avian influenza outbreaks virus subtype h5n8 in poultry

presentation design outbreaks virus subtype h5n8 avian influenza poultry 2020–2022 outbreak emerging strain highly pathogenic reassortant bird flu oie genetic h5n1 h9n2 zoonotic sicks chickens poultry 2023 2022 h9n2 h7n9 viruses mutations mutan 3d model diseases mortality symptoms