More H5N1 Outbreaks in Togo
Recombinomics Commentary
August 11, 2007
The new cases were found in dead birds on farms in the Lacs, Golfe and Zio regions east of the capital Lome, national television reported.
The above comments describe new H5N1 outbreaks in Togo near the coast (see satellite map). Togo report its first cases of H5N1 in June, following reports of H5N1 in neighboring Ghana, which had also reported H5N1 for the first time in 2007.
The initial outbreaks in Ghana had NA G743A, which was also detected on multiple genetic backgrounds in human and bird isolates in Egypt, as well as bird isolates in Ghana. The concurrent acquisition of the same polymorphism onto diverse genetic backgrounds strongly implicated recombination in H5N1.
Similarly, Nigeria reported its first human H5N1 case this year. The HA sequence has aggregated a number of new polymorphisms which were regional markers in the prior year in Germany, Egypt, and sub-Sahara Africa. The Nigerian case, like the new cases in Ghana and Togo was along the coast where multiple migratory bird flyways overlap.
The west African isolates in Niger, Nigeria, Burkina Faso, Ivory Coast, and Ghana represented multiple distinct sub-clades, signaling multiple introductions by wild birds followed by significant dispersal and aggregation of the polymorphism via recombination to create new genes.
The continued co-circulation of multiple clade 2.2 sub-clades, including at least one human case, remains a cause for concern.
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