A Journal mBio study confirmed Hurricane Ian, which struck Southwest Florida in September 2022, unleashed various Vibrio bacteria that can cause illness and death in humans.
The study, conducted in October 2022 by scientists from the University of Florida and the University of Maryland, was based on data and samples gathered off the coast of Lee County, where Hurricane Ian made landfall last year.
The researchers from UF’s Herbert Wertheim College of Engineering, UF’s College of Medicine and the University of Maryland Institute for Advanced Computer Studies used DNA samples and findings to conclude the presence of two particularly concerning species in Florida coastal waters: Vibrio parahaemolyticus and Vibrio vulnificus.
“We were very surprised to be able to detect, without any difficulty, the presence of these pathogens,” Rita Colwell, the study’s senior author, said in a University of Maryland press release.
According to a UF press release, and Vibrio experts, these DNA samples revealed the presence of Vibrio parahaemolyticus and Vibrio vulnificus bacteria.
The species of Vibrio live in warm salt waters and grow rapidly during times of hurricanes, floods and storm surges, according to the press release.
Anwar Huq, a research professor of cell biology and molecular genetics at the University of Maryland and one of Colwell’s co-authors, explained that Vibrio infection cases increase due to a hurricane’s speed and mobility.
Hurricanes cause motion, resulting in Vibrio bacteria to relocate. When people eat infected seafood from these locations or enter the water they become infected and therefore rates increase.
“The organisms are always there,” Huq said. “These are naturally occurring organisms in terms of carpophagous members of the aquatic environment, but hurricanes allow these organisms to move quickly in an area where they usually are not there.”
Both press releases go into detail on where Vibrio bacteria live and the factors causing Vibrio bacteria to live and thrive after hurricanes.
According to Colwell, who has studied Vibrio for 50 years, within the last 50 years the number of Vibrio species has skyrocketed from half a dozen to 110.
Both Colwell and Huq said the bacteria can cause illness or death for people who eat raw or undercooked seafood or go into the ocean with an open wound.
“Anyone with liver disease, cirrhosis, alcoholism, Hepatitis C or Hepatitis B infection should not consume raw oysters,” Colwell said.
There is a 150 to 200-case annual increase in Vibrio vulnificus infections in the eastern region of the United States, according to a recent report from the Centers for Disease Control and Prevention.
Most illnesses are caused by bacteria entering an open wound, although eating raw or undercooked shellfish is responsible for 10% of cases. Meanwhile, 20% of Americans die after contracting the bacteria, according to the report.
“This study highlights how important it is to understand climate, weather, and environmental processes on the distribution of clinically relevant pathogens that impact humans,” Antarpreet Jutla, Ph.D., an associate professor in the Herbert Wertheim College of Engineering at UF said in a press release. “It is unlikely to result in an outbreak, but the public should be aware of what is in the water and food they eat.”
In addition, the Florida Department of Health reported 38 infections and 11 deaths linked to vibriosis in Lee County — the highest caseload in the state — after Hurricane Ian struck, the UM press release stated.
Side effects or symptoms of vibrio infections may include wound infections, gastroenteritis or necrotizing fasciitis, which eats away at human flesh, according to the press release.
“With Hurricane Ian, we saw an increase in necrotizing (flesh-eating) skin and soft tissue infections among those exposed to storm surge in that region,” Dr. Norman Beatty, an assistant professor at UF’s College of Medicine, said in the UF press release. “The wound infection can rapidly evolve with pain, redness and swelling.”
Beatty also explained in the release that blood-filled fluid blisters caused by Vibrio infections can develop without immediate medical attention. He said early symptom detection is crucial, as it could help avoid the need for surgical intervention or amputation in serious cases.
Colwell advised that, if infected, individuals need to tell their physicians if they were either swimming or eating undercooked seafood.
While Vibrio bacteria’s effects on animals are uncertain at this time, the consensus from both Huq and Jutla is that the bacteria would pass in and out of the subjects’ system, possibly causing diarrhea.
Julta said this is mainly filter feeders including shellfish, clams, oysters and mollusks.
While vibrio cases in Florida have increased, they are not just found in the South. The UM press release reported that in August 2023, three people in New York and Connecticut died after contracting Vibrio infections.
The current and water temperature are causing the bacteria to travel up the East Coast, Huq said.
“The Eastern Coast is primarily warmer here. [It’s] coming from the Gulf[of Mexico], [and] going upward,” he said.
Colwell and Huq have predicted the recent surge in vibriosis cases based on environmental trends in the northeast. Chesapeake Bay may be impacted as ocean temperatures continue to climb, she said.
“On the positive side, knowing that these infections are associated with the increased variability of a changing climate, perhaps now is the time to develop mechanisms to understand and mitigate it,” Colwell said in the UM release. “Climate change and flooding are clearly linked to infectious disease, and we need to take it seriously.”
Huq said predictive models are being developed to infer when the bacteria could be in a particular area.
“We can predict the potential occurrence of these organisms in an area almost four to six weeks in advance,” Huq said. “What it does is it helps public health officials to take precautionary measures.”
While these predictive models are in development, they are nowhere near ready. Civilians can’t visit a website or app to check if the lake, river or beach they want to enter has been reported for vibrio detection.
“We do not have those tools developed yet, and I think one of our team’s goals is to create real-time reports that can help Floridians understand what regions are at heightened risk for vibriosis,” Beatty said.
With water temperatures around Florida and the northeast rising, Vibrio infection rates will continue to rise, especially with the help of hurricanes and tropical storms.