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Help, PLS - What are the best tests for prior H5N1 exposure?

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  • Help, PLS - What are the best tests for prior H5N1 exposure?

    Hello Trackers -

    I have been looking into questions of seropositivity on the part of people, cats, whatever, and I can't find reliable info on what tests they use to determine exposure.

    The presence or absence of antibodies is frequently mentioned, but my Googling did not reveal any consistent test or data. I have seen hints that some exposed people might not even carry detectable antibodies for long.

    I find PCR intriguing in good and poor ways, but that, too seems foggy in reported application.

    This implies to me that there is no accepted way to find out if many people have been exposed.

    Does anyone have literature, links, insights into what tests are on the table and why some are viewed as better than others?

    Is there any consistency? We hear about the Vietnam study so loved by debunkers, and the Cambodia study that showed no general antibody presence in the population. Then the study of the cats in Jakarta....

    I'll be very grateful for any help, nudges, etc. Dr. Niman, are you out there?

    Thanks!

    DA

  • #2
    Re: Help, PLS - What are the best tests for prior H5N1 exposure?

    DA not sure if there are any clues for you in this document.

    Collection and Handling of Human Specimens for Laboratory Diagnosis of Influenza with Pandemic Potential

    http://www.moh.govt.nz/moh.nsf/pagesmh/4845/$File/national-laboratory-guidelines-pandemic-influenza.pdf

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    • #3
      Re: Help, PLS - What are the best tests for prior H5N1 exposure?

      Just a few general terms and tests off the top of my head:
      [] Agent, parasite, virus, microbe, graft - all refer to the potential disease causing unit.
      [] Vector, fomite - something that carries, transports the agent. Vectors are alive, fomites are inanimate objects
      [] host - the organism that can be a target of the agent
      [] antigen - a molecule or fragment from the agent that triggers an immune response from the host

      {} Exposure - the infecting agent is on or near the host (ie the person)

      {} infection - exposure that results in the agent entering into the host, frequently elicits a defensive (immune, possible antibody) response
      {} disease - may result from infection - the agent creates some disruption in normal host function. Infection has to occur for disease to result, but disease most often does not result from every infection.

      [] blood tests, serology, antibody tests - tests for evidence that the host has responded to an agent. Difficult to determine the time frame for that exposure. Generally requires a sample while the host is sick and then 2 weeks later in order to provide associative evidence of cause and effect.

      It is possible to do antigen testing or direct agent testing on blood samples but not typical.

      [] PCR = polymerase chain reaction test - used in most rapid tests for H5N1 - takes a small piece of antigen and amplifies the quantity for easy detection. In practice the clinician takes a sample of fluid or tissue that might have some agent in it (eg sputum produced from coughs) and then tries to find a needle in a haystack. The PCR in effect produces an abundance of needles so that you can find them.

      JT
      Thought has a dual purpose in ethics: to affirm life, and to lead from ethical impulses to a rational course of action - Teaching Reverence for Life -Albert Schweitzer. JT

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      • #4
        Re: Help, PLS - What are the best tests for prior H5N1 exposure?

        Many thanks to both of you. The NZ pdf has a lot of material, but....
        It SEEMS that there aren't reliable ways to test for exposure to H5N1 long afterwards. It might explain why the arguments about uncharted seropositives go nowhere.
        I'll keep looking for stories about this.
        Stay well,
        DA

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        • #5
          Re: Help, PLS - What are the best tests for prior H5N1 exposure?

          DeadAHead this OIE, veterinarian field manual, chapter 2.1.14, may help.
          Are you working on something?,

          http://www.oie.int/Eng/Normes/Mmanual/A_summry.htm

          Updated: 21.11.2006
          Manual of Diagnostic Tests and Vaccines
          for Terrestrial Animals 2004

          <hr><hr>
          OIE LISTED DISEASES
          <table class="texte" border="0" width="100%"><tbody><tr><td width="2%"> </td><td colspan="2" nowrap="nowrap" valign="top" width="2%">SECTION 2.1. </td><td>LIST A DISEASES</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.1. </td> <td>Foot and mouth disease (NB: version adopted May 2006) </td> </tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.2. </td><td>Vesicular stomatitis</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.3. </td><td>Swine vesicular disease</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.4. </td><td>Rinderpest</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.5. </td><td>Peste des petits ruminants</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.6. </td><td>Contagious bovine pleuropneumonia</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.7. </td><td>Lumpy skin disease</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.8. </td><td>Rift valley fever</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.9. </td><td>Bluetongue</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.10. </td><td>Sheep pox and goat pox</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.11. </td><td>African horse sickness</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.12. </td><td>African swine fever</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.13. </td><td>Classical swine fever (hog cholera)</td></tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.14. </td> <td>Avian influenza (NB: version adopted May 2005) </td> </tr> <tr><td width="2%"> </td><td width="2%"> </td><td nowrap="nowrap" valign="top" width="2%">Chapter 2.1.15. </td><td>Newcastle disease</td></tr></tbody></table>

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          • #6
            Re: Help, PLS - What are the best tests for prior H5N1 exposure?

            I thought I'd read that 1918 survivors have antibody levels 1000 times normal, even today, but can't find that article. However, this may be interesting......


            Original Antigenic Sin

            Any narrative on the swine flu episode would be incomplete without mentioning the work of Richard Shope on the possible relationship between the putative influenza virus of 1918 and its eventful residence in pigs in Iowa, where it caused an influenzalike syndrome and where it remained as a reservoir (5). Whatever the merits of this argument about the cause of swine flu virus infection in adults in the 1930s, of interest here is Francis's suggestion that the swine flu antibody in humans was the result of repeated exposure to human strains, and perhaps not due to prior infection with the 1918 virus. Surely his thoughts about this matter were the genesis of the concepts expressed in On the Doctrine of Original Antigenic Sin, published in 1960 (6).



            Francis wrote, "The antibody of childhood is largely a response to dominant antigen of the virus causing the first type A influenza infection of the lifetime. The antibody-forming mechanisms are highly conditioned by the first stimulus, so that later infections with strains of the same type successfully enhance the original antibody to maintain it at the highest level at all times in that age group. The imprint established by the original virus infection governs the antibody response thereafter. This we have called the Doctrine of the Original Antigenic Sin."


            http://www.cdc.gov/ncidod/EID/vol12no01/05-1132.htm
            "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

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