Anisakis is a genus of parasitic nematodes, which have life cycles involving fish and marine mammals. They are infective to humans and cause anisakiasis. People who produce immunoglobulin E in response to this parasite may subsequently have an allergic reaction, including anaphylaxis, after eating fish that have been infected with Anisakis species.
- Sudden, severe stomach pain
- Spasmodic abdominal pain
Anisakiasis is the disease caused by infection with Anisakis worms. It is frequently reported in areas of the world where fish is consumed raw, lightly pickled or salted. The areas of highest prevalence are Scandinavia (from cod livers), Japan (after eating sushi and sashimi), the Netherlands (by eating infected fermented herrings (Maatjes)), and along the Pacific coast of South America (from eating ceviche). Heating to 60 °C, or freezing to below −20 °C is an effective method of killing Anisakis.
For the worm, humans are a dead-end host. Anisakis and Pseudoterranova larvae cannot survive in humans and eventually die. Treatment therefore in the vast majority of cases is symptomatic, with a heavy dose of re-assurance. The only indication for treatment is small bowel obstruction due to Anisakis larvae, which may require emergency surgery, although there are case reports of treatment with albendazole alone (avoiding surgery) being successful.