Two reassortant types of highly pathogenic H5N8 avian influenza virus from wild birds in Central China in 2016

Abstract

Since 2016, the highly pathogenic avian influenza H5N8 virus has emerged in the Central Asian flyway and Europe, causing massive deaths in poultry and wild birds. In this study, we isolated and identified three H5N8 viruses from swan goose and black swans in Hubei province during the 2016/2017 winter season. Whole-genome sequencing and phylogenetic analysis revealed that the three viruses clustered into a group of H5N8 viruses from Qinghai Lake and Europe. A novel reassortment virus from swan goose was distinguished from that of black swans, in that its PA and NP genes were distinct from those of Qinghai Lake viruses. Molecular dating revealed that the ancestral strain of these H5N8 viruses emerged around July 2015. From sequence comparison, we discovered eight amino acid substitutions in HA and NA during the adaption process from poultry to wild birds. The three viruses were isolated from wild birds in the East Asian-Australasian flyway; however, the viral genomes were similar to H5N8 viruses circulating along the Central Asian flyway. From these data, we conclude that wetlands and lakes in Central China may play a key role in disseminating H5N8 viruses between the East Asian-Australasian and Central Asian flyways.

Low Pathogenic Avian Influenza A (H5N7) Virus Isolated from a Domestic Duck in Dongting Lake Wetland of China, 2016

“…Wetlands are important for wild migratory birds as stopover for resting and breeding. In China, millions of domestic ducks are also raised near Dongting Lake Wetland Nature Reverse (Hunan Province Rural Social and Economic Investigation Team 2008), and thus, these sites play key roles in the transmission of AIVs from wild birds to domestic birds (Ma et al 2018). Moreover, domestic ducks are usually asymptomatic after AIV infection (Kuchipudi et al 2014), and these healthy appearing ducks may serve as a hidden infection source.…”

Avian influenza overview November 2017 ‐ February 2018

“…Another study has shown that an exchange of internal genes with genes deriving from A(H5N1) viruses enhance pathogenicity and virulence (Park et al, 2018). Such reassorted viruses with different gene compositions have already been discovered (Beerens et al, 2018;Ma et al, 2018;Poen et al, 2018). Not even reassortment events with other viruses, but substitution of amino acids (PB2 (E627K), PA (F35S), HA (R227H), and NA (I462V)) can also alter the virulence in a mammalian model mouse (Yu et al, 2018).…”

“…showed a relationship of genome segments with AIV detected in Far East, Central Asia and Europe. The authors suggest that wetlands intersecting East Asian-Australasian and Central Asian flyways constitute the starting point for intercontinental spread of A(H5N8) viruses (Ma et al, 2018).…”

Circulation of Influenza A(H5N8) Virus, Saudi Arabia

“…Polymerase acidic protein (PA), HA, nucleoprotein (NP), neuraminidase (NA), M, and nonstructural protein (NS) segments were genetically similar to those derived from recent group B H5N8 viruses ( Technical Appendix Table 2, Figure 1). No genetic markers associated with mammalian host adaptation, α2,6 receptor-binding specificity, or antimicrobial drug resistance were detected (data not shown) ( 4 ). The gene constellation of PA, HA, NP, NA, M, and NS segments of these H5N8 viruses is similar to those of some H5N8 viruses detected in wild migratory birds from different geographic areas (e.g., A/Anser_cygnoides/Hubei/FW44/2016 and A/green-winged teal/Egypt/877/2016) ( 4 , 5 ).…”

“…No genetic markers associated with mammalian host adaptation, α2,6 receptor-binding specificity, or antimicrobial drug resistance were detected (data not shown) ( 4 ). The gene constellation of PA, HA, NP, NA, M, and NS segments of these H5N8 viruses is similar to those of some H5N8 viruses detected in wild migratory birds from different geographic areas (e.g., A/Anser_cygnoides/Hubei/FW44/2016 and A/green-winged teal/Egypt/877/2016) ( 4 , 5 ). The polymerase basic protein (PB) 1 and 2 segments of these viruses are similar to those of HPAI H5N5 viruses detected in the Far East (e.g., A/environment/Kamchatka/18/2016) and Europe (e.g., A/swan/Germany-SN/R10645/2016) ( Technical Appendix Figure 1).…”