Vibrio bacteria live naturally in warm coastal waters. They enter the body through broken skin or by eating raw or under‑cooked seafood, especially shellfish. When the body’s defenses are weakened—such as in people with diabetes or liver disease—Vibrio can cause skin infections, sepsis, or gastrointestinal illness.

The most common species associated with human disease is Vibrio vulnificus, but Vibrio parahaemolyticus and Vibrio cholerae also pose risks. Symptoms range from mild abdominal pain to severe, potentially fatal systemic infections. Because the bacteria thrive in warm, brackish water, summer travel to the Gulf Coast or Southeast Asia heightens exposure.