title: Anisakid nematodes in beaked redfish (Sebastes mentella) from three fishing grounds in the North Atlantic, with special notes on distribution in the fish musculature.
abstract: Parasitic anisakid nematodes commonly occur in the musculature and visceral organs of many fish species from the North Atlantic. In this respect, the presence of the third stage larvae of Anisakis spp. in the fish musculature may pose a potential consumer hazard due to the parasite's ability to cause anisakidosis. Thus, knowledge on the occurrence and distribution of these potentially zoonotic parasites in the commercially important North Atlantic fish species is crucial in order to evaluate and consequently prevent human infections. In the present study, 300 Sebastes mentella from three North Atlantic fishing grounds (Northern North Sea: Tampen; Barents Sea: off Bear Island; Irminger Sea: off SE Greenland) were examined for anisakid nematodes, with emphasis on occurrence and distribution in the musculature. Overall larval prevalence and mean intensity were significantly higher in redfish from Tampen (94%; 13.5±20.0) and Bear Island (94%; 14.5±19.4) than in fish from SE Greenland (75%; 6.0±5.8; p<0.01). The same trend was observed for larval infection in the musculature showing prevalence and mean intensities of 79%, 73%, and 55%, and 5.9±6.6, 5.8±6.5, and 3.2±2.4, in the musculature of redfish from Tampen, Bear Island, and Greenland, respectively. Conventional microscopy and rDNA ITS-gene sequencing of various subsamples of muscle-dwelling nematode larvae of redfish from every catching locality revealed the presence of two anisakid species; Anisakis simplex sensu stricto and the non-zoonotic Hysterothylacium aduncum. Since the larvae of H. aduncum typically occur in or on the viscera of fish, our findings of two specimens in the belly flaps of redfish were unusual. Additionally, more than 92% of the muscle-dwelling larvae occurred in the belly flaps, i.e. the hypaxial part of the musculature surrounding the visceral organs on either fish side. Thus, trimming the fillets of beaked redfish by removal of most of the belly flaps would significantly reduce the probability of anisakid nematode larvae to be present in the final product.
authors.affiliation: Department of Safety and Quality of Milk and Fish Products, Federal Research Institute for Nutrition and Food, Max Rubner-Institute, Palmaille 9, D-22767 Hamburg, Germany; Goethe-University (GU), Institute for Ecology, Evolution and Diversity, Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung (SGN), Max-von-Laue-Str. 13, D-60439 Frankfurt/Main, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Klapper
authors.affiliation: Goethe-University (GU), Institute for Ecology, Evolution and Diversity, Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung (SGN), Max-von-Laue-Str. 13, D-60439 Frankfurt/Main, Germany. Electronic address: t.kuhn@bio.uni-frankfurt.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kuhn
authors.affiliation: Goethe-University (GU), Institute for Ecology, Evolution and Diversity, Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung (SGN), Max-von-Laue-Str. 13, D-60439 Frankfurt/Main, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Münster
authors.affiliation: National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029, Nordnes, N-5817 Bergen, Norway.
authors.forename: Arne
authors.initials: A
authors.lastname: Levsen
authors.affiliation: Department of Safety and Quality of Milk and Fish Products, Federal Research Institute for Nutrition and Food, Max Rubner-Institute, Palmaille 9, D-22767 Hamburg, Germany.
authors.forename: Horst
authors.initials: H
authors.lastname: Karl
authors.affiliation: Goethe-University (GU), Institute for Ecology, Evolution and Diversity, Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung (SGN), Max-von-Laue-Str. 13, D-60439 Frankfurt/Main, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Klimpel
mesh_terms: D000818:Animals; D017129:Anisakiasis / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D017163:Anisakis / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D001267:Atlantic Ocean / Q000453:epidemiology; D001483:Base Sequence; D018509:DNA, Helminth / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005393:Fish Diseases / Q000453:epidemiology* / Q000469:parasitology; D016266:Food Parasitology; D006116:Greenland / Q000453:epidemiology; D006801:Humans; D007814:Larva; D009132:Muscles / Q000469:parasitology; D009659:North Sea / Q000453:epidemiology; D010473:Perciformes / Q000469:parasitology*; D017422:Sequence Analysis, DNA / Q000662:veterinary
chemical_list: D018509:DNA, Helminth; D004275:DNA, Ribosomal
keywords: Anisakis simplex; Beaked redfish; Food safety; Hysterothylacium aduncum; Sebastes mentella