A novel highly pathogenic H5N8 avian influenza virus isolated from a wild duck in China

Abstract

Migrating wild birds are considered natural reservoirs of influenza viruses and serve as a potential source of novel influenza strains in humans and livestock. During routine avian influenza surveillance conducted in eastern China, a novel H5N8 (SH-9) reassortant influenza virus was isolated from a mallard duck in China. blast analysis revealed that the HA, NA, PB1, PA, NP, and M segments of SH-9 were most closely related to the corresponding segments of A/duck/Jiangsu/k1203/2010 (H5N8). The SH-9 virus preferentially recognized avian-like influenza virus receptors and was highly pathogenic in mice. Our results suggest that wild birds could acquire the H5N8 virus from breeding ducks and spread the virus via migratory bird flyways.

Keywords: H5N8; highly pathogenic avian influenza virus; wild duck.

Figure 1

Putative genomic compositions of the novel avian influenza (H5N8) virus with possible donor viruses. The genomic segments of three putative donor viruses are coded by color with each of the eight viral genomic segments represented by a horizontal bar. k1203 (H5N8), A/duck/Jiangsu/k1203/2010; 23(H11N9), A/environment/Jiangxi/28/2009; S11643 (H4N9), A/duck/Hunan/S11643/2013; SH-9 (H5N8), A/mallard duck/Shanghai/SH-9/2013.

Figure 2

Receptor-binding properties and pathogenicity of the novel H5N8 SH-9 virus in mice. (A, B) Receptor-binding specificities of a human H1N1 virus collecting during the 2009 pandemic (A/Changchun/01/2009(H1N1), panel (A) and the novel SH-9 virus (A/mallard duck/Shanghai/SH-9/2013 (H5N8), panel (B) were evaluated using a biotinylated α-2,3 glycan (blue line) and an α-2,6 glycan (red line). (C, D) Weight loss (C) and survival (D) were monitored for 14 days following inoculation of mice with 10^6·0 EID₅₀ SH-9 virus. Weight loss is expressed as the mean of percent starting body weight for mice at each time point.