Before You Swim or Slurp Oysters: Understand Vibrio Bacteria

Recently, there have been numerous reports of people becoming seriously ill after coming into contact with salt water along the East Coast—from Texas to Maine Sadly, some of these infections have resulted in loss of life or limb.

Liver disease — including fatty liver — increases the risk of a severe foodborne Vibrio infection from eating raw oysters. This risk is eliminated when oysters are thoroughly cooked or roasted.

The Culprit: Vibrio vulnificus

The bacteria Vibrio vulnificus thrives in warm salt water and brackish water (a mix of salt and fresh water). It’s naturally found in coastal waters, especially when temperatures rise.

Who Is at Risk?

Anyone with a weakened immune system or open wound is at risk for infection. Even a tiny cut can provide an entry point for the bacteria.

It’s especially risky to enter the water:

• If you have recent cuts, scrapes, or surgical wounds

• After tattoos or piercings

• When oyster shells or debris can cause unnoticed skin breaks

During the warmer months—May through October—water temperatures rise, allowing Vibrio to multiply rapidly. In coastal regions such as South Carolina, Georgia, and Florida, the bacteria may be present year-round but peak during these months.

Wound Safety

If you’ve had surgery or a recent wound, avoid salt or brackish water until the area is completely healed—which can take up to six weeks, depending on depth and tissue recovery. Even a small unhealed area can allow bacteria to enter and cause a serious infection.

Avoid contact with salt water—or any natural water—if you have an open wound.

Foodborne Vibrio: A Hidden Risk

By far the more common and bigger concern is Vibrio infections as a food-borne illness. Vibrio can also cause illness when eating raw or undercooked seafood, particularly oysters. Those with liver disease (such as cirrhosis and fatty liver) or weakened immune systems are at the greatest risk of severe illness. The old saying that you should “only eat oysters in months that contain the letter R” (September–April) reflects that cooler water months carry a lower risk—but the danger is never zero.

What the Numbers Say

There are actually many species of Vibrio bacteria. According to the CDC, about 80,000 Vibrio infections occur each year in the United States. Roughly 55,000 cases are foodborne, from eating contaminated seafood.The majority are mild, causing diarrhea, nausea, vomiting, stomach cramps, fever, and chills. However, Vibrio vulnificus infections can be devastating, leading to necrotizing (flesh-eating) infections, amputations, or death.

Infection Rate

Compared to 2024, the number of severe, life-threatening Vibrio infections appears to be about 25% lower in Florida in 2025. In contrast, Louisiana has seen more than double the number of cases this year. In South Carolina, infections remain sporadic, while Georgia continues to report none—with no confirmed cases in the past decade.

It raises an interesting question of whether the unique tidal swings and offshore currents along the Lowcountry coast may have a protective effect, reducing bacterial concentration near shore.

Based on the data available, it seems that the most severe Vibrio vulnificus cases are being somewhat sensationalized in the media. While these infections can be devastating, they remain relatively rare compared to the overall number of mild or foodborne Vibrio illnesses each year.