{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T23:03:59Z","timestamp":1790809439425,"version":"4.1.0"},"reference-count":25,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,6,20]],"date-time":"2026-06-20T00:00:00Z","timestamp":1781913600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Jiangsu Provincial Center for Disease Control and Prevention","award":["001004401HT"],"award-info":[{"award-number":["001004401HT"]}]},{"award":["001004401HT"],"award-info":[{"award-number":["001004401HT"]}],"id":[{"id":"https:\/\/ror.org\/02ey6qs66","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>H9N2 avian influenza viruses inherently carry cross-species transmission potential, making continuous surveillance critical for pandemic prevention. This study focused on monitoring the 2024 H9N2 epidemic in Jiangsu Province\u2019s external environment, analyzing its molecular evolution and receptor binding properties, assessing cross-species transmission and pandemic risks, and investigating serological antibody levels across different human populations. Environmental samples were collected from live poultry markets, farms, slaughterhouses, and bird habitats across Jiangsu, screened via quantitative PCR (qPCR), with positive samples used for virus isolation and whole-genome sequencing. Receptor binding properties were tested by hemagglutination assay, and H9N2 antibody levels were measured in 370 occupationally exposed individuals and 240 non-exposed individuals using hemagglutination inhibition (HI) assays. Among the 5779 collected samples, 6.89% tested H9N2-positive, and 12 strains belonging to the Eurasian lineage Y280-like clade G57 genotype were successfully isolated. All strains carried the HA-Q226L mutation, with 11 showing preferential binding to human \u03b1-2,6 receptors and one strain possessing dual receptor binding capability. Internal genes harbored mammalian adaptation mutations, and M2 proteins contained mutations conferring complete resistance to amantadine-class antiviral drugs. Serological tests revealed antibody positive rates of 4.05% in exposed populations and 2.5% in non-exposed populations, with no statistically significant difference between groups. These findings confirm that Jiangsu\u2019s circulating H9N2 viruses have acquired human receptor preference and mammalian adaptation, posing silent infection and pandemic risks. Enhanced surveillance and the development of candidate vaccine stockpiles are strongly recommended.<\/jats:p>","DOI":"10.3390\/v18060687","type":"journal-article","created":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T08:14:12Z","timestamp":1782375252000},"page":"687","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Epidemiological and Virological Characteristics of H9N2 Avian Influenza Virus in Jiangsu Province, China, 2024"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-2863-9895","authenticated-orcid":false,"given":"Xue","family":"Gao","sequence":"first","affiliation":[{"name":"Department of Microbiology, Xuzhou Center for Disease Control and Prevention, Xuzhou 221006, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Huiyan","family":"Yu","sequence":"additional","affiliation":[{"name":"Department of Acute Infectious Disease Control and Prevention, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210008, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Na","family":"Zhang","sequence":"additional","affiliation":[{"name":"National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liqi","family":"Liu","sequence":"additional","affiliation":[{"name":"National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jing","family":"Tong","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Xuzhou Center for Disease Control and Prevention, Xuzhou 221006, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xian","family":"Qi","sequence":"additional","affiliation":[{"name":"Department of Acute Infectious Disease Control and Prevention, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210008, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haodi","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Acute Infectious Disease Control and Prevention, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210008, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shenjiao","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Acute Infectious Disease Control and Prevention, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210008, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zi","family":"Li","sequence":"additional","affiliation":[{"name":"National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yangguang","family":"Du","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Xuzhou Center for Disease Control and Prevention, Xuzhou 221006, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liguo","family":"Zhu","sequence":"additional","affiliation":[{"name":"Department of Acute Infectious Disease Control and Prevention, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210008, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"a38588","DOI":"10.1101\/cshperspect.a038588","article-title":"H9 Influenza Viruses: An Emerging Challenge","volume":"10","author":"Carnaccini","year":"2020","journal-title":"Cold Spring Harb. 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