Anisakis pegreffii

Abstract

Anisakis pegreffii belongs to the Anisakis simplex species complex that causes anisakiasis, an important fish-borne zoonosis worldwide. The parasite typically reproduces in the gastric chambers of toothed whales (final hosts). Larvae hatch from the eggs that are expelled in seawater; the larvae are ingested by crustaceans and small fish (intermediate hosts). Many fish and cephalopod species (paratenic hosts) that prey upon them transport infective third-stage larvae (L3) to the final host. Humans are accidentally infected by L3 through consumption of uncooked seafood. Anisakiasis is characterised by four main types: gastric, intestinal, ectopic, and gastroallergic that elicit mostly mild, only occasionally severe symptoms. Recently, a fifth type has been proposed based on many asymptomatic Anisakis-IgE seropositive subjects, predominately in countries with high per capita fish consumption. In humans, L3 fails to develop into the adult stage, dies, and decomposes in infected tissues, evoking a local proinflammatory response characterized by eosinophilic granulomatosis.