Detection of a Novel Reassortant H9N9 Avian Influenza Virus in Free-Range Ducks in Bangladesh

Abstract

Wild aquatic birds are the primary natural reservoir for influenza A viruses (IAVs). In this study, an A(H9N9) influenza A virus (A/duck/Bangladesh/44493/2020) was identified via routine surveillance in free-range domestic ducks in Bangladesh. Phylogenetic analysis of hemagglutinin showed that the H9N9 virus belonged to the Y439-like lineage. The HA gene had the highest nucleotide identity to A/Bean Goose (Anser fabalis)/South Korea/KNU 2019-16/2019 (H9N2). The other seven gene segments clustered within the Eurasian lineage.

The origin of internal genes contributes to the replication and transmission fitness of H7N9 avian influenza virus

“…There is an ever-present concern that geographical expansion of H7N9 could facilitate reassortment with a more diverse range of AIVs, leading to the generation of novel AIVs which are more transmissible or pathogenic in poultry and have a higher propensity for zoonotic transmission to humans (29). Indeed, H9N9 and H7N2 subtypes have already been seen to arise as a result of natural reassortment in the field (30)(31)(32)(33) or after experimental co-infection between H7N9 and H9N2 (34), with the progeny having been shown to have increased virulence both experimentally and naturally (34,35). We have previously demonstrated how a novel H9N9 reassortant virus emerged as the dominant genotype following in vivo co-infection between China-origin H7N9 and G1-like H9N2 viruses (34).…”

The Origin of Internal Genes Contributes to the Replication and Transmission Fitness of H7N9 Avian Influenza Virus

“…There is an ever-present concern that geographical expansion of H7N9 could facilitate reassortment with a more diverse range of AIVs, leading to the generation of novel AIVs which are more transmissible or pathogenic in poultry and have a higher propensity for zoonotic transmission to humans ( 29 ). Indeed, H9N9 and H7N2 subtypes have already been seen to arise as a result of natural reassortment in the field ( 30 – 33 ) or after experimental coinfection between H7N9 and H9N2 ( 34 ), with the progeny having been shown to have increased virulence both experimentally and naturally ( 34 , 35 ). We have previously demonstrated how a novel H9N9 reassortant virus emerged as the dominant genotype following in vivo coinfection between A/Anhui/1/2013-lineage H7N9 and G1-like H9N2 viruses ( 34 ).…”