you have a cut or wound that seems to be getting infected and you’ve recently spent time in the ocean or semi-salty bays and estuaries, you should immediately seek medical care.
Symptoms of an infected wound can include swelling at the site, pain, redness, warmth, fever, discoloration, and discharge.
“The infection can proceed incredibly fast, I worked with one woman whose husband was infected and it went from looking like a spider bite to necrotizing fasciitis within four hours,” he said.
“It’s very important not to tough it out,” said Schaffner. “If you sustained an injury and you think have a wound infection, have it attended to as quickly as possible. That’s key.”
Something else to worry about: Uncooked seafood
The same bacteria can infect oysters, mussels, clams and scallops. Because all but oysters are typically cooked before eating, generally only oysters are a problem with the foodborne form of Vibrio vulnificus.
The infection can cause watery diarrhea, often accompanied by stomach cramps, nausea, vomiting, and fever. It can also get into the bloodstream, causing fever, chills, dangerously low blood pressure, and blistering skin lesions, according to the Centers for Disease Control and Prevention.
The CDC estimates that about 80,000 people in the United States get vibriosis every year and 100 die from it. Most of these illnesses happen from May through October when water temperatures are warmer.
“Vulnificus is the deadliest food-borne disease in the world,” said Oliver.