U. S. Food and Drug Administration
Center for Food Safety and Applied Nutrition
FDA Prime Connection

Oysters Processors Section of the SE Fishers Association - Vibrio vulnificus
 
 
                              Vibrio vulnificus
 
 
The impetus for this brochure was initiated by the Oyster Processors Section of
the Southeastern Fisheries Association, Tallahassee, FL with support from the
Gulf and South Atlantic Fisheries Development Foundation, Inc., Tampa, FL and the
U.S. Department of Agriculture's Cooperative Extension Service.
 
SGEF-10 - Reproduced December, 1989 from the initial production July, 1988.
 
 
 
This information is meant for certain individuals who are at a higher risk for
infections from a bacterium of public health significance in our coastal waters.
The bacterium, Vibrio vulnificus (Vib-'re-o vul-nif'-e-kus) has probably always
been a part of our marine environment, but increasing scientific investigations
and medical knowledge have raised concerns for its occurrence in coastal waters
and certain raw foods.
 
What is Vibrio vulnificus?
 
Vibrio vulnificus is a bacterium that can be found in warm coastal waters most
common about the Gulf of Mexico, but it also has been found in water samples from
both the Atlantic and Pacific coasts. It occurs naturally, rather than as a
result of pollution. Thus Vibrio vulnificus is often present in clean waters,
including those that are approved for the harvest of oysters and clams. Little
else is known about the organism, but reports of illnesses and infections
associated with this bacterium are most prevalent during warm months of the year,
primarily April through October, leading scientists to believe there might be a
correlation between the bacterium's presence and seawater temperatures.
 
Concern for Vibrio vulnificus exists because certain people who eat raw molluscan
shellfish or expose open wounds to warm seawater can develop a severe and
potentially fatal infection. Most people's immune systems are able to ward off
these infections; however, certain conditions do put some individuals in a "high
risk" category. People in the high risk category must consider diet modifications
and general changes in life style in order to maintain good health.
 
Conditions for "high risk" category
 
    <*> Liver disease including cirrhosis and hemochromatosis
    <*> Chronic alcohol use
    <*> Cancer (especially if taking anti-cancer drugs or radiation treatment)
    <*> Lymphoma, leukemia, AIDS, Hodgkin's disease
    <*> Diabetes mellitus
    <*> Chronic kidney disease
    <*> Inflammatory bowel disease (or any person receiving immunosuppressive
        drugs)
    <*> Steroid dependency (as used for conditions such as chronic obstructive
        pulmonary disease, etc.)
    <*> Achlorhydria (a condition in which the normal acidity of the stomach is
        reduced or absent)
    <*> Medicines that reduce stomach acid
 
How can people in this "high risk" category avoid Vibrio vulnificus?
 
Vibrio vulnificus infections are either transmitted to humans through open wounds
in contact with seawater or through consumption of certain improperly cooked or
raw shellfish. Studies have shown that Vibrio vulnificus is most likely to be
present during warm months (April-October).
 
1. Avoid exposure of recent or healing wounds, cuts, punctures, burns, etc. to
warm seawater. When swimming or wading, temporarily cover the wound with a water
tight wrap. The Vibrio vulnificus lives naturally in warm seawater, can enter a
person's wound and, in some cases, extend to the bloodstream and cause a
potentially fatal illness. The highly invasive nature of this bacterium is cause
for special concern.
 
2. Consumers in high risk categories should avoid consumption of raw shellfish,
particularly oysters. Oysters are filter feeding animals that can concentrate
Vibrio bacteria from the water into their system. This concern exists for any raw
oysters regardless of harvest from approved or questionable waters.
 
3. When eating shellfish, particularly oysters, be sure that they are properly
and thoroughly cooked. Thorough cooking kills the Vibrio bacteria and markedly
reduces the risk of becoming ill. Steaming to open the oyster shells or blanching
the shellfish does not always provide enough heat to kill all the Vibrio
bacteria. Additional heating is necessary to impart a noticeable cooked
appearance.
 
4. Avoid cross-contamination of previously cooked shellfish with raw shellfish.
A common cause of cross-contamination is storing cooked shellfish in the original
container used for raw shellfish, or storing raw and cooked shellfish in the same
area.
 
What are the chances for an infection?
 
Rare! Most healthy individuals are not troubled by Vibrio vulnificus infections
from water or food. Also, extensive federal and state regulatory programs monitor
the production and marketing of raw shellfish to assure product safety.  Thus,
the Vibrio vulnificus problem is primarily restricted to individuals in the risk
categories. These individuals should restrict consumption of raw shellfish.
 
This text was a collaborative effort of the following professionals who can be
reached for more advice.
 
Dietetics, Microbiology, and Commercial Concerns
Christine Anderson, Ph.D., R.D.*
W. Steven Otwell, Ph.D.
Gary Rodrick, Ph.D.
Food Science & Human Nutrition Dept.
University of Florida
Gainesville, FL 32611
(904) 392-1991
 
Medical Advice
Richard Howard, M.D., Ph.D.
College of Medicine
Dept. of Surgery, J-286
University of Florida
Gainesville, FL 32610
(904) 392-1300
 
State Regulations
John Schneider, Chief*
Bureau of Marine Resource
Regulation and Development
3900 Commonwealth Blvd.
Fla. Dept. of Natural Resources
Tallahassee, FL 32399
(904) 488-5471
 
Epidemiology
Karl C. Klontz, M.D., M.P.H.*
E.I.S. Officer
Dept. Health and Rehabilitative Services
Disease Control Epidemiology Section
1317 Winewood Blvd.
Bldg. 6, Room 466
Tallahassee, FL 32399-0700
(904) 488-2905
 
* Individuals reassigned as of the reproduction of this brochure, December 1989.
 
                                                                    (06/09/95)