John Duffy grew up on the water, but he hasn't dipped a toe into the Mississippi Sound since he almost lost his leg after he went wade fishing last summer.
"I will not wade fish again," Duffy, who lives in Pass Christian, told the Sun Herald. "Never. No way I would expose myself to that much water."
The Mississippi State Health Department for 2015 reported 14 cases of vibrio illness, including one that was deadly.
Duffy didn't feel a thing when he went wade fishing between 8:30 a.m. and noon July 3. He also didn't notice any cuts or open wounds on his left foot.
That evening, he developed a fever. He took aspirin because he thought he was coming down with a cold or the flu.
He did notice a red spot on his ankle when he sat down the next morning to read his newspaper and work the crossword puzzle. When he looked down 1½ hours later, his leg was red up to his groin and swollen to twice its normal size.
He and his wife headed straight for the emergency room because, having spent so much time on the water, he knew about vibrio bacteria.
"I like talking about it and the reason I like talking about it is because so many people are unaware of it," Duffy said. "If people knew about it, and they just knew the little basic rule: You're swimming, within 24 hours you get a fever -- you go to the emergency room. It could save all kinds of limbs."
Duffy developed cellulitis in his left leg, which still swells.
But vibrio can kill, especially vibrio vulnificus and vibrio parahaemolyticus, said Paul Byers, deputy state epidemiologist for the state Health Department. Both types of bacteria can cause infections, either from exposure to saltwater through a cut or wound or by eating raw seafood, especially oysters. The bacteria is prevalent from May to October, he said.
Spread is rapid
Both types of vibrio can even lead to the blood infection sepsis, which can be deadly. Vibrio ingested in raw seafood also can cause gastrointestinal illnesses. People with chronic liver disease or otherwise compromised immune systems are at the highest risk of contracting vibrio.
Byers said: "These are not new infections. This is not a new bacteria. This is a bacteria that has been around for a long time. But it is very important for those people who may be at higher risk to take appropriate precautions to avoid infection.
"This is an infection that can develop rapidly and have some severe consequences. We do see deaths associated with it. So if you think you may be at high risk, talk to your doctor about what you need to do. If he recommends avoiding exposure to sea water when you have a cut or an abrasion, and avoiding raw or under-cooked seafood, those are important take-home messages, I think, for folks to do to prevent infection."
Though vibrio has long been present in saltwater and brackish water, a study from the Centers for Disease Control and Prevention noted an increase in reported cases of illness from the bacteria from 1996 to 2010. The study did not pinpoint a cause, but said warming of coastal waters could contribute to the bacteria's growth and persistence.
An article from the National Oceanic and Atmospheric Administration in January noted "that half of the global ocean heat content increase since 1865 has occurred over the past two decades."
Infection is rare
Still, Karen K. Wong of CDC said: "These infections are very rare in the scheme of things, considering how many people go in the water every year. It is quite rare."
Illnesses from vibrio vulnificus do not appear to be on the increase, Wong said, but the number of reported illnesses from vibrio alginolyticus have gone up. Alginolyticus, she said, tends to cause milder wound and ear infections.
Also, she cautioned, though vibrio illnesses are more common in people with compromised immune systems, they can strike anyone at any age and are not necessarily associated with underlying medical conditions.
Duffy said he has a neighbor who had to have a leg amputated due to vibrio. Duffy feels fortunate his infection was caught in time.
"The ER doctor told me if I had waited 12 more hours," he said, "they would have had to cut my leg off."