Anisakis simplex (s.s.) larvae (Nematoda: Anisakidae) hidden in the mantle of European flying squid Todarodes sagittatus (Cephalopoda: Ommastrephidae) in NE Atlantic Ocean: Food safety implications

Paolo Cipriani,Marialetizia Palomba,Lucilla Giulietti,Miguel Bao,Simonetta Mattiucci,Arne Levsen

doi:10.1016/j.ijfoodmicro.2020.109021

Paolo Cipriani, Marialetizia Palomba + Show 4 more

Open Access

https://doi.org/10.1016/j.ijfoodmicro.2020.109021

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Abstract

Few reports exist upon the occurrence and localization of zoonotic anisakid nematodes in T. sagittatus, especially in the mantle of the squid. The occurrence and site of infection of larval anisakids in 98 T. sagittatus caught West off St. Kilda, NE Atlantic Ocean, were investigated. Squids were examined for anisakids using the UV-Press method. In total, 689 nematodes were detected in the viscera and mantle. According to morphology, all the larvae (L3) were assigned to genus Anisakis. Diagnostic allozymes and mtDNA cox2 sequence analysis permitted to genetically identify all larvae as Anisakis simplex (s.s.) (N = 100). Overall prevalence (P = 81%) and mean intensity (mI = 8.6) of infection with A. simplex are provided. Most of the larvae present in the mantle cavity were embedded in the stomach wall or attached in the outer layer of the stomach and caecum (49%). Over a third of squids (37%) hosted A. simplex (s.s.) larvae in the mantle. A novel schematized representation of larvae distribution in the mantle is provided, showing where they were mostly located. According to the results obtained, the risk of anisakiasis associated with consumption of raw or undercooked T. sagittatus should be considered.

Highlights

The flying squids belonging to the Family Ommastrephidae, are commercially valuable cephalopod species, occurring throughout the oceans
Three sequences of A. simplex (s.s.) recovered from T. sagittatus were deposited in GenBank under these accession numbers: MW082624, MW082625, MW082626
The overall infection level of A. simplex (s.s.) in T. sagittatus in the present study (P = 81% mean intensity (mI) = 8.58) were higher than previous findings of anisakid nematodes in the same host species originating from other lo calities of the NE Atlantic Ocean and from the Mediterranean Sea

Summary

Introduction

The flying squids belonging to the Family Ommastrephidae, are commercially valuable cephalopod species, occurring throughout the oceans. Members of this family have an important role in marine foodwebs, and they represent key trophic elements in marine communities (Clarke, 1996). Todarodes sagittatus is thought to be an opportunistic predator, consuming mainly a variety of pelagic and mesopelagic fish, Crustacea and other cephalopod species (Breiby and Jobling, 1985; Joy, 1990; Piatkowski et al, 1998; Quetglas et al, 1999; Wiborg et al, 1982). In Japan, squids are a traditional and valuable food resource, consumed in a large quantity, mainly raw, as sashimi and sushi (Nagasawa and Moravec, 1995)

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