Vibrio vulnificus is a bacterium in the same family as
those that cause cholera. It normally lives in warm
seawater and is part of a group of vibrios that are
called “halophilic” because they require salt.
What type of illness does V. vulnificus cause?
V. vulnificus can cause disease in those who eat eat
contaminated seafood or have an open wound that is
exposed to seawater.
Among healthy people, ingestion of V. vulnificus can cause:
immunocompromised persons, particularly those
with chronic liver disease, V. vulnificus can infect
the bloodstream, causing a severe and lifethreatening illness characterized by:
Fever and chills
Decreased blood pressure (septic shock)
Blistering skin lesions
V. vulnificus bloodstream
infections are fatal about 50% of the time.
V. vulnificus can also cause an infection of the skin
when open wounds are exposed to warm seawater;
these infections may lead to skin breakdown and ulceration.
Persons who are immunocompromised
are at higher risk for invasion of the organism into
the bloodstream and potentially fatal complications.
How common is V. vulnificus infection?
V. vulnificus is a rare cause of disease, but it is also
underreported. Between 1988 and 1995, CDC
received reports of over 300 V. vulnificus infections from the Gulf Coast states, where the majority of
There is no national surveillance system
for V. vulnificus, but CDC collaborates with the states of Alabama, Florida, Louisiana, Texas, and
Mississippi to monitor the number of cases of V.
vulnificus infection in the Gulf Coast region.
How do persons get infected with V.
Persons who are immunocompromised, especially
those with chronic liver disease, are at risk for V.
vulnificus when they eat raw seafood, particularly oysters.
A recent study showed that people with
these pre-existing medical conditions were 80 times
more likely to develop V. vulnificus bloodstream infections than were healthy people.
is frequently isolated from oysters and other
shellfish in warm coastal waters during the summer months. Since it is naturally found in warm marine
waters, people with open wounds can be exposed to
V. vulnificus through direct contact with seawater.
There is no evidence for person-to-person
transmission of V. vulnificus.
How can V. vulnificus infection be diagnosed?
V. vulnificus infection is diagnosed by routine stool,
wound, or blood cultures; the laboratory should be
notified when this infection is suspected by the physician, since a special growth medium can be
used to increase the diagnostic yield.
have a high suspicion for this organism when
patients present with gastrointestinal illness, fever,
or shock following the ingestion of raw seafood,
especially oysters, or with a wound infection after
exposure to seawater.
How is V. vulnificus infection treated?
V. vulnificus infection is treated with antibiotics.
Doxycycline or a third-generation cephalosporin
(e.g., ceftazidime) is appropriate.
Are there long-term consequences of V.
V. vulnificus infection is an acute illness, and those
who recover should not expect any long-term
What can be done to improve the safety of
Although oysters can be harvested legally only from
waters free from fecal contamination, even legally
harvested oysters can be contaminated with V. vulnificus because the bacterium is naturally present
in marine environments.
V. vulnificus does not alter
the appearance, taste, or odor of oysters.
Timely, voluntary reporting of V. vulnificus infections to
CDC and to regional offices of the Food and Drug
Administration (FDA) will help collaborative efforts
to improve investigation of these infections.
Regional FDA specialists with expert knowledge
about shellfish assist state officials with tracebacks of shellfish and, when notified rapidly about cases, are
able to sample harvest waters to discover possible
sources of infection and to close oyster beds when
problems are identified.
Ongoing research may help
us to predict environmental or other factors that
increase the chance that oysters carry pathogens.
How can I learn more about V. vulnificus?
You can discuss your medical concerns with your
doctor or other health care provider. Your local city
or county health department can provide
information about this and other public health
problems that are occurring in your area.