Tracking Blastocystis sp. in mussels from Northern France in a One Health context: Seasonal dynamics, implications in marine fecal pollution and risk in human health
Year: 2026
Type: article
Abstract: Blastocystis sp. is an intestinal protozoan with recognized zoonotic potential that is increasingly investigated in animals closely associated with humans or intended for food production. However, studies on mollusks remain limited, despite their high filtration capacity and ability to accumulate biological contaminants, making them valuable indicators of environmental pollution. Within a One Health framework, this study investigated the seasonal circulation of Blastocystis sp. in a coastal ecosystem in northern France through the analysis of mussels, cattle, and river water samples using real-time PCR. A total of 892 samples were analyzed, of which 14.5% tested positive. Mussels showed a prevalence of 22.7%, with marked seasonal variations suggesting fluctuations in environmental contamination. Cattle exhibited the highest prevalence (38.3%), while 18.8% of river water samples were contaminated. Sanger and next-generation sequencing of positive samples revealed substantial genetic diversity, with 14 subtypes (STs) identified in mussels, 8 in cattle, and 3 in water samples. The lack of host-specific STs, together with the low parasite loads assessed in mussels, suggests that these organisms act as passive accumulators rather than true hosts. Moreover, the broad ST diversity observed highlights ongoing circulation of Blastocystis sp. within this aquatic environment and widespread fecal contamination consistent with human, bovine, and avian sources. Overall, mussels appear to be effective bioindicators of multisource fecal pollution across interconnected ecosystems, emphasizing the potential risk of exposure to Blastocystis sp. through the handling or consumption of raw shellfish and the importance of strengthened environmental and public health surveillance.
Source: Environmental Pollution
Institutions: Centre National de la Recherche Scientifique, Inserm, Université de Lille, Institut Pasteur de Lille, Université du littoral côte d'opale, Centre Hospitalier Universitaire de Lille, Center for Infection and Immunity of Lille, Laboratoire d’Océanologie et de Géosciences, Consejo Superior de Investigaciones Científicas, Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide
Language: English
Subfield: Parasitology
Field: Immunology and Microbiology
Domain: Life Sciences
SDG: Life below water
Open Access status: hybrid
Estimated APC paid: $4,090
Funders: Université de Lille, European Cooperation in Science and Technology, Agence Nationale de la Recherche, Institut National de la Santé et de la Recherche Médicale, Institut Pasteur, Centre National de la Recherche Scientifique, Association du Syndrome de Lowe, Région Hauts-de-France, Institute Pasteur De Lille
OpenAlex ID: W7204929628