‘1 in 5 people … die, sometimes within a day or two of becoming ill’

A bacterial infection once considered rare, with a frighteningly high mortality rate, is now surging, and experts warned that rising temperatures and warming seas are the culprit, CNN reported.

What’s happening?

Vibrio vulnificus is an “opportunistic bacterial pathogen” that proliferates in warm waters with a low salt content, according to the journal Nature.

That article was published in March 2023, and it indicated that one type of Vibrio vulnificus infection was “infrequent, but mortality rates are high.”

Vibrio vulnificus, which causes an illness called vibriosis, thrives near coastlines. In particular, the bacteria become plentiful in brackish seas and rivers, where freshwater bodies merge with saltwater.

Infections typically occur in one of two ways: through the consumption of raw or undercooked shellfish, or when warm, low-salinity water enters an open wound.

CNN noted that vibriosis has long been associated with the Gulf Coast, but in recent years, cases have occurred further north on the East Coast. A 2021 article in the Delaware Journal of Public Health noted that an average of 100 vibriosis-related deaths occurred in the U.S. each year.

Summer hasn’t officially ended in the United States, and Vibrio vulnificus infections have soared this year. The Massachusetts Department of Health confirmed 71 cases of vibriosis in the state in 2025; 30% of those infected were hospitalized, but no fatalities occurred.

Why is an uptick in Vibrio vulnificus concerning?

Eating shellfish and swimming in warm water are both common summer activities — and as the pathogen slowly moves up the East Coast, infections happen more frequently.

In 2023, the USDA’s Economic Research Service warned that vibriosis was likely to become more frequent in the near future as a result of higher temperatures and warming seas.

The following year, the interdisciplinary journal The Lancet Planetary Health published an article along the same lines.

“Crucially, we appear to be on the cusp of an alarming global increase in Vibrio disease,” the authors wrote, citing contributing factors like increased seafood consumption, recreational swimming, and changing temperature patterns.

Vibrio is one of several types of bacterial pathogens sometimes referred to as “flesh-eating,” as vibriosis can cause necrotizing fasciitis. These pathogens attack soft tissue, leading to amputations for some who survive it.

In 2023, JAMA observed that Vibrio vulnificus had a 33% case fatality rate in the United States, accounting for “more than 95% of seafood-related deaths.” CNN quoted the Centers for Disease Control on the severity of vibriosis.

“About 1 in 5 people with this infection die, sometimes within a day or two of becoming ill,” the CDC said.

What can be done about it?

The worrisome spread of Vibrio vulnificus serves as a reminder to remain vigilant about critical environmental issues.

According to South Florida’s WTVJ, there are ways to lower the risk of a Vibrio infection.

Forgoing warm water swimming when you have an open wound is one, as is avoiding raw shellfish and taking measures to prevent cross-contamination.

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