The Emergence and Decennary Distribution of Clade 2.3.4.4 HPAI H5Nx

Fan

Journal of General Virology

et al. 2020

The predominance of H5N6 in ducks and continuous human cases have heightened its potential threat to public health in China. Therefore, the detection of emerging variants of H5N6 avian influenza viruses has become a priority for pandemic preparedness. Questions remain as to its origin and circulation within the wild bird reservoir and interactions at the wild-domestic interface. Samples were collected from migratory birds in Poyang Lake, Jiangxi Province, PR China during the routine bird ring survey in 2014-16. Phylogenetic and coalescent analyses were conducted to uncover the evolutionary relationship among viruses circulating in wild birds. Here, we report the potential origin and phylogenetic diversity of H5N6 viruses isolated from wild birds in Poyang Lake. Sequence analyses indicated that Jiangxi H5N6 viruses most likely evolved from Eurasian-derived H5Nx and H6N6 viruses through multiple reassortment events. Crucially, the diversity of the HA gene implies that these Jiangxi H5N6 viruses have diverged into two primary clades − clade 2.3.4.4 and clade 2.3.2.1 c. Phylogenetic analysis revealed two independent pathways of reassortment during 2014-16 that might have facilitated the generation of emerging variants within wild bird populations as well as inter-species infections. Our findings contribute to our understanding of the genetic diversification of H5N6 viruses in the wild bird population. These results highlight the necessity of large-scale surveillance of wild birds in the Poyang Lake area to address the threat of regional epizootic epidemics and attendant pandemics.

Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Diversity of avian influenza A(H5N6) viruses in wild birds in southern China

Fan

Journal of General Virology

et al. 2020

“…Simultaneously, HPAI H5N6 subtype viruses from the same clade caused multiple outbreaks in China, Viet Nam, and Lao People's Democratic Republic and was associated with the first HPAI non-H5N1 virus human infection, in April 2014 in China 9 , 10 . Currently, H5N6 viruses have spread to multiple countries in Europe, the Middle East, and Africa 11 . A total of 24 laboratory-confirmed human cases have been reported in China that include at least 7 deaths 6 .…”

Section: Introductionmentioning

confidence: 99%

Characterization of highly pathogenic avian influenza H5Nx viruses in the ferret model

Pulit-Penaloza

Brock

Pappas

et al. 2020

Sci Rep

Highly pathogenic avian influenza (HPAI) H5 viruses, of the A/goose/Guangdong/1/1996 lineage, have exhibited substantial geographic spread worldwide since the first detection of H5N1 virus in 1996. Accumulation of mutations in the HA gene has resulted in several phylogenetic clades, while reassortment with other avian influenza viruses has led to the emergence of new virus subtypes (H5Nx), notably H5N2, H5N6, and H5N8. H5Nx viruses represent a threat to both the poultry industry and human health and can cause lethal human disease following virus exposure. Here, HPAI H5N6 and H5N2 viruses (isolated between 2014 and 2017) of the 2.3.4.4 clade were assessed for their capacity to replicate in human respiratory tract cells, and to cause disease and transmit in the ferret model. All H5N6 viruses possessed increased virulence in ferrets compared to the H5N2 virus; however, pathogenicity profiles varied among the H5N6 viruses tested, from mild infection with sporadic virus dissemination beyond the respiratory tract, to severe disease with fatal outcome. Limited transmission between co-housed ferrets was observed with the H5N6 viruses but not with the H5N2 virus. In vitro evaluation of H5Nx virus replication in Calu-3 cells and the identification of mammalian adaptation markers in key genes associated with pathogenesis supports these findings.

“…The process of genome reassortment plays an important role in this. Some subtypes may evolve and acquire a pathogenic phenotype that causes serious disease and is associated with epizootics and pandemics (such as H5Nx and H7Nx) [3,4]. Highly pathogenic avian influenza viruses (HPAIVs) originate from low-pathogenic precursors with the HA subtypes H5 and H7 [3,4].…”

Section: Introductionmentioning

confidence: 99%

“…Some subtypes may evolve and acquire a pathogenic phenotype that causes serious disease and is associated with epizootics and pandemics (such as H5Nx and H7Nx) [3,4]. Highly pathogenic avian influenza viruses (HPAIVs) originate from low-pathogenic precursors with the HA subtypes H5 and H7 [3,4]. However, the avian influenza virus subtypes H2, H4, H8, and H14 have been shown to support a highly pathogenic phenotype after the genetically engineered introduction of the polybasic cleavage site into the HA [5].…”

Section: Introductionmentioning

confidence: 99%

Characterization and Phylodynamics of Reassortant H12Nx Viruses in Northern Eurasia

et al. 2019

Wild waterfowl birds are known to be the main reservoir for a variety of avian influenza viruses of different subtypes. Some subtypes, such as H2Nx, H8Nx, H12Nx, and H14Nx, occur relatively rarely in nature. During 10-year long-term surveillance, we isolated five rare H12N5 and one H12N2 viruses in three different distinct geographic regions of Northern Eurasia and studied their characteristics. H12N2 from the Far East region was a double reassortant containing hemagglutinin (HA), non-structural (NS) and nucleoprotein (NP) segments of the American lineage and others from the classical Eurasian avian-like lineage. H12N5 viruses contain Eurasian lineage segments. We suggest a phylogeographical scheme for reassortment events associated with geographical groups of aquatic birds and their migration flyways. The H12N2 virus is of particular interest as this subtype has been found in common teal in the Russian Far East region, and it has a strong relation to North American avian influenza virus lineages, clearly showing that viral exchange of segments between the two continents does occur. Our results emphasize the importance of Avian Influenza Virus (AIV) surveillance in Northern Eurasia for the annual screening of virus characteristics, including the genetic constellation of rare virus subtypes, to understand the evolutionary ecology of AIV.