Molecular Characterization of an H5N3 Influenza Virus Isolated from Spot-Billed Duck

Abstract

Among the 16 hemagglutinin (HA) subtypes of avian influenza virus (AIV), only the H5 and H7 subtypes have caused highly pathogenic avian influenza (HPAI) in poultry. However, most H5 or H7 subtype viruses are categorized as low pathogenic avian influenza (LPAI). Some AIVs, including the H5 and H7 HPAI viruses, have shown the ability to infect humans directly. In this study, we describe the biological and molecular characterization of an H5N3 AIV (SBD/KR/KNU SYG06/06) isolated from spot-billed duck (Anas poecilorhyncha) in Korea. A phylogenetic analysis of the eight viral genes showed that the SBD/KR/KNU SYG06/06 isolate belongs to the Eurasian lineage and that the SBD/KR/KNU SYG06/06 isolate was clearly different from HPAI H5N1 strains, including human isolates and the Italian HPAI H5N2 strains. Additionally, no relationship was found between SBD/KR/KNU SYG06/06 and the Korean HPAI H5N1 isolates. The SBD/KR/ KNU SYG06/06 isolate had avian specific receptor binding site residues in the HA protein and the four C-terminal amino acids in the NS1 protein. The HA protein of the SBD/KR/KNU SYG06/06 isolate exhibited the typical LPAI motif at the cleavage site and this virus produced no cytopathic effects in MDCK cells without trypsin. Given these results, we suggest that the H5N3 AIV isolated from the spot-billed duck should be considered an LPAI virus and should have no pathogenic effect in humans.

Emergence of a Novel Reassortant H5N3 Avian Influenza Virus in Korean Mallard Ducks in 2018

“…Molecular characterization identified the pathogenic potential of the KNU18-91 isolate and showed that it had a PQRETR/ GLF sequence at the HA cleavage site, suggesting low pathogenicity [8]. Similar to that reported by Lee et al [22] (2013) for H5N3 isolates in South Korea, the fragment deletion in the NA gene stalk region that represents wild bird virus adaptation to a new host was absent in the isolate under study, supporting LPAI of the new isolates [22,74]. The 274H and 292R residues retained viral sensitivity to neuraminidase (oseltamivir and zanamivir) inhibitors [75].…”

Assessment of the spatiotemporal risk of avian influenza between waterfowl and poultry farms during the annual cycle: A spatial prediction study focused on seasonal distribution changes in resident waterfowl in South Korea

“…Lee et al., 2011; J.‐H. Lee et al., 2013). Both migratory populations from northern Russia, China and Mongolia and resident populations usually move to river estuaries and form huge wintering flocks from October to March (W.‐S.…”

“…The mandarin, mallard and spot-billed duck, well-known winter migrants and resident birds in South Korea, were selected since most HPAI viruses have been detected in them (E.-T. H.-R. Kim et al, 2011;D.-H. Lee et al, 2011;J.-H. Lee et al, 2013). Both migratory populations from northern Russia, China and Mongolia and resident populations usually move to river estuaries and form huge wintering flocks from October to March (W.-S. Shin et al, 2012).…”

“…Therefore, in this study, to assess changes in potential exposure to AI viruses depending on spatiotemporal variations, we predicted the spatial distributional changes in representative resident waterfowl that also exist as winter migrants in South Korea: the mandarin (Aix galericulata), mallard (Anas platyrhynchos) and spot-billed duck (A. zonorhyncha). In these ducks, not only LPAI but also HPAI viruses are detected frequently (E.-T. H.-R. Kim et al, 2011;D.-H. Lee et al, 2011;J.-H. Lee et al, 2013).…”

“…Lee et al., 2011; J.‐H. Lee et al., 2013). In addition, these ducks are broadly distributed with high population densities and easily form mixed population flocks with other waterfowl species during the wintering season in South Korea (W.‐S.…”