H5N1 Amantadine Resistance in Israel
Recombinomics Commentary 16:15
April 17, 2008
Full sequences from H5N1 in Israel, A/chicken/Israel/1055/2008(H5N1), are being released. The M2 sequence contains S31N, indicating it is amantadine resistant. Although amantadine resistance is common in clade 1, its frequency in clade 2 is markedly lower. S31N is also in the only public clade 2.2 sequence from Shantou, A/Guinea fowl/Shantou/1341/2006(H5N1) as well as the recently released turkey sequence from Saudi Arabia, A/turkey/Saudi Arabia/6732-6/2007(H5N1).
The HA sequence from the isolate from Israel is closely related to the vaccine resistant isolates from Egypt. These sequences have a large number of non synonymous changes, including M230V. These changes pose a challenge for vaccine development.
The presence of amatadine resistance in the same isolate raises concerns of this change spreading. The vaccine resistant strain was found in multiple locations in Egypt and may also be in human sequences. None of the human H5N1 sequences in Egypt have been released from this season, including those that were collected at the end of 2007.
Last season patients in Egypt were treated with amantadine because of the Tamiflu resistance in the Gharbiya cluster. The relationship of resistance in Egypt to resistance in Israel and Saudi Arabia are unclear, since sequence data from Egypt has been limited to HA and NA.
Release of full sequences from Egypt would be useful.
Media Links
Recombinomics Presentations
Recombinomics Publications
Recombinomics Paper at Nature Precedings