Characterization of avian influenza H5N3 reassortants isolated from migratory waterfowl and domestic ducks in China from 2015 to 2018

Abstract

Wild and domestic aquatic birds are the natural reservoirs of avian influenza viruses (AIVs). All subtypes of AIVs, including 16 hemagglutinin (HA) and nine neuraminidase (NA), have been isolated from the waterfowls. The H5 viruses in wild birds display distinct biological differences from their highly pathogenic H5 counterparts. Here, we isolated seven H5N3 AIVs including three from wild birds and four from domestic ducks in China from 2015 to 2018. The isolation sites of all the seven viruses were located in the region of the East Asian‐Australasian Migratory Flyway. Phylogenetic analysis indicated that the surface genes of these viruses originated from the wild bird H5 HA subtype and the N3 Eurasian lineage. The internal genes of the seven H5N3 isolates are derived from the five gene donors isolated from the wild birds or ducks in Eastern‐Asia region. They were also divided into five genotypes according to their surface genes and internal gene combinations. Interestingly, two of the seven H5N3 viruses contributed their partial internal gene segments (PB1, M and NS) to the newly emerged H7N4 reassortants, which have caused first human H7N4 infection in China in 2018. Moreover, we found that the H5N3 virus used in this study react with the anti‐serum of the H5 subtype vaccine isolate (Re‐11 and Re‐12) and reacted well with the Re‐12 anti‐serum. Our findings suggest that worldwide intensive surveillance and the H5 vaccination (Re‐11 and Re‐12) in domestic ducks are needed to monitor the emergence of novel H5N3 reassortants in wild birds and domestic ducks and to prevent H5N3 viruses transmission from the apparently healthy wild birds and domestic ducks to chickens.

Genetic and biological characteristics of the globally circulating H5N8 avian influenza viruses and the protective efficacy offered by the poultry vaccine currently used in China

“…The HA gene of H5 viruses has evolved into multiple clades, from clade 0 to clade 9, with some of these clades further divided into subclades (WHO, 2008). The H5 viruses continually reassort with other influenza viruses, forming different genotypes and subtypes (Cui et al, 2020;Lewis et al, 2021;Li et al, 2019).…”

Novel Reassortant Avian Influenza A(H9N2) Virus Isolate in Migratory Waterfowl in Hubei Province, China

“…Interestingly, the HA, NP, and NA segments were obtained in January-March 2013 ( Table 1 and Supplementary Figures S2D-F), whereas the PB2, PB1, and PA segments emerged in January-September 2014 ( Table 1 and Supplementary Figures S2A-C). The M segment was obtained from a duck H5N3 virus (Li et al, 2019) in August 2016 and the NS segment was obtained from a duck H11N3 virus in early 2016 ( Table 1 and Supplementary Figures S2G,H). In addition, we analyzed the Jiangsu poultry and human H7N4 viruses using BEAST software to determine the tMRCA, and found that the PA and M segments of the human H7N4 virus were most likely obtained in January/March 2017, respectively ( Table 1 and Supplementary Figures S2C,G).…”

Genetic Characterization of Avian Influenza A (H11N9) Virus Isolated from Mandarin Ducks in South Korea in 2018

“…Recently, A/duck/Jiangsu/SE0261/2018 (H5N3) was isolated from domestic ducks in a poultry market in Jiangsu Province in the spring of 2018 [81].…”