Characterization of Anisakidae in marine fish : development of an identification method by high-throughput sequencing and prevalence study

• Main Author: Seesao, Yuwalee
• Other Authors: Centre d’Infection et d’Immunité de Lille - INSERM U 1019 - UMR 9017 - UMR 8204 (CIIL), Centre National de la Recherche Scientifique (CNRS)-Centre Hospitalier Régional Universitaire Lille (CHRU Lille)-Université de Lille-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Pasteur de Lille, Réseau International des Instituts Pasteur (RIIP)-Réseau International des Instituts Pasteur (RIIP), Université du Droit et de la Santé - Lille II, Eric Viscogliosi
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2015
• Subjects: Fish; Sanger method of sequencing; Anisakid family; Analyse statistique; Biologie moléculaire; PCR; Séquençage haut débit; Sécurité alimentaire; Identification; Zoonoses; Prévalence; Intensité; Parasitologie; Nématodes; Poissons; Anisakidae; [SDV.MHEP]Life Sciences [q-bio]/Human health and pathology; Atlantic salmon; Salmo salar
• Online Access: https://tel.archives-ouvertes.fr/tel-01412878; https://tel.archives-ouvertes.fr/tel-01412878/document; https://tel.archives-ouvertes.fr/tel-01412878/file/2015LIL2S043.pdf

Anisakis, Pseudoterranova, Hysterothylacium and Contracaecum genera, members of the Anisakids family, are nematodes which larvae are recovered from numerous fish and cephalopods species. These larvae may induce digestive and/or allergic pathologies in human being. In France, the consumption of fishery products, mostly raw or undercooked is increasing. This PhD work is part of the research program Fish-Parasites funded by the ANR (ANR-10-ALIA-004). It aimed to assess risks related to fishery products consumption and its main goal was to study the distribution of Anisakids in fishery products.The sampling plan was based on a risk-ranking analysis using data on fishery products consumption, fishing areas and prevalence data from previous work on Anisakids. A total of 1 768 fish from 18 species were collected. All the organs were dissected for parasites isolation. Parasites were identified using two approaches : i) single analysis by Sanger sequencing for organs containing less than 11 nematodes ii) pooled analysis by high throughput sequencing (HTS) for the remaining. The development of numerous tools (database creation with reference sequences, primers design, set up of the sequencing template preparation and development of an automatic analytical pipeline) was necessary for the HTS method set up. From the sequencing results, acquisition and structuring of the prevalence data has been carried out on parasites potentially pathogenic for human being and recovered from commonly consumed fishery products.On 1 768 sampled fish, two species were not parasitized at all: plaice (Pleuronectes platessa) and aquacultured Atlantic salmon (Salmo salar). 43.30 % of the fish were not infected by Anisakids. Concerning infected fish, 28.62% were contaminated in the visceral organs; 22.96% in both visceral organs and fillets and, finally, 5.49% of the fish were infected by Anisakids only in fillets.The five fish species with an elevated prevalence in their fillets were by decreasing values: blue ling (100 %), megrim (70 %), saithe ...