Genetic characterization of low-pathogenic avian influenza subtypes H10N6 and H10N7 from free-grazing ducks in Thailand

Vet World Vol.17 September-2024 Article - 25

Research Article

Veterinary World, 17(9): 2166-2176

https://doi.org/10.14202/vetworld.2024.2166-2176

Supanat Boonyapisitsopa^1,2,3, Supassama Chaiyawong², Kamonpan Charoenkul^1,2, Kitikhun Udom², Ekkapat Chamsai², Waleemas Jairak², Wikanda Tunterak², Napawan Bunpapong^2,3, and Alongkorn Amonsin^1,2

1. Department of Veterinary Public Health, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand.
2. Emerging and Re-emerging Infectious Diseases in Animals, Center of Excellence, and One Health Research Cluster, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand.
3. Veterinary Diagnostic Laboratory, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand.

Background and Aim: Free-grazing duck (FGD) raising is a unique domestic duck production system that is widely practiced in several Asian countries, including Thailand. FGD is a significant reservoir for influenza A viruses (IAVs). In this study, we genetically characterized IAV-H10N6 and IAV-H10N7 isolated from avian influenza surveillance in FGDs in Thailand.

Materials and Methods: We collected 640 swab samples from 29 FGD flocks located in 6 provinces of Thailand. IAVs were isolated from swab samples using egg inoculation. Hemagglutination test-positive samples were then subjected to IAV detection. Viral RNA was subjected to IAV detection using real-time reverse-transcription polymerase chain reaction (rRT-PCR) specific to matrix (M) gene. IAV subtypes were identified using the RT-PCR assay specific to all hemagglutinin and neuraminidase subtypes. Whole-genome sequencing of IAVs was performed to genetically characterize IAV-H10N6 and IAV-H10N7.

Results: Our results showed that 41 (6.41%) samples tested positive for IAV using rRT-PCR specific to the M gene. Among these, only two IAVs were subtypes as IAV-H10N6 and IAV-H10N7 and were subjected to whole-genome sequencing. IAV-H10N6 and IAV-H10N7 belonged to the Eurasian lineage and did not show any evidence of reassortment from the North American lineage. The viruses exhibited low-pathogenic characteristics and preferred binding to avian-type receptors. Genetic analysis revealed no mutations in PB2 and M genes, unlike human IAV-H10N3 and IAV-H10N8, which exhibited increased virulence in mammals.

Conclusion: IAV-H10N6 and IAV-H10N7 viruses have less potential as zoonotic viruses. However, IAV in FGDs should be monitored for novel reassortant or zoonotic viruses. This study provides information on the genetic characteristics and diversity of IAV-H10N6 and IAV-H10N7 that are circulated in FGDs in Thailand.

Keywords: free-grazing ducks, genetic characterization, H10N6, H10N7, influenza A virus.

How to cite this article: Boonyapisitsopa S, Chaiyawong S, Charoenkul K, Udom K, Chamsai E, Jairak W, Tunterak W, Bunpapong N, and Amonsin A (2024) Genetic characterization of low-pathogenic avian influenza subtypes H10N6 and H10N7 from free-grazing ducks in Thailand, Veterinary World, 17(9): 2166–2176.

Received: 2024-06-02 Accepted: 2024-08-30 Published online: 2024-09-28

Corresponding author: Alongkorn Amonsin E-mail: alongkorn.a@chula.ac.th

DOI: 10.14202/vetworld.2024.2166-2176

Copyright: Boonyapisitsopa, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/ by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.