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Cold fronts linked to bird flu outbreaks in Europe

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  • Cold fronts linked to bird flu outbreaks in Europe

    Cold fronts linked to bird flu outbreaks in Europe

    08 Apr 2010 21:03:03 GMT
    <!-- 08 Apr 2010 21:03:03 GMT ## for search indexer, do not remove -->Source: Reuters

    <!-- AN5.0 article title end --><SCRIPT language=JavaScript src="/bin/js/article.js"></SCRIPT></SPAN>
    <!-- Cold fronts linked to bird flu outbreaks in Europe --><!-- Reuters -->* Cold snaps caused change in wild bird migration patterns
    * Freezing forecasts may help predict future outbreaks

    By Kate Kelland

    LONDON, April 8 (Reuters) - Outbreaks of H5N1 flu among birds in Europe came at the edges of cold fronts that caused wild birds to change migration patterns, scientists said on Thursday, suggesting cold snaps may signal future outbreaks.

    Dutch and American researchers found European outbreaks of avian influenza during the 2005-2006 winter were driven by collective movements of wild waterbirds to places where the fresh water they need to feed and survive had not frozen.

    "This has important implications for surveillance, which should target areas where temperatures are close to freezing in winter, especially in poultry-dense regions close to areas where waterfowl aggregate," the researchers wrote in a study in the Public Library of Science journal PloS Pathogens.

    The study can be found at

    It is difficult for people to catch H5N1 bird flu, but when they do it can be deadly. Since 2003 it has infected 492 people and killed 291 of them, according to the World Health Organisation, and experts fear the H5N1 virus could mutate at any time into a form easily passed from one person to another.

    The virus emerged more than a decade ago in poultry in Southeast Asia. In 2005 it spread outside Asia infecting both poultry and wild birds in the Middle East, Europe and Africa.

    Most human cases have been in Asia but Egypt has had 108 cases and 33 deaths.

    Romanian officials reported an outbreak of bird flu last month on a poultry farm close to Ukraine in an area on an important migratory pathway for wild birds. [ID:nLDE62F18M]

    Leslie Reperant of Princeton University in the United States and Thijs Kuiken of the Erasmus Medical Centre in the Netherlands said their findings offered a possible way to predict and control where and when bird flu might erupt again.

    "Forecasts predicting near-freezing temperatures in Europe may act as an indication for concern," they wrote.

    They found that most H5N1 outbreaks occurred at sites where maximum temperatures were between 0 degrees Celsius and 2 degrees Celsius. This was usually on the edge of cold fronts where fresh water remained unfrozen.

    Read more at:
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  • #2
    Re: Cold fronts linked to bird flu outbreaks in Europe

    after more than 4 years ...

    I think this just only applies to the Feb.2006 outbreak in
    Europe. We also had H5N1-outbreaks in summer 2007, permanent
    outbreaks in Egypt,Indonesia,Vietnam with different temperature patterns.

    Do they suggest that mallards played a role in H5N1-transmission,
    Europe 2006 ? It's not clear to me yet, whether they do, haven't
    read the whole paper. Main found species were the swans in 2006.

    Do they suggest waterborne transmission ?

    > freezing and thawing are known to substantially decrease AIV infectivity by up to 10 fold,
    > despite having little effect on AIV RNA [27].

    > LPAIV RNA has been recovered in ice from Siberian lakes, yet no infectious virus could
    > be isolated [28].

    I thought that were contaminations, sequencing errors ?!?

    > the poultry trade may have introduced HPAIV H5N1 into Russia, the Middle East
    > or eastern Europe in fall and early winter of 2005–2006 [1],[3],

    we may have similar migration patterns away from freezing water
    in the Siberian wetlands where the West-migration started in 2005.

    Breeding is in ~May and some birds start South/West migration
    already in July, most in fall.
    Then we had outbreaks in the black-sea region in late
    2005 and the cold-spell on Jan.25,2006 which drove
    birds (swans ?) westward


    not only mallards but also several other duck species are healthy carriers of HPAI H5N1

    A careful analysis of the spread of the virus from central Asia into eastern Europe in the autumn of 2005 shows that wild birds, especially mallard ducks, were the chief spreaders of the virus.
    "We conclude that the spread of (highly pathogenic avian influenza) H5N1 virus from Russia and Kazakhstan to the Black Sea basin is consistent in space and time with the hypothesis that birds in the Anatidae family have seeded the virus along their autumn migration routes," the researchers wrote in the journal Emerging Infectious Diseases.
    Anatidae include geese, ducks and swans, some of which are killed by H5N1, and other species of which often show no ill effects from the virus but which can spread it. Mallard ducks are the main suspect.
    I'm interested in expert panflu damage estimates
    my current links: [url][/url] ILI-charts: [url][/url]


    • #3
      Re: Cold fronts linked to bird flu outbreaks in Europe

      they were sampling ~300000 life wild birds but found no HP-H5N1
      (but many other serotypes)
      H5N1 was found in all sorts of dead birds, swans,geese,birds of

      ducks aren't harmed much by any flu. They are better adapted. Since
      These large amounts of poultry,swine,humans are relatively new.


      Experimental studies have demonstrated bird-to-bird transmission of HPAI
      H5N1 in mallards, but these studies were completed under confinement

      We conclude that the epidemiology of HPAIV H5N1 in mallards and probably
      other aquatic wild bird species is massively influenced by interfering

      oropharyngeal sampling should be used routinely in the surveillance of
      HPAI H5N1 in Mallards

      Polymerase genes associated with virulence of H5N1 in Mallards

      H5N1 oropharyngeal in mallards ! Very unusual. Usually flu is waterborn in
      oral-fecal or duck-sex

      maybe that's the reason, why H5N1 doesn't establish in the normal mallard population -
      waterborne is more effective there.
      I'm interested in expert panflu damage estimates
      my current links: [url][/url] ILI-charts: [url][/url]