{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T23:04:37Z","timestamp":1790809477772,"version":"4.1.0"},"reference-count":18,"publisher":"SAGE Publications","issue":"3","license":[{"start":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T00:00:00Z","timestamp":1782864000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"},{"start":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T00:00:00Z","timestamp":1782864000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"funder":[{"name":"Peking University-Merck Infectious Disease Prevention and Control Technology Joint Laboratory Medical Innovation Fund","award":["10001202421"],"award-info":[{"award-number":["10001202421"]}]}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Journal of Public Health Research"],"published-print":{"date-parts":[[2026,7]]},"abstract":"<jats:p>\n                    H9N2 avian influenza virus poses a persistent public health concern due to its zoonotic potential. This study investigated the epidemiological and clinical characteristics of human H9N2 avian influenza infection in Changsha City, along with related environmental surveillance data, to provide a scientific basis for disease prevention and control. From January 2015 to December 2025, a total of 11 human H9N2 avian influenza cases were collected from historical surveillance data of the Changsha CDC in Changsha City. Cases occurred sporadically throughout the year; most (90.91%, 10\/11) were mild, one severe case was co-infected with two types of respiratory pathogens, and the majority (72.73%, 8\/11) were children under 5 years old. Among the 10 cases with available exposure history, 70.00% had been exposed to live poultry or LPMs, with the H9 and N2 subtypes detected in related environmental samples at rates of about 76%. Genetic analysis showed that the H9N2 viruses from human cases were highly homologous to H9N2 viruses found in the live poultry environment in Changsha City, while also exhibiting diverse mutations in key functional sites and domains. Environmental samples from large live poultry markets exhibited a significant year-on-year increase in positive rate (\u03c7\n                    <jats:sup>2<\/jats:sup>\n                    =111.30,\n                    <jats:italic toggle=\"yes\">P<\/jats:italic>\n                    &lt;0.001), resulting in a substantially higher average rate in 2020-2024 versus 2014-2019 (77.11% vs. 47.43%; \u03c7\n                    <jats:sup>2<\/jats:sup>\n                    =158.24,\n                    <jats:italic toggle=\"yes\">P<\/jats:italic>\n                    &lt;0.001). In conclusion, sporadic human H9N2 infections, predominantly affecting children, were mostly associated with live poultry exposure, with no evidence of human-to-human spread, while environmental data revealed a sharply increasing contamination trend in markets, pointing to a heightened risk.\n                  <\/jats:p>","DOI":"10.1177\/22799036261470475","type":"journal-article","created":{"date-parts":[[2026,7,16]],"date-time":"2026-07-16T11:00:56Z","timestamp":1784199656000},"update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":1,"title":["Epidemiological and clinical characterization of human infections with H9N2 avian influenza virus in Changsha city, China, 2015-2025"],"prefix":"10.1177","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0677-3923","authenticated-orcid":false,"given":"Shuilian","family":"Chen","sequence":"first","affiliation":[{"name":"Department of Infectious Disease Prevention and Control, Changsha Municipal Center for Disease Control and Prevention"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xuewen","family":"Yang","sequence":"additional","affiliation":[{"name":"Department of Infectious Disease Prevention and Control, Changsha Municipal Center for Disease Control and Prevention"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jingsong","family":"Qiu","sequence":"additional","affiliation":[{"name":"Department of Infectious Disease Prevention and Control, Changsha Municipal Center for Disease Control and Prevention"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jin","family":"Zhao","sequence":"additional","affiliation":[{"name":"Department of Infectious Disease Prevention and Control, Changsha Municipal Center for Disease Control and Prevention"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ruchun","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Infectious Disease Prevention and Control, Changsha Municipal Center for Disease Control and Prevention"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peipei","family":"Deng","sequence":"additional","affiliation":[{"name":"Department of Infectious Disease Prevention and Control, Changsha Municipal Center for Disease Control and Prevention"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qiangming","family":"Xie","sequence":"additional","affiliation":[{"name":"Department of Infectious Disease Prevention and Control, Changsha Municipal Center for Disease Control and Prevention"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yinzhu","family":"Zhou","sequence":"additional","affiliation":[{"name":"Department of Infectious Disease Prevention and Control, Changsha Municipal Center for Disease Control and Prevention"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2026,7,16]]},"reference":[{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.20506\/rst.28.1.1869"},{"key":"e_1_3_4_3_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1473-3099(24)00234-2"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1007\/s13238-014-0111-7"},{"key":"e_1_3_4_5_2","doi-asserted-by":"publisher","DOI":"10.1111\/zph.12685"},{"key":"e_1_3_4_6_2","doi-asserted-by":"publisher","DOI":"10.1186\/s13567-017-0453-2"},{"key":"e_1_3_4_7_2","volume-title":"Avian influenza weekly update number 1014","author":"Organization WH","year":"2025","unstructured":"Organization WH. Avian influenza weekly update number 1014, 2025. Available. https:\/\/cdn.who.int\/media\/docs\/default-source\/wpro---documents\/emergency\/surveillance\/avian-influenza\/ai_20250912.pdf?sfvrsn=c5ef0bff_1&download=true, Accessed 2025\/10\/142025."},{"key":"e_1_3_4_8_2","first-page":"3225","article-title":"[Isolation and molecular characteristics of the first case of human avian influenza (H9N2) in Changsha] (in Chinese)","volume":"43","author":"Liu X","year":"2016","unstructured":"Liu X, Yuan J, Ou X, et al. [Isolation and molecular characteristics of the first case of human avian influenza (H9N2) in Changsha] (in Chinese). Modern Preventive Medicine 2016; 43: 3225\u20133231.","journal-title":"Modern Preventive Medicine"},{"key":"e_1_3_4_9_2","first-page":"1004","article-title":"[Molecular tracing and evolutionary characteristics analysis of H9N2 avian influenza virus from two human infections] (in Chinese)","volume":"25","author":"Xiao S","year":"2025","unstructured":"Xiao S, Li L, Huang Z, et al. [Molecular tracing and evolutionary characteristics analysis of H9N2 avian influenza virus from two human infections] (in Chinese). China Tropical Medicine 2025; 25: 1004\u20131010+1015.","journal-title":"China Tropical Medicine"},{"key":"e_1_3_4_10_2","first-page":"177","article-title":"Investigation and Analysis of the cases of Human Infection with Avian Influenza A (H9N2) Virus in Anhui Province] (in Chinese)","volume":"29","author":"Hou S","year":"2023","unstructured":"Hou S, Feng Y, Zhu M, et al. Investigation and Analysis of the cases of Human Infection with Avian Influenza A (H9N2) Virus in Anhui Province] (in Chinese). Anhui Journal of Preventive Medicine 2023; 29: 177\u2013180.","journal-title":"Anhui Journal of Preventive Medicine"},{"key":"e_1_3_4_11_2","doi-asserted-by":"publisher","DOI":"10.3390\/v11070620"},{"key":"e_1_3_4_12_2","first-page":"1","article-title":"An epidemiological overview of human infections with HxNy avian influenza in the Western Pacific Region, 2003-2022","volume":"13","author":"Skufca J","year":"2022","unstructured":"Skufca J, Bell L, Molino JCP, et al. An epidemiological overview of human infections with HxNy avian influenza in the Western Pacific Region, 2003-2022. 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