Avian influenza surveillance among migratory birds, poultry, and occupationally exposed population in Quzhou City, China, 2023—2025

Quzhou City, located in western Zhejiang Province, China, is a critical stopover site on the East Asian-Australasian Flyway and has previously reported human cases of avian influenza. However, simultaneous surveillance data across migratory birds, poultry environments, and occupationally exposed populations remain limited. This study aimed to assess the prevalence of avian influenza viruses (AIVs) using a One Health approach. From 2023 to 2025, we conducted longitudinal surveillance in Quzhou City. Samples included migratory bird feces and swabs ( n = 2020), poultry-associated environmental samples ( n = 920), and serum samples from occupationally exposed workers ( n = 171). Viral RNA was detected by RT-qPCR, and antibodies were detected by hemagglutination inhibition (HI) assays. Multivariate logistic regression was used to identify risk factors for AIV positivity. AIV RNA was detected in 1.93% (39/2020) of migratory bird samples, but none could be subtyped due to low viral load. In contrast, 26.85% (247/920) of poultry-associated samples tested positive for AIV RNA, with H9 ( n = 122) being the predominant subtype, followed by H7 ( n = 6) and H5 ( n = 3); 115 positive samples remained unsubtyped. Among occupationally exposed individuals, the seroprevalence of AIV antibodies was 13.45% (23/171), with H9N2 ( n = 17) and H5N6 ( n = 4) being the most common. Workers engaged in catching and transporting live poultry had significantly higher odds of AIV seropositivity (adjusted OR = 3.51, 95% CI: 1.26–9.75, P = 0.016). Poultry-associated environments, particularly live poultry markets and farms, exhibited substantially higher AIV RNA positivity than migratory bird-associated samples, indicating that these environments may represent important settings for AIV circulation and potential human exposure in Quzhou. Occupational protection measures could prioritize workers in the live poultry trade. Continued surveillance integrating environmental and human data is warranted.