OLD SAYBROOK, Conn. (WTNH) — An extremely rare but serious threat is apparently lingering in the brackish and salt waters of the Long Island Sound.

The Vibrio vulnificus bacteria has infected five people since July, prompting the Connecticut Department of Public Health to issue a warning to anyone who may come in contact with those waters. 

“We had to get the information out because 1 in 5 people who develop this type of infection can die,” said epidemiologist Paul Gacek, with the Connecticut Department of Public Health.

The infections can also lead to blood infections and limb amputations. 

In the last 10 years, there have been seven cases in Connecticut, so officials said having five in just July and August is alarming. The four men and one woman — ranging in age from 49 to 85 — are from Fairfield, New Haven and Middlesex counties.

According to the Department of Public Health, each person had reported they’d either been swimming, boating or crabbing, and each of them also said they had an open wound or sustained a wound during those activities.

“I’m very concerned because I swim in the river,” said Ron Cozzolino, of Essex.

Mike Sheehan is also concerned. He’s the yard manager at South Yard Marina.

“It’s physical, so by nature of it, I have open wounds most of the time, and I’m dealing with the water and the river every day,” said Sheehan.

He plans to take extra precautions now.

“I’m going to be washing all my cuts today after I get near the water,” said Sheehan.

That is one way to protect yourself. DPH has other tips to prevent a Vibrio wound infection:

  • If you have a wound, stay out of salt water or brackish water. This includes wading at the beach.
  • Cover your wound with a waterproof bandage. 
  • Wash wounds and cuts thoroughly with soap and water after they have contact with salt water, brackish water, raw seafood or its juices.

“There would be swelling at the site or there could be a discharge or a fever or pain,” said Gacek.

Those infected were hospitalized and survived, but people who are immune-compromised or the elderly may be more at risk.

“I don’t think I’ll be swimming again this year in the water, said Cozzolino.