A Pearl of Wisdom, Prevent Vibrio
Don’t Eat Raw Oysters!
What is Vibrio?
Vibrio is a genus of bacteria that can cause foodborne
illness usually associated with eating contaminated undercooked or raw
shellfish such as oysters, mussels, clams, crabs and scallops. Strains
of Vibrio usually cause gastroenteritis (abdominal pain, nausea,
vomiting and diarrhea) but can also infect open wounds, causing serious,
possibly fatal infections. Exposure of wounds to contaminated seawater
may occur with injury from contaminated seashells or barnacles. Vibrio
septicemia is a serious, possibly fatal blood infection that may result
from ingesting raw or undercooked seafood or from wound infection.
The Centers for Disease Control & Prevention estimates that 80,000
Vibrio infections (200 V. vulnificus, 45,000 V. parahaemolyticus, and
35,000 Vibrio species) and approximately 100 deaths related to Vibrio
infections may occur annually in the United States.
Two Types of Vibrio
V. parahaemolyticus is the leading
cause of seafood-associated gastroenteritis in the United States.
It’s found in warm coastal waters, particularly states bordering the
Gulf of Mexico, because the bacilli multiply better when water
temperatures exceed 70° in the summer. Most cases of illness occur
between April and October.
In Florida, most people become infected with V. parahaemolyticus by
eating raw oysters. To prevent Vibrio infection in high-risk groups,
Florida requires warning notices everywhere raw oysters are sold.
High-risk groups include people with underlying health problems such
as liver disease. These individuals are urged to eat only fully
V. vulnificus is found in the warm coastal waters
bordering the Gulf of Mexico, where the water temperature exceeds
70°. During the warmer months, the concentration of bacteria can be
high and most cases of illness occur between April and October. Of
all the Vibrio infections reported in Florida’s residents and
tourists alike, V. vulnificus causes the most severe disease and
kills the most people.
Most people become infected with V. vulnificus by eating raw or
undercooked seafood, especially oysters. People with cirrhosis who
consumed raw oysters were 80 times more likely to develop V.
vulnificus infection and 200 times more likely to die of the
infection than those without liver disease who consumed raw oysters.
People may also become infected with V. vulnificus through wound
infections causing serious, possibly fatal illness.
Vibrio gastroenteritis is self-limited and no specific medical
treatment is required. Antibiotics do not shorten the course of the
illness and are not recommended. As in most vomiting and diarrhea
illnesses, fluid replacement is important.
Vibrio septicemia, (blood infection) is a more serious illness.
Individuals with Vibrio septicemia frequently have other serious
health problems such as liver disease, high alcohol consumption,
diabetes, or AIDS. Medical treatment consists of prompt initiation
of antibiotic therapy, fluid replacement and aggressive treatment of
wound infections, including amputation if necessary. Wound
infections of the limbs can be serious and may be fatal. .
In an effort to prevent Vibrio infections,
all restaurants in Florida are required by law to display
“either on menus, table placards, or elsewhere in plain view
of all patrons”, the following notice:
There is risk associated with eating raw oysters. If you
have chronic illness of the liver, stomach or blood, or have
immune disorders, you are at greater risk of serious illness
from raw oysters, and should eat oysters fully cooked. If
unsure of your risk, consult a physician.
You may not find a pearl in your oyster, but a
pearl of wisdom is more valuable: “avoid Vibrio illnesses, don’t eat raw
For More Information:
From the Palm Beach County Health Dept.
Epidemiology & Disease Control.