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H5N1/H9N2 Recombinants
Recombinomics Commentary
November 11. 2004
The warning linked abpve re-emphasizes the significance of yet another ingredient in the creation of a pandemic eclipsing 1918. The next pandemic will be a recombinant and the setting is ripe for a recombination in ducks without a mammalian requirement.
The ability of lethal H5N1 strains to grow in asymptomatic ducks sets the stage for dual infections between H5N1 and H9N2, the most prevalent serotype in wild ducks. Some H9N2 isolates have acquired the ability to bind to mammalian receptors, and the current H5N1 strains in Asia can produce a high case mortality rate. 2003 H9N2 isolates in Hong Kong have H5N1 gene sequences, providing additional evidence of dual infections involving H5N1 and H9N2.
A dual infection that resulted in the acquisition of the mammalian receptor binding sequences recombined onto a lethal H5N1 backbone could generate the efficient human to human transmission, the missing requirement for a significant flu pandemic. The detection of H5N1 sequences in the hawk falcons being smuggled through Belgium as well as and H5N1 isolate in Russia, suggests H5N1 is already widespread and dual infections between H5N1 and H9N2 appear to be increasingly likely.
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