Vibrio vulnificus (Warm Seawater Bacteria Infection)

What is Vibrio vulnificus?

Vibrio vulnificus is a bacterium that normally lives in warm seawater and is part of a group of vibrios that are called "halophilic" because they require salt.

How do persons get infected with Vibrio vulnificus?

People can get infected with Vibrio vulnificus when they eat raw shellfish, particularly oysters. Occurring naturally in the warm coastal waters, particularly during the summer months, Vibrio vulnificus has the potential to cause serious illness. Persons who have wounds, cuts or scratches and wade in estuarine areas or seawater where the bacteria might be present can become ill. There is no evidence of person-to-person transmission of Vibrio vulnificus.

What type of illness does Vibrio vulnificus cause?

Symptoms of Vibrio vulnificus in wound infections typically include swelling, pain and redness at the wound site. Other symptoms of Vibrio vulnificus infection include; nausea, vomiting, abdominal pain, diarrhea, fever, chills and the formation of blistering skin lesions. Individuals experiencing these symptoms should contact a physician immediately for diagnosis and treatment.

Individuals with liver disease, including Hepatitis C and cirrhosis, are most at risk for developing serious illness from Vibrio vulnificus obtained from eating raw oysters. Others who should avoid consuming raw shellfish are those with hemochromatosis (iron overload), diabetes, cancer, stomach disorders or any illness or treatment that weakens the immune system. Thoroughly cooking oysters, either by frying, stewing, or roasting eliminates harmful bacteria and viruses in the meat. Consuming raw oysters that have undergone a post-harvest treatment process to eliminate the bacteria can also reduce the risk of illness.  

How common is Vibrio vulnificus infection?

Vibrio vulnificus is a rare cause of disease, but it is also underreported. Between 1988 and 2006, the Centers for Disease Control and Prevention (CDC) received reports of more than 900 Vibrio vulnificus infections from the Gulf Coast states, where most cases occur.  Before 2007, there was no national surveillance system for Vibrio vulnificus, but CDC collaborated with Alabama, Florida, Louisiana, Texas and Mississippi to monitor the number of cases in the Gulf Coast region.  In 2007, infections caused by Vibrio vulnificus and other vibrio species became nationally notifiable.

A total of 45 cases of Vibrio vulnificus were reported during 2015 resulting in 14 deaths. For the latest information, please go to the Florida Department of Health’s online newsroom information page at http://www.floridahealth.gov/diseases-and-conditions/vibrio-infections/vibrio-vulnificus/.

What are some tips for preventing Vibrio vulnificus infections?

  • Do not eat raw oysters or other raw shellfish.
  • Cook shellfish (oysters, clams, mussels) thoroughly.
  • For shellfish in the shell, either a) boil until the shells open and continue boiling for 5 more minutes or b) steam until the shells open and then continue cooking for 9 more minutes. Do not eat those shellfish that do not open during cooking. Boil shucked oysters at least 3 minutes or fry them in oil at least 10 minutes at 375°F.
  • Avoid cross-contamination of cooked seafood and other foods with raw seafood and juices from raw seafood.
  • Eat shellfish promptly after cooking and refrigerate leftovers.
  • Avoid exposure of open wounds or broken skin to warm salt or brackish water, or to raw shellfish harvested from such waters.
  • Wear protective clothing (e.g., gloves) when handling raw shellfish.

For more information on care and treatment specifics, please visit the CDC’s website.

For general food safety questions, call the FDA Food Safety Hotline at 1-888-723-3366.

If the situation is critical, phone the FDA's emergency number at 301-796-8240 or 1-866-300-4374, which is staffed 24 hours a day.  More on food safety can be found at http://www.foodsafety.gov.

The sources for the information in this document are the Florida Department of Health and the Centers for Disease Control and Prevention. To learn more, visit their websites at http://www.floridahealth.gov/diseases-and-conditions/vibrio-infections/vibrio-vulnificus/  and http://www.cdc.gov/vibrio/vibriov.html or call your local county health department.

Symptoms of Vibrio vulnificus in wound infections typically include swelling, pain and redness at the wound site. Other symptoms of Vibrio vulnificus infection include; nausea, vomiting, abdominal pain, diarrhea, fever, chills and the formation of blistering skin lesions. Individuals experiencing these symptoms should contact a physician immediately for diagnosis and treatment.

Individuals with liver disease, including Hepatitis C and cirrhosis, are most at risk for developing serious illness from Vibrio vulnificus obtained from eating raw oysters. Others who should avoid consuming raw shellfish are those with hemochromatosis (iron overload), diabetes, cancer, stomach disorders or any illness or treatment that weakens the immune system. Thoroughly cooking oysters, either by frying, stewing, or roasting eliminates harmful bacteria and viruses in the meat. Consuming raw oysters that have undergone a post-harvest treatment process to eliminate the bacteria can also reduce the risk of illness.