Genetic characterization of the first detected human case of avian influenza A (H5N6) in Anhui Province, East China

Abstract

We compared complete genome sequences of two strains of an avian influenza A (H5N6) virus isolated from a patient in Anhui Province with those of other strains from GenBank and Global initiative on sharing all influenza data (GISAID). The HA gene of the isolated virus shared homology with that of A/chicken/Zhejiang/727155/2014 (H5N6) at the level of similarity of 98%. The six internal genes of the Anhui strains were close to those of H9N2 viruses from Zhejiang, Shandong, and Guangdong provinces, with a similarity of 99%. In addition, the similarity between the internal antigens (NP and MP) of the isolated H5N6 virus and H7N9 and H10N8 viruses was 99%. Based on the data of phylogenetic analysis, the H5N6 influenza virus isolated in Anhui Province belonged to clade 2.3.4.4. The virus was shown to have molecular characteristics of highly pathogenic avian influenza viruses, including eight glycosylation sites and an amino acid sequence of the HA protein cleavage site, PLRERRRKKR/GLF, containing multiple basic amino acids. Additionally, the stalk domain of the NA protein was found to have a deletion in NA stalk region (11 amino acids in N6, positions 58–68). Our study demonstrated that the H5N6 virus from Anhui Province represented a triple-reassortant virus and could be highly pathogenic to humans. The prevalence of this virus should be closely monitored.

Mouse adaptation of the H9N2 avian influenza virus causes the downregulation of genes related to innate immune responses and ubiquitin-mediated proteolysis in mice

“…In addition, H9N2 virus can act as a "vehicle" to deliver different subtypes of AIVs to humans. The internal genes of H5N1, H5N6, H7N9, and H10N8 viruses, which pose a substantial threat to public health, came from H9N2 viruses [10][11][12][13]. The mechanisms through which the H9 avian influenza virus adapts to mammals and crosses the species barrier are a scientific problem that needs to be solved now.…”

“…significantly, H9N2 viruses function as a "vehicle" that deliver different subtypes of influenza viruses from avian species to humans [9]. H9N2 viruses contributed internal genes to H5N1, H5N6, H7N9, and H10N8 viruses isolated from humans with infections [10][11][12][13][14]. In our previous studies, the co-infection of a bird with H4N6 and H9N2 viruses led to a high frequency of reassortment and generated some reassortants that had higher virulence than that of the wildtype viruses in mammals [15].…”

Avian influenza overview August – November 2018

“…The genetic characterisation of a virus from a human case infected with HPAI A(H5N6) in Anhui Province, China, showed a high level of similarity of the HA gene to a chicken isolate belonging to clade 2.3.4.4. (He et al, 2018a). This virus was considered a triple reassortant with internal genes closely related to A(H9N2) and the NP and MP gene derived from A(H7N9) and A(H10N8) viruses.…”

A Novel Reassortant Avian H7N6 Influenza Virus Is Transmissible in Guinea Pigs via Respiratory Droplets

“…Since 2000, N6 subtypes of AIVs have been found in poultry in China. N6 subtype influenza viruses circulated widely in duck populations in southern and eastern China in 2006 (Bi et al, 2016), and the first human infection with an N6 (H5N6) subtype virus was reported in 2014 (Yang et al, 2015; Zhang et al, 2016; He et al, 2018). Notably, H5N6 viruses have become a dominant subtype in poultry in southern China (Bi et al, 2016).…”