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H6 Virus with 7 H5 like internal Genes

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  • H6 Virus with 7 H5 like internal Genes

    Studies about H9 virusses showing identity of internal genes with H5 Guangdong like Viruses have been cited in this forum. These identities show the circulation of different subtypes on HK poultry markets, reassortment between them, and they confer some immunicological cross resistance attenuating the impact of HPAI H5 strains. Some of the H9 viruses were isolated in human infection demonstrating the possible threat to public health of H9 viruses.

    Here is the description of a class of H6 virusses showing a 7 of 11 gene- identity to H5 viruses. In other words: Quasi "a H5N1 virus with a different HA"
    The porential of these viruses is unpredictable:

    Molecular Evolution of H6 Influenza Viruses from Poultry in Southeastern China: Prevalence of H6N1 Influenza Viruses Possessing Seven A/Hong Kong/156/97 (H5N1)-Like Genes in Poultry

    Journal of Virology, January 2002, p. 507-516, Vol. 76, No. 2
    0022-538X/01/$04.00+0 DOI: 10.1128/JVI.76.2.507-516.2002
    P. S. Chin,<SUP>1</SUP><SUP>*</SUP> E. Hoffmann,<SUP>2</SUP> R. Webby,<SUP>2</SUP> R. G. Webster,<SUP>2</SUP> Y. Guan,<SUP>1</SUP> M. Peiris,<SUP>1</SUP> and K. F. Shortridge<SUP>1</SUP>

    Department of Microbiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong Special Administrative Region, People?s Republic of China,<SUP>1</SUP> Department of Virology, St. Jude Children?s Research Hospital, Memphis, Tennessee 38105-2794<SUP>2</SUP> Received 24 July 2001/ Accepted 12 October 2001
    <!-- null -->

    <TABLE cellSpacing=0 cellPadding=0 width="100%" bgColor=#e1e1e1><TBODY><TR><TD vAlign=center align=left width="5%" bgColor=#ffffff></TD><TH vAlign=center align=left width="95%"> ABSTRACT </TH></TR></TBODY></TABLE>
    <TABLE cellPadding=5 align=right border=1><TBODY><TR><TH align=left>Top
    Abstract
    Introduction
    Materials and Methods
    Results
    Discussion
    References
    </TH></TR></TBODY></TABLE>

    The A/teal/Hong Kong/W312/97 (H6N1) influenza virus and the<SUP> </SUP>human H5N1 and H9N2 influenza viruses possess similar genes<SUP> </SUP>encoding internal proteins, suggesting that H6N1 viruses could<SUP> </SUP>become novel human pathogens. The molecular epidemiology and<SUP> </SUP>evolution of H6 influenza viruses were characterized by antigenic<SUP> </SUP>and genetic analyses of 29 H6 influenza viruses isolated from<SUP> </SUP>1975 to 1981 and 1997 to 2000. Two distinct groups were identified<SUP> </SUP>on the basis of their antigenic characteristics. Phylogenetic<SUP> </SUP>analysis revealed that all H6N1 viruses isolated from terrestrial<SUP> </SUP>poultry in 1999 and 2000 are closely related to A/teal/Hong<SUP> </SUP>Kong/W312/97 (H6N1), and the nucleotide sequences of these viruses<SUP> </SUP>and of A/Hong Kong/156/97 (H5N1) were more than 96% homologous.<SUP> </SUP>The hemagglutinin (HA) of the 1999 and 2000 terrestrial viruses<SUP> </SUP>does not have multiple basic amino acids at the site of cleavage<SUP> </SUP>of HA1 to HA2; however, a unique insertion of aspartic acid<SUP> </SUP>in HA1 between positions 144 and 145 (H3 numbering) was found.<SUP> </SUP>The neuraminidase of these terrestrial H6N1 viruses has a deletion<SUP> </SUP>of 19 amino acids characteristic of A/Hong Kong/156/97 (H5N1).<SUP> </SUP>Evolutionary analysis suggested that these H6N1 viruses coevolved<SUP> </SUP>with A/quail/Hong Kong/G1/97-like H9N2 viruses and became more<SUP> </SUP>adapted to terrestrial poultry. These terrestrial 1999 and 2000<SUP> </SUP>A/teal/Hong Kong/W312/97 (H6N1)-like viruses, along with the<SUP> </SUP>H9N2 viruses, could have been involved in the genesis of the<SUP> </SUP>pathogenic H5N1 influenza viruses of 1997. The presence of H6N1<SUP> </SUP>viruses in poultry markets in Hong Kong that possess seven of<SUP> </SUP>the eight genes of the A/Hong Kong/156/97 (H5N1) virus raises<SUP> </SUP>the following fundamental questions relevant to influenza pandemic<SUP> </SUP>preparedness: could the pathogenic H5N1 virus reemerge and could<SUP> </SUP>the H6N1 viruses directly cross the species barrier to mammals?<SUP> </SUP>
    <SUP></SUP>
    <SUP>Full text</SUP>

  • #2
    Re: H6 Virus with 7 H5 like internal Genes

    see also this thread:



    the similarities are similarly distributed over the 6 genes, HA and NA
    are special, of course.

    H6N1 and H9N2 are as close to random H5N1 as they are to other random
    H6N1 resp. H9N2 , when we exclude the HA and NA segments.

    These reassortments of H5N1 with H6N1,H9N2 were before 2004, seems that H5N1
    is finetuning now with reassortment between similar strains , e.g. within Qinghai-strain
    last year in Nigeria and within Indonesia-strain just recently.
    And it still evolves by point-mutations too and sometimes recombination.


    here is a list with the average cross-differences between the strains
    since 2000 :
    Average difference in 0/00
    over 6 segments, (HA,NA excluded)


    Code:
     
     
         H1N1 H3N2 H5N1 H6N1 H9N2 H1N2 H2N2 
    ---------------------------------------- 
    H1N1 137  145  154  150  153  145  133 
    H3N2 145  106  139  138  142  142  117                                              
    H5N1 154  139   73   92   95  152  116                                                  
    H6N1 150  138   92   85  102  149  113                                                
    H9N2 153  142   95  102   97  151  120                                                
    H1N2 145  142  152  149  151  150  133                                              
    H2N2 133  117  116  113  120  133  109
    I'm interested in expert panflu damage estimates
    my current links: http://bit.ly/hFI7H ILI-charts: http://bit.ly/CcRgT

    Comment


    • #3
      Re: H6 Virus with 7 H5 like internal Genes

      Journal of Virology, July 2000, p. 6309-6315, Vol. 74, No. 14
      0022-538X/00/$04.00+0

      Characterization of the Influenza A Virus Gene Pool in Avian Species in Southern China: Was H6N1 a Derivative or a Precursor of H5N1?
      Erich Hoffmann,1 Juergen Stech,1 Irina Leneva,1 Scott Krauss,1 Christoph Scholtissek,1 Po San Chin,2 Malik Peiris,2 Kennedy F. Shortridge,2 and Robert G. Webster1,3,*
      Department of Virology and Molecular Biology, St. Jude Children's Research Hospital,1 and Department of Pathology, University of Tennessee at Memphis,3 Memphis, Tennessee, and Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China2

      Received 28 December 1999/Accepted 7 April 2000

      ABSTRACT

      In 1997, an H5N1 influenza virus outbreak occurred in chickens in Hong Kong, and the virus was transmitted directly to humans. Because there is limited information about the avian influenza virus reservoir in that region, we genetically characterized virus strains isolated in Hong Kong during the 1997 outbreak. We sequenced the gene segments of a heterogeneous group of viruses of seven different serotypes (H3N8, H4N8, H6N1, H6N9, H11N1, H11N9, and H11N8) isolated from various bird species. The phylogenetic relationships divided these viruses into several subgroups. An H6N1 virus isolated from teal (A/teal/Hong Kong/W312/97 [H6N1]) showed very high (>98%) nucleotide homology to the human influenza virus A/Hong Kong/156/97 (H5N1) in the six internal genes. The N1 neuraminidase sequence showed 97% nucleotide homology to that of the human H5N1 virus, and the N1 protein of both viruses had the same 19-amino-acid deletion in the stalk region. The deduced hemagglutinin amino acid sequence of the H6N1 virus was most similar to that of A/shearwater/Australia/1/72 (H6N5). The H6N1 virus is the first known isolate with seven H5N1-like segments and may have been the donor of the neuraminidase and the internal genes of the H5N1 viruses. The high homology between the internal genes of H9N2, H6N1, and the H5N1 isolates indicates that these subtypes are able to exchange their internal genes and are therefore a potential source of new pathogenic influenza virus strains. Our analysis suggests that surveillance for influenza A viruses should be conducted for wild aquatic birds as well as for poultry, pigs, and humans and that H6 isolates should be further characterized.

      full text

      Comment


      • #4
        Re: H6 Virus with 7 H5 like internal Genes

        H5N1 has already reassorted with other flu a lot, but
        virulence didn't change much.
        H3N2 and H1N1 are more different from H5N1 than H6N1,H9N2 ,
        tests in a laboratory couldn't make H5N1 reassort with H3N2.
        Why do people like Salzberg still expect, that a H5N1-pandemic
        would probably happen by reassortment and H5 would adapt in virulence
        to seasonal flu ?
        I'm interested in expert panflu damage estimates
        my current links: http://bit.ly/hFI7H ILI-charts: http://bit.ly/CcRgT

        Comment


        • #5
          Re: H6 Virus with 7 H5 like internal Genes

          Evolution and molecular epidemiology of H9N2 influenza A viruses from quail in southern China, 2000 to 2005.

          Xu KM, Li KS, Smith GJ, Li JW, Tai H, Zhang JX, Webster RG, Peiris JS, Chen H, Guan Y. J Virol. 2006 Dec 27

          Joint Influenza Research Centre (SUMC & HKU), Shantou University Medical College, Shantou, Guangdong 515031, China; State Key Laboratory of Emerging Infectious Diseases, Department of Microbiology, Li Ka Sing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China; and Virology Division, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.

          H9N2 influenza viruses have become established and maintain long-term endemicity in terrestrial poultry in Asian countries. Occasionally these viruses transmit to other mammals including humans. Increasing epidemiological and laboratory findings suggest that quail may be an important host as they are susceptible to different subtypes of influenza viruses. To better understand the role of quail in influenza ecology and evolution, H9N2 viruses isolated from quail during 2000 to 2005 were antigenically and genetically characterized. Our results showed that H9N2 viruses are prevalent year-round in southern China and mainly replicate asymptomatically in the respiratory tract of quail. Genetic analysis revealed that both the G1-like and Ck/Bei-like H9N2 lineages were co-circulating in quail since 2000. Phylogenetic analyses demonstrated that most of the isolates tested were double or multiple reassortant variants, with four G1-like and 16 Ck/Bei-like genotypes recognized. A novel genotype of G1-like virus became predominant in quail since 2003, while multiple Ck/Bei-like genotypes were introduced to quail wherein they incorporated G1-like gene segments, but none of them became established in this host. Those Ck/Bei-like reassortants generated in quail have then been introduced to other poultry. These complex interactions form a two-way transmission system between quail and other types of poultry. The present study provides evidence that H9N2 and H5N1 subtype viruses have also exchanged gene segments to generate currently circulating reassortants of both subtypes that have pandemic potential. Continuing influenza surveillance in poultry is critical to understanding the genesis and emergence of potentially pandemic strains in this region.

          PMID: 17192315 [PubMed - as supplied by publisher] <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

          <o:p></o:p>

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