Objective To understand the distribution of avian influenza virus in the poultry related external environment of Qianxinan Buyi and Miao Autonomous Prefecture, Guizhou Province, and provide evidence for the prevention and control of human infection with avian influenza.

Methods For 1412 environmental samples were collected from live poultry markets and farm produce markets in 9 counties and urban areas of Qianxinan from 2020 to 2023.The detection of nucleic acid of influenza A virus was conducted by quantitative real-time polymerase chain reaction. For the positive samples influenza A virus, the H5,H7,H9 subtype were further detected. For H5-positive samples,the N1 and N6 subtype was detected. Software Excel 2007 and SPSS 25.0 were used to analyze the differences in annual distribution of avian influenza virus in different samples and surveillance sites.

Results From 2020 to 2023, a total of 1412 environmental samples were collected, of which 867 samples were positive for influenza A virus, the positive rate was 61.40%. The positive rates of H5N1, H5N6 and H9 subtypes were 0.58%, 2.65% and 82.35%, respectively. In addition, the positive rates of H5N1+H9, H5N6+H9, H5N1+H5N6+H9 were 2.42%, 11.42% and 0.58%,respectively. No H7 subtypes was detected.The positive rate of avian influenza virus was higher in Ceheng (80.00%) and Zhenfeng (76.84%), and lowest in Qinglong (46.00%). The positive rate of avain influenza virus was highest in environment sewage samples(68.33%), and lowest in poultry stool samples.

Conclusion The contaminations of H5N1, H5N6, H9 and other subtypes of avian influenza virus exsited in external environment of live poultry markets and farm produce markets in Qianxinan, and H9 subtype was the most frequently detected. It is necessary to further strengthen the real-time surveillance for avian influenza virus in external environment and the sanitary supervision in urban and rural poultry markets.