Lisbon: Doctors are warning that there is a rise in parasitic infections in Japanese food sushi. From nigiri to temaki, sushi has boomed in popularity in the west.
According to a report by UK daily the Guardian, a team of doctors from Portugal raised concerns after a 32-year old man was admitted to hospital complaining of pain in his abdomen just below his ribs, vomiting and had a slight fever, all of which had lasted for a week.
An endoscopy soon revealed the culprit: the larvae of a type of parasitic worm from the genus Anisakis. The doctors note that the condition, known as anisakiasis, is caused by eating undercooked or raw fish or seafood that has been contaminated: indeed, questioning of the patient revealed that he had recently eaten sushi.
After the larva was removed the man rapidly recovered, say the medics. Writing in the journal BMJ Case reports, the team warns that with sushi in vogue in the west, awareness of anisakiasis is growing.
“Most of the cases were described in Japan due to food habits; however, it has been increasingly recognised in western countries,” the authors write, pointing to a Spanish study that reported 25 cases of the condition over a three year period from 1999 to 2002, with all patients having eating raw anchovies, as well as Italian research which flagged both anchovies and sushi as routes by which individuals could become infected.
The Italian study added that medical professionals should suspect the condition should patients complain of severe abdominal pain after eating raw fish, pointing out that “no effective pharmacological treatment is able to kill the larvae once eaten”.
The authors of the latest report add that besides the symptoms shown in the Portuguese case, the condition can also trigger a host of other symptoms including severe allergic reaction, as well as complications such as digestive bleeding, bowel obstruction and peritonitis.
The Food Standards Agency noted that raw fish occasionally contain parasitic larvae, but said that under European food hygiene legislation fish that is to be eaten raw should be frozen before it is sold to consumers to ensure any parasites have been killed.
The FSA added that fish and meat should always be cooked properly according to the producer’s instructions, but offered a few tips to those planning to make their own sushi.