Molecular characterization of anisakid nematode larvae from 13 species of fish from Western Australia

This study characterized anisakid nematodes in estuarine and near-shore species of fish in southern Western Australia. A total of 108 fish representing 13 species were examined for anisakid larvae. For the molecular characterization of anisakid larvae (n=218), we used PCR-coupled mutation scanning-sequencing-phylogenetic analyses of sequence variation in the internal transcribed spacers of nuclear ribosomal DNA. With the exception of Sillaginoides punctatus and Sillago schomburgkii, all the fish species examined (Aldrichetta forsteri, Arripis georgianus, Hyporhamphus regularis, Mugil cephalus, Platycephalus speculator, Pomatomus saltatrix, Pseudocaranx dentex, Pseudocaranx wrighti, Thysanophrys cirronatus, Trachurus novaezeelandiae and Upeneichthys lineatus) harboured at least one species of anisakid. Mutation scanning analysis identified 11 different genotypes of anisakid larvae. Phylogenetic analyses of the sequence data, employing reference sequence data for a wide range of anisakids (31 species) from public databases, revealed the presence of Anisakis pegreffii (n=3), Contracaecum multipapillatum (49), Contracaecum ogmorhini (1), Hysterothylacium larval type IV (82), Hysterothylacium larval type Vb (14), Hysterothylacium larval type VIII (3), Hysterothylacium larval type X (65), and Terranova type I (1) in the fish examined. The present study provides valuable information on the diversity of anisakids in southern Western Australia and also a basis for future investigations to assess the public health significance of these parasites.