Molecular Characterization of a Novel Avian Influenza A (H2N9) Strain Isolated from Wild Duck in Korea in 2018.

Seon-Ju Yeo,Hong-Seog Park,Haan Woo Sung,Hyun Park,Duc-Duong Than

doi:10.3390/v11111046

Abstract

A novel avian influenza virus (A/wild duck/Korea/K102/2018) (H2N9) was isolated from wild birds in South Korea in 2018, and phylogenetic and molecular analyses were conducted on complete gene sequences obtained by next-generation sequencing. Phylogenetic analysis indicated that the hemagglutinin (HA) and neuraminidase (NA) genes of the A/wild duck/Korea/K102/2018 (H2N9) virus belonged to the Eurasian countries, whereas other internal genes (polymerase basic protein 1 (PB1), PB2, nucleoprotein (NP), polymerase acidic protein (PA), matrix protein (M), and non-structural protein (NS)) belonged to the East Asian countries. A monobasic amino acid (PQIEPR/GLF) at the HA cleavage site, E627 in the PB2 gene, and no deletion of the stalk region in the NA gene indicated that the A/wild duck/Korea/K102/2018 (H2N9) isolate was a typical low pathogenicity avian influenza (LPAI). Nucleotide sequence similarity analysis of HA revealed that the highest homology (98.34%) is to that of A/duck/Mongolia/482/2015 (H2N3), and amino acid sequence of NA was closely related to that of A/duck/Bangladesh/8987/2010 (H10N9) (96.45%). In contrast, internal genes showed homology higher than 98% compared to those of other isolates derived from duck and wild birds of China or Japan in 2016–2018. The newly isolated A/wild duck/Korea/K102/2018 (H2N9) strain is the first reported avian influenza virus in Korea, and may have evolved from multiple genotypes in wild birds and ducks in Mongolia, China, and Japan.

Highlights

Influenza viruses are classified based on 18 hemagglutinin (HA) and 11 neuraminidase (NA)surface proteins into a large variety of subtypes, some of which are a public health threat [1]
We describe the characterization of a H2N9. The A/wild duck/Korea/K102/2018 (H2N9) isolate from a wild duck in Korea for the first time
Due to the similarity of the genes, the species could not be differentiated among the four birds and the host was described as wild duck for our isolate

Summary

Introduction

Influenza viruses are classified based on 18 hemagglutinin (HA) and 11 neuraminidase (NA). Surface proteins into a large variety of subtypes, some of which are a public health threat [1]. Among these various subtypes, 16 subtypes of HA (H1–H16) and 9 subtypes of NA (N1–N9) belong to avian influenza viruses (AIV), while H17N10 and H18N11 subtypes are only detected in bats [2]. HA plays a central role in the life cycle of influenza A viruses through its involvement in receptor recognition, virus attachment, membrane fusion, and entry [4]. HA is a single-pass type I transmembrane glycoprotein present as a homotrimer on the viral surface that extends ~130 Å from the membrane. Each HA monomer contains two subunits, HA1 and HA2, produced by protease cleavage

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Conclusion