Anisakiasis - Life Cycle

Anisakis, Pseudoterranova, Contracecum

1) Definitive hosts excrete unembryonated eggs in

2a) Eggs become embryonated in water and L3 larvae form in the eggs. 

2b) L3 larvae hatch from eggs as ensheathed, free-swimming forms.

3) Free-swimming larvae are ingested by crustaceans, and develop in the hemocoel.

4) Infected crustaceans are eaten by fish or cephalopod paratenic hosts. L3 larvae released in digestion migrate to the mesentery and muscle tissues, and can be transferred to other paratenic hosts via predation.

5) Paratenic hosts maintain L3 larvae in tissues, which are infective to definitive hosts.

6) Marine mammal definitve hosts ingest fish/squid paratenic hosts, and L3 larvae develop into adults in the gastric mucosa.

7) Transmission to humans via raw or undercooked seafood consumption.

Diagnosis of anisakiasis can be made by gastroscopic examination during which the larvae can be removed.



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