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Comp Immunol Microbiol Infect Dis. 2015 Oct;42:21-30. doi: 10.1016/j.cimid.2015.08.001. Epub 2015 Aug 28.

The evolutionary dynamics of highly pathogenic avian influenza H5N1 in south-central Vietnam reveals multiple clades evolving from Chinese and Cambodian viruses.

Author information

1
Department of Microbiology, Chung-Ang University College of Medicine, Seoul, South Korea; Central Vietnam Veterinary Institute, Nha Trang, Vietnam.
2
Department of Microbiology, Chung-Ang University College of Medicine, Seoul, South Korea.
3
Central Vietnam Veterinary Institute, Nha Trang, Vietnam.
4
Department of Genetic Engineering and Graduate School of Biotechnology, Kyung Hee University, Yongin, South Korea.
5
Viral Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.
6
Viral Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea; National Primate Research Center, Ochang, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.
7
Department of Microbiology, Chung-Ang University College of Medicine, Seoul, South Korea. Electronic address: kimwy@cau.ac.kr.

Abstract

In Vietnam, highly pathogenic avian influenza (HPAI), such as that caused by H5N1 viruses, is the most highly contagious infectious disease that has been affecting domestic poultry in recent years. Vietnam might be an evolutionary hotspot and a potential source of globally pandemic strains. However, few studies have reported viruses circulating in the south-central region of Vietnam. In the present study, 47 H5N1-positive samples were collected from both vaccinated and unvaccinated poultry farms in the South Central Coast region of Vietnam during 2013-2014, and their genetic diversity was analyzed. A common sequence motif for HPAI virus was identified at HA-cleavage sites in all samples: either RERRRKR/G (clades 2.3.2.1c and 2.3.2.1a) or REGRRKKR/G (clade 1.1.2). Phylogenetic analysis of HA genes identified three clades of HPAI H5N1: 1.1.2 (n=1), 2.3.2.1a (n=1), and 2.3.2.1c (n=45). The phylogenetic analysis indicated that these Vietnamese clades may have evolved from Chinese and Cambodian virus clades isolated in 2012-2013 but are less closely related to the clades detected from the Tyva Republic, Bulgaria, Mongolia, Japan, and Korea in 2009-2011. Detection of the coexistence of virus clades 2.3.2.1 and the very virulent 1.1.2 in the south-central regions suggests their local importance and highlights concerns regarding their spread, both northwards and southwards, as well as the potential for reassortment. The obtained data highlight the importance of regular identification of viral evolution and the development and use of region-specific vaccines.

KEYWORDS:

Highly pathogenic avian influenza H5N1; Poultry; South-central Vietnam

PMID:
26577194
DOI:
10.1016/j.cimid.2015.08.001
[Indexed for MEDLINE]

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