As climate change warms coastal waters, a rare bacterial infection could pose more of a threat

Several people along the East Coast have contracted a rare “flesh-eating” bacterial infection that scientists say is exacerbated by climate change.

At least a dozen people have died from the Vibrio vulnificus infection outbreak this summer, including two in Connecticut, and others in New York and Florida. Several others are recovering after being infected and hospitalized.

The bacteria spreads through consuming raw or undercooked oysters and other seafood as well as exposing an open wound to salt water or brackish water.

Among the cases in Connecticut, two have been linked to swimming in Long Island Sound with open wounds, and one person consumed oysters from an out-of-state establishment.

Connecticut public health officials describe the infection as “extremely rare.” Five cases were reported in Connecticut in 2020 and none in 2021 and 2022.

The bacteria replicates faster in warmer water, which poses a higher risk for Vibrio vulnificus infections, said Dr. Brandon Ogbuno, an assistant professor in Yale University’s ecology and evolutionary biology department, who’s studying such infections in his lab.

“A lot of these things are just naturally occurring and living on their own in aquatic settings, to no harm, 99% of the time,” Ogbuno said. “And when we see these sorts of outbreaks, it’s because something changes.”

Trends show the average temperature of Long Island Sound has been rising over time; further north, the Gulf of Maine off the New England coast is also warming at a rapid rate.

For nearly a decade, most Connecticut harvesters have cooled oysters through a special process so bacteria goes into an inactive state. The Connecticut Department of Agriculture has said that Vibrio vulnificus illnesses have not been tied to Connecticut oysters, and they monitor bacteria levels in oyster harvest areas.

The Connecticut Department of Energy and Environmental Protection said in a statement that they don’t currently regularly test for Vibrio vulnificus in state swimming areas.

If temperatures continue to climb, the bacteria will likely become a bigger concern, said Dr. Andrea Ayala, a postdoctoral fellow in Ogbuno’s lab at Yale.

“What we've found from research that we've conducted in human cases is that warmer temperatures are correlated with poor patient outcomes,” Ayala said. “We're going to see probably more cases of Vibrio vulnificus in the Northeast and along the Atlantic coast.”

Ayala said the lab is studying how various Vibrio bacteria react to different temperatures in Florida mottled ducks, and hope to continue the work along the Atlantic seaboard.

The Connecticut Public Health Department is recommending that those with open wounds not swim in salt water or brackish water, and that immunocompromised people avoid eating raw or undercooked shellfish.

This story is a production of the New England News Collaborative. It was originally published by Connecticut Public Radio.