biostudies-literatureZhu HNational Program on Key Research Project of ChinaFundamental Research Funds for the Central UniversitiesNational Key Research and Development Program of China205https://www.ebi.ac.uk/biostudies/studies/S-EPMC9716174biostudies-literatureUnknown19(1)<h4>Background</h4>Swine influenza viruses (SIV), considered the "mixing vessels" of influenza viruses, posed a significant threat to global health systems and are dangerous pathogens. Eurasian avian-like H1N1(EA-H1N1) viruses have become predominant in swine populations in China since 2016.<h4>Methods</h4>Lung tissue samples were obtained from pregnant sows with miscarriage and respiratory disease in Heilongjiang province, and pathogens were detected by Next-generation sequencing (NGS) and PCR. The nucleic acid of isolates was extracted to detect SIV by RT-PCR. Then, SIV-positive samples were inoculated into embryonated chicken eggs. After successive generations, the isolates were identified by RT-PCR, IFA, WB and TEM. The genetic evolution and pathogenicity to mice of A/swine/Heilongjiang/GN/2020 were analyzed.<h4>Results</h4>The major pathogens were influenza virus (31%), Simbu orthobunyavirus (15%) and Jingmen tick virus (8%) by NGS, while the pathogen that can cause miscarriage and respiratory disease was influenza virus. The SIV(A/swine/Heilongjiang/GN/2020) with hemagglutination activity was isolated from lung samples and was successfully identified by RT-PCR, IFA, WB and TEM. Homology and phylogenetic analysis showed that A/swine/Heilongjiang/GN/2020 is most closely related to A/swine/Henan/SN/10/2018 and belonged to EA-H1N1. Pathogenicity in mice showed that the EA-H1N1 could cause lethal or exhibit extrapulmonary virus spread and cause severe damage to respiratory tracts effectively proliferating in lung and trachea.<h4>Conclusion</h4>A/swine/Heilongjiang/GN/2020 (EA-H1N1) virus was isolated from pregnant sows with miscarriage and respiratory disease in Heilongjiang province, China. Clinical signs associated with influenza infection were observed during 14 days with A/swine/Heilongjiang/GN/2020 infected mice. These data suggest that A/swine/Heilongjiang/GN/2020 (EA-H1N1) had high pathogenicity and could be systemic spread in mice.Virology journalGenetic characterization and pathogenicity of a Eurasian avian-like H1N1 swine influenza reassortant virus.PMC97161742021YFD18013002018YFD05008012662016PY003Li XQian PZhu HChen HfalseGenetic characterization and pathogenicity of a Eurasian avian-like H1N1 swine influenza reassortant virus.<h4>Background</h4>Swine influenza viruses (SIV), considered the "mixing vessels" of influenza viruses, posed a significant threat to global health systems and are dangerous pathogens. Eurasian avian-like H1N1(EA-H1N1) viruses have become predominant in swine populations in China since 2016.<h4>Methods</h4>Lung tissue samples were obtained from pregnant sows with miscarriage and respiratory disease in Heilongjiang province, and pathogens were detected by Next-generation sequencing (NGS) and PCR. The nucleic acid of isolates was extracted to detect SIV by RT-PCR. Then, SIV-positive samples were inoculated into embryonated chicken eggs. After successive generations, the isolates were identified by RT-PCR, IFA, WB and TEM. The genetic evolution and pathogenicity to mice of A/swine/Heilongjiang/GN/2020 were analyzed.<h4>Results</h4>The major pathogens were influenza virus (31%), Simbu orthobunyavirus (15%) and Jingmen tick virus (8%) by NGS, while the pathogen that can cause miscarriage and respiratory disease was influenza virus. The SIV(A/swine/Heilongjiang/GN/2020) with hemagglutination activity was isolated from lung samples and was successfully identified by RT-PCR, IFA, WB and TEM. Homology and phylogenetic analysis showed that A/swine/Heilongjiang/GN/2020 is most closely related to A/swine/Henan/SN/10/2018 and belonged to EA-H1N1. Pathogenicity in mice showed that the EA-H1N1 could cause lethal or exhibit extrapulmonary virus spread and cause severe damage to respiratory tracts effectively proliferating in lung and trachea.<h4>Conclusion</h4>A/swine/Heilongjiang/GN/2020 (EA-H1N1) virus was isolated from pregnant sows with miscarriage and respiratory disease in Heilongjiang province, China. Clinical signs associated with influenza infection were observed during 14 days with A/swine/Heilongjiang/GN/2020 infected mice. These data suggest that A/swine/Heilongjiang/GN/2020 (EA-H1N1) had high pathogenicity and could be systemic spread in mice.2022-01-01T00:00:00Z2022 Dec2026-05-29T18:58:08.256Z2025-04-19T22:48:05.571ZS-EPMC97161743646100710.1186/s12985-022-01936-6