Limits...
Novel genotypes of H9N2 influenza A viruses isolated from poultry in Pakistan containing NS genes similar to highly pathogenic H7N3 and H5N1 viruses.

Iqbal M, Yaqub T, Reddy K, McCauley JW - PLoS ONE (2009)

Bottom Line: The NS gene segment showed greater genetic diversity and shared a high level of similarity with NS genes from either H5 or H7 subtypes rather than with established H9N2 Eurasian lineages.These results indicate that during recent years the H9N2 viruses have undergone extensive genetic reassortment which has led to the generation of H9N2 viruses of novel genotypes in the Indian sub-continent.The novel genotypes of H9N2 viruses may play a role in the increased problems observed by H9N2 to poultry and reinforce the continued need to monitor H9N2 infections for their zoonotic potential.

View Article: PubMed Central - PubMed

Affiliation: Division of Microbiology, Institute for Animal Health, Compton Laboratory, Compton, Newbury, Berkshire, UK. munir.iqbal@bbsrc.ac.uk

ABSTRACT
The impact of avian influenza caused by H9N2 viruses in Pakistan is now significantly more severe than in previous years. Since all gene segments contribute towards the virulence of avian influenza virus, it was imperative to investigate the molecular features and genetic relationships of H9N2 viruses prevalent in this region. Analysis of the gene sequences of all eight RNA segments from 12 viruses isolated between 2005 and 2008 was undertaken. The hemagglutinin (HA) sequences of all isolates were closely related to H9N2 viruses isolated from Iran between 2004 and 2007 and contained leucine instead of glutamine at position 226 in the receptor binding pocket, a recognised marker for the recognition of sialic acids linked alpha2-6 to galactose. The neuraminidase (NA) of two isolates contained a unique five residue deletion in the stalk (from residues 80 to 84), a possible indication of greater adaptation of these viruses to the chicken host. The HA, NA, nucleoprotein (NP), and matrix (M) genes showed close identity with H9N2 viruses isolated during 1999 in Pakistan and clustered in the A/Quail/Hong Kong/G1/97 virus lineage. In contrast, the polymerase genes clustered with H9N2 viruses from India, Iran and Dubai. The NS gene segment showed greater genetic diversity and shared a high level of similarity with NS genes from either H5 or H7 subtypes rather than with established H9N2 Eurasian lineages. These results indicate that during recent years the H9N2 viruses have undergone extensive genetic reassortment which has led to the generation of H9N2 viruses of novel genotypes in the Indian sub-continent. The novel genotypes of H9N2 viruses may play a role in the increased problems observed by H9N2 to poultry and reinforce the continued need to monitor H9N2 infections for their zoonotic potential.

Show MeSH

Related in: MedlinePlus

Phylogenetic relationships of the NS genes of H9N2 avian influenza viruses isolated from poultry in Pakistan.Analysis was based on nucleotides 27–870 of segment eight of all viruses included in this analysis. NS gene sequences were compared with closely related H5, H7 and H9 viruses (the viruses highlighted in red were sequenced in this study and H9N2, H7N3 and H5N1 viruses isolated in Pakistan previously are indicated in blue, pink and brown respectively). The phylogenetic methods and abbreviations were as described for figure 1.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2690689&req=5

pone-0005788-g008: Phylogenetic relationships of the NS genes of H9N2 avian influenza viruses isolated from poultry in Pakistan.Analysis was based on nucleotides 27–870 of segment eight of all viruses included in this analysis. NS gene sequences were compared with closely related H5, H7 and H9 viruses (the viruses highlighted in red were sequenced in this study and H9N2, H7N3 and H5N1 viruses isolated in Pakistan previously are indicated in blue, pink and brown respectively). The phylogenetic methods and abbreviations were as described for figure 1.

Mentions: In contrast to the other segments phylogenetic analysis of the NS gene segment of UDL viruses split the 12 viruses into three distinct groups (Figure 8). Six isolates of one group cluster together with 97.8% to 100% identity to each other and showed closest nucleotide identity (95.9–96.6%) with Ck/Pak/NARC-100/04, an H7N3 virus (Figure 8 and Table 3). The second group (represented by a single virus, A/Ck/Pak/UDL-01/06) showed a strikingly close relationship with 99.8 to 100% nucleotide identity within the NS1 coding region to H7N3 viruses isolated from Pakistan between 1995 and 2005. Members of this group contained a 13 amino acid deletion at the C-terminus of NS1 and this group was quite distinct from the Ck/Pak/NARC-100/04, H7N3 - group of viruses. The third group of five H9N2 viruses showed highest nucleotide similarity (99.3–99.7%) with Ck/Rawalakot/NARC2441A/06 and Ck/Sihala/NARC3033.4/2006, Ck/Afghanistan/1207/06 and Ck/Afghanistan/1573-47/06 (H5N1) viruses (Table 3) and clustered together with Clade 2.2 highly pathogenic H5N1 viruses of the Z-genotype (Figure 8), the closest related H5N1 viruses being isolated in Pakistan, India, Iran and Russia during 2006 [28], [29]. These five viruses were able to be differentiated into two groups, but both groups were very similar to other viruses isolated in the region.


Novel genotypes of H9N2 influenza A viruses isolated from poultry in Pakistan containing NS genes similar to highly pathogenic H7N3 and H5N1 viruses.

Iqbal M, Yaqub T, Reddy K, McCauley JW - PLoS ONE (2009)

Phylogenetic relationships of the NS genes of H9N2 avian influenza viruses isolated from poultry in Pakistan.Analysis was based on nucleotides 27–870 of segment eight of all viruses included in this analysis. NS gene sequences were compared with closely related H5, H7 and H9 viruses (the viruses highlighted in red were sequenced in this study and H9N2, H7N3 and H5N1 viruses isolated in Pakistan previously are indicated in blue, pink and brown respectively). The phylogenetic methods and abbreviations were as described for figure 1.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2690689&req=5

pone-0005788-g008: Phylogenetic relationships of the NS genes of H9N2 avian influenza viruses isolated from poultry in Pakistan.Analysis was based on nucleotides 27–870 of segment eight of all viruses included in this analysis. NS gene sequences were compared with closely related H5, H7 and H9 viruses (the viruses highlighted in red were sequenced in this study and H9N2, H7N3 and H5N1 viruses isolated in Pakistan previously are indicated in blue, pink and brown respectively). The phylogenetic methods and abbreviations were as described for figure 1.
Mentions: In contrast to the other segments phylogenetic analysis of the NS gene segment of UDL viruses split the 12 viruses into three distinct groups (Figure 8). Six isolates of one group cluster together with 97.8% to 100% identity to each other and showed closest nucleotide identity (95.9–96.6%) with Ck/Pak/NARC-100/04, an H7N3 virus (Figure 8 and Table 3). The second group (represented by a single virus, A/Ck/Pak/UDL-01/06) showed a strikingly close relationship with 99.8 to 100% nucleotide identity within the NS1 coding region to H7N3 viruses isolated from Pakistan between 1995 and 2005. Members of this group contained a 13 amino acid deletion at the C-terminus of NS1 and this group was quite distinct from the Ck/Pak/NARC-100/04, H7N3 - group of viruses. The third group of five H9N2 viruses showed highest nucleotide similarity (99.3–99.7%) with Ck/Rawalakot/NARC2441A/06 and Ck/Sihala/NARC3033.4/2006, Ck/Afghanistan/1207/06 and Ck/Afghanistan/1573-47/06 (H5N1) viruses (Table 3) and clustered together with Clade 2.2 highly pathogenic H5N1 viruses of the Z-genotype (Figure 8), the closest related H5N1 viruses being isolated in Pakistan, India, Iran and Russia during 2006 [28], [29]. These five viruses were able to be differentiated into two groups, but both groups were very similar to other viruses isolated in the region.

Bottom Line: The NS gene segment showed greater genetic diversity and shared a high level of similarity with NS genes from either H5 or H7 subtypes rather than with established H9N2 Eurasian lineages.These results indicate that during recent years the H9N2 viruses have undergone extensive genetic reassortment which has led to the generation of H9N2 viruses of novel genotypes in the Indian sub-continent.The novel genotypes of H9N2 viruses may play a role in the increased problems observed by H9N2 to poultry and reinforce the continued need to monitor H9N2 infections for their zoonotic potential.

View Article: PubMed Central - PubMed

Affiliation: Division of Microbiology, Institute for Animal Health, Compton Laboratory, Compton, Newbury, Berkshire, UK. munir.iqbal@bbsrc.ac.uk

ABSTRACT
The impact of avian influenza caused by H9N2 viruses in Pakistan is now significantly more severe than in previous years. Since all gene segments contribute towards the virulence of avian influenza virus, it was imperative to investigate the molecular features and genetic relationships of H9N2 viruses prevalent in this region. Analysis of the gene sequences of all eight RNA segments from 12 viruses isolated between 2005 and 2008 was undertaken. The hemagglutinin (HA) sequences of all isolates were closely related to H9N2 viruses isolated from Iran between 2004 and 2007 and contained leucine instead of glutamine at position 226 in the receptor binding pocket, a recognised marker for the recognition of sialic acids linked alpha2-6 to galactose. The neuraminidase (NA) of two isolates contained a unique five residue deletion in the stalk (from residues 80 to 84), a possible indication of greater adaptation of these viruses to the chicken host. The HA, NA, nucleoprotein (NP), and matrix (M) genes showed close identity with H9N2 viruses isolated during 1999 in Pakistan and clustered in the A/Quail/Hong Kong/G1/97 virus lineage. In contrast, the polymerase genes clustered with H9N2 viruses from India, Iran and Dubai. The NS gene segment showed greater genetic diversity and shared a high level of similarity with NS genes from either H5 or H7 subtypes rather than with established H9N2 Eurasian lineages. These results indicate that during recent years the H9N2 viruses have undergone extensive genetic reassortment which has led to the generation of H9N2 viruses of novel genotypes in the Indian sub-continent. The novel genotypes of H9N2 viruses may play a role in the increased problems observed by H9N2 to poultry and reinforce the continued need to monitor H9N2 infections for their zoonotic potential.

Show MeSH
Related in: MedlinePlus