Home FAQs Reporting Investigation Immunization Resources
Vibrio vulnificus is the most important member of the Vibrio family due to the high fatality and invasiveness associated with infections. The bacteria exist naturally in marine and estuarine environments throughout the world, including the warm coastal waters and some inland brackish lakes of the United States and Canada. Like Vibrio parahaemalyticus, the bacteria infect marine fish and shellfish, especially oysters, from warmer waters.
Around half of Vibrio vulnificus illness is associated with wound and soft tissue infections that arise after the exposure of a new or pre-existing wound to warm marine, estuarine or brackish water. Infections also commonly occur after individuals have lacerated themselves on coral, rocks or while fishing, harvesting, processing and handling fresh seafood and their drippings.
Bloodstream infections, or primary septicemia, represent the other half of Vibrio vulnificus cases. These infections can occur in certain individuals who ingest contaminated/infected fish or seafood, primarily oysters, clams and crabs. Individuals at risk include those who have weakened immune systems, liver conditions or disease and iron-related disorders (such as hemochromatosis). Studies indicate these individuals are 80 times more at risk of developing severe infection.
Smaller numbers of gastrointestinal illness can occur after the consumption of infected/contaminated raw and improperly cooked, or cooked and then re-contaminated fish and shellfish, especially oysters. A higher risk of transmission has been linked to the warmer months of the year.
Illness onset can occur between 16 hours to 7 days after the consumption of contaminated food or exposure of a wound to contaminated water.
Wound infection symptoms include:
- Blistering and ulceration
- Swelling and reddening
- Fluid build-up
- Sepsis and shock
Symptoms of severe bloodstream infection in susceptible individuals can occur rapidly after ingestion and include:
- Sudden chills and fever
- Decreased blood pressure
- Skin lesions on the limbs and trunk of the body
The risk of severe complications and death in susceptible individuals who succumb to primary septicemia is high (50% mortality).
Gastrointestinal symptoms include:
- Abdominal pain
Illnesses caused by Vibrio vulnificus are either gastrointestinal in nature, associated with the consumption of raw, undercooked or contaminated cooked seafood, especially oysters; or wound related, due to the exposure of a new or pre-existing wound to marine, estuarine and brackish waters.
General recommendations for avoiding Vibrio vulnificus gastrointestinal illness and severe infection in susceptible individuals:
- Implement refrigeration of seafood from harvesting/purchase to consumption.
- Avoid the consumption of raw seafood, especially oysters, if:
- They have come from coastal waters during the warmer months of the year
- You have a weakened immune system, liver disease/condition or an iron-related disorder
- When preparing oysters, mussels or other molluscan shellfish –
- Before cooking, discard any opened shells
- Boil, broil or fry (at 375°F) for at least 3-5 minutes
- Bake at 450°F for 10 minutes
- As a rule – discard any unopened shells after cooking
- Only eat seafood or shellfish that is thoroughly cooked until steaming hot.
- Eat shellfish immediately after cooking and refrigerate leftovers.
- Avoid cross contaminating raw juices from seafood with other foods, and immediately cleanup any spills with hot water and soap and clean rinsing water.
- Keep raw seafood separate from other food.
- Thoroughly wash hands, utensils and surfaces after preparing or handling raw seafood.
General recommendations for avoiding wound infections:
- Do not handle raw seafood of any kind if you have a pre-existing wound.
- Wear protective clothing (ie. Gloves) when handling raw seafood.
- Avoid marine, estuarine or brackish (sea/ocean) water if you have a pre-existing wound.
- If you sustain a wound or injury while exposed to salty seawater or while handling seafood, thoroughly clean and disinfect the area immediately and seek medical attention if the area becomes inflamed.
Recent Texas Trends
The annual number of cases of Vibrio vulnificus infection over the last decade in Texas range in number from 15 to 30. The majority of primary septicemia cases of Vibrio vulnificus infection have been linked to the consumption of shellfish, mainly oysters. Infections also appear to be seasonal in nature, with most occurring between May and October.