Mapping Clinostomum complanatum infections of perch (Perca fluviatilis) in French freshwaters ecosystems
Résumé
Over the last two decades, the diffusion of new eating habits and the increase of fish products demand lead to a raising risk for consumers due to food-borne parasitic zoonoses. Clinostomum Leidy, 1856 are digenetic trematodes widely distributed in the world. They are present, at the larval stage, in numerous freshwater fish. One of the most distributed of this genera is Clinostomum complanatum (Platyhelminthes: Digenea), is zoonotic and may induce pharyngitis or laryngitis in humans following consumption of raw fish infected by the larvae. Until now, the occurrence of the zoonotic trematode Clinostomum complanatum in Europe was restricted to the Danube basin and the North-East of Italy. The present study reports the distribution of these parasites from wild perch (Perca fluviatilis) in French freshwaters. An epidemiological study was performed on batches of wild perch from different departments. The samples were collected from December 2020 to September 2023. Fish were dissected, metacercariae were isolated and characterized from a molecular perspective. Infection levels were calculated. Comparison of generated sequences with available data of literature confirmed the presence of Clinostomum complanatum in France. Phylogeny and BLAST analysis of the new specimens showed high homology with individuals from Italy and Australia. Prevalences were very variable from 4 to 80% of infected fish per batch. This survey constitutes the first mapping of Clinostomum complanatum in French freshwaters ecosystems. As these parasites are zoonotic, these findings emphasize the importance of monitoring and controlling the presence of Clinostomum in aquatic environments to minimise the risk of infections and ensure food safety. Moreover, further samplings with abiotic parameters associated are needed to understand in details the distribution of these parasites.