Severe 'flesh-eating' infections tied to heat waves in eastern US, CDC reports

illustration of rod-shaped, green bacteria on a cloudy background
Cases of vibriosis, an infection caused by this pictured bacterium, are expected to rise along with average global temperatures. (Image credit: Dr_Microbe via Getty Images)

In the wake of record-breaking heat waves in the summer of 2023, three East Coast states saw upticks in severe, "flesh-eating" infections, a new report says.

The report concerns Vibrio vulnificus, a deadly bacterial species that lives in coastal waters. If the microbe enters an open wound, it can lead to a "flesh-eating" infection known as necrotizing fasciitis. This is a severe, inflamed infection that causes the surrounding tissue to rapidly die. 

If ingested — for example, in raw or undercooked seafood — the same bacteria can cause gastrointestinal infection. This commonly leads to symptoms of watery diarrhea, vomiting and fever, but it can also lead to sepsis, the extreme immune response that can progress to life-threatening septic shock.

V. vulnificus is known to thrive in warm water, and between June and August 2023, the U.S. experienced widespread heat waves and above-average sea surface temperatures. Around that time, in July and August, Connecticut, New York and North Carolina reported a number of severe V. vulnificus infections, according to a new Morbidity and Mortality Weekly Report, published by the Centers for Disease Control and Prevention (CDC) Thursday (Feb. 1).

Related: The link between climate change and 'flesh-eating' bacteria  

"A notable feature of these cases, beyond their severe clinical outcomes, is that they occurred in the wake of record-breaking U.S. heat waves," the report says. The cases can't be attributed solely to the heat waves, but the link between infections with Vibrio bacteria, like V. vulnificus, and environmental conditions that are favorable to the microbe's growth "is well-documented," the report adds. 

The report describes 11 cases of V. vulnificus infection, or vibriosis — seven in North Carolina, two in Connecticut and two in New York. The affected people ranged from 37 to 84 years old. Five patients died in total, including three who died after experiencing septic shock. One additional patient experienced septic shock but survived.  

Six of the infected people were likely exposed to V. vulnificus via marine or estuarine water along the U.S. Atlantic coast between July 7 and Aug. 22, 2023. Two additional cases likely stemmed from the microbe entering a cut on the person's hand while they handled raw seafood during food preparation. 

One case was tied to the person eating raw oysters. In another, the person reported both eating raw oysters and having a wound exposed to brackish water — a mix of salty and fresh water — so the exact route of exposure couldn't be determined.

"As coastal water temperatures increase, V. vulnificus infections are expected to become more common," the report states. "Persons can take steps to prevent illness by avoiding wound contact with brackish water, salt water, and raw seafood, and by thoroughly cooking oysters and other seafood before eating."

This article is for informational purposes only and is not meant to offer medical advice.

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Nicoletta Lanese
Channel Editor, Health

Nicoletta Lanese is the health channel editor at Live Science and was previously a news editor and staff writer at the site. She holds a graduate certificate in science communication from UC Santa Cruz and degrees in neuroscience and dance from the University of Florida. Her work has appeared in The Scientist, Science News, the Mercury News, Mongabay and Stanford Medicine Magazine, among other outlets. Based in NYC, she also remains heavily involved in dance and performs in local choreographers' work.