Doctors Issue Warning About Sushi Parasites Anisakiasis

Doctors are warning people who eat sushi Sushi the dangers of ingesting parasites from raw and undercooked fish.

Writing in the British journal BMJ Case Reports, researchers based in Lisbon, Portugal, found a healthy 32-year-old man who became violently ill after eating raw fish.

According to the report, the Lisbon man was admitted to a hospital after suffering severe abdominal pain, vomiting, and a fever for a week after eating a sushi meal.

An endoscopy found that worm-like parasite larva had formed in his gut, indicative of a disease called anisakiasis. The larva was removed, and the patient’s symptoms improved immediately, according to the BMJ report.

Sushi parasites
Sushi parasites

It was only when he told them he had recently eaten sushi that doctors suspected he had anisakiasis, a parasitic disease caused by worms (anisakid nematodes) that can invade the stomach and intestines of the man.

A special kind of net was used to remove the larvae “and the patient’s symptoms resolved immediately”, the team from a central Lisbon hospital said.

They added that most cases of anisakiasis to date had been reported in Japan, but warned: “However, it has been increasingly recognised in Western countries.”

The medics warned that “owing to changing food habits, anisakiasis is a growing disease in Western countries, which should be suspected in patients with a history of ingestion of raw or uncooked fish.”

The report said most cases of anisakiasis had been reported in Japan, where sushi originates.

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Benjamin Diaz

About the Author: Benjamin Diaz

Benjamin Diaz started working for Debate Report in 2017. Ben grew up in a small town in northern Ontario. He studied chemistry in college, graduated, and married his wife a year later. Benhas been a proud Torontonian for the past 10 years. He covers politics and the economy. Previously he wrote for CTV News and the Huffington Post Canada.


  1. This is a terrible report written by people who don’t know about Japan. In Japan, there are only ~100 cases per year. Sushi chefs there all know how to prepare sushi in order to prevent anisakiasis.

  2. Raw fish? No thanks, tried sushi but just can’t get past the texture of chewing raw fish. Makes me what to throw up.

  3. I knew it from history that all stone age people eat anything as raw. But civilized people never eat anything before cook, except fruit and few other edible things. So the choice is ours.

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