Warm Waters, Hidden Risk: How to Protect Against Flesh-Eating Bacteria

Warm coastal waters are creating conditions that can help Vibrio vulnificus, a potentially dangerous bacterium, spread into new areas.

Although infections remain rare, the illness can become severe quickly, making awareness and prevention especially important for people who swim in coastal waters or eat raw shellfish.

What makes Vibrio vulnificus dangerous?

Vibrio vulnificus can enter the body through cuts, sores or other breaks in the skin. In some cases, the infection can lead to necrotizing fasciitis, a rare condition in which bacteria damage tissue beneath the skin.

The infection can progress rapidly and may require urgent medical treatment. Vibrio vulnificus can also cause serious illness when contaminated raw or undercooked shellfish is consumed.

How does infection occur?

The bacterium is most commonly found in warm seawater and brackish water, where freshwater and seawater mix. Infections are more common during warmer months.

People can be exposed while swimming, fishing or wading if contaminated water comes into contact with an open wound. Handling raw seafood with an uncovered cut can also provide a route for infection.

Eating raw or undercooked shellfish, particularly oysters harvested from contaminated waters, can cause illness.

Why are cases being reported in more places?

Rising ocean temperatures are expanding the environments where Vibrio vulnificus can survive. The bacterium has increasingly been detected in coastal areas farther north than traditionally associated with it.

Climate-related changes can also increase exposure. Storms, hurricanes and coastal flooding can push people into contact with warm seawater or brackish water, potentially increasing the risk of infection.

Certain groups are particularly vulnerable to severe illness, including older adults and people with conditions or treatments that weaken the immune system. Liver disease, diabetes, cancer and HIV are among the factors associated with higher risk.

What symptoms should you watch for?

An infected wound may initially become painful, red, swollen or warm, and fever can develop. Because serious soft-tissue infections can worsen rapidly, anyone developing concerning symptoms after exposure to coastal or brackish water should seek medical attention promptly.

Treatment may involve antibiotics and, in severe cases, surgery to remove infected tissue. Early medical care is important because delaying treatment can allow the infection to spread.

How can you reduce the risk?

• The safest approach is to prevent contaminated water or seafood from coming into contact with broken skin.
• Avoid swimming or wading in potentially contaminated coastal or brackish water if you have an open wound, including a fresh piercing or tattoo.
• If you cannot avoid exposure, keep wounds completely covered with a waterproof bandage.
• Wash cuts or wounds thoroughly with soap and clean water after contact with seawater or brackish water.
• Avoid handling raw seafood if you have an open wound.
• Cook shellfish thoroughly instead of eating it raw or undercooked.
• Take extra precautions if you have health conditions that increase the risk of severe infection.

Vibrio vulnificus infections remain uncommon, but their potential severity means basic precautions are worthwhile, particularly during periods of unusually warm coastal water. Prompt medical attention is important if concerning symptoms develop after exposure.