“Sushi lover’s entire body left riddled with WORMS after eating contaminated sashimi,” the Daily Mail headline screamed in a news story from 2014. A man in China complained to his doctor about an aching stomach and itchy skin.
Diagnostic scans revealed that the sushi lover’s innards were riddled with tapeworms. Contaminated sashimi (slices of raw fish) was determined to be the culprit of the man’s health problem which almost killed him.
An assortment of parasitic infections, including tapeworms, are linked to eating raw or undercooked fish:
“Tapeworm infections occur after ingesting the larvae of diphyllobothrium, found in freshwater fish such as salmon, although marinated and smoked fish can also transmit the worm.”
Tapeworms are flat, segmented parasites typically grow from 4 to 28 inches in length and survive as long as 30 years in a host. However, parasites measuring as long as 82 feet have been documented medically!
The body of an adult tapeworm is composed of a head and neck, and linked segments (called proglottids) which grow and produce eggs. A single proglottid can produce up to 100,000 eggs.
After a fish eats tapeworm eggs, the larvae hatch and attach themselves to the intestinal wall of the fish with a series of hooks or suckers. The adult worms infect the flesh of the fish.
Once ingested, a tapeworm can thrive in a human’s digestive tract, feeding off the host’s food and growing to incredible lengths in a relatively short time – a few weeks. Often, the parasite lives on undetected by the human host for weeks, months or years. Upon maturity, the tapeworm deposits its own eggs inside the host body, leading to further infections.
While many cases of intestinal tapeworms prove harmless, adequate cooking destroys the larval tapeworm and other harmful bacteria present in raw fish that can infect humans and lead to dire medical consequences.
Symptoms of tapeworm include:
- Abdominal discomfort and obstruction
- Weight loss
Consider the case of a 30-year-old California man who visited the University of California San Franciso’s Community Regional Medical Center in Fresno. He showed up carrying a plastic grocery bag and requested treatment for tapeworms.
Dr. Kenny Banh was on duty in the ER and shared the incredible story. The man had been suffering from abdominal cramps and bloody diarrhea. One August morning in 2017, while doing what people do in bathrooms, he noticed something dangling from his bottom. Dr. Banh repeated what the patient had told him:
“He was like, ‘Oh my goodness, my guts are coming out from me!'”
Dr. Bahn said the man tugged on the extrusion and was surprised when it kept coming out of his body:
“And he thinks it’s very odd. He doesn’t get it until he pulls it out, and then it wiggles and he drops it and is like oh. It’s a worm.”
Dr. Bahn opened the patient’s plastic bag. Inside was a cardboard toilet paper tube with a tapeworm wrapped around it. The worm was pronounced dead on arrival but had been quite alive and wiggling when the man removed it forcibly from his body. Fully extended, the parasite measured five and a half feet long.
The ER physician observed:
“It got long enough that some of it was sneaking out of him.”
The Californian was sure he picked up the hitchhiking tapeworm from eating raw fish – he ate sushi or sashimi nearly every day. The parasite most likely had been growing in the man’s guts for at least six months.
As he left the hospital, the man in Fresno told the staff he would never eat sashimi again.
Tapeworms are easily diagnosed by medical professionals. A stool sample is tested to reveal it the parasitic infection is present. If so, antiparasitic medications may provide a fast and effective cure. More severe cases may require surgical or endoscopic removal.
Left untreated, tapeworm larvae can travel throughout the host body and feed on the liver, eyes, heart, and brain, creating potentially lethal medical conditions.
The U.S. Food and Drug Administration (FDA) has published specific guidelines for retailers who sell fish intended to be eaten raw, including freezing the fish to -31°F for 15 hours or -4°F for 7 days to kill parasites. A physical examination called “candling” – inspection before a penetrating light in a darkened room for signs of fertility, defects, or freshness – is recommended to detect the presence of worms in fish products.