Diversified reassortant H9N2 avian influenza viruses in chicken flocks in northern and eastern China

Evolution of the H9N2 influenza genotype that facilitated the genesis of the novel H7N9 virus

“…These H9N2 vaccines initially limited the outbreaks and virus spread. However, despite multiple doses, the H9N2 vaccines became less effective, especially after 2007, and H9N2 influenza virus continues to circulate in vaccinated chicken flocks and has caused sporadic disease outbreaks (8,10,(12)(13)(14)(15)(16)(17)(18)(19)(20). However, the recent prevalence and molecular evolution of the H9N2 viruses in chickens especially in the flocks receiving large-scale vaccination, and their role in the emergence of human H7N9 virus, are not fully understood.…”

Isolation and characterization of H6N1 and H9N2 avian influenza viruses from Ducks in Hanoi, Vietnam

“…H6 and H9 AI viruses are widely distributed subtypes among poultry and wild birds in Asia (Huang et al, 2010;Moon et al, 2009;Nagarajan et al, 2009). The first H6 influenza 4 virus was isolated from a turkey in 1965, and since then, H6 viruses have been isolated with increasing frequency from wild birds and poultry in southern China and Southeast Asia (Webster et al, 1992).…”

Complete Genome Sequence of a Novel H9N2 Subtype Influenza Virus FJG9 Strain in China Reveals a Natural Reassortant Event

“…The reassortment can happen within all of the segments of influenza virus A, HA, NA, NP, M, PB1, PB2, PA, and NS (4). Panorama phylogenetic analysis from recent studies revealed that H9N2 viral genomes include at least 74 lineages (2,3 (3,5,6,7,10,11).…”

“…Genotype analysis results showed that the FJ/G9 virus belongs to genotype T, which was a novel genotype in chickens (6,11). The results of gene-sequence analysis revealed that FJ/G9 virus was a six-way reassortant virus with PB2 that probably originated from homologous genes of DK/ST/163/04 (H9N2); the PB1, HA, and NS genes were most closely associated with CK/BJ/ 1/94 (H9N2); the most likely origin of the PA gene was DK/ HK/Y439/97 (H9N2); the most likely origin of the NP gene was CK/SH/F/98 (H9N2); the most likely origin of the NA gene was CK/HK/G9/97 (H9N2), and the most likely origin of the M gene was Qa/HK/G1/97 (H9N2).…”