Genetic Characterization of H5N8 Highly Pathogenic Avian Influenza Viruses Isolated from Falcated Ducks and Environmental Water in Japan in November 2020.

Ahmed Magdy Khalil,Isshu Kojima,Makoto Ozawa,Mana Esaki,Tsutomu Matsui,Tatsunori Masatani,Yoshikazu Fujimoto,Kyonha Ri

doi:10.3390/pathogens10020171

Abstract

We isolated two highly pathogenic avian influenza viruses (HPAIVs) of subtype H5N8 clade 2.3.4.4b from falcated duck (Anas falcata) feces and environmental water collected at an overwintering site in Japan. Our isolates were almost genetically identical to each other and showed high genetic similarity with H5N8 HPAIVs recently isolated in South Korea, a distant part of Japan, and European countries. These results suggest the potential role of falcated ducks in the dissemination of HPAIVs.

Highlights

To identify the closest relatives of all the viral gene segments from A/falcated duck/KUd3/2020 (H5N8) isolate, the sequences were subjected to BLAST search against the Global Initiative on Sharing Avian Influenza Data (GISAID) and NCBI databases (Table 2)
The gene segments from A/falcated duck/KU-d3/2020 (H5N8) showed high similarity to European poultry isolates from the winter of 2019/2020 [21], they were less similar than those against the Asian isolates. These findings indicated that H5N8 highly pathogenic avian influenza viruses (HPAIVs) recently isolated in East Asia and Europe share a recent common ancestor without genetic reassortment
Falcated ducks are a minor duck species that host AIVs: among 18,502 AIVs isolated from duck species deposited in the GISAID database as of 9 December 2020, only 0.037% were associated with falcated duck, whereas more AIVs were isolated from mallards (30.82%), northern pintails (4.79%), and Eurasian wigeons (0.28%)

Summary

Introduction

To identify the closest relatives of all the viral gene segments from A/falcated duck/KUd3/2020 (H5N8) isolate, the sequences were subjected to BLAST search against the Global Initiative on Sharing Avian Influenza Data (GISAID) and NCBI databases (Table 2). To genetically characterize the two H5N8 isolates, the nucleotide sequences of all eight gene segments from both isolates were determined (Table 1).

Results

Conclusion