Summary
The Centers for Disease Control and Prevention (CDC) is issuing this Health Alert Network (HAN) Health Advisory to:
- Notify healthcare providers, laboratories, and public health departments about recent reports of fatal Vibrio vulnificus (V. vulnificus ) infections, including wound and foodborne infections.
- Urge healthcare professionals to consider V. vulnificus as a possible cause of infected wounds that were exposed to coastal waters, particularly near the Gulf of Mexico or East Coast, and during periods with warmer coastal sea surface temperatures.
- Share important guidance for managing V. vulnificus wound infections.
Background
Vibrio are bacteria that cause an estimated 80,000 illnesses each year in the United States. About a dozen species of Vibrio are pathogenic to humans. V. parahaemolyticus causes the most infections in the United States, accounting for about 40% of reported cases of vibriosis, followed by V. alginolyticus, which accounts for about 20%. Most people with Vibrio infection have diarrhea. Some people might also have stomach cramping, nausea, vomiting, fever, and chills. One species, V. vulnificus, is known to cause life-threatening infections. About 150–200 V. vulnificus infections are reported to CDC each year and about one in five people with this infection die—sometimes within 1–2 days of becoming ill.
Vibrio naturally live in coastal waters, including salt water and brackish water, which is a mixture of salt water and fresh water. Most people get infected with Vibrio by eating raw or undercooked shellfish, particularly oysters. Some people get infected when an open wound is exposed to salt water or brackish water containing Vibrio [1]. People can also get infected if an open wound comes in contact with raw or undercooked seafood. Open wounds include those from a recent surgery, piercing, tattoo, and other cuts or scrapes—including those acquired during aquatic activity. Extreme weather events, such as coastal floods, hurricanes, and storm surges, can force coastal waters into inland areas, putting people that are exposed to these waters—especially evacuees who are older or have underlying health conditions—at increased risk for Vibrio wound infections. This effect was observed in Florida after Hurricane Ian in 2022 [2].
Unlike other Vibrio species, V. vulnificus is primarily transmitted through open-wound contact with salt water or brackish water, but occasionally (in approximately 10% of cases) the bacteria also can infect people if they eat raw or undercooked shellfish. Person-to-person transmission has not been reported. People at higher risk for wound infection include those with underlying health conditions such as liver disease, diabetes, and immunocompromising conditions [3]. V. vulnificus wound infections have a short incubation period and are characterized by necrotizing skin and soft tissue infection, with or without hemorrhagic bullae. Many people with V. vulnificus wound infection require intensive care or surgical tissue removal.
V. vulnificus bacteria thrive in warmer waters—especially during the summer months (May to October) and in low-salt marine environments like estuaries. In the United States, V. vulnificus infections have been most commonly reported by Gulf Coast states. However, V. vulnificus infections in the Eastern United States increased eightfold from 1988–2018, and the northern geographic range of infections has increased 48 km per year [4]. During July–August 2023, the United States has experienced above-average coastal sea surface temperatures and widespread heat waves [5]. During the same period, several East Coast states, including Connecticut, New York, and North Carolina, have reported severe and fatal V. vulnificus infections. Many of these infections were acquired after an open wound was exposed to coastal waters in those states. Some of these infections were associated with consumption of raw or undercooked seafood or had unclear etiology.
Amid increasing water temperatures and extreme weather events (e.g., heat waves, flooding, and severe storms) associated with climate change [6], people who are at increased risk for V. vulnificus infection should exercise caution when engaging in coastal water activities. Prompt treatment is crucial to reduce mortality from severe V. vulnificus infection. CDC continues to monitor reports of V. vulnificus infections.