Objective To investigate the distribution of avian influenza virus (AIV) in external environment of 17 prefectures (municipality) in Hubei province from 2020 to 2023, analyze the epidemiological characteristics of AIV, and provide evidence for the development of targeted prevention strategies and surveillance measures.

Methods Real-time reverse transcription quantitative polymerase chain reaction (RT-PCR) was used to detect influenza A virus, including subtype H5, H7, and H9, in environmental surveillance samples for avian influenza collected in Hubei from 2020 to 2023. Descriptive epidemiological methods were used for statistical analysis on the detection results.

Results From 2020 to 2023, a total of 8 514 environmental samples were collected, in which 1 842 were positive for AIV, the positive rate was 21.63%. In the positive samples, the proportions of subtype H9, H5, and H7 positive samples were 84.80%, 3.75%, and 0.05%, respectively. The annual positive rates of AIV were 16.50%, 25.35%, 24.00%, and 18.16% from 2020 to 2023, showing a trend of increasing first and then decreasing, the differences were significant (χ²=65.837, P<0.05). The positive rates of AIV varied significantly with surveillance sites (χ²=1 415.746, P<0.05), with the highest rate observed in live poultry markets in urban and rural areas (37.03%), and the lowest rate in wild migratory bird habitats (0.00%). There were also significant differences in the positive rate of AIV among different types of samples (χ²=200.066, P<0.05), with the highest rate found in samples from cutting boards in slaughterhouse (31.84%), and the lowest rate in stool samples (15.90%). Notably, there were significant differences in AIV positive rate between peak and off-peak seasons (χ²=4.978, P<0.05), with the highest rate in the first quarter (22.48%) and the lowest rate in the third quarter (18.82%). Additionally, significant area specific difference in AIV positive rate was observed (χ²=1 544.622, P<0.001), with the highest rate observed in Ezhou (61.52%) and the lowest observed in Tianmen (0.80%).

Conclusion AIV contamination is common in external environments in different areas of Hubei with the incidence peak occurring during winter and spring, and the contamination was mainly caused by subtype H9 virus. The contamination in urban and rural live poultry markets was the most severe, indicating the importance to strengthen the surveillance and hygienic management in live poultry markets as a key measure for avian influenza prevention and control.