George Billiris fished with his grandson near the Anclote power plant, around 30 miles from the city of Tampa, on July 22, he told the Tampa Bay Times. Around 24 hours after the pair had stood knee-deep in the Gulf of Mexico, the 63-year-old’s calf started to burn.

Billiris, who owns the St. Nicholas Boat Line sponge diving line at Tarpon Springs, was on a boat tour when he was hit by fever and chills, WFLA reported. Billiris told WFLA: “At first, my legs starting to get a little red and sore. Kind of like a burning feeling.”

Worried, he headed to Mease Countryside Hospital. Doctors told him he had caught vibrio vulnificus: a bacterium which can cause necrotizing fasciitis, or a so-called “flesh eating” infection. This caused a swollen, discolored blister to form on his leg, the Tampa Bay Times reported.

Vibrio vulnificus live in some coastal waters, with vibrio season spanning between May and October. The Centers for Disease Control and Prevention warn that the bug can enter the body when a person eats raw or undercooked seafood, particularly oysters, or when contaminated salty or brackish water gets inside a wound.

Billiris told WFLA: “I was just wading in the water there in the canal. And apparently, I had a couple of scabs on my legs that must have entered through.”

Medics prescribed antibiotics, and removed the blister, WFLA reported. The grandfather is recovering in hospital.

“If I didn’t get treatment, I’d probably be dead,” Billiris told Fox 13. “I am more thankful [my grandson] didn’t contract it. He was in the water with me. He is 10 years old.”

“I didn’t realize how quickly it can become really serious,” he told the Tampa Bay Times. “I was lucky when I came to the hospital when I did. I grew up on the water here and this is just a reminder to take precautions. I don’t think most people are aware,” he told the newspaper.

Vibrio vulnificus infections are rare, according to Florida Health Department. However, cases have been gradually rising since 2008, when there were 16 reported incidents, with 46 in 2013, and 50 in 2017. Last year, 42 cases were identified, leading to nine deaths. This year, 10 cases have been reported so far, with no deaths resulting.

Necrotizing fasciitis is commonly known as a “flesh-eating” infection, even though the body isn’t actually devoured. Instead, the infected flesh dies away. The condition is caused by more than one type of bacteria, according to the CDC, with A. Streptococcus thought to be the most common culprit.

The symptoms overlap with other conditions and can be confused for flu or gastroenteritis. In the early stages, a person can experience a high temperature, as well as severe pain that seems unusual for the size of the injury. Hours or days later, the infected area may swell and fluid-filled blisters form. The individual can also experience vomiting and diarrhea.

If left untreated, the infection can cause sepsis and organ failure. Treatments include antibiotics and surgery to cut away the infected tissue. This can result in amputations in serious cases.

Earlier this year, a Florida man was also hospitalized by a “flesh-eating” bacterial infection which he contracted on a fishing trip. Mike Walton from Ozona was fishing in the Gulf of Mexico when he was nicked by a hook. Walton was fishing with the Ozona Fish Camp group.

Eric McLendon, the owner of Ozona Fish Camp, told Newsweek at the time: “[Walton] is optimistic and looking forward to fishing again. He has been fishing his whole life here and fishes as often as possible. He would fish every day if time would allow.”