Anisakid and Cod Worms

These species of Anisakis and Pseudoterranova can be an inch/2.5 centimeters or more long, with a diameter of a few human hairs. Both often cause only a harmless tingling in the throat, but they sometimes invade the lining of the stomach or small intestine and cause pain, nausea, and diarrhea. They’re commonly found in herring, mackerel, cod, halibut, salmon, rockfish, and squid, and can be contracted from sushi or lightly marinated, salted, or cold-smoked preparations. Farmed salmon are much less likely to be infected than wild salmon.