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

Md Shafaet Hossen; Skye Wassens; Shokoofeh Shamsi

doi:10.1016/j.fawpar.2021.e00120

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

Food Waterborne Parasitol. 2021 Mar 16:23:e00120. doi: 10.1016/j.fawpar.2021.e00120. eCollection 2021 Jun.

Authors

Md Shafaet Hossen^{1

2}, Skye Wassens³, Shokoofeh Shamsi¹

Affiliations

¹ School of Animal and Veterinary Sciences & Graham Centre for Agricultural Innovation, Charles Sturt University, Wagga Wagga, NSW 2678, Australia.
² Department of Fisheries Biology and Genetics, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh.
³ School of Environmental Sciences & Institute of Land, Water and Society, Charles Sturt University, Albury, NSW 2640, Australia.

Abstract

In Australia and New Zealand (NZ), snapper Chrysophrys auratus 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 (Anisakis types I & III, and Terranova type II) and Cucullanidae (Dichelyne 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 Anisakis types I & III were confirmed as Anisakis pegreffii and A. brevispiculata, respectively of which A. pegreffii is considered globally as a zoonotic nematode. The specific identification of Terranova type II and Dichelyne spp. was not possible as no comparable sequence data were available in GenBank. The phylogenetic tree clustered Anisakis types I & III with A. pegreffii and A. brevispiculata, respectively; Terranova type II sequences as a separate clade with previously identified larval and adult Terranova and Pseudoterranova species. Based on phylogenetic analyses the present Cucullanid specimens were assigned herein as Dichelyne cf. pleuronectidis, and an unknown species Dichelyne 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 D. cf. pleuronectidis and Dichelyne 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.

Keywords: Anisakidae; Cucullanidae; Fish; Public health; Seafood safety; Zoonotic nematodes.