ObjectiveTo analyze the genetic evolution and mutation of the first case of human infection with highly pathogenic avian influenza (HPAI) virus H5N8 in the world, so as to provide scientific basis for the prevention and control of HPAI H5N8.
MethodsThe complete genomic sequences of HPAI H5N8 viruses were searched from the Global Initiative on Sharing All Influenza Data (GISAID) database. Phylogenetic trees were generated by maximum likelihood (ML) method using MEGA software. The key genetic variations in the genome were analyzed.
ResultsThe highly pathogenic avian influenza virus H5N8 belonged to clade 2.3.4.4b. The genomes of the virus had high similarity (99%~100%) with the virus genomes of A/chicken/Astrakhan/2171-1/2020, A/chicken/Astrakhan/321-10/2020 and A/chicken/Astrakhan/321-06/2020. The receptor binding site at the position aa222-224 in HA gene was QRG (H5 encoding). The virus was preferentially bound to avian α-2,3-linked sialic acids receptor. No mammalian adaptive amino acid mutation sites, such as E627K and D701N, were found in PB2 gene. NA and M2 genes had no resistance mutations to neuraminidase inhibitors and amantadine. The virus remained to be sensitive to antiviral therapy.
ConclusionsThe current highly pathogenic avian influenza virus H5N8 has not adapted to humans and had no ability of human-to-human transmission. Surveillance for avian influenza virus H5N8 should be maintained.