Travel Advisory: Raw Oyster-Associated Vibrio Parahaemolyticus Risk
- Denby Williams
- 1 minute ago
- 3 min read
Pensacola, a city located on the Florida panhandle in the United States. Given that it's the only city in Escambia County, Pensacola attracts a large number of tourists during the warmer months. One of these tourists includes Dallas native, Rodney Jackson, who joined roughly 80,000 illnesses and 100 deaths annually in the United States; unfortunately passing in 2022 after buying oysters from a seafood market. The cause of this is the bacteria Vibrio Parahaemolyticus.
WHAT IS IT?
As observed by the previous statistic, while Vibrio parahaemolyticus causes a large amount of sickness, it is rare that the bacteria will evolve to something fatal. From an epidemiological standpoint, cases are seen to peak during the month of July, with this 2013 epi curve illustrating the peaks from mid-to-late July in particular. While the bacteria are steadily on the rise in the United States, with an incidence rate of 0.45 cases per 100,000, it is more prevalent in Japan.
Vibrio parahaemolyticus is a bacterial species found in the coastal marine and estuarine waters. It is a member of the Vibrio genus, most notably "Vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio fischeri." (Yildiz, Visick 2009). It measures 0.5-0.8 pm in width and 1.4-2.4 pm in length, with curved or comma-shaped rods. The bacteria are highly motile, meaning the microorganism can propel itself independently using purely metabolic energy. As seen by the illustration, it possesses a single polar flagellum.
INFECTION
Given that the bacteria are found in seawater, infection begins when the individual eats contaminated raw or undercooked seafood. It is important to note, however, that fully cooked seafood can be contaminated simply by rinsing it with seawater.
There are two known points of entry: ingestion of contaminated seafood and open wound exposure with saltwater. For our case, we will be elaborating on oyster consumption in particular. Once the bacteria are ingested, it advances through a process called bile sensing. Produced by the liver and stored by the gallbladder, bile is released during fat emulsification and digestion. Vibrio parahaemolyticus senses the bile, and then 'attacks' by activating its mechanism in which the bacteria adhere with proteins to the intestinal lining. Pores are then formed in the lipid membrane of intestinal cells, allowing the toxin Thermostable direct hemolysin (TDH) to enter and "causes cells toxicity and forms a channel in the cell membrane, which induces an increase in the in the extracellular Ca2+ concentration and CI- secretion." (Matsuda et al., 2010) While this accounts for the majority of infections, there is a small percentage (specifically TDH-related hemolysin) that contributes to clinical manifestations as well.
SYMPTOMS
Once the bacteria enter the system via consumption of seafood, gastrointestinal symptoms appear within 12 to 24 hours. Symptoms of Vibrio parahaemolyticus infection may include:
abdominal cramps
watery diarrhea
nausea
vomiting
fever
chills
headache
It is also important to note that in severe cases, an individual may develop dehydration due to rapid loss of fluids.
While the average duration is 3 days, illness can last from 1 to 7 days total. For mild infections, treatment can be at home with adequate rest and hydration; however, in severe cases, hospitalization with antibiotics and intravenous fluid rehydration will be required.
PREVENTION
Means of prevention for Vibrio parahaemolyticus are satisfactory cooking conditions. These conditions include thoroughly cooking seafood, with instructions provided by The Massachusetts Department of Public Health stating, "Wash your hands with soap and water after handling raw shellfish. Keep raw foods from touching cooked foods and surfaces used for cooking and eating." Below are specified cooking preparations
Preparing oysters and other shellfish in the shell:
Before cooking, discard any shellfish with open shells
During cooking, boil on high for 3-5 minutes after shells open, or add to a steamer when water is already steaming and cook for another 4-9 minutes
After cooking, discard any with shells that did not open
Preparing shucked oysters:
Boil or simmer for at least 3 minutes
Fry at 375 degrees Fahrenheit for at least 3 minutes
Broil 3 inches from heat for 3 minutes
Bake at 450 degrees Fahrenheit for 10 minutes
As the summer season begins, and tourists flock to seaside resorts, it is important to continue public awareness; whether this be in maintaining safe seafood handling, proper cooking practices, and prompt recognition of symptoms.
REFERENCES:
doi:10.3389/fmicb.2015.00144
Assessed and Endorsed by the MedReport Medical Review Board