RALEIGH, N.C. (AP) — Three North Carolina residents died in July from infections from bacteria naturally found in warm seawater and brackish water, state health officials said Friday.

Cases of Vibrio are rare in North Carolina. While healthy people typically develop mild illness, infections can be severe or life-threatening for those with weakened immune systems or chronic liver disease, the Department of Health and Human Services said in a statement.

The bacteria are naturally found in warm waters, meaning people can be exposed when open wounds, cuts or scratches make direct contact with seawater or brackish water. Vibrio can also sicken people who eat raw or undercooked oysters and shellfish.

Two of the three deaths in July 2023 involved scratches exposed to brackish water in North Carolina and another East Coast state. The third case also involved exposure to brackish water in North Carolina and the person also consumed personally caught seafood that was not shared or commercially distributed.

No links were identified between the cases or the areas where they were likely exposed to Vibrio, and investigations are ongoing, officials said.

About 100 cases of Vibrio are reported in the United States each year, but because people with mild infections aren’t tested, the actual number isn’t known, according to the Journal of the American Medical Association. About a third of reported cases are fatal.

Of 47 Vibrio cases among North Carolina residents since 2019, eight have been fatal, health officials said. Vibrio infection reports associated with brackish water contact have increased in recent decades and the range of waters associated with infection has spread north due to increasing water temperatures, officials said.

In an effort to educate the public further on how to safely enjoy the water, the Dare County Department of Health and Human Services released a video with safety recommendations.

Following these recommendations will help reduce your likelihood of exposure and infection: 

  • If you have a wound (including from a recent surgery, piercing or tattoo), stay out of saltwater or brackish water, if possible. This includes wading at the beach.
  • Cover your wound with a waterproof bandage if it could come into contact with saltwater, brackish water or raw or undercooked seafood.
  • If you sustain any type of wound while in salt or brackish water (e.g., cutting your hand on a boat propeller or crab pot) immediately get out of the water and wash with soap and water. 
  • Wash wounds and cuts thoroughly with soap and water after contact with saltwater, brackish water or raw seafood.
  • Thoroughly cook all shellfish to an internal temperature of at least 145 degrees Fahrenheit for 15 seconds, according to the U.S. Department of Agriculture