It’s already been a difficult year for beach goers on the east coast, as if shark bites on two different beaches in North Carolina weren’t bad enough now the most recent scare: what the media is calling a”flesh-eating bacteria” in Florida. A recent report noted that 7 Floridians have been infected with the Vibrio vulnificus organism so far in 2015, and three of them have died.
Understandably, when terms like “flesh-eating bacteria” are thrown around as it has been in the case of V. vulnificus, fear follows. That’s one reason health departments don’t like that term—and it’s not scientific, in any case, as the clinical term is “necrotizing fasciitis.” Various news outlets have reported deaths and serious infections this year associated with “flesh eating bacteria,” but these are not all due to Vibrio vulnificus. In this news story, the cause of infection is actually a completely different organism called Streptococcus pyogenes, but they inexplicably discuss Vibrio vulnificus throughout the body of the story, clearly not the same thing. So, let’s sort out just what V. vulnificus does, and how concerned a parent should be.
What is Vibrio vulnificus?
Vibrio vulnificus is part of a group of bacteria that typically cause gastrointestinal illnesses, including vomiting and diarrhea. The best known of the Vibrio family is probably the organism that causes cholera, a water-borne disease that is frequently life threatening. While Vibrio cholerae causes somewhere on the order of 2-4 million cases of illness and up to 140,000 deaths worldwide per year, it is rare in the United States; most cases of cholera diagnosed here are due to international travel. More common are other members of the Vibrio bacteria family. Vibrio parahaemolyticus is the most common Vibrio infection in the United States, and like its cousin V. cholerae, it causes gastroenteritis (though it’s typically much more mild than cholera). Most cases of V. parahaemolyticus infections come from eating seafood, such as oysters, clams, and mussels—especially when they are eaten raw. V. vulnificus can also cause gastroenteritis, but it’s not very well-described. Like V. parahaemolyticus, most cases of V. vulnificus gastrointestinal disease have been linked to seafood, and especially oysters and shrimp.
More commonly, V. vulnificus causes skin and soft tissue infections or “SSTIs.” These can range from a mild skin infection to a very invasive disease, including necrotizing fasciitis (the misrepresented “flesh eating” component), where the fascia—the tissues that line and separate the muscles—are attacked by bacterial infection. As the bacteria spread and these tissues die, infections like these can require amputation of the infected limb or removal of diseased tissue—that’s where many of the most gruesome reports of these infections come from. It’s also worrisome because symptoms can progress very quickly. Symptoms can present in less than 12 hours from exposure to the bacterium, and death can occur within 24-48 hours. In the worst case, these infections can lead to bacteria in the blood (sepsis), and death.
Where is it found?
V. vulnificus is most commonly found associated with waters of the Gulf of Mexico and the Atlantic seaboard, though it can be found in other areas as well. It can be associated with natural disasters – an increase in V. vulnificus infections was detected following Hurricane Katrina and the hurricane’s associated floodwaters. The bacterium flourishes in brackish waters, where fresh and saltwater merge, and is thought to be increasing in abundance due to decreases in ocean salinity associated with climate change. It also is more common in the summer months, due to rising water temperatures that encourage bacterial growth. Most cases occur between May and October. In Florida, V. vulnificus is the most common Vibrio illness, associated with wound infections primarily, and oyster consumption secondarily.
How common is it?
Luckily, not very. One report documented only 944 cases of V. vulnificus infections reported in the United States between 2001 and 2009. States in the Gulf Coast region average about 50 cases, 45 hospitalizations and 16 deaths annually, according to the Florida Department of Health. It should be noted that this is probably a low estimate, as many individuals with mild infections may not go to a physician for diagnosis and treatment. Of those who do become ill with V. vulnificus, many of them have other health conditions that make them more vulnerable, in particular, people with diabetes, liver disease, alcoholism, or cancer are particularly susceptible.
How can it be avoided?
For the vast majority of people, coming into contact with V. vulnificus will not result in any harm. Those who are at risk include individuals with pre-existing conditions as noted above, and individuals with open wounds. Carefully covering wounds, or better yet, staying out of the water if an open wound is present, can reduce the chance of acquiring a serious V. vulnificus infection. Avoiding brackish waters can also lower one’s risk. If you experience a cut or scrape while swimming, clean the wound carefully and seek medical attention immediately if it becomes swollen, red, and/or hot to the touch. Wear shoes or some kind of foot protection in rocky areas, to avoid cuts that can introduce V. vulnificus. Cooking seafood rather than eating it raw will also lessen exposure to the bacterium.
While V. vulnificus can be scary, the risk to healthy individuals is quite low, particularly if simple precautions are followed. Have a good time at the beach, and with simple precautions, you should likely be more concerned about sunburn than a “flesh-eating disease!”
Brian Clark Howard. What You Should Know About Shark Attacks After Recent Bites. National Geographic. Accessed 6/23/15
Officials: Don’t call it ‘flesh eating bacteria’. Wstp.com – Channel 10 News. Accessed 6/23/15
Philip Ross, Flesh-Eating Bacteria From The Ocean? Necrotizing Fasciitis Coming To US Beaches This Summer. International Business Times. Accessed 6/23/15.
Janda JM, Newton AE, Bopp CA. Vibriosis. CLin Lab Med 35:273-288. 2015. Accessed 6/23/15.
Scott Gold, Newest Peril From Flooding Is Disease. Los Angeles Times, September 6, 2005. Accessed 6/23/15.
Weis KE, Hammond RM, Hutchinson R, Blackmore CG. Vibrio illness in Florida, 1998-2007. Epidemiol Infect 139:591-8. 2011. Accessed 6/23/15.