Recombinomics: Novel H5N1 Migrating Through China?

Commentary

Novel H5N1 Migrating Through China?
Recombinomics Commentary 22:04
December 16, 2008

Preliminary analysis by ministry experts indicated the virus could have been spread by birds migrating through the area, and that it was a different type from the variety usually found in the southern part of the country.

A ministry laboratory yesterday was testing samples of the virus to see if it had mutated.

The above comments indicate the H5N1 isolated in Jiangsu is not the Fujian strain (clade 2.3), which has spread throughout southern China. Last season a sub-clade (2.3.2) was found in wild birds in Hong Kong as well as whooper swans in Japan, but it is unlikely that clade 2.3.2 would be considered a “different type” since it circulates in southern China.

More likely chances would be the Qinghai (clade 2.2) strain, or a novel (clade 0) strain identified at Qinghai Lake this season. Although the Qinghai strain does circulate in southern China, most assays use fecal samples that rarely detect clade 2.2. For the 2005/2006 there were 404 H5N1 isolates identified by researchers in Hong Kong, and only one was the Qinghai strain. The Qinghai strain is more commonly isolated from nasopharyngeal swabs from live birds, or tissue extracts from dead or dying birds.

However, a recent ProMED report which cited the two confirmed regions in Jiangsu province also noted that birds with similar symptoms were found in multiple provinces in China, raising concerns that a novel strain that was not well covered by the current vaccines may be circulating, which could be the clade 0 strain isolated from a fecal sample at Qinghai Lake. It was most closely related to sequences in circulation five years ago, which were related to isolates from 1997.

Media reports indicate an OIE report has been filed. Additional information, including sequences data on the “different type” of H5N1 in Jiangsu would be useful.

Media Links