First Report on the Prevalence and Subtype Distribution of Blastocystis sp. in Edible Marine Fish and Marine Mammals: A Large Scale-Study Conducted in Atlantic Northeast and on the Coasts of Northern France

Nausicaa Gantois (1) , Angélique Lamot (1) , Yuwalee Seesao (2) , Colette Creusy (3) , Luen-Luen Li (2, 4) , Sébastien Monchy (4, 5) , Sadia Benamrouz-Vanneste (1, 6) , Jacky Karpouzopoulos (7) , Jean-Luc Bourgain (7) , Célia Rault (7) , Fabien Demaret (8) , Martha Baydoun (1) , Magali Chabé (1) , Emilie Fréalle (1) , Cécile-Marie Aliouat-Denis (1) , Mélanie Gay (2) , Gabriela Certad (1, 3) , Eric Viscogliosi (1)

1 CIIL - Centre d’Infection et d’Immunité de Lille - INSERM U 1019 - UMR 9017 - UMR 8204
2 Laboratoire de Boulogne sur mer
3 GHICL - Groupement des Hôpitaux de l'Institut Catholique de Lille
4 LOG - Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187
5 ULCO - Université du Littoral Côte d'Opale
6 ICL - Institut Catholique de Lille
7 Groupe Mammifères Marins
8 PELAGIS - Observatoire pour la Conservation de la Mégafaune Marine

Blastocystis is frequently identified in humans and animal hosts and exhibits a large genetic diversity with the identification of 17 subtypes (STs). Despite its zoonotic potential, its prevalence and ST distribution in edible marine fish and marine mammals remain unknown. A large-scale survey was thus conducted by screening 345 fish caught in Atlantic Northeast and 29 marine mammals stranded on the coasts of northern France for the presence of the parasite using real-time Polymerase Chain Reaction PCR. The prevalence of the parasite was about 3.5% in marine fish. These animals were mostly colonized by poikilotherm-derived isolates not identified in humans and corresponding to potential new STs, indicating that fish are natural hosts of Blastocystis. Marine fishes are also carriers of human STs and represent a likely limited source of zoonotic transmission. 13.8% of the marine mammals tested were colonized and 6 different STs were identified including 3 potential new STs. The risk of zoonotic transmission through marine mammals is insignificant due to the lack of repeated contact with humans. The present survey represents the first data regarding the prevalence and ST distribution of Blastocystis in marine fish and marine mammals and provides new insights into its genetic diversity, host range and transmission.

Mots clés: Blastocystis sp.; edible marine fish; intestinal parasites; marine mammals; molecular epidemiology; real-time quantitative PCR; SSU rDNA sequence; subtyping; transmission; zoonosis

Domaines: Biodiversité et Ecologie; Médecine vétérinaire et santé animale

Nausicaa Gantois, Angélique Lamot, Yuwalee Seesao, Colette Creusy, Luen-Luen Li, et al.. First Report on the Prevalence and Subtype Distribution of Blastocystis sp. in Edible Marine Fish and Marine Mammals: A Large Scale-Study Conducted in Atlantic Northeast and on the Coasts of Northern France. Microorganisms, 2020, 8 (3), pp.460. ⟨10.3390/microorganisms8030460⟩. ⟨hal-03086927⟩