TY - JOUR TI - Co-circulation of multiple influenza A reassortants in swine harboring genes from seasonal human and swine influenza viruses AU - Ryt-Hansen, Pia AU - Krog, Jesper Schak AU - Breum, Solvej Østergaard AU - Hjulsager, Charlotte Kristiane AU - Pedersen, Anders Gorm AU - Trebbien, Ramona AU - Larsen, Lars Erik A2 - van der Meer, Jos WM VL - 10 PY - 2021 DA - 2021/07/27 SP - e60940 C1 - eLife 2021;10:e60940 DO - 10.7554/eLife.60940 UR - https://doi.org/10.7554/eLife.60940 AB - Since the influenza pandemic in 2009, there has been an increased focus on swine influenza A virus (swIAV) surveillance. This paper describes the results of the surveillance of swIAV in Danish swine from 2011 to 2018. In total, 3800 submissions were received with a steady increase in swIAV-positive submissions, reaching 56% in 2018. Full-genome sequences were obtained from 129 swIAV-positive samples. Altogether, 17 different circulating genotypes were identified including six novel reassortants harboring human seasonal IAV gene segments. The phylogenetic analysis revealed substantial genetic drift and also evidence of positive selection occurring mainly in antigenic sites of the hemagglutinin protein and confirmed the presence of a swine divergent cluster among the H1pdm09Nx (clade 1A.3.3.2) viruses. The results provide essential data for the control of swIAV in pigs and emphasize the importance of contemporary surveillance for discovering novel swIAV strains posing a potential threat to the human population. KW - influenza A virus KW - swine KW - viral drift KW - viral shift KW - zoonotic potential JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -