First morphological and molecular identification of third-stage larvae of (Nematoda: Anisakidae) from marine fishes in Vietnamese water.

Anisakid nematodes are parasites of cetaceans, their larval stages live in marine fishes. The third-stage larvae of some species are also the etiological agents of human anisakiasis caused by consumption of raw or undercooked infected fish. Thus, identification of larvae at the species level is crucial for their ecology and epidemiology. In Vietnam, although larvae have been reported, they have not been identified to the species level. The aim of this study was, therefore, to identify third-stage larvae of collected from marine fishes in Vietnamese water, based on morphological characteristics and molecular analysis. All larvae found in this study were morphologically similar to each other and identical to . In addition, molecular analysis based on ITS1-5.8S-ITS2 sequences confirmed them as . Vietnamese population was genetically close to those from Asian countries and Australia. The third-stage larvae of were collected from eight fish species from three localities in the South of Vietnam. Among them, seven were recorded as new intermediate hosts of . This is the first identification of larvae in Vietnamese water with records of new fish hosts.