In a viral TikTok video with 2.2 million views, TikTok user @malamamaofficial opens a $1 Whole Foods bag of raw oysters, revealing a pea crab in one of the shells. “This is why it’s $1,” the TikTok user says as she digs into the oyster. “It’s a parasite crab!”
Although pea crabs can be eaten with oysters, there might be a bigger concern found in your favorite seafood.
In a now-viral video made in response to the first one, Morticia, a microbiologist in Boise, Idaho, who worked on research under grants from the United States Department of Agriculture and the National Institutes of Health, shares the risks associated with eating oysters ― or any seafood ― as oceans get warmer as a result of climate change. One of the rising concerns Morticia (who asked to use a pseudonym because of digital safety) mentions is an increase in Vibrio vulnificus, a bacteria found in marine environments.
Vibrio vulnificus can make its way into the body through eating raw or uncooked seafood, or exposing a wound to seawater where the bacteria is found.
“Oysters are especially susceptible because they are filter feeders, so this bacteria can travel through into the organism and just kind of get stuck in its tissue,” she says in the video. “You cannot tell if an oyster is contaminated with Vibrio bacteria by looking at it.”
The bacteria doesn’t make the oyster look, smell or taste any different, which makes it hard to tell you’ve been exposed to Vibrio until you start experiencing symptoms. Although rates of infection are low overall, oysters have the highest amount of seafood related deaths in the U.S.
“If you are healthy and what we call ‘immunocompetent,’ which really just means your immune system is able to work properly and eliminate infections, your body will be able to clear the infection without a hospital visit or antibiotics. But in the context of a tissue infection or someone who already has a compromised immune system, these infections can quickly turn fatal,” Morticia told HuffPost. “This is where that high mortality rate we associate with Vibrio infections comes from.”
The most recent outbreak was in 2019, causing gastrointestinal illnesses linked to oysters imported from Mexico. (No deaths were reported.) Climate change ― which is causing a rise in sea temperature ― has caused an increase in bacteria in water, leading to more cases of the infection.
While you may not need to stop eating fresh oysters entirely, there are still important factors to consider. We asked general physicians, microbiologists and seafood distributors about the risks of consuming the shellfish, symptoms of Vibrio infection and treatment options. Here’s what to know:
Symptoms of Vibrio vulnificus include gastrointestinal problems and even sepsis.
Oysters are filter-feeders, so when bacteria attach to particles and other organisms in the water that then pass through the oyster, the shellfish can accumulate a concentration of bacteria up to 100 times that of surrounding waters. Since oysters are typically eaten raw, the infection risk is higher compared to eating cooked or boiled seafood.
As a result, there are an estimated 84,000 people in the U.S. who contract an infection from Vibrio every year. Timothy J. Sullivan, the national program leader at Animal Health and Aquaculture, a division of the USDA National Institute of Food and Agriculture, explained the differences between symptoms among healthy and immunocompromised people.
“It typically results in mild GI distress with healthy individuals experiencing fever, chills, cramping, diarrhea or nausea within 48 hours of ingestion,” he said. “Mortality is extremely rare in healthy individuals, but for individuals with certain medical conditions, it can cause severe side effects.”
Immunocompromised people are more vulnerable to infections, and since the immune system plays a role in defending the body from bacterial, fungal, parasitic and viral infections, this puts them at a higher risk for complications, one of which is sepsis.
Primary sepsis, or the body’s extreme response to an infection, appears in about 60% of Vibrio cases. People with certain illnesses ― including people with chronic liver disease, diabetes, cancer, renal disease, HIV or other immunocompromised conditions ― can more easily get sepsis, which can rapidly lead to tissue damage and organ failure if left untreated. Infections can progress rapidly when symptoms are severe. When gastrointestinal symptoms are completely absent — which happens in about 10 to 15% of people with the infection — cases of sepsis and death are minimal.
If you’re an oyster fan, there are ways to reduce your risk.
Almost all of Vibrio infections stem from eating raw or uncooked oysters. As a result, several regulations have been placed to reduce risk through sanitation. The National Shellfish Sanitation Program, recognized by the Food and Drug Administration, ensures that shellfish-producing states are following safety guidelines, including certification, handling and process procedures.
However, harvesting regulations do not eliminate the risk of Vibrio. As a result, shellfish states are providing customers with warning about infection risk. You may be able to find these on seafood packaging and menus.
Christina Z. (who asked to keep her full name private for her job), a third-generation seafood industry professional and a seafood wholesale distributor, told HuffPost that eating oysters, whether from a grocery store or a high-end restaurant, doesn’t change how the seafood is prepared. In a viral video she posted on TikTok, she shared that she would never eat raw shellfish.
“As long as the oyster is eaten raw, the risk remains the same. Restaurants and grocery stores are both held to high standards to responsibly buy from reputable distributors and maintain the cold chain preventing any spoilage,” Christina said. “However, the preparation method to reduce the risk is key. Raw/uncooked oysters will always present the highest risk. If oysters are a must, opt for them steamed or baked.”
If you’re going to eat oysters, it’s important to take note as to how the shellfish was prepared and where it comes from.
“Some safe seafood practices I would recommend is to buy most of your seafood flash frozen at sea if available,” Christina said. “This maintains the integrity and peak freshness of the seafood, kills any living parasites and prevents the conditions needed for bacterial growth after the catch. However, if you do buy fresh, make sure to buy from a reputable monger who can tell you when the seafood was caught, and consume within one to two days after your purchase.”
All coastal waters contain Vibrio bacteria. However, infections from Vibrio species are on the rise, and as mentioned, climate change can increase cases.
“Most bacteria relevant for human disease love warmth, and they need it to proliferate. Vibrio already likes heat. It lives in warm, coastal seawater,” Morticia said. “As those waters get warmer because of a warming planet and climate change, they’re not going to only grow to higher numbers in that water, they’re also going to spread to new places as oceans that were once on the colder side become more temperate.”
There’s always a risk associated with eating raw oysters, Sullivan said. However, preventing consequences can start with preparation, knowing where your oysters come from, and recognizing symptoms of infection.