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Literature detail

Evolution of H7N9 highly pathogenic avian influenza virus in the context of vaccination.

Yujie Hou1,2 Guohua Deng1 Pengfei Cui1 Xianying Zeng1 Bin Li1 Dongxue Wang1 Xinwen He1 Cheng Yan1 Yaping Zhang1 Jiongjie Li1 Jinming Ma1,3 Yanbing Li1 Xiurong Wang1 Guobin Tian1 Huihui Kong1 Lijie Tang2 Yasuo Suzuki4 Jianzhong Shi1,3 Hualan Chen1,5
Affiliations 5 institutions
  1. State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, CAAS, Harbin, People's Republic of China.
  2. College of Veterinary Medicine, Northeast Agricultural University, Harbin, People's Republic of China.
  3. Institute of Western Agriculture, CAAS, Changji, People's Republic of China.
  4. Department of Medical Biochemistry, University of Shizuoka School of Pharmaceutical Sciences, Shizuoka, Japan.
  5. National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, CAAS, Harbin, People's Republic of China.
PMID 38629574 2024 Emerg Microbes Infect eng ppublish
PubMed DOI Browse context

Article

Publication summary

Human infections with the H7N9 influenza virus have been eliminated in China through vaccination of poultry; however, the H7N9 virus has not yet been eradicated from poultry. Carefully analysis of H7N9 viruses in poultry that have sub-optimal immunity may provide a unique opportunity to witness the evolution of highly pathogenic avian influenza virus in the context of vaccination. Between January 2020 and June 2023, we isolated 16 H7N9 viruses from samples we collected during surveillance and samples that were sent to us for disease diagnosis. Genetic analysis indicated that these viruses belonged to a single genotype previously detected in poultry. Antigenic analysis indicated that 12 of the 16 viruses were antigenically close to the H7-Re4 vaccine virus that has been used since January 2022, and the other four viruses showed reduced reactivity with the vaccine. Animal studies indicated that all 16 viruses were nonlethal in mice, and four of six viruses showed reduced virulence in chickens upon intranasally inoculation. Importantly, the H7N9 viruses detected in this study exclusively bound to the avian-type receptors, having lost the capacity to bind to human-type receptors. Our study shows that vaccination slows the evolution of H7N9 virus by preventing its reassortment with other viruses and eliminates a harmful characteristic of H7N9 virus, namely its ability to bind to human-type receptors.

Avian influenza virus; H7N9; evolution; receptor-binding properties; pathogenicity; antigenicity Chickens Influenza A Virus, H7N9 Subtype Influenza in Birds Influenza Vaccines Vaccination Animals China Evolution, Molecular Female Humans Influenza, Human Mice Mice, Inbred BALB C Phylogeny Poultry Poultry Diseases Virulence

Structured evidence records

Evidence records

7 total
Host Range Experiment 3 records
Host Range Experiment Extraction confidence 0.80
Key finding

H7N9 viruses isolated from poultry were nonlethal in mice, less virulent in chickens, and demonstrated restricted receptor binding to avian-type receptors without ability to bind human-type receptors.

Virus
IAV H7N9
Location
Not specified
Supporting text

Animal studies indicated that all 16 viruses were nonlethal in mice, and four of six viruses showed reduced virulence in chickens upon intranasally inoculation. Importantly, the H7N9 viruses detected in this study exclusively bound to the avian-type receptors, having lost the capacity to bind to human-type receptors.

Method
intranasal inoculation; animal study
Experimental system
in vivo animal experiment
Host Range Experiment Extraction confidence 0.80
Key finding

Four of six H7N9 viruses showed reduced virulence in chickens after intranasal inoculation.

Virus
IAV H7N9
Location
Not specified
Supporting text

Animal studies indicated that all 16 viruses were nonlethal in mice, and four of six viruses showed reduced virulence in chickens upon intranasally inoculation.

Method
intranasal inoculation; animal study
Experimental system
in vivo animal experiment
Host Range Experiment Extraction confidence 0.80
Key finding

Receptor-binding assays showed H7N9 viruses bind exclusively to avian-type receptors and cannot bind human-type receptors.

Virus
IAV H7N9
Host
Aves Aves
Location
Not specified
Supporting text

The H7N9 viruses detected in this study exclusively bound to the avian-type receptors, having lost the capacity to bind to human-type receptors.

Method
receptor-binding assay
Experimental system
receptor-binding assay
Genomic Evolution 1 records
Genomic Evolution Extraction confidence 0.90
Key finding

Genetic and phylogenetic analyses showed that the H7N9 viruses from poultry in China between 2020 and 2023 all clustered within a single genotype, suggesting constrained genomic evolution under vaccination.

Virus
IAV H7N9
Host
Aves
Location
Not specified
Supporting text

Genetic analysis indicated that these viruses belonged to a single genotype previously detected in poultry.

Genes or proteins
whole genome
Analysis methods
genetic analysis; phylogenetic analysis
Molecular Adaptation 1 records
Molecular Adaptation Extraction confidence 0.90
Key finding

H7N9 viruses isolated after poultry vaccination lost the ability to bind human-type receptors and retained avian-type receptor binding, indicating molecular adaptation affecting host tropism.

Virus
IAV H7N9
Host
Not specified
Location
Not specified
Supporting text

Importantly, the H7N9 viruses detected in this study exclusively bound to the avian-type receptors, having lost the capacity to bind to human-type receptors. Our study shows that vaccination slows the evolution of H7N9 virus by preventing its reassortment with other viruses and eliminates a harmful characteristic of H7N9 virus, namely its ability to bind to human-type receptors.

Receptors
avian-type receptor; human-type receptor
Mechanism types
receptor_binding; tissue_tropism
Receptor Usage 1 records
Receptor Usage Extraction confidence 0.95
Key finding

H7N9 viruses isolated from poultry bound only to avian-type receptors and no longer recognized human-type receptors, showing a shift in receptor specificity.

Virus
IAV H7N9
Host
Aves
Location
Not specified
Supporting text

Importantly, the H7N9 viruses detected in this study exclusively bound to the avian-type receptors, having lost the capacity to bind to human-type receptors.

Receptors
avian-type receptors
Zoonotic Surveillance 1 records
Zoonotic Surveillance Extraction confidence 0.95
Key finding

Surveillance of poultry in China from 2020 to 2023 identified 16 H7N9 avian influenza viruses for genetic and antigenic analysis.

Virus
IAV H7N9
Host
Aves
Location
China China
Supporting text

Between January 2020 and June 2023, we isolated 16 H7N9 viruses from samples we collected during surveillance and samples that were sent to us for disease diagnosis.

Method
surveillance
Geographic raw
China
Country inferred
China