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PB2/627 in pigs - from 1930 to 2009

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  • PB2/627 in pigs - from 1930 to 2009

    I was curious to see what swine had in PB2/627. This is the location of a "switch" that controls at what temperature a virus will best replicate. The higher (bird) setting is an "E", while the lower (mammalian) is a "K".

    What I found was very interesting.

    Back in the 1930s and up through 1980, all swine samples showed a "K" - for mammalian body temperatures.

    However, starting in 1981 in Europe (but not North America), there were several changes, including position 627 - it was now showing some instances of "E" - for bird body temperatures. That change stayed in only European samples until 2000 in Thailand, then in Canada for the first time in 2002. The first "E" sample in the US was in 2004 - Ohio/75004. All samples since have been "E".

    While the PB2 in H1N1/2009 originates largely from birds, it appears that the bird-temp "E" is comfortable in at least 3 mammals at present - pigs, humans, and pikas.

    So is influenza repeating in humans what it did in swine? If so, why?

    .
    "The next major advancement in the health of American people will be determined by what the individual is willing to do for himself"-- John Knowles, Former President of the Rockefeller Foundation

  • #2
    Re: PB2/627 in pigs - from 1930 to 2009

    a new virus went from birds to swine in Europe 1979,
    "Eurasian Swine lineage".
    It gave the NA and M (segments 6,7) to ******

    Also in 1998 we had the triple reassortment in America,
    where an avian PB2 entered into swine, that segment
    went to ******.
    So I'm surprised that you have no US-swine since 1998 with
    avian "E". Almost all North-American swine since 1998 should
    have it ?
    I'm interested in expert panflu damage estimates
    my current links: http://bit.ly/hFI7H ILI-charts: http://bit.ly/CcRgT

    Comment


    • #3
      Re: PB2/627 in pigs - from 1930 to 2009

      Originally posted by gsgs View Post
      a new virus went from birds to swine in Europe 1979,
      "Eurasian Swine lineage".
      It gave the NA and M (segments 6,7) to ******

      Also in 1998 we had the triple reassortment in America,
      where an avian PB2 entered into swine, that segment
      went to ******.
      So I'm surprised that you have no US-swine since 1998 with
      avian "E". Almost all North-American swine since 1998 should
      have it ?
      Re: So I'm surprised that you have no US-swine since 1998 with
      avian "E". Almost all North-American swine since 1998 should
      have it
      .

      I wrote - "The first "E" sample in the US was in 2004 - Ohio/75004. All samples since have been "E"."


      I was looking only at "classic" swine - H1N1, since it was predominant for so long. Just now rereading the sequences, I see I missed 2 "K"s in Ohio/2006.

      But searching for PB2/H1N1/USA/1998-2009, 14 of the 16 sequences are "E".

      Re: Also in 1998 we had the triple reassortment in America,
      where an avian PB2 entered into swine
      .

      I can see it now - I did a new search for PB2/H1N1/1981-2009/USA and it clearly shows the major changes first showing up in 2004 US sequences. There are no USA PB2/H1N1 sequences after 1991 and before 2004.

      It all made me wonder if there is a "trend" away from PB2/627K - for some reason the "E" is proving more "fit." I looked at all the other mammals and there appears to be a similar change pattern. So many scientific papers refer to the "K" as being specific to mammals (some just say humans) and perhaps that is no longer true. IF my little theory is correct, that might diminish the chances that human H1N1/2009 will acquire PB2/627K.

      .
      "The next major advancement in the health of American people will be determined by what the individual is willing to do for himself"-- John Knowles, Former President of the Rockefeller Foundation

      Comment


      • #4
        Re: PB2/627 in pigs - from 1930 to 2009

        1998 swine was mainly H3N2, not H1N1 (avian PB2)
        still some classical H1N1 around, but most are triple reassortant H3N2
        (or H1N2 or...- quite some reasortments since then)

        now, 627K provides replication in some cells and temperatures
        while 627E improves it in others

        We had some new Avian viruses entering swine and
        they are adapted to 627E

        ****** is since 11 years in swine, sometimes it takes
        decades for such mutations to establish.

        look at old mammalean viruses, classical H1N1 (including human H3N2,
        since PB2 didn't change in 1957,1968) or Eqine H7N7,
        they should have 627K (I guess...)
        I'm interested in expert panflu damage estimates
        my current links: http://bit.ly/hFI7H ILI-charts: http://bit.ly/CcRgT

        Comment


        • #5
          Re: PB2/627 in pigs - from 1930 to 2009

          There are no sequences available for swine/H3N2 for 1997-1999, so we cannot make accurate statements about it's 627 status.

          your...
          look at old mammalean viruses, classical H1N1 (including human H3N2,
          since PB2 didn't change in 1957,1968) or Eqine H7N7,
          they should have 627K (I guess...)
          In #1, I wrote...
          Back in the 1930s and up through 1980, all swine samples showed a "K" - for mammalian body temperatures.
          My concern is the implications of broad changes from 627K to 627E. Is it becoming SOP for some reason? Will it mean more mild flu for mammals?

          .
          "The next major advancement in the health of American people will be determined by what the individual is willing to do for himself"-- John Knowles, Former President of the Rockefeller Foundation

          Comment


          • #6
            Re: PB2/627 in pigs - from 1930 to 2009

            accession length host segment subtype country year Virus name 14 nucleotide sequences Age Gender
            AF153240 1557 Swine 1 (PB2) H3N2 USA 1998 Influenza A virus (A/Swine/North Carolina/35922/98 (H3N2))
            AF153241 1557 Swine 1 (PB2) H3N2 USA 1998 Influenza A virus (A/Swine/Texas/4199-2/98(H3N2))
            AF153242 1557 Swine 1 (PB2) H3N2 USA 1998 Influenza A virus (A/Swine/Minnesota/9088-2/98 (H3N2))
            AF153243 1557 Swine 1 (PB2) H3N2 USA 1998 Influenza A virus (A/Swine/Iowa/8548-1/98)
            AF251410 2335 Swine 1 (PB2) H3N2 USA 1998 Influenza A virus (A/Swine/Nebraska/209/98 (H3N2))
            AF251418 2335 Swine 1 (PB2) H3N2 USA 1999 Influenza A virus (A/Swine/Iowa/533/99 (H3N2))
            AF251426 2335 Swine 1 (PB2) H3N2 USA 1999 Influenza A virus (A/Swine/Iowa/569/99 (H3N2))
            AF251434 2335 Swine 1 (PB2) H3N2 USA 1999 Influenza A virus (A/Swine/Minnesota/593/99 (H3N2))
            AF268165 498 Swine 1 (PB2) H3N2 USA 1999 Influenza A virus (A/Swine/Wisconsin/14094/99(H3N2))
            AF268166 493 Swine 1 (PB2) H3N2 USA 1999 Influenza A virus (A/Swine/Colorado/23619/99(H3N2))
            AF268167 496 Swine 1 (PB2) H3N2 USA 1999 Influenza A virus (A/Swine/Oklahoma/18089/99(H3N2))
            AF268168 474 Swine 1 (PB2) H3N2 USA 1999 Influenza A virus (A/Swine/Oklahoma/18717/99(H3N2))
            AF268169 475 Swine 1 (PB2) H3N2 USA 1999 Influenza A virus (A/Swine/Illinois/21587/99(H3N2))
            AF268170 475 Swine 1 (PB2) H3N2 USA 1999 Influenza A virus (A/Swine/NorthCarolina/16497/99(H3N2))


            4 of these have position 627 available - all are E

            is it "changing" from K to E or is it just only for new viruses being introduced from birds ?
            (in 1998 USA, in 1979 Europe)
            (and then reassorting with existing viruses in swine...)
            I'm interested in expert panflu damage estimates
            my current links: http://bit.ly/hFI7H ILI-charts: http://bit.ly/CcRgT

            Comment


            • #7
              Re: PB2/627 in pigs - from 1930 to 2009

              I must have had one parameter wrong to miss those H3N2 sequences.

              I see where the 4 have "E" at 627.

              your...
              is it "changing" from K to E or is it just only for new viruses being introduced from birds ?
              Good point. Introduced and maintained as "fit"?

              I was very surprised to see so many mammals (including other species) carrying a bird temperature gene.

              This may relate to the fact that we look at the 107 years of data for trends, when in fact influenza genetic cycles may actually span hundreds of years.

              .
              "The next major advancement in the health of American people will be determined by what the individual is willing to do for himself"-- John Knowles, Former President of the Rockefeller Foundation

              Comment


              • #8
                Re: PB2/627 in pigs - from 1930 to 2009

                Climate change? Just a thought....

                Comment


                • #9
                  Re: PB2/627 in pigs - from 1930 to 2009

                  all the horses have 627E, are horse noses warmer than human ones ?
                  What about swine ?

                  It was said that E627K was suitable for virus replication in human noses
                  at 32°C , vs. avian which are warmer.
                  I'm interested in expert panflu damage estimates
                  my current links: http://bit.ly/hFI7H ILI-charts: http://bit.ly/CcRgT

                  Comment

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