An investigation on avian influenza virus distribution in poultry-related environment in Nanping city

Objective To profile the distribution of avian influenza virus in poultry-related environment in poultry industry developed area in Fujian province, an investigation was conducted in Nanping city from Dec.2021 to Dec.2023.

Methods The samples from multiple types of external environment related to poultry in Nanping city were collected from Dec. 2021 to Dec. 2023, and the real-time fluorescence quantitative RT-PCR used to detect and subtype the influenza A virus (FluA). SPSS 26.0 software was used to analyze the distribution characteristics of FluA in poultry-related environment and the differences in time, places and sample types.

Results The overall positive rate of FluA in samples from poultry-related environment was 49.16% (1 435/2 919). The positive rates of H3, H5, H9 and H10 subtypes were 0.72% (21/2 919), 9.42% (275/2 919), 33.20% (969/2 919), 0.89% (26/2 919) respectively, and no H7 subtype was detected. The positive rate of mixed type (more than one subtype of FluA detected in a same sample) was 6.51% (190/2 919), and the positive rate of unknown subtype (positive for FluA but negative for H3/5/7/9/10) was 11.58% (338/2 919). The higher positive rate of FluA mainly occurred in autumn-winter season (September to February of the following year). In live poultry markets and slaughterhouses, the positive rates of FluA, H9 subtype, mixed type and unknown subtype were significantly higher than that in poultry farms. The positive rate of FluA in poultry drinking water and feces was higher than samples of other types, most of the positive samples were H9 subtype.

Conclusions The positive rate of FluA in poultry-related environment in Nanping city was higher in autumn-winter season. The investigation also showed that higher FluA positive rate in drinking water and feces sample and diversity of the virus existed in the place of multiple types of poultry clustered, such as live poultry markets and slaughterhouses.