Occurrence and abundance of zoonotic nematodes in snapper , a popular table fish from Australian and New Zealand waters.

In Australia and New Zealand (NZ), snapper is known for delicate mild flavoured flesh and is a favoured species to serve raw as sashimi or in sushi. The diet of snapper includes a variety of intermediate hosts of larval nematodes, and as a result, snapper has potential to become highly infected with zoonotic/non-zoonotic nematodes. The aims of this study were to survey nematodes in snapper from Australia and New Zealand waters and to identify nematode species using combined morphological and molecular methods. The zoonotic potential of nematodes identified in this study are discussed. A total of 112 snapper were purchased from the Sydney fish market, New South Wales, Australia. Fish were dissected and only the visceral content and digestive tract were examined for nematode infection. Parasites were initially identified by the microscopic method as four different types belonging to the families Anisakidae ( types I & III, and type II) and Cucullanidae ( spp.). All Anisakidae nematodes were at infective stages. Species-level identification was actualised through sequencing of the internal transcribed spacer (ITS-1, 5.8S, ITS-2) regions. The types I & III were confirmed as and , respectively of which is considered globally as a zoonotic nematode. The specific identification of type II and spp. was not possible as no comparable sequence data were available in GenBank. The phylogenetic tree clustered types I & III with and , respectively; type II sequences as a separate clade with previously identified larval and adult and species. Based on phylogenetic analyses the present Cucullanid specimens were assigned herein as cf. , and an unknown species sp. 1. This study represents the first host record globally for zoonotic Anisakid nematodes in this popularly consumed table fish and a new region record for cf. and sp. 1. Further investigation is required, using more comprehensive parasite detection and recovery methods, to assess the health risk these nematodes may pose to human and fish health in Australia/NZ.