{ "abstract": "West Nile virus (WNV) and Usutu virus (USUV) are neurotropic Orthoflaviviruses sharing a similar enzootic transmission cycle primarily involving Culex pipiens mosquitoes as vectors and birds as amplifying hosts. First identified in Africa, both viruses established endemicity across Europe over the past two decades, most likely introduced and spread by migratory bird species along Mediterranean flyways. In avian species, infection outcomes range from subclinical to fatal neuroinvasive disease, varying by viral strain, host immunity, and species sensibility. Southern France emerges as a key hotspot for the circulation of these viruses, supported by diverse avian habitats conducive to year-round viral maintenance. This study investigated the RNA prevalence of WNV and USUV in more than 2500 sedentary and migratory wild birds from this region during 2024–2025 using molecular surveillance. Samples were collected using mists net and bird boxes, across multiple passerine and non-passerine taxa, spanning wetlands, urban fringes, and agricultural zones. Our analyses revealed widespread viral detection across diverse species, mainly among passerines such as great tits, house sparrows, and barn swallows with USUV detected at higher rates than WNV in both study years. Overall RNA prevalence was markedly higher in 2024 than in 2025, potentially reflecting climatic or ecological drivers. These results highlight the pivotal role of mixed avifauna in arbovirus dynamics within Mediterranean Europe and emphasize the necessity for integrated, year-round surveillance targeting high-risk species and habitats. Author summary: West Nile virus and Usutu virus are two closely related viruses spread by mosquitoes that mainly infect birds but can occasionally cause severe neurological disease in humans and horses. Southern France, and in particular the Camargue wetlands near Montpellier, is a long-recognised hotspot for both viruses. Over two years (2024–2025), we sampled more than 2,500 wild birds of 69 species in this region, testing cloacal swabs and droppings for viral RNA. Both viruses circulated widely, with Usutu virus detected roughly three times more often than West Nile virus, and overall circulation was higher in 2024 than in 2025 and more frequent in rural, wetland-associated sites. Our findings reinforce the value of active, non-invasive avian surveillance as a complement to existing human and veterinary case reporting for these viruses in Europe.", "abstract_shown": true, "affiliations": [], "article_type": "Research Article", "arxiv": null, "author_total": 9, "authors": [ { "name": "Rachel Beaubaton" }, { "name": "Justine Revel" }, { "name": "Laetitia Pigeyre" }, { "name": "Alexandre Lepeule" }, { "name": "Julien Joly" }, { "name": "Christophe de Franceschi" }, { "name": "Anne Charmantier" }, { "name": "Benjamin Vollot" }, { "name": "Yannick Simonin" } ], "bibtex": "https://research.draconitic.com/paper/1ajg3waes0emc.bib", "cited_by": 0, "doi": "10.1371/journal.pntd.0014397", "fulltext_url": "https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014397", "id": "1ajg3waes0emc", "issns": [ "1935-2727", "1935-2735" ], "landing_url": "https://hal.science/hal-05756786v1", "language": "en", "licence": "CC-BY-4.0", "licence_label": "CC BY 4.0", "licence_source": "article", "licence_url": "https://creativecommons.org/licenses/by/4.0/", "metadata_licence": null, "native_subjects": [ [ "hal", "0.sdv" ], [ "hal", "1.sdv.mhep" ], [ "hal", "1.sdv.mp" ], [ "hal", "1.sdv.spee" ], [ "hal", "2.sdv.mhep.me" ], [ "hal", "2.sdv.mhep.mi" ], [ "hal", "2.sdv.mp.vir" ], [ "openalex", "2739|Mosquito-borne diseases and control" ], [ "plos", "/Biology and life sciences/Microbiology/Medical microbiology/Microbial pathogens/Viral pathogens/Flaviviruses/West Nile virus" ], [ "plos", "/Biology and life sciences/Organisms/Eukaryota/Animals/Invertebrates/Arthropoda/Insects/Mosquitoes" ], [ "plos", "/Biology and life sciences/Organisms/Eukaryota/Animals/Vertebrates/Amniotes/Birds" ], [ "plos", "/Biology and life sciences/Organisms/Eukaryota/Animals/Vertebrates/Amniotes/Birds/Passerines" ], [ "plos", "/Biology and life sciences/Organisms/Viruses/RNA viruses/Flaviviruses/West Nile virus" ], [ "plos", "/Biology and life sciences/Organisms/Viruses/Viral pathogens/Flaviviruses/West Nile virus" ], [ "plos", "/Biology and life sciences/Psychology/Behavior/Animal behavior/Animal migration" ], [ "plos", "/Biology and life sciences/Species interactions/Disease vectors/Insect vectors/Mosquitoes" ], [ "plos", "/Biology and life sciences/Zoology/Animal behavior/Animal migration" ], [ "plos", "/Biology and life sciences/Zoology/Animals/Invertebrates/Arthropoda/Insects/Mosquitoes" ], [ "plos", "/Biology and life sciences/Zoology/Animals/Vertebrates/Amniotes/Birds" ], [ "plos", "/Biology and life sciences/Zoology/Animals/Vertebrates/Amniotes/Birds/Passerines" ], [ "plos", "/Biology and life sciences/Zoology/Entomology/Insects/Mosquitoes" ], [ "plos", "/Earth sciences/Geomorphology/Topography/Landforms/Wetlands" ], [ "plos", "/Earth sciences/Marine and aquatic sciences/Aquatic environments/Freshwater environments/Wetlands" ], [ "plos", "/Ecology and environmental sciences/Aquatic environments/Freshwater environments/Wetlands" ], [ "plos", "/Medicine and health sciences/Medical conditions/Infectious diseases/Co-infections" ], [ "plos", "/Medicine and health sciences/Medical conditions/Infectious diseases/Disease vectors/Insect vectors/Mosquitoes" ], [ "plos", "/Medicine and health sciences/Pathology and laboratory medicine/Pathogens/Microbial pathogens/Viral pathogens/Flaviviruses/West Nile virus" ], [ "plos", "/People and places/Geographical locations/Europe" ], [ "plos", "/Social sciences/Psychology/Behavior/Animal behavior/Animal migration" ] ], "openalex": "W7162137462", "pdf_url": "https://hal.science/hal-05756786/document", "pmcid": null, "pmid": null, "published": "2026-09-03", "publisher": "Public Library of Science", "ris": "https://research.draconitic.com/paper/1ajg3waes0emc.ris", "sources": [ { "first_seen": "2026-10-30T12:17:36Z", "native_id": "hal-05756786", "source": "hal", "url": "https://hal.science/hal-05756786v1" }, { "first_seen": "2026-10-30T12:18:02Z", "native_id": "10.1371/journal.pntd.0014397", "source": "plos", "url": "https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014397" } ], "subjects": [ { "field": "biology", "origin": "hal:1.sdv.mp", "subfield": "microbiology" }, { "field": "biology", "origin": "plos:animal behavior", "subfield": "zoology-behaviour" }, { "field": "medicine", "origin": "hal:1.sdv.spee", "subfield": "epidemiology-public-health" }, { "field": "medicine", "origin": "hal:2.sdv.mhep.me", "subfield": "infectious-disease" } ], "title": "Widespread circulation of West Nile and Usutu viruses in sedentary and migratory avifauna: A two-year study (2024–2025) of active surveillance in South of France", "title_text": "Widespread circulation of West Nile and Usutu viruses in sedentary and migratory avifauna: A two-year study (2024–2025) of active surveillance in South of France", "type": "peer-reviewed", "updated_at": "2026-10-30T12:18:02Z", "url": "https://research.draconitic.com/paper/1ajg3waes0emc", "venue": "PLoS Neglected Tropical Diseases", "versions": [] }