California freshwater fish found to be teeming with parasites. How to keep from getting sick
LOS ANGELES - More than 90% of popular freshwater fish in Southern California are carrying human-infecting parasites, researchers say. This poses a significant danger for those who like to eat freshly caught freshwater fish. But there are ways to protect yourself.
The parasites are called trematodes. Two species of the flatworms were discovered in California's freshwater fish, according to a study published Tuesday in the Journal of Infectious Diseases. The tiny, flattened and sluglike creatures can cause gastrointestinal problems, weight loss and lethargy when a person eats an infected fish.
In some rare and severe cases, the parasites have caused strokes or heart attacks.
"Americans don't usually think about parasites when they eat freshwater fish because it hasn't historically been an issue here," said Ryan Hechinger, the study's senior author.
In fact, even when a person has fallen ill from a locally caught infected freshwater fish, their healthcare provider will typically ask if the patient has recently traveled outside of the United States, Hechinger said.
California wasn't this parasite's first home
Researchers identified two species of trematode: Haplorchis pumilio and Centrocestus formosanus.
These two parasite species have historically infected people in Southeast Asia who eat raw fish, crustaceans or vegetables that carry the parasite larvae.
A trematode has a very specific life cycle, leeching onto three hosts that include a freshwater snail, a fish and then a bird or human who ate the infected fish.
The parasite was probably carried to the U.S. by the red-rimmed melania, or Malaysian trumpet snail, which is host to a number of parasitic species and was introduced to the United States, Hechinger estimates, decades ago.
It inhabits "freshwater springs, streams, lakes and swamps," according to the Smithsonian Environmental Research Center, but can occasionally be found in "brackish and marine habitats, especially mangroves" (think the Everglades).
The snail first popped up in California in 1972 in a Riverside County ditch, according to the center.
Hechinger, through previous and new research, found that the snail and its associated trematode parasites can be widely found in lakes and reservoirs across the state.
He's identified the snails in Los Angeles, Imperial, Orange, Riverside, San Bernardino and San Diego counties.
Some fish harbor thousands of parasites
In summer and fall 2023, researchers, with the help of the California Department of Fish and Wildlife, analyzed fresh fish that were collected at five fishing localities in San Diego County: Miramar, Murray, Lower Otay and San Vicente reservoirs as well as Chollas Lake.
The fish included largemouth bass and bluegill.
Hechinger and his team found that 93% of all the fish in the study were infected with the H. pumilio parasite, with some individual fish harboring thousands of the parasites.
The second parasite, C. formosanus, was found at two of the five locations, where it occurred in 91% of the fish.
The parasites are each found on different parts of the fish. H. pumilio is found at the base of the fins and C. formosanus is found on the gills.
But the parasites can infect the muscles and connective tissue of the fish, Hechinger said, which is how a person eating it can get sick despite cutting off the head and fins.
"The other thing we have to remember," he said, "is the possibility of contamination on the food preparation surfaces and utensils."
How to protect yourself
The risk is real, but the precautions you can take against illness are straightforward.
Thorough cooking of any freshwater fish that could potentially be infected can prevent illness, according to the U.S. Food and Drug Administration.
If you choose to eat the fish raw, the agency advises you eat freshwater fish that has been previously frozen.
Freezing will kill parasites that may be present. However, the FDA said freezing doesn't kill all harmful germs, so the safest route is to thoroughly cook your seafood.
Some food prep is fishy
As part of this study, researchers conducted a survey of 125 YouTube videos with a total of 5 million views and found that 65% of these videos did not mention proper cooking or freezing of caught fish.
The lack of proper food preparation not only promotes the transmission of parasites but can also increase the odds of infection, Hechinger said.
Copyright (C) 2025, Tribune Content Agency, LLC. Portions copyrighted by the respective providers.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Newsweek
an hour ago
- Newsweek
How Animal Testing in US Could Be Transformed Under Trump
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. Millions of animals each year are killed in U.S. laboratories as part of medical training and chemical, food, drug and cosmetic testing, according to the non-profit animal rights organization People for the Ethical Treatment of Animals (PETA). For many animals held captive for research, including a huge range of species from dogs, cats and hamsters to elephants, dolphins and many other species, pain is "not minimized," U.S. Department of Agriculture data shows. The issue of animal testing is something most Americans agree on: it needs to change and gradually be stopped. A Morning Consult poll conducted at the end of last year found that 80 percent of the 2,205 participants either agreed or strongly agreed with the statement: "The US government should commit to a plan to phase out experiments on animals." Since President Donald Trump began his second term, his administration has been making moves to transform and reduce animal testing in country, although the question remains as to whether it will be enough to spare many more animals from pain and suffering this year. Animal Testing In US Could Be Transformed Animal Testing In US Could Be Transformed Photo-illustration by Newsweek/Getty/Canva What Is The Trump Administration Doing About It? There have been various steps taken in different federal agencies to tackle the issue of animal testing since Trump was sworn in on January 20. In April, the Food and Drug Administration (FDA) announced it was "taking a groundbreaking step to advance public health by replacing animal testing in the development of monoclonal antibody therapies and other drugs with more effective, human-relevant methods." The FDA said that its animal testing requirement will be "reduced, refined, or potentially replaced" with a range of approaches, including artificial intelligence-based models, known as New Approach Methodologies or NAMs data. A Department of Health and Human Services (HHS) official told Newsweek: "The agency is paving the way for faster, safer, and more cost-effective treatments for American patients. "As we restore the agency's commitment to gold-standard science and integrity, this shift will help accelerate cures, lower drug prices, and reaffirm U.S. leadership in ethical, modern science." The National Institutes of Health (NIH) announced it was "adopting a new initiative to expand innovative, human-based science while reducing animal use in research," in alignment with the FDA's initiative. The agency said that while "traditional animal models continue to be vital to advancing scientific knowledge," new and emerging technologies could act as alternative methods, either alone or in combination with animal models. The NIH Office of Extramural Research told Newsweek it was "committed to transparently assessing where animal use can be reduced or eliminated by transitioning to [new approach methodologies (NAMs)]." "Areas where research using animals is currently necessary represent high-priority opportunities for investment in NAMs," the agency added. It added that it will "further its efforts to coordinate agency-wide efforts to develop, validate, and scale the use of NAMs across the agency's biomedical research portfolio and facilitate interagency coordination and regulatory translation for public health protection." During Trump's first term, the Environmental Protection Agency (EPA) signed a directive to "prioritize efforts to reduce animal testing and committed to reducing testing on mammals by 30 percent by 2025 and to eliminate it completely by 2035," an EPA spokesperson told Newsweek. Although, the spokesperson added: "the Biden Administration halted progress on these efforts by delaying compliance deadlines." As a member of the House, Lee Zeldin, the EPA's current administrator, co-sponsored various bills during Trump's first term regarding animal cruelty, covering issues such as phasing out animal-based testing for cosmetic products; ending taxpayer funding for painful experiments on dogs at the Department of Veteran Affairs; empowering federal law enforcement to prosecute animal abuse cases that cross state lines; and others, the spokesperson said. What The Experts Think Needs To Be Done The Trump administration's efforts to tackle the issue of animal testing appear to be a step in the right direction, according to experts who spoke with Newsweek. "I was pleasantly surprised and quite frankly a bit shocked to read the simultaneous announcements by the NIH and the FDA regarding a new emphasis on the use of alternatives to animals," Jeffrey Morgan, a professor of pathology and laboratory medicine at Brown University in Rhode Island, told Newsweek. Morgan, who is also the director of the Center for Alternatives to Animals in Testing at Brown University, said that both agencies are moving together in the same direction on the issue "sends a unified and very powerful message to the research and biotech communities." He added that the announcements showed "a major acknowledgement of the limitations of the use of animals in research and testing." "What is especially exciting is that the NIH announcement will encourage the entry of new investigators into the field, further accelerating innovation in alternatives with exciting impacts for both discovery and applied research across all diseases," he said. He added that the FDA announcement and its emphasis on a new regulatory science that embraces data from alternatives was "equally exciting." "The demands of this new regulatory science will likewise accelerate innovation because it will establish the much-needed regulatory framework for the rigorous evaluation of data from alternatives," he said. While the administration's initiatives to shift research away from animal testing is heading in the right direction, its policies are "overdue," Dr. Thomas Hartung, a professor in the department of environmental health and engineering at Johns Hopkins Bloomberg School of Public Health, Maryland, told Newsweek. "The animal tests for safety were introduced more than 50 years ago. There is no other area of science where we do not adapt to scientific progress," he said. Hartung added that animal "testing takes too long and is too expensive to really provide the safety consumers want." He said that running animal tests for new chemicals can cost millions and take years in some cases. "Nobody can wait that long, even if they can afford the testing costs," he said. Hartung also believes the shifts in the industry to reduce animal testing have been "coming for a while," as over the last two decades, America's opposition to animal use in medical research has been increasing. "The alignment of FDA and NIH really makes the difference now, which I think is evidence of a strong relationship of their leaderships," he said. Yet in order to make a real difference, Hartung said clear deadlines are key to show that "this is not just lip service." He also said that he thought "the transformative nature of artificial intelligence in this field is not fully acknowledged." "We also need an objective framework for change to better science, such as the evidence-based toxicology approach," he said.
Boston Globe
14 hours ago
- Boston Globe
Supreme Court finds retired firefighter cannot sue for disability discrimination
Advertisement In a dissent, Justice Ketanji Brown Jackson, joined, in part, by Justice Sonia Sotomayor, argued that the justices had abandoned protections for vulnerable retirees. Get Starting Point A guide through the most important stories of the morning, delivered Monday through Friday. Enter Email Sign Up 'Disabled Americans who have retired from the work force simply want to enjoy the fruits of their labor free from discrimination,' Jackson wrote, adding that Congress had 'plainly protected their right to do so' when it drafted the federal disability rights law. Sotomayor, in a separate writing, argued that a majority of the justices appeared in agreement that retirees may be able to bring disability discrimination claims for actions that occurred while they were still employed. Stanley might have been able to argue that this would apply in her case, too, Sotomayor wrote, but the court had not been asked to weigh in on that question. Advertisement Stanley worked as a firefighter in Sanford, Florida, a city of about 65,000 people northeast of Orlando. When she started her job in 1999, the city offered health insurance until age 65 for two categories of retirees -- those with 25 years of service and those who retired early because of disability. In 2003, the city changed its policy, limiting health insurance to those who retired because of disability to just 24 months of coverage. After nearly two decades, Stanley retired in 2018 at age 47 after she was diagnosed with Parkinson's disease. She expected that the city would continue to pay for most of her health insurance until she turned 65, but it refused, citing its changed policy. Stanley sued, claiming that the city had violated the ADA by providing different benefits to 25-year employees versus those who retired because of a disability. She argued that the city's policy amounted to impermissible discrimination based on disability. A federal trial judge dismissed her claim under the ADA, and the U.S. Court of Appeals for the 11th Circuit agreed. In asking the justices to hear the case, lawyers for Stanley said it could affect millions of disabled Americans who rely on retirement benefits that they earned while employed. One section of the ADA specifies that it is illegal to discriminate in compensation because of a disability. The justices wrestled with whether the section included retirees. Deepak Gupta, a lawyer for Stanley, said in an emailed statement that the decision had created 'a troubling loophole that allows employers to discriminate against retirees simply because they can no longer work due to their disabilities.' Advertisement In her dissent, Jackson wrote that she hoped Congress might step in and provide a 'legislative intervention' to shield other disabled retirees. This article originally appeared in
Atlantic
14 hours ago
- Atlantic
It Has Come to Protein Iced Tea
In the early 1950s, 'Hi-Proteen' powder, one of the first modern protein supplements, hit the market. Initially, it tasted awful. But after its creator, Bob Hoffman, added in Hershey's chocolate, the flavor improved. (He used a canoe paddle to stir his mixture in a giant vat.) Protein products have come a long way since then. Perhaps, they have come too far: Last weekend, at the gym, I was offered a can of lemon-flavored ' protein ice tea.' The summery, yellow-striped packaging advertised 15 grams of protein per can, or about the same as what you might get from three eggs. Apparently protein shakes and protein bars don't cut it anymore. Americans are so obsessed with protein that even an Arnold Palmer comes infused with it. Perhaps protein iced tea was inevitable. Whenever something is trendy, the food industry can't help but push things to the extreme—consider ' plant-based ' peanut butter (as if the spread was not already vegetarian) and gluten-free pumpkin dog biscuits. But even compared with other food trends, the protein situation has gotten out of hand. Just last week, Starbucks announced that it's piloting a high-protein, banana-flavored cold foam. There is protein water, Kardashian-branded protein popcorn, and ' macho ' protein pasta sauce. If you want to get drunk while bulking up, consider a protein-fortified pale ale or a 'Swoleberry' spiked protein seltzer. Nothing is safe from the protein pandemonium. Name a food, and the protein version of it probably exists. Even if you, like me, aren't trying to maximize your protein intake, all of these products can be hard to escape. They have infiltrated every inch of the supermarket: On Monday, I went grocery shopping with the mission of finding the most ridiculous protein-enriched ingredients possible. While preparing my meal, I crunched on ranch-flavored protein tortilla chips (13 grams) and sipped from a bottle of grapefruit-flavored protein water (20 grams). Dinner began with a salad made of 'OrganicGirl Protein Greens,' which feature an assortment of mixed greens including naturally protein-rich sweet-pea leaves (5 grams). My main course was chickpea protein pasta (20 grams) and salmon (40 grams). I topped it all off with a frozen peanut-butter-banana bar for dessert (another 5 grams). In total, I ate more than 170 grams of protein on Monday, or the equivalent of 31 medium eggs. According to the federal government's recommendations, that's almost four times what someone of my build and activity level needs in a day to maintain a ' nutritionally adequate ' diet. The official dietary guidelines suggest that a person needs at least 0.36 grams of protein per pound of body weight to stay healthy. That's not all that much protein. Before my dinner experiment, I had gone through the day without thinking about my protein consumption, and had already surpassed my recommended amount by more than 30 percent. The average American adult regularly exceeds the federal recommendation. So why is protein showing up in iced tea? Some health experts think that the current federal recommendation is insufficient. They believe that for optimal health—to get beyond simply meeting basic nutritional needs—we should be consuming double, if not triple, the recommended amount. Some people—those who strength train, for instance—certainly benefit from increased intake. But for the average person, most experts don't see the point in going wild with protein, as my colleague Katherine J. Wu has written. What makes protein so appealing is that it has been offered as an answer for lots of people's dietary goals. Want to build muscle? Eat protein. Want to feel fuller for longer? Eat protein. Want to lose weight? Eat protein. The nutrient can indeed help with all of those, but sometimes, the claims turn absurd. Cargill, the food giant, recently suggested that protein might help solve broken marriages: 'Protein helps individuals become better parents, partners and employees,' the company wrote in a report this spring. In other words, protein has become synonymous with 'healthy.' The message seems to be resonating: Last year, 71 percent of American adults said they were trying to consume more of it. For food companies, adding protein to virtually everything is an easy way to make their products more alluring. No Starbucks executive is going to suggest a new line of 'fat enhanced' cold foam or iced tea with extra carbs. But extra protein—sure. And that's how we end up in a world of protein mania. The protein shake has given way to protein coffees and protein matchas and protein energy drinks and protein sodas. The protein bar has similarly descended into madness: Last week, Hershey's announced a 'Double Chocolate flavored protein bar' that looks like its normal chocolate bar (Hoffman would be proud). For the purists, there's the recently launched David bar, named after Michelangelo's, which bills itself as 'the most effective portable protein on this planet.' You can eat protein-fortified vanilla glazed donuts for breakfast, top your double cheeseburger with protein-laced ketchup, and finish the day with protein powder mixed with melatonin that promises a good night's sleep. If you're suspicious of these products, it's for good reason. Shoppers might think that certain foods are healthier now that they have a protein label slapped on them. Some of the new products are truly good for you—but eating a ton of protein-packed candy (or even just lots of red meat) comes with health risks that could offset whatever dubious benefit all that added protein might provide. A Snickers bar with 20 grams of protein is still a Snickers bar. By the time I finished my protein dinner, I was starting to feel bloated. Still, I wasn't quite done. I cued up the trailer for Protein, a film that debuted in U.K. cinemas last weekend. The movie tells the story of 'a gym-obsessed serial killer' who 'murders and eats a local drug dealer' for—what else?—protein. I took a bite of a protein-packed double-chocolate cookie and hit 'Play.'
