H5N1 Evolution in Indonesia
Recombinomics Commentary
November 26, 2007
The researcher Molecular Biology from University Airlangga Surabaya, Dr C. A, Nidom, on Monday (26/11) said, in Indonesia the Virus H5N1 has mutated became 5 sub groups.
In fact in the other country only was found by the mutation to 3 variants of the virus, said Nidom. Sub the virus group that mutated in Indonesia was divided into the A kind, B, C, C1, and D.
For the A category and B, spread dikawasan Sumatra. Now for the C category spread in Kalimantan.
Whereas to C1 spread in various places, and for D the region spreading him covered the Papua area and Sumatra the southern part.
The above translation describes H5N1 evolution in Indonesia. Region differences in H5N1 are common because H5N1 evolves via recombination, and local strains commonly act as donor sequences for incoming sequences brought by migratory birds. Although the isolates in Indonesia are Clade 2.1, over time multiple sub-clades evolve.
Analysis of human isolates demonstrated this evolution. Initial human isolates almost universally had the novel HA cleavage site, RESRRKKR. Initially this was not found in bird isolates, but did begin to appear in more recent isolates. Earlier bird sequences had the common cleavage site RERRRKKR, as did the Karo cluster, which was distinct from the human isolates on Java. The relationship of the human cases this year to the above two groupings is unknown, because sequences have not been released. The Karo cluster was in northern Sumatra and was similar to bird isolates in that region. This year there have been six confirmed cases in Riau, in central/northern Sumatra, but none of the human sequences have been made public.
These sequences are not only useful for development of clade 2.1 vaccines, but also impact the evolution of H5 outside of Indonesia. Recently, H5N1 sequences from North America were released. Although these sequences were most closely related to earlier low path H5N1 in North America, the sequences had acquired multiple polymorphisms found in high path H5N1 in Asia, including several polymorphisms largely limited to Indonesia. These acquisitions identify exchanges between Indonesia and North America and help identify newly emerging polymorphisms which are important for vaccine development against a number of H5N1 clades and sub-clades.
Release of the human H5N1 sequences from Indonesia would be useful.
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