The short version
- Vibrio vulnificus is a bacterium of warm, low-salt seawater; a cut that meets that water can become a fast, deep infection[2].
- CDC surveillance counted 2,989 US cases from 2000 to 2022: 83% went to hospital and 23% died[1].
- Wound infections in the eastern US rose eightfold from 1988 to 2018, and the northern edge moved about 48 km a year[2].
- Speed decides it: reaching hospital more than 2 days after symptoms nearly tripled the odds of death[3].
What Vibrio vulnificus does, and how people catch it
There are two routes: eating raw or undercooked shellfish, and seawater getting into a wound[1]. Wound cases are the more common route, while eating it is the deadlier one[1].
| US cases, 2000 to 2022[1] | Share of cases | Death rate |
|---|---|---|
| Not from food (mostly wounds) | 54% (1,619) | 12% |
| From food | 22% (656) | 40% |
| All cases | 2,989 | 23%; 83% hospitalized |
Older CDC data shows where the food cases come from: 96% of bloodstream infections followed raw oysters, and 89% of traced oysters came from Gulf of Mexico water above 22 °C[4]. Cases grew 70% between 2000 to 2004 and 2018 to 2022[1].
What a Vibrio wound infection looks like
| Wound infections from seawater, 1997 to 2006[3] | Share of patients |
|---|---|
| Cellulitis (red, hot, swollen skin) | 85% |
| Fever | 72% |
| Amputation | 10% |
| Death | 17% |
| Lived in a Gulf Coast state | 72% |
In a Taiwan series of 67 patients with flesh-destroying Vibrio infection, 74.7% started in the arm or hand[6]. Patients treated late had more fever, blood-filled blisters and shock[6]. For a deckhand, that means cuts from fish, crab shells, hooks and gear, made or soaked in warm brackish water.
Who is most at risk
Liver disease or heavy drinking raised the odds of death 6.5 times in the 2000 to 2022 data[1], and 7.8 times in the earlier wound data[3]. In the Taiwan surgical series, 40% had liver disease and 25.4% chronic kidney disease[6]. Antibiotic treatment cut the odds of death by two thirds[1]. The CDC authors advise warning people with liver disease about seawater exposure when they have an open wound[3].
The clock: why hours matter
| Evidence | Finding |
|---|---|
| CDC wound data, 1997 to 2006[3] | Hospital more than 2 days after symptoms: odds of death 2.9 times higher |
| Taiwan, 67 patients[6] | Surgery within 24 hours of injury: 4.9% died, against 23% later |
| Taiwan, 121 patients[5] | 29% died overall; surgery within 12 hours of admission carried the lowest risk |
| 2025 review[7] | Treatment is doxycycline with a third-generation cephalosporin, plus prompt surgery for flesh-destroying infection |
What to do on board
- Clean every cut with fresh water and soap and cover it before going back to work in seawater or the catch.
- Ask about liver disease, diabetes and drinking when a crew member has a cut; those are the crew at highest risk[1].
- Check the wound every few hours for spreading redness, swelling, fever or blisters[3][6].
- Call for radio medical advice at the first sign and say “seawater wound, possible Vibrio”; antibiotics only as the physician directs[7].
- Decide on evacuation early. Reaching hospital more than 2 days after symptoms began nearly tripled the odds of death[3]. Log it in the medical log.
When a seawater wound is an emergency
Fever, blood-filled blisters or signs of shock after a seawater cut need hospital care now: in the Taiwan series those signs came with late surgery, and late surgery came with a death rate of 23%[6]. At sea, start the medevac decision immediately.
It is moving north
The 2023 climate study projects that by 2041 to 2060 wound infections may reach the New York area, and by 2081 to 2100 every eastern US state under medium to high warming[2]. Crews on Atlantic boats can no longer treat Vibrio as a Gulf problem. Related: fish handler’s disease, stingray sting, degloving injury and marine animal injury statistics.
On Gulf and southern Atlantic boats, a seawater cut on the wrong crew member is a timed emergency, so the plan should exist before the season. Discovery Health MD writes it: maritime medical consulting for the wound infection and evacuation protocol, and ship medical chest management for the dressings and antibiotics it calls for. Ask a physician to review your fleet’s wound infection plan.
Common questions
What is Vibrio vulnificus?
A bacterium of warm, low-salt seawater that infects wounds and people who eat raw shellfish[1][2].
How deadly is Vibrio vulnificus?
23% of 2,989 US patients died from 2000 to 2022; 40% of foodborne and 12% of other cases[1].
How do you get Vibrio from the ocean?
Seawater in a cut or scrape; wound infections from seawater have a death rate near 18%[2].
What are the first signs of a Vibrio wound infection?
Red, hot, swollen skin in 85% of cases and fever in 72%[3].
Who is most at risk from Vibrio vulnificus?
People with liver disease or heavy drinking, whose odds of death were 6.5 times higher[1].
How is Vibrio vulnificus treated?
Doxycycline with a third-generation cephalosporin, and prompt surgery when flesh is dying[7].
Where does Vibrio vulnificus occur in the US?
Mostly the Gulf Coast, where 72% of wound patients lived, and it is spreading north along the Atlantic[3][2].
