Anisakis simplex: current knowledge.

Anisakiasis, firstly described in 1960s in the Netherlands, is a fish-borne parasitic disease caused by the consumption of raw or undercooked fish or cephalopods contaminated by third stage (13) larvae of the Anisakidae family, in particular Anisakis simplex (As), A. pegreffii and Pseudoterranova decipiens. Every year, approximately 20,000 cases of anisakiasis were reported worldwide, over 90% are from Japan and most others in Spain, the Netherlands and Germany, depending on the habits of fish consuming. Live As larvae can elicit i) a parasitic infection of the digestive tract or, occasionally, other organs, causing erosive and/or haemorrhagic lesions, ascites, perforations until granulomas and masses, if larva is not removed, and ii) allergic reactions, as anaphylaxis, acute/chronic urticaria and angioedema. Like other parasite infestations, As larva induces an immune adaptive response characterised by T-lymphocyte proliferation with polyclonal and monoclonal (responsible for As allergic symptoms) IgE production, eosinophilia and mastocytosis. Several As allergens, many of which thermostable, were described In particular the major allergen Ani s 1 and Ani s 7 could characterized a past or a recent infection. There is a general agreement that an active infection is required to initiate allergic sensitivity to Anisakis. Until now, the only effective treatment for anisakiasis is the endoscopic removal of live larvae and the best protection against anisakiasis is to educate consumers about the dangers of eating raw fish and to recommend avoiding the consumption of raw or inadequately thermally treated marine fish or cephalopods.