The dog days of summer are here, and with them come reports of illnesses and deaths caused by Vibrio vulnificus, nicknamed the “flesh-eating bacteria.” As a marine biologist, I find myself getting frustrated when I read media reports of people infected by V. vulnificus because they often leave the reader with a sense of panic and the idea that our beaches are not safe.
What is Vibrio vulnificus?
V. vulnificus bacteria are naturally-occurring in warm coastal waters around the world. Though this species is present in the Gulf of Mexico year-round, levels are highest during warmer months. Not surprisingly, reports of infections are highest when the water is warmest, with 85% of cases reported between May and October. Exposure of an open wound to saltwater is not the only way to contract a V. vulnificus infection. Concentrations of V. vulnificus also build up in oyster meat and cause illness in people who eat raw or undercooked oysters. There are three types of illness caused by a V. vulnificus infection: gastroenteritis or food poisoning, wound infection, and sepsis. Sepsis, when the infection enters the bloodstream, can occur following either gastroenteritis or wound infection, and is fatal over 50% of the time in people with compromised immune systems due to underlying illness.
How common are infections?
Despite the impression you may have, infections due to V. vulnificus are actually rare. To visualize this, think about how many people visit the bays and beaches along the Gulf of Mexico on any given day – anglers, swimmers, beachcombers, boaters, and more. Tens of thousands? Hundreds of thousands? More? Now think about the comparatively small number of news stories on people who have contracted a V. vulnificus infection. According to the U.S. Centers for Disease Control (CDC), each year sees an average of 50 culture-confirmed cases, 45 hospitalizations, and 16 deaths reported from the 5 Gulf Coast states.
Who is at risk for infection?
Healthy people without any underlying conditions can often be treated with antibiotics if they contract V. vulnificus. Chronic diseases, however, can leave your immune system unable to fight off a V. vulnificus infection. There are certain risk factors that can leave a person more susceptible to severe infection, particularly those requiring hospitalization. Liver disease, including alcoholism, cirrhosis and hepatitis, stands out as the primary risk factor. Cancer, chemotherapy, diabetes, AIDS, kidney disease, hemochromatosis (iron overload disease), and gastrointestinal disorders (even ulcers or gastric surgery – remember that you can become infected by eating undercooked oysters) are all known risk factors. According to the CDC, a study has shown that “people with these pre-existing medical conditions were 80 times more likely to develop V. vulnificus bloodstream infections than were healthy people.”
How can I minimize my risk?
There will likely be more stories of V. vulnificus in the news before summer is over, as the salinity of our bays are at 15 to 25 parts per thousand, optimum conditions for these bacteria to thrive. Don’t feel hesitant about enjoying our coastal waters; follow the guidelines for minimizing your risk:
• Don’t go in the water with an open wound or broken skin, even if you do not have one of the aforementioned risk factors.
• If you cut or scrape yourself while at the beach or fishing, wash the area thoroughly with soap and clean water and do not expose it to saltwater. It’s smart to bring along a jug of tap water and a bar of soap in case you’re in an area without available bathrooms.
• Apply an antibiotic ointment as soon as you can and watch for redness or any signs of infection.
• If the area does become infected, see a doctor right away.
• This bears repeating: see a doctor as soon as you notice any signs of infection.
As a side note, last year my kids and I were at the beach when I got hit by a stingray barb on the outside of my foot. (Yes, I was doing the “stingray shuffle”!) I went straight to the bathroom, washed my foot and stayed on the sand for the rest of the day. My foot still bears the scar from the barb, but it never became infected and it hasn’t scared me away from my beloved Texas coast. For more information on V. vulnificus, visit www.safeoysters.org and www.cdc.gov/vibrio.
