Commentary
High Path H5N2 Recombinants in Wild Birds in Nigeria
Recombinomics Commentary 21:17
August 28, 2008
The presence of coexisting but genetically distinguishable avian influenza viruses with an HP viral genotype in two cohabiting species of wild waterfowl, with evidence of non-lethal infection at least in one species and without evidence of prior extensive circulation of the virus in domestic poultry, suggest that some strains with a potential high pathogenicity for poultry could be maintained in a community of wild waterfowl.
The above comments are from the recently published PLOS paper “Evidence of Infection by H5N2 Highly Pathogenic Avian Influenza Viruses in Healthy Wild Waterfowl” and as noted above, acknowledge possible maintenance in wild waterfowl. However, the paper fails to acknowledge that the HA cleavage site matches H5N1 in waterfowl in Thailand, supporting acquisition by homologous recombination, as well as long range transport and transmission in waterfowl, since the above isolates are from Nigeria (see list below).
The H5 is phylogenetically related to low path H5 in Europe, Africa, and Asia, but contains multiple polymorphisms that are shared with high path H5N1, including clade 2.2 isolates in Egypt. These relationships provide additional evidence for the evolution of both high and low path H5 via recombination.
The N2 is related to a number of serotypes containing N2, providing evidence for reassortment. The N2 does not have the deletion found in the N1 in H5N1 but the HA cleavage site suggests the virus would be lethal in poultry and could cause problems in commercial poultry, which could lead to further evolution of the H5.
The presence of the cleavage site from H5N1 in Thailand raises concerns of long range movement of high path H5N2, and demonstrates the genetic diversity and plasticity of H5 and the associated highly pathogenic cleavage site
A/spur-winged goose/Nigeria/5388-2/2007(H5N2)
A/spur-winged goose/Nigeria/5388-5/2007(H5N2)
A/spur-winged goose/Nigeria/5388-8/2007(H5N2)
A/white-faced whistling duck/Nigeria/3927-1/2007(H5N2)
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