Characterization of H9N2 avian influenza viruses from the Middle East demonstrates heterogeneity at amino acid position 226 in the hemagglutinin and potential for transmission to mammals

Abstract

Next-generation sequencing (NGS) technologies are a valuable tool to monitor changes in viral genomes and determine the genetic heterogeneity of viruses. In this study, NGS was applied to clinical poultry samples from Jordan to detect eleven H9N2 low pathogenic avian influenza viruses (LPAIV). All of the viruses tested belonged to Middle East A genetic group of G1 lineage. Deep sequencing demonstrated a high degree of heterogeneity of glutamine and leucine residues at position 226 in the hemagglutinin (HA) gene, which increases specificity to either avian or mammalian-type receptors. Moreover, additional amino acid changes in PB1, PA, M1, M2, and NS1 were identified among the viruses tested. Compared to single gene amplification, application of NGS for surveillance and characterization of H9N2 LPAIV provides a complete genetic profile of emerging isolates and better understanding of the potential of zoonotic transmissions to mammals.

Acquisition of Innate Inhibitor Resistance and Mammalian Pathogenicity During Egg Adaptation by the H9N2 Avian Influenza Virus

“…Egg adaptation of human IAVs results in increased affinity to avian-like receptor and/or escape from binding to inhibitors in the allantoic fluid ( Hardy et al, 1995 ; Gambaryan et al, 1997 , 1999 ). Given that the chicken may be a potential intermediate host to force H9N2 avian influenza viruses to acquire the mammalian adaptive markers ( Wan and Perez, 2007 ; Kuchipudi et al, 2009 ; Chrzastek et al, 2018 ), egg adaptive mutations of avian IAVs may affect viral pathogenicity in mammals. The recombinant viruses containing the 01310-CE20 HA (rH 20 N 2 and rH 20 N 20 ) displayed increased binding affinities to both avian-like and mammalian-like receptors, and increased resistance to the innate inhibitors in egg white and mouse lungs.…”

The Drivers of Pathology in Zoonotic Avian Influenza: The Interplay Between Host and Pathogen

“…One of the commonly associated amino acid substitutions for LPAI strains converting from avian to mammalian receptor-specificity is a HA Q226L substitution ( 58 , 95 – 97 ). For example, LPAI H9N2 isolates from birds can adopt a Q226L substitution, which increases its mammalian receptor binding affinity and potentially infect mammalian hosts ( 98 , 99 ). However, with regards to H7N9 human isolates, Belser and colleagues described the Q226 bearing Shanghai/1 and the L226 bearing Anhui/1 as binding to largely avian α-2,3-Gal receptor analogs and mixed α-2,3/α-2,6-Gal receptors, respectively ( 64 ).…”

Avian influenza overview August – November 2018

“…Domestic and wild birdsDetectionAs mentioned in previous reports(EFSA et al, 2018b;EFSA et al, 2018c), A(H9N2) is the most commonly detected non-notifiable subtype of influenza viruses in poultry in Asia, the Middle East and North Africa(Bonfante et al, 2018;Chrzastek et al, 2018;Xu et al, 2018; Zhu et al, 2018). This has also reduced the human exposure to the virus and no human cases have been reported since March 2018 (Zeng et al, 2018).4.4.5.…”