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Journal Article Ppublish

PubMed: 40752201 DOI: 10.1016/j.psj.2025.105580

Characterization of H9N2 avian influenza virus isolated from chickens and waterfowl in parts of Southern China from 2018 to April 2024.

Poult Sci 104(10):105580

Authors: Wanting Zhou, Jun He, Fangfang Qiao, Mengyao Wang, Qinghang Zeng, Yang Liu, Yue Zhao, Liji Zhang, Ting Li, Shouwen Du, Minhua Sun, Ming Liao

Affiliations

  • College of Animal Science & Technology, Zhong Kai University of Agriculture and Engineering, Guangzhou 510225, China; Institute of Animal Health, Guangdong Province Key Laboratory of Livestock Disease Prevention, Guangdong Province Key Laboratory for Prevention and Control of Avian Influenza and Other Major Poultry Diseases, Guangdong Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, 510640, China.
  • Institute of Laboratory Animal Science, Prevention and Control (Jinan University), Ministry of Education, Guangzhou Key Laboratory for Germ-Free Animals and Microbiota Application, Jinan University, Guangzhou 510632, China.
  • College of Animal Science & Technology, Zhong Kai University of Agriculture and Engineering, Guangzhou 510225, China.
  • State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China.
  • Institute of Animal Health, Guangdong Province Key Laboratory of Livestock Disease Prevention, Guangdong Province Key Laboratory for Prevention and Control of Avian Influenza and Other Major Poultry Diseases, Guangdong Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, 510640, China; Institute of Ecological Sciences, South China Normal University, Guangzhou 510631, China.
  • Institute of Animal Health, Guangdong Province Key Laboratory of Livestock Disease Prevention, Guangdong Province Key Laboratory for Prevention and Control of Avian Influenza and Other Major Poultry Diseases, Guangdong Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, 510640, China; College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
  • Institute of Animal Health, Guangdong Province Key Laboratory of Livestock Disease Prevention, Guangdong Province Key Laboratory for Prevention and Control of Avian Influenza and Other Major Poultry Diseases, Guangdong Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, 510640, China.
  • College of Animal Science & Technology, Zhong Kai University of Agriculture and Engineering, Guangzhou 510225, China; Institute of Animal Health, Guangdong Province Key Laboratory of Livestock Disease Prevention, Guangdong Province Key Laboratory for Prevention and Control of Avian Influenza and Other Major Poultry Diseases, Guangdong Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, 510640, China; College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.

Abstract

The H9N2 subtype of avian influenza virus (AIV) has become endemic in poultry farms across China, providing internal genes for other subtypes of viruses and occasionally having the ability to infect humans, thereby posing a significant public health threat. In this study, 61 H9N2 viruses were isolated from chickens and waterfowl in Southern China between 2018 and April 2024. We characterized their genetic derivation, antigenic diversity, receptor-binding specificity, neuraminidase (NA) activity, replication, and transmission in chickens and systematic pathological analysis. Genetic analysis revealed that 60 isolates belonged to the h9.4.2.5 lineage, while 7, 20, and 33 H9 strains belonged to the h9.4.2.5a, b, and c branches, respectively. One isolate belonged to the h9.4.2.1 lineage. Mainly tested H9N2 strains preferentially bound to human-type receptors, except one virus exhibiting dual receptor-binding specificity. Antigenicity analysis indicated that these tested viruses could be classified into 2 separate antigenic clusters. In addition, the selected viruses efficiently replicated and transmitted in chickens at a high dose induction. Continuous and systematic surveillance of H9N2 virus mutation and infection in poultry farms is crucial for early detection of novel recombinant viruses with pandemic potential and for enhancing biosecurity control.

MeSH

Influenza A Virus, H9N2 Subtype, Poultry, Farms, Influenza In Birds, Influenza, Human, Viruses, Orthomyxoviridae