Commentary
H5N1 Clade 2.3.2 in Korea Raises Concerns - Correction
Recombinomics Commentary 13:44
May 19, 2008
H5N1' Elder brother virus ' 2.3.2' Was confirmed as the channel virus
The above translation confirms that the H5N1 in South Korea is the Fujian sub-clade 2.3.2. This sub-clade has the HA cleavage site of RERRRKR and the most recent clade 2.3.2 isolate in the phylogenetic tree in the WHO vaccine target update is A/common magpie/Hong Kong/645/2006, which is among the Fujian isolates that annually appear in Hong Kong around the beginning of the year.
CORRECTION: The above Hong Kong isolate is clade 2.3.4. The sequence used in the WHO report to represent clade 2.3.2, A/common magpie/Hong Kong/5052/2007, as a vaccine traget has not been made public.
This identification increases the likelihood that the H5N1 in South Korea and Japan this season is linked to the northern migration of wild birds infected with clade 2.3.2 from the south. Movement of clade 2.3.2 into areas where clade 2.2 has been reported would result in recombination and acquisition of clade 2.2 polymorphisms. Analysis of newly acquire polymorphisms in the above isolate indicates that most are shared with clade 2.2 isolates.
The report of clade 2.3.2 in whooper swans in Japan increases the likelihood that these type of exchanges will increase, and clade 2.2 migrating into Europe, the Middle East, and Africa will have additional clade 2.3.2 polymorphisms. Moreover, the report of 2.3.2 in South Korea and northern Japan increases the likelihood that clade 2.3.2 will migrate into areas where clade 2.2 was reported previously, as well as Alaska, which lies within the East Asia flyway that is delivering clade 2.3.2 to Korea and Japan.
The finding of clade 2.3.2 in Korea and northern Japan significantly increases pandemic concerns and the likelihood that H5N1 will once again significantly expand its global reach and genetic diversity.
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