JACKSONVILLE, Fla. -

With a Palm Coast man dead and a Nassau County man infected by a bacteria that lives in warm, brackish water, health officials are urging people to avoid going into salt water with open wounds or eating raw oysters.

Palm Coast resident Henry Konietzky was infected 10 days ago when he was setting crab traps in the Halifax River in Volusia county. He died within 28 hours.

On Thursday, Nassau County health officials said a 77-year-old man was hospitalized with a dangerous infection after getting pinched by a crab.

George Clark (pictured below with wife) is in critical condition at Baptist Medical Center. Family members say he was pinched Saturday night while fishing and crabbing at Yates and Faye roads by the Nassau River in Yulee. He then developed the infection (Clark's arm pictured below).

Debbie Stack said the bacteria killed her brother-in-law in what seemed like the blink of an eye.

"It's just horrifying. It's just totally horrifying," said Debbie Stack, Konietzky's sister-in-law. "They did everything. They tried multiple antibiotics, but nothing was touching it, nothing even phased it."

Doctors say Konietzky and Clark were exposed to Vibrio vulnificus, a bacteria can shut down a victim's kidneys and liver.  Health officials report 27 cases have been reported in Florida this year, and there have been nine deaths.

The bacteria is found in warm salt water, meaning brackish or seawater. It's also found in raw shellfish. It is more apparent during the warmest times of the year.

Dr. Vandana Bhide, of Mayo Clinic, said even those who stay out of the water should watch what they eat.

"Oysters, clams, mussels: Those are the big three," Bhide said. "We worry about could it potentially be in others? I think it can."

Doctors say it's commonly found in raw oysters, so make sure seafood is properly cooked in the case of oysters steamed well.

"We do all the things that we try to protect them, but there is a 50 percent mortality rate with this infection," Bhide said.

The symptoms of contracting the bacteria are vomiting, diarrhea, abdominal pain, fever and chills.

Doctors say until the end of this month, avoid swimming in warm brackish or salt water for those who have open wounds or broken skin, and make sure to wear gloves and wash hands after handling raw shellfish.

For those who plan to cook shellfish at home head, click here to learn how to do so safely.