The Science Behind The Rise In Deadly Flesh-Eating Bacteria In America’s Waterways

CREDIT: AP Photo/Florida Keys News Bureau, Andy Newman

In this photo provided by the Florida Keys News Bureau, Dale LeClair, emerges from the Atlantic Ocean as the top individual finisher of the inaugural Alligator Reef Lighthouse Swim Saturday, Sept. 21, 2013, in Islamorada, Fla.

Some vacationers have been getting more than they bargained for during visits to the beach and pools this summer. Vibrio vulnificus – a warm water-dwelling, flesh eating bacteria – has infected more than a dozen people this year, some of whom have succumbed. Recent cases in Florida and the D.C. metropolitan area – including one where a Stafford, Va. man was admitted to a hospital after a swim in the Potomac River – have brought attention to an increase in seawater temperatures that experts say make the bodies of water the perfect breeding ground for deadly bacteria.

In 2011, members of the Chesapeake Bay Foundation likened the Chesapeake Bay to “a warm pond with a broth of nutrients at the right temperature to breed algae and bacteria.” According to a report conducted by the environmental group, cases of Vibrio vulnificus more than doubled in the last decade in Virginia and Maryland, a period during which seawater temperatures in the region increased by half of a degree Fahrenheit. The study also identified the increasing presence of mercury, nitrates, and blue green algae in warm bodies of water.

Symptoms of Vibrio vulnificus include vomiting, diarrhea, abdominal pain, ulcers and the breakdown of skin. People usually come into contact with the bacteria by consuming raw shellfish and swimming in water with open wounds. While healthy people often experience mild symptoms, people with weakened immune systems have cause for concern, especially those who suffer from liver disease. Studies have shown that risk of Vibrio vulnificus exposure in people with preexisting medical conditions were 30 percent higher than the general population. People who contract Vibrio vulnificus through open wounds may also need amputation to ensure recovery. This week, officials in Florida advised residents against taking dips into water with open wounds and consuming raw oysters and clams after Vibrio vulnificus killed three people in the state.

Unfortunately, Vibrio vulnificus is not the first warm water-dwelling bacteria to wreak havoc on swimmers and marine animals. Last summer, officials in Hartford, Connecticut issued a recall of oysters and clams after more than five people reported seafood-related illnesses. The state’s Bureau of Agriculture later linked the illnesses to a warm water-dwelling bacteria, prompting a suspension of shellfish harvests until the fall, when seawater was expected to cool down.

For the last three years, a brain-eating amoeba by the name of Naegleria fowleri – often confined to fresh water in southern states like Arizona and Texas – has infected and killed people in Kansas, Virginia, and Minnesota who swam in warm rivers, lakes, and improperly chlorinated swimming pools. In February, sea otters living off the Alaskan coast contracted Vibrio parahaemolyticus, a warm water-dwelling bacteria that also causes diarrhea and vomiting. In a 2005 New England Journal of Medicine study about a 2004 outbreak in the region also drew a connection to seawater temperatures that rose above 56 degrees Fahrenheit.

Climate Change and European Marine Ecosystem Research, a group of 17 European marine institutes, produced a 200-page report in 2011 that drew connections between climate change, the increasingly warm ocean waters, and the spread of water-dwelling bacteria. The report predicted millions in future healthcare and environmental costs as a result of exposure to contaminated food by humans and marine animals. Researchers focused primarily on bacteria from the genus of Vibrio, which they considered to be by far the most dangerous, causing gastroenteritis, septicemia, and cholera.