Identification of H1N2 influenza viruses in turkeys after spillover from swine and in vitro characterization
Influenza A viruses (IAVs) circulate among animals and humans and can cross species barriers to adapt to new hosts. In France, since 2020, a new genotype named H1<sub>av</sub>N2#E has predominated in pig farms. In parallel, this virus was detected in 19 breeding turkey flocks and in a human case, indicating interspecies transmission. The objectives of this study were (i) to analyze viral sequences detected in turkeys between April 2020 and January 2023 and compare them with swine sequences to identify potential markers of adaptation and (ii) to characterize three representative viruses in vitro and in ovo on MDCK, MLE15 and A549 cells, as well as on embryonated chicken eggs. Results suggest that following initial swine-to-turkey spillovers, the virus circulated between turkey farms. Phylogenetic analyses and host origin guided the selection of three viruses: a reference swine virus (A), a turkey strain closely related to swine viruses (B) and a virus apparently circulating in turkeys (C). Three molecular markers may contribute to turkey adaptation: the E233K, under positive selection pressure, or E236K mutations in the 220-loop of the receptor-binding site of HA protein and two NA substitutions, T401N in antigenic site 2d and S416N. Replication kinetics showed that at low MOI (0.001), virus C produced more infectious particles on MDCK and A549 cells, whereas at high MOI (0.1), virus B produced more. In ovo, infectious particles were generated for viruses A and B but not efficiently for virus C, in contrast to mammalian cells where production was higher.
Authors
- Audrey Schmitz
- Edouard Hirchaud (ORCID: https://orcid.org/0000-0001-6991-8491)
- Claire Martenot
- Sophie Le Bouquin‐Leneveu
- Aurélie Le Roux (ORCID: https://orcid.org/0009-0008-0786-748X)
- Pascale Massin (ORCID: https://orcid.org/0000-0003-1182-0736)
- Gaëlle Simon (ORCID: https://orcid.org/0000-0003-1099-5075)
- Béatrice Grasland (ORCID: https://orcid.org/0000-0001-5777-673X)
- Severine Hervé (ORCID: https://orcid.org/0000-0002-2223-7071)
- François‐Xavier Briand (ORCID: https://orcid.org/0000-0002-8094-9368)
- Florent Souchaud
- Éric Niqueux (ORCID: https://orcid.org/0009-0008-1551-1934)
- Yannick Blanchard (ORCID: https://orcid.org/0000-0002-4711-6671)
- Ronan Le Goffic (ORCID: https://orcid.org/0000-0002-2012-0064)
- Céline Deblanc (ORCID: https://orcid.org/0009-0008-0131-0920)
- Axelle Scoizec (ORCID: https://orcid.org/0009-0000-0007-2862)
- Katell Louboutin
- Gautier Richard (ORCID: https://orcid.org/0000-0003-3663-4569)
- Rachel Busson (ORCID: https://orcid.org/0009-0006-0507-0966)
- Chloé Chavoix
Institutions
- École nationale d'ingénieurs de Brest (FR)
- Hendrix Genetics (France) (FR)
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (FR)
- Virologie et Immunologie Moléculaires (FR)
- Mathématiques et Informatique Appliquées du Génome à l'Environnement (FR)
Publication Details
- Journal
- Virus Research
- Published
- 2025-09-22
- DOI
- https://doi.org/10.1016/j.virusres.2025.199634
- Primary Topic
- Influenza Virus Research Studies
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement