Genetic and antigenic evolution of H9N2 subtype avian influenza virus in domestic chickens in southwestern China, 2013–2016

Abstract

H9N2 avian influenza virus (AIV) has caused significant losses in chicken flocks throughout china in recent years. There is a limited understanding of the genetic and antigenic characteristics of the H9N2 virus isolated in chickens in southwestern China. In this study a total of 12 field strains were isolated from tissue samples from diseased chickens between 2013 and 2016. Phylogenetic analysis of the Hemagglutinin (HA) and Neuraminidase (NA) nucleotide sequences from the 12 field isolates and other reference strains showed that most of the isolates in the past four years could be clustered into a major branch (HA-branch A and NA-branch I) in the Clade h9.4.2 lineages. These sequences are accompanied by nine and seven new amino acids mutations in the HA and NA proteins, respectively, when compared with those previous to 2013. In addition, four new isolates were grouped into a minor branch (HA-branch B) in the Clade h9.4.2 lineages and two potential N-glycosylation sites were observed due to amino acid mutations in the HA protein. Three antigenic groups (1–3), which had low antigenic relatedness with two commonly used vaccines in China, were identified among the 12 isolates by antigenMap analysis. Immunoprotection testing showed that those two vaccines could efficiently prevent the shedding of branch A viruses but not branch B viruses. In conclusion, these results indicate the genotype of branch B may become epidemic in the next few years and that a new vaccine should be developed for the prevention of H9N2 AIV.

Genetic and biological characterization of H9N2 avian influenza viruses isolated in China from 2011 to 2014

“…The hemadsorbing sites (HBS’s, 366–373, 399–403, and 431–433, N2 numbering), active center (140–157), and antigenic determinants (153, 197–199, 328–336, 339–347, 367–370, 400–403, and 431–434) in the NA protein from 9 representative isolates in the two branches were also analyzed [ 29 ]. All the sequences from NA in the branch B isolates had mutations at the HBS’s positions 368, 369, and 401–402 (S/R368N, D/G369N/S, and DS401-402EN/DD, respectively) compared with the branch A isolates, which did not have.…”

Passive surveillance of clinical poultry diseases in an Upazila Government Veterinary Hospital of Bangladesh

“…The prevalence of aspergillosis higher in earlier age may be due to inhalation of spore from litter, contaminated hatching incubator, higher moisture containing litter and sawdust litter (Sultana et al, 2015). Avian influenza is endemic in Bangladesh causes huge economic losses in the poultry sub-sector through reduced egg production and high mortality (Xia et al, 2017). The strain H5N1 causes high mortality in birds and poses a serious health risk to the human population (Sarker et al, 2016).…”

Prevalence of avian influenza, Newcastle disease, and infectious bronchitis viruses in broiler flocks infected with multifactorial respiratory diseases in Iran, 2015–2016

“…Of these, infectious bronchitis, Newcastle disease, and H9N2 influenza have been the major endemic diseases in Iran with numerous studies carried out in this regard (Hadipour and Golchin 2011;Hosseini et al 2015;Hosseini et al 2014;Pourbakhsh et al 2008;Seifi et al 2010). Furthermore, these diseases were found to be some of the most critical factors for infections in the poultry industry, particularly in broilers, in other countries too (Hassan et al 2016;Naeem et al 2007;Xia et al 2017).…”