Live roundworms, most likely of the genus Anisakis or the related Pseudoterranova, were discovered in seafood dishes served to guests at a restaurant in downtown Reykjavík.
Sóley Kaldal and her friend had ordered fish courses at the unnamed restaurant, and were about to dig in, when they noticed the worms.
She spoke with the head chef to alert him of the incident. “He said that they cooked the fish at around 65°C (150°F), but the worms could sometimes survive heat up to 85°C (185°F). When I asked why they didn’t cooked the fish thoroughly at that temperature, he said that would ‘ruin the fish,’” Sóley told Vísir.
“As the day went on this began to bother me, and as a responsible pregnant woman should, I called a midwife to ask whether ingesting the worm could have caused me or my child any harm. They couldn’t tell me much.” Her further attempts to contact health professionals with the inquiry also yielded no answers.
Zoologist Karl Skírnisson spoke with Vísir about the potential dangers of consuming live roundworms.
While the worms cannot survive in humans, human digestive systems are similar enough to that of marine mammals that an ingested worm will try to burrow through the intestinal wall—but fail and get stuck, causing anisakiasis in the host.
This is due to an immune response triggered by the worm’s attack on the intestinal lining. Immune cells which build up around the worm “can block the digestive system, causing severe abdominal pain, malnutrition and vomiting.”
Several incidents have been reported in Iceland in recent years, all due to the consumption of raw or undercooked seafood.
“It is imperative that fish used for [raw] dishes has been thoroughly cleaned of worms (using a light-table), but even safer is to freeze the materials used for an adequate length of time beforehand so that any larvae are definitely dead,” Karl wrote in an article on the matter for the Icelandic Medical Journal in 2006.
Worms cooked for at least one minute at temperatures above 70°C (160°F), or frozen below -20°C (-4°F) for a week, should all be dead.
For the most part anisakids and related worms due not pose a health risk once frozen or cooked. However a severe allergic response to biochemicals released by the worm is possible, albeit rare.
For these individuals, consumption of the worm, dead or alive, can be extremely dangerous, and even lethal, triggering acute anaphylaxis, hives and other serious symptoms.