Anisakidosis: report of 25 cases and review of the literature

Abstract

Anisakidosis (previously known as anisakiasis) is a disease caused by the accidental ingestion of larval nematodes (Anisakis and sometimes Pseudoterranova) in raw fish. Two groups of patients are studied: 5 clinical cases and 20 serological diagnoses. 55 French cases are already published. Most of them complained of acute symptoms, which occurred within 12 h of eating the seafood meal--epigastric pain, occlusion, diffuse abdominal pain, and appendicitis. Larvae were attached to the gastric mucosa (25 cases), including an inflammatory response (erythema, oedema ulceration). Diagnosis of anisakiasis is made by gastroscopy which allows removal of the worms, and cures the patients. In gastro-intestinal tract X-rays, oedema in the mucosa, pseudo tumour formation, and filling defects (worm) were observed. In chronic infections, cases with intermittent feelings of ill health and abdominal pain, lasting from several weeks to months, were misdiagnosed as another intestinal disease. Positive serological reactions are helpful, and surgery is necessary for resection of the lesion; diagnosis is made histologically by an eosinophilic granuloma, and the presence of a larva with Y shaped lateral cords. Infestation rate is high in fishes: cod (88%), rock fish (86%), herring (88%), salmon, mackerel. Public health education should discourage the eating of raw fish. Thorough cooking to 70 degrees C or adequate freezing to -20 degrees C for 72 h are the best preventive measures. Such legislation is only in force in the Netherlands, where cases have decreased dramatically.