Are Cases of Flesh-eating Bacteria Really on the Rise?

When it comes to the Gulf of Mexico, swim—and eat—at your own risk.

That has essentially been the message in the mainstream press since the first case of Vibrio vulnificus was reported earlier this summer. Dubbed a “flesh-eating bacteria,” Vibrio vulnificus actually infiltrates the space between the muscles and skin, releasing a toxin that can, initially, cause blisters and rash and, if left untreated, lead to death.

Through July 5, health officials in the state of Florida have reported 13 cases of the bacterial infection, and four deaths, in four counties in the state that lie along the Gulf coast. Mississippi reported its first case on July 7.

Swimmers can contract Vibrio vulnificus if they swim in water with high levels of the bacteria, particularly if they have open cuts or wounds; however, most cases have been attributed to eating contaminated shellfish.

It’s perhaps not surprising that Vibrio vulnificus has garnered significant media attention this summer, given the nature of how the infection is transmitted, and its effects on those infected. However, it is hardly new to the Gulf region.

James D. Oliver, PhD, Bonnie E. Cone Distinguished Professor in biological sciences at the University of North Carolina-Charlotte told Contagion that Vibrio vulnificus “has been part of the normal flora [of the Gulf of Mexico] probably forever.” According to Dr. Oliver, the bacteria, which was first identified by researchers in 1976, “belongs in coastal environments, and is relatively common [in the Gulf] because of warm water and ideal salinities.”

Dr. Oliver, who has devoted much of his research work to Vibrio vulnificus, added, “Concern is warranted for certain at risk people”—those who are immunocompromised, HIV-positive, and/or diabetic, as well the elderly—but “not the general population.”

Although the news media has implied that there has been a “spike” in cases of Vibrio vulnificus in recent years, the numbers say otherwise. The US Food and Drug Administration reports that the bacterial infection causes, on average, 96 deaths annually nationwide, and that 90% of the cases each year result from the consumption of raw, contaminated shellfish from the Gulf.

Some have speculated that there has been a rise in levels of Vibrio vulnificus in Gulf waters since the BP plc oil spill in 2010. However, according to Dr. Oliver, the bacteria thrive in waters with low salinity or salt levels. In bodies of water such as the Gulf of Mexico, salt levels generally decline as waters warm; rain also affects salt levels—the more it rains, the lower the salinity, meaning Vibrio vulnificus will thrive.

“I don't believe [the recent cases of Vibrio vulnificus] have anything to do with oil spill,” Dr. Oliver told Contagion. “Again, [the bacteria] has always been in Gulf waters. [The reported] increase [in cases] is probably due to increased recognition [of the bacterial infection], and more people living in coastal regions.”

Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous healthcare-related publications. He is the former editor of Infectious Disease Special Edition.