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A California man pulled a shockingly large tapeworm from his body, which he may have contracted from eating sushi, according to his doctors.
The man, who lives in Fresno, went to the emergency room and told doctors that he had experienced bloody diarrhea and needed to be treated for parasitic worms, according to Dr. Kenny Banh, an emergency-medicine doctor at the University of California, San Francisco-Fresno who treated the patient and recounted the story on a recent episode of the medical podcast "This Won't Hurt a Bit."
At first, Banh said, he was skeptical of the man's need for worm treatment. "I get asked this [to treat for tapeworms] a lot," Banh said on the podcast. "Truthfully, a lot of times I don't think they have" parasites, he added.
But then, the patient opened a bag and showed Banh a tapeworm wrapped around a toilet-paper roll. The patient said that when he went to the bathroom, he at first thought his intestines were coming out of his body, before he realized it was, in fact, a tapeworm. [27 Oddest Medical Cases]
When Banh unraveled the worm from the roll and laid it out on paper towels, it came in at 5 feet 6 inches (1.7 meters) long.
A man in Fresno, California removed a 5-foot long tapeworm from his body. Above, the whole tapeworm laid out on the floor.
(Image credit: Dr. Kenny Banh/This Won't Hurt A Bit Podcast)
But how did the man get infected? The patient told Banh that he hadn't traveled out of the country or consumed well water, both of which are risk factors for worm exposure. But the patient did eat sushi almost every day — specifically, raw-salmon sashimi.
People can contract a type of tapeworm called Diphyllobothrium latum by consuming raw or undercooked fish, including salmon, trout, perch and walleyed pike, according to the Centers for Disease Control and Prevention (CDC). Last year, a study in the journal Emerging Infectious Diseases found this tapeworm in wild salmon caught in Alaska, prompting warnings about contracting the worm from fish caught along the Pacific coast.
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D. latum can grow up to 30 feet (9 m) long, making it the largest tapeworm that can infect people, according to the CDC.
To prevent infection with D. latum, the CDC recommends avoiding consumption of raw or undercooked fish. But people who just can't quit sushi may be glad to know you can kill the parasite by freezing fish at specific temperatures for a certain amount of time, according to the Food and Drug Administration.
To treat the patient in the recent case, Banh prescribed a single treatment of an anti-parasitic drug that kills tapeworms.
Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.
