Differential beta-coronavirus infection dynamics in human bronchial epithelial organoids.

The lower respiratory system serves as the target and barrier for beta-coronavirus (beta-CoV) infections. In this study, we explored beta-CoV infection dynamics in human bronchial epithelial (HBE) organoids, focusing on HCoV-OC43, SARS-CoV, MERS-CoV, and SARS-CoV-2. Utilizing advanced organoid culture techniques, we observed robust replication for all beta-CoVs, particularly noting that SARS-CoV-2 reached peak viral RNA levels at 72 h postinfection.

Evolutional dynamics of highly pathogenic avian influenza H5N8 genotypes in wintering bird habitats: Insights from South Korea's 2020-2021 season.

The winter of 2020-2021 in South Korea witnessed severe outbreaks of Highly Pathogenic Avian Influenza (HPAI) viruses, specifically multiple genotypes of the H5N8 subtype. These outbreaks prompted an extensive investigation into the genetic characteristics and evolutionary dynamics of these viruses. Under the auspices of the National Institute of Wildlife Disease Control and Prevention (NIWDC), we conducted a nationwide surveillance program, collecting 7588 specimens from diverse wild bird habitats.

HA N193D substitution in the HPAI H5N1 virus alters receptor binding affinity and enhances virulence in mammalian hosts.

During the 2021/2022 winter season, we isolated highly pathogenic avian influenza (HPAI) H5N1 viruses harbouring an amino acid substitution from Asparagine(N) to Aspartic acid (D) at residue 193 of the hemagglutinin (HA) receptor binding domain (RBD) from migratory birds in South Korea. Herein, we investigated the characteristics of the N193D HA-RBD substitution in the A/CommonTeal/Korea/W811/2021[CT/W811] virus by using recombinant viruses engineered via reverse genetics (RG). A receptor affinity assay revealed that the N193D HA-RBD substitution in CT/W811 increases α2,6 sialic acid receptor binding affinity.