Sushi has boomed in popularity in the West, but doctors are now warning that eating raw fish might not be the best idea. A team of doctors from Portugal are concerned after a 32-year-old man was admitted to the hospital complaining of pain in his abdomen just below his ribs, vomiting and with a fever.
An endoscopy revealed that the larvae of a parasitic worm from the genus Anisakis was to blame. The condition, known as anisakiasis, is caused by eating undercooked or raw fish that has been contaminated. The invader burrows into the stomach walls and intestines of humans, and can be deadly if left unchecked.
When the patient in question revealed that he had recently eaten sushi, doctors performed an endoscopy on the man, inserting a long tube with a camera into the stomach. A special net was then used to remove the larvae, and according to doctors, his symptoms resolved immediately.
Writing in British Medical Journal Case Reports, the team warned that anisakiasis is becoming more and more common in the West. They quote a Spanish study that reported 25 cases of the condition over a three year period from 1999 to 2002.
An Italian study also saw a rise, and pointed out that “no effective pharmacological treatment is able to kill the larvae once eaten.” The US Center for Disease Control and Prevention notes that treatment for anisakiasis usually requires endoscopy or surgery.
The condition can also trigger other symptoms including severe allergic reaction, digestive bleeding, bowel obstruction, and peritonitis.
But it's not all doom and gloom. The Food Standards Agency in the United Kingdom noted that if fish is frozen before consumption, it will kill off any parasites. They added:
“If you do choose to make your own sushi from fish at home, ensure you follow a reputable recipe. If wild fish are to be eaten raw or lightly cooked, ensure that all parts, especially the thickest part, have been frozen for at least four days in a domestic freezer at -15C or colder. This will ensure that any undetected Anisakis larvae are killed.”
Is this enough to put us off from eating sushi? Probably not. Is this enough to put us off from eating cheap sushi from convenience stores? Probably.