Pathogenicity and zoonotic potential of a novel pdm09-lineage H1N2 swine influenza A virus spatiotemporally linked to transboundary pig trade
6 affiliations
- 1College of Veterinary Medicine, Jeonbuk National University, Iksan, Republic of Korea
- 2Department of Microbiology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
- 3WOOGENE B&G Co., LTD., Seoul, Republic of Korea
- 4College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon, Republic of Korea
- 5Department of Clinical Pathology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
- 6Untreatable Infectious Disease Institute, Kyungpook National University, Daegu, Republic of Korea
Abstract
International swine trade can disseminate influenza A viruses across borders, creating opportunities for reassortment with endemic swine viruses and the emergence of novel strains with zoonotic potential. Here, we characterize a novel H1N2 reassortant, A/swine/Korea/1030–3/2023 (1030–3), detected in South Korea and spatiotemporally associated with European swine lineages and international pig movement. 1030–3 harbors seven gene segments (PB2, PB1, PA, HA, NP, M and NS) closely related to a recent Danish zoonotic H1N1 virus of the 2009 pandemic (pdm09) lineage, and an N2 segment derived from an endemic Korean HxN2. In vitro assays demonstrated that 1030–3 preferentially bound human-type α2,6-linked sialic acid receptors and replicated efficiently in polarized human airway epithelial cells, although these properties were also observed in the endemic Korean H1N2 comparator 1027–1. In mice, 1030–3 caused moderate clinical signs and respiratory replication comparable to an early pdm09 reference strain NL09. In guinea pigs, 1030–3 transmitted to a subset of direct-contact animals but showed no detectable aerosol transmission under the conditions tested. In pigs, the natural host, 1030–3 replicated efficiently and transmitted to all direct-contact animals, with high respiratory shedding and a greater cumulative shedding burden in contact pigs than NL09. Contemporary human sera showed reduced neutralizing activity against 1030–3 relative to both human seasonal H1N1 and 1027–1, while antiserum against a recent H1N1 vaccine antigen also neutralized 1030–3 less efficiently. These findings identify a European-associated H1N2 swine influenza reassortant detected in South Korea that combines a distinct pdm09-derived genomic and antigenic background with efficient replication and transmission in pigs, α2,6-linked receptor preference, and reduced neutralization by human sera, underscoring the need for trade-aware surveillance of swIAVs and continued monitoring at the swine-human interface. Author summary: Swine influenza A viruses are important animal pathogens and recurring sources of viruses with pandemic potential. International movement of pigs can introduce influenza viruses into new regions, where they may reassort with endemic strains and generate variants whose biological properties cannot be predicted from genetic surveillance alone. In this study, we identified a novel H1N2 swine influenza virus in South Korea that contains a pdm09-derived backbone closely related to European swine viruses, including a recent Danish zoonotic strain, and an N2 segment derived from endemic Korean swine influenza viruses. This virus replicated and transmitted efficiently in pigs and showed preferential binding to human-type receptors and robust growth in human airway epithelial cells. While these phenotypes are not unique to 1030–3, the virus combines them with a distinct pdm09-derived genomic background and reduced neutralization by contemporary human sera compared with endemic Korean swine H1N2 and seasonal H1N1 viruses. Antiserum against a recent H1N1 vaccine antigen also neutralized 1030–3 less efficiently than human pdm09 strains. Together, our findings highlight the importance of monitoring swIAV evolution in the context of international livestock movement and reassortment and support trade-aware surveillance of viruses with antigenic and biological features relevant to the swine–human interface.
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BibTeX
@article{kim2026pathogenicity,
title = {{Pathogenicity and zoonotic potential of a novel pdm09-lineage H1N2 swine influenza A virus spatiotemporally linked to transboundary pig trade}},
author = {Seung-Chai Kim and Hwan-Ju Kim and Bitgoeul Kim and Gyeong-Seo Park and Byeong-Joo Seo and Chonghan Kim and Chang-Gi Jeong and Jae-Ku Oem and Sung-Hyun Moon and Se-Kyung Jung and Yeonsu Oh and Ho-Seong Cho and Yu Kyung Kim and Chung-Young Lee and Won-Il Kim},
journal = {PLOS Pathogens},
year = {2026},
month = nov,
doi = {10.1371/journal.ppat.1014779},
url = {https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1014779},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Pathogenicity and zoonotic potential of a novel pdm09-lineage H1N2 swine influenza A virus spatiotemporally linked to transboundary pig trade
AU - Seung-Chai Kim
AU - Hwan-Ju Kim
AU - Bitgoeul Kim
AU - Gyeong-Seo Park
AU - Byeong-Joo Seo
AU - Chonghan Kim
AU - Chang-Gi Jeong
AU - Jae-Ku Oem
AU - Sung-Hyun Moon
AU - Se-Kyung Jung
AU - Yeonsu Oh
AU - Ho-Seong Cho
AU - Yu Kyung Kim
AU - Chung-Young Lee
AU - Won-Il Kim
PY - 2026
DA - 2026/11/03
JO - PLOS Pathogens
DO - 10.1371/journal.ppat.1014779
UR - https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1014779
AB - International swine trade can disseminate influenza A viruses across borders, creating opportunities for reassortment with endemic swine viruses and the emergence of novel strains with zoonotic potential. Here, we characterize a novel H1N2 reassortant, A/swine/Korea/1030–3/2023 (1030–3), detected in South Korea and spatiotemporally associated with European swine lineages and international pig movement. 1030–3 harbors seven gene segments (PB2, PB1, PA, HA, NP, M and NS) closely related to a recent Danish zoonotic H1N1 virus of the 2009 pandemic (pdm09) lineage, and an N2 segment derived from an endemic Korean HxN2. In vitro assays demonstrated that 1030–3 preferentially bound human-type α2,6-linked sialic acid receptors and replicated efficiently in polarized human airway epithelial cells, although these properties were also observed in the endemic Korean H1N2 comparator 1027–1. In mice, 1030–3 caused moderate clinical signs and respiratory replication comparable to an early pdm09 reference strain NL09. In guinea pigs, 1030–3 transmitted to a subset of direct-contact animals but showed no detectable aerosol transmission under the conditions tested. In pigs, the natural host, 1030–3 replicated efficiently and transmitted to all direct-contact animals, with high respiratory shedding and a greater cumulative shedding burden in contact pigs than NL09. Contemporary human sera showed reduced neutralizing activity against 1030–3 relative to both human seasonal H1N1 and 1027–1, while antiserum against a recent H1N1 vaccine antigen also neutralized 1030–3 less efficiently. These findings identify a European-associated H1N2 swine influenza reassortant detected in South Korea that combines a distinct pdm09-derived genomic and antigenic background with efficient replication and transmission in pigs, α2,6-linked receptor preference, and reduced neutralization by human sera, underscoring the need for trade-aware surveillance of swIAVs and continued monitoring at the swine-human interface. Author summary: Swine influenza A viruses are important animal pathogens and recurring sources of viruses with pandemic potential. International movement of pigs can introduce influenza viruses into new regions, where they may reassort with endemic strains and generate variants whose biological properties cannot be predicted from genetic surveillance alone. In this study, we identified a novel H1N2 swine influenza virus in South Korea that contains a pdm09-derived backbone closely related to European swine viruses, including a recent Danish zoonotic strain, and an N2 segment derived from endemic Korean swine influenza viruses. This virus replicated and transmitted efficiently in pigs and showed preferential binding to human-type receptors and robust growth in human airway epithelial cells. While these phenotypes are not unique to 1030–3, the virus combines them with a distinct pdm09-derived genomic background and reduced neutralization by contemporary human sera compared with endemic Korean swine H1N2 and seasonal H1N1 viruses. Antiserum against a recent H1N1 vaccine antigen also neutralized 1030–3 less efficiently than human pdm09 strains. Together, our findings highlight the importance of monitoring swIAV evolution in the context of international livestock movement and reassortment and support trade-aware surveillance of viruses with antigenic and biological features relevant to the swine–human interface.
SN - 1553-7374
ER -