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Tamiflu Resistance in Turkey Exactly Matches US and UK
Recombinomics Commentary 16:23
April 19, 2008
A full NA H1N1 sequence from England was just released at Genbank which had the Tamiflu resistance marker, H274Y. That sequence was an exact match of three sequences from the United States, indicating the sequence was evolutionarily fit and widespread.
A few days earlier, a partial (495 BP) NA H1N1 sequence was released from Turkey. That sequence also had the H274Y. The partial sequence represent more than 1/3 of the NA gene and it was an exact match of the sequences from the United States and England described above. It was also an exact match of additional sequences from the United States from Arizona and New Jersey. Thus, the total number of public sequences that exactly match the partial sequence from Turkey is eight (one from England and seven from the US – see list here).
Thus, it is clear that the above Brisbane sequences are widespread. However, earlier isolates from the US, which were New Caledonian-like and isolated last season also had the H274Y. Thus, the acquisitions began in the 2006/2007 season and were on a New Caledonia genetic background, but the frequency increased dramatically in the 2007/2008 season, where most of the acquisitions are on a Brisbane genetic background.
Thus, H274Y has been reported recently on four distinct genetic backgrounds. Initial reports were in early 2005 on human clade 1 H5N1 in Vietnam. This was followed by clade 2.2 in wild birds in Astrakhan in late 2005, which was then followed by human New Caledonian-like H1N1 in the United States in 2006/2007, followed by Brisbane-like H1N1 worldwide (but highest in Norway, Russia, and France) in 2007/2008.
This movement is easily explained by acquisitions via recombination.
Recombinomics Paper at Nature Precedings