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Commentary
Massive H5N1
Wild Bird Outbreak In Krasnodar
Recombinomics
Commentary 18:15
November 29, 2012
The above translation describes a massive H5N1 outbreak in wild birds in western Krasnodar. Multiple stories in Russian media describe the outbreak with estimates ranging from 600 to 1000’s of dead birds. H5 has been confirmed and it is likely that the deaths are due to clade 2.3.2.1 (Fujian strain) which is now widespread in wild birds in eastern Asian countries including China, Japan, and South Korea.
The number of dead birds is similar to prior reports of clade 2.2 (Qinghai) outbreaks in China, Russia, Mongolia, and Kazakhstan in 2005 and 2006. The last large outbreak of H5N1 in Krasnodar was in 2006 and was due to clade 2.2.
However, clade 2.3.2.1 (Fujian) has largely replaced clade 2.2 (Qinghai) in wild birds in Asia and clade 2.3.2.1 has been reported in Europe previously. However, this outbreaks appears to be significantly larger and likely signals a serious spread of this sub-clade to Europe, the Middle East, and Africa.
In Egypt, clade 2.2.1 is endemic and also appears in Israel at a lower frequency. The sub-clade with the 3 BP deletion has become dominant in Egypt and accounts for all human cases since 2009. The movement of clade 2.3.2.1 into the Middle East and northern Africa could lead to rapid H5N1 evolution via recombination and reassortment.
As has been noted previously, the human H5N1 cases in Egypt lack the glycosylation that was abolished in H5N1 transmission studies by Kawaoka and Fouchier. This site is also abolished in clade 2.3.2.1 in wild birds and many isolates also have V223I and M230I. Some also have S227R, which involves the same position as S227N which was found in cases in Turkey in 2006 as well as more recent human cases in Egypt.
Release of sequence data from the wild birds in Krasnodar would be useful.
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