California freshwater fish found parasites full of parasites. How to avoid illness
More than 90% of the prevalent freshwater fish in Southern California carry human-infected parasites, researchers say. This poses a significant danger for those who like to eat freshly caught freshwater fish. But there are some ways to protect yourself.
Parasites are called trematides. Two flatworms were found in freshwater fish in California, according to a study published in the Journal of Infectious Diseases. When a person eats an infected fish, tiny, flat and light organisms can cause gastrointestinal problems, weight loss and lethargy.
In some rare and severe cases, parasites cause stroke or heart attack.
“Americans usually don't consider parasites when eating freshwater fish, because this wasn't a problem in the past,” said Ryan Hechinger, senior author of the study.
In fact, even when a person gets sick from infected freshwater fish caught locally, their healthcare providers usually ask the patient if he has recently traveled outside the United States.
California is not the first home of this parasite
The researchers identified two trematodes: Haplorchis Pumilio and Centrocestus formosanus.
These two parasite species have historically been infected in Southeast Asia, and they have eaten raw fish, crustaceans or vegetables that carry parasite larvae.
Trematode has a very specific life cycle, in three hosts, including freshwater snails, a fish, and then a bird or human who eat the infected fish.
Decades ago, the parasites were probably brought to the United States by red-patterned Melania or Malaysian trumpet snails (Malaysian trumpet snails), a number of parasite species that were introduced to the United States.
According to the Smithsonian Center for Environmental Research, it lives in “freshwater springs, streams, lakes and swamps” but can occasionally be found in “salted and marine habitats, especially mangroves” (think Everglades).
The center said the snail popped up in a ditch in Riverside County for the first time in California in 1972.
Through previous and new research, Hechinger has found that snails and their associated hybrid parasites can be found widely in lakes and reservoirs across the state.
He identified snails in Los Angeles, Empire, Orange, Riverside, San Bernardino and San Diego counties.
Some fish contain thousands of parasites
In the summer and fall of 2023, researchers analyzed fresh fish collected in five fishing areas in San Diego County: Miramar, Murray, Lower Otay and San Vicente Reservoirs, and Chollas Lake, with the help of the California Department of Fish and Wildlife.
Fish include largemouth bass and blue g.
Hechinger and his team found that 93% of all fish in the study were infected H. Pumilio Parasites, some people who carry thousands of species of parasites.
The second parasite, C. FormosanusIt was found in two of the five locations, and it was found in 91% of the fish.
San Vicente Reservoir, north of the lakeshore of San Diego County.
(Daniel Gaines/Los Angeles Times)
These parasites are found in different parts of the fish. H. Pumilio Found at the bottom of the fin, C. Formosanus Found on ill.
But these parasites can infect fish's muscles and connective tissue, which is the person who eats it, despite chopping off the head and fins, Hechinger said.
“The other thing we have to remember is the possibility of contamination on the surface and vessels of food preparation,” he said.
How to protect yourself
The risks are real, but the precautions you can take are straightforward.
According to the U.S. Food and Drug Administration, thorough cooking of any freshwater fish that may be infected can prevent disease.
If you choose to eat raw fish, the agency recommends eating freshwater fish that was previously frozen.
Freezing kills possible parasites. However, the FDA says freezing won’t kill all harmful bacteria, so the safest route is to thoroughly cook seafood.
Some food preparations are fishy
As part of the study, researchers surveyed 125 YouTube videos with a total of 5 million views and found that 65% of these videos did not mention proper cooking or frozen fish.
The lack of proper food preparation not only promotes parasite transmission, but also increases the chance of infection, Hechinger said.
