Identification of Two novel reassortant avian influenza a (H5N6) viruses in whooper swans in Korea, 2016

Jipseol Jeong,Saemi Lee,Jeonghwa Shin,Kwanghee Lee,Seong-Deok Jo,Jonathan Sleeman,Injung An,Youngsik Kim,Chanjin Woo,Kidong Son,Seung-Jun Wang,Yongkwan Kim,Hon S Ip,Weonhwa Jheong,Jae-Ku Oem

doi:10.1186/s12985-017-0731-7

Abstract

BackgroundOn November 20, 2016 two novel strains of H5N6 highly pathogenic avian influenza virus (HPAIVs) were isolated from three whooper swans (Cygnus cygnus) at Gangjin Bay in South Jeolla province, South Korea. Identification of HPAIVs in wild birds is significant as there is a potential risk of transmission of these viruses to poultry and humans.ResultsPhylogenetic analysis revealed that Gangjin H5N6 viruses classified into Asian H5 clade 2.3.4.4 lineage and were distinguishable from H5N8 and H5N1 HPAIVs previously isolated in Korea. With the exception of the polymerase acidic (PA) gene, the viruses were most closely related to A/duck/Guangdong/01.01SZSGXJK005-Y/2016 (H5N6) (98.90 ~ 99.74%). The PA genes of the two novel Gangjin H5N6 viruses were most closely related to AIV isolates previously characterized from Korea, A/hooded crane/Korea/1176/2016 (H1N1) (99.16%) and A/environment/Korea/W133/2006 (H7N7) (98.65%). The lack of more recent viruses to A/environment/Korea/W133/2006 (H7N7) indicates the need for analysis of recent wild bird AIVs isolated in Korea because they might provide further clues as to the origin of these novel reassortant H5N6 viruses.ConclusionsAlthough research on the origins and epidemiology of these infections is ongoing, the most likely route of infection for the whooper swans was through direct or indirect contact with reassortant viruses shed by migratory wild birds in Korea. As H5N6 HPAIVs can potentially be transmitted to poultry and humans, continuous monitoring of AIVs among wild birds will help to mitigate this risk.

Highlights

On November 20, 2016 two novel strains of H5N6 highly pathogenic avian influenza virus (HPAIVs) were isolated from three whooper swans (Cygnus cygnus) at Gangjin Bay in South Jeolla province, South Korea
In most instances when avian influenza viruses (AIVs) of wild-bird origin are transmitted to poultry, infections are initially mild and represent a low pathogenic phenotype
The polymerase acidic (PA) subunit segments of Gangjin 48 and Gangjin 49–2 were identical to each other but differed (94.05% identity) from Gangjin 49–1, which suggests that at least two kinds of novel H5N6 HPAIV strains have circulated among wild birds in Korea

Summary

Introduction

On November 20, 2016 two novel strains of H5N6 highly pathogenic avian influenza virus (HPAIVs) were isolated from three whooper swans (Cygnus cygnus) at Gangjin Bay in South Jeolla province, South Korea. Short report As a natural reservoir for avian influenza viruses (AIVs), wild birds do not typically exhibit clinical signs of infection [1]. In most instances when AIVs of wild-bird origin are transmitted to poultry, infections are initially mild and represent a low pathogenic phenotype.

Results

Conclusion