Objective
To investigate the contamination of avian influenza virus (AIV for short) in external environments of Changshou District, Chongqing from 2022 to 2024, and to provide scientific evidence for the prevention and control of human avian influenza infections.
Methods
Real-time quantitative RT-PCR was employed for universal influenza A virus nucleic acid detection. Positive samples were further tested for H5, H7, and H9 AIV subtypes. Samples meeting sequencing criteria underwent influenza virus amplicon sequencing.
Results
Among 1 482 environmental samples collected during 20222024, the overall AIV positivity rate was 35.43% (525/1482), with no statistically significant annual variation (χ2=5.857, P> 0.05). Subtype distribution showed H5 at 9.71% (51/525), H9 at 64.19% (337/525), and H5+H9 co-infection at 16.19% (85/525), while H7 was undetected. Significant differences in positivity rates were observed among quarters (χ2=16.445), sample types (χ2 =75.414), and surveillance sites (χ2 =202.363) (all P<0.001). A total of 119 sequencing results were obtained.
Conclusions
Persistent AIV contamination exists in Changshou District´s external environments, with live poultry markets showing the highest contamination levels and multiple subtype co-circulation. Enhanced interagency collaboration and risk mitigation measures are recommended.