That H9N2 avian influenza viruses circulating in different regions gather in the same live-poultry market poses a potential threat to public health

Tengfei Liu; Shumin Xie; Zhiyi Yang; Aimin Zha; Yuting Shi; Lingyu Xu; Junhong Chen; Wenbao Qi; Ming Liao; Weixin Jia

doi:10.3389/fmicb.2023.1128286

That H9N2 avian influenza viruses circulating in different regions gather in the same live-poultry market poses a potential threat to public health

Front Microbiol. 2023 Feb 16:14:1128286. doi: 10.3389/fmicb.2023.1128286. eCollection 2023.

Authors

Tengfei Liu¹, Shumin Xie¹, Zhiyi Yang¹, Aimin Zha¹, Yuting Shi¹, Lingyu Xu¹, Junhong Chen¹, Wenbao Qi^{1

2

3}, Ming Liao^{1

2

3}, Weixin Jia^{1

2

3}

Affiliations

¹ National Avian Influenza Para-Reference Laboratory, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.
² Key Laboratory of Zoonosis, Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, Guangzhou, China.
³ Key Laboratory of Zoonoses Prevention and Control of Guangdong Province, Guangzhou, China.

Abstract

H9N2 avian influenza viruses are endemic and persistent in China, but those that are prevalent in different provinces are also causes of wide epidemics, related to the spread of wild birds and the cross-regional trade in live poultry. For the past 4 years, beginning in 2018, we have sampled a live-poultry market in Foshan, Guangdong, in this ongoing study. In addition to the prevalence of H9N2 avian influenza viruses in China during this period, we identified isolates from the same market belonging to clade A and clade B, which diverged in 2012-2013, and clade C, which diverged in 2014-2016, respectively. An analysis of population dynamics revealed that, after a critical divergence period from 2014 to 2016, the genetic diversity of H9N2 viruses peaked in 2017. Our spatiotemporal dynamics analysis found that clade A, B, and C, which maintain high rates of evolution, have different prevalence ranges and transmission paths. Clades A and B were mainly prevalent in East China in the early stage, and then spread to Southern China, becoming epidemic with clade C. Strains from different regions converge at the same live-poultry market to communicate, which may be one reasons the H9N2 viruses are difficult to eradicate and increasingly dominant throughout China. Selection pressure and molecular analysis have demonstrated that single amino acid polymorphisms at key receptor binding sites 156, 160, and 190 under positive selection pressure, suggesting that H9N2 viruses are undergoing mutations to adapt to new hosts. Live-poultry markets are important because people who visit them have frequent contact with poultry, H9N2 viruses from different regions converge at these markets and spread through contact between live birds and humans, generating increased risks of human exposure to these viruses and threatening public health safety. Thus, it is important to reducing the cross-regional trade of live poultry and strengthening the monitoring of avian influenza viruses in live-poultry markets to reduce the spread of avian influenza viruses.

Keywords: H9N2; avian influenza virus; concentration; live-poultry trade; potential threat; spread.

Grants and funding

This research was supported by the China Agriculture Research System of MOF and MARA (CARS-41), China National Animal Disease Surveillance and Epidemiological Survey Program (2021-2025) (no. 202111), and the Science and Technology Program of Guangdong Province (2021B1212030015).