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Commentary
Taiwan Fujian H5N8 & Novel H5N2 Signal
Global Epansion
Recombinomics Commentary
January 12, 2015 15:00
The above translation describes two Fujian H5 serotypes which have been confirmed on multiple farms in multiple provinces in Taiwan. The positive waterfowl (geese and ducks) supports a wild bird source and represents the first introduction of Fujian H5 into Taiwan, in spite of the proximity (80 miles) from the coast of Fujian Province.
The detection of H5N8 and H5N2 in Taiwan raises surveillance concerns since neither serotype has been reported on Fujian Province. The most recent H5N8 OIE reports from China are outbreaks in Liaoning the ended in September (see H5N8 map), which is also true for H5N2 (in Liaoning, Hubei, Tibet, Ningxia, Guangxi, and Heilongjiang). Only Shandong is listed as continuing (with last update in September). Thus, although these outbreaks may have led to the cases in Taiwan, the most recent H5N2 sequences from China is from a July 2013 collection from a Henan chicken, while the most recent H5N8 sequence is from January 2014 in Beijing, which is similar to early 2014 sequences from South Korea.
Thus, the similarity between the H5N2 sequences in China with those in Taipei is unclear, but the similarity with a Jilin 2011 N2 sequence suggests the reassortment to produce the novel serotype may have happened in China and may have involved H9N2 in wild birds.
Moreover, H9N2 internal genes are linked to the evolution of H7N9, which in addition to the loss of the glycosylation site at position 158 has acquitted Q226L, increasing affinity for gal 2,6 receptors. H5N8 has also lost the glycosylation site and has increased affinity for gal 2,6.
The appearance of the two Fujian H5 serotypes in Taiwan raises concerns of a significant global expansion, which is supported by the detection of two Fujian H5 serotypes in the US (also H5N8 and H5N2). H5N2 has also been reported in British Columbia, less than 7 miles from the wild bird positives in Washington, but Canada has not reported H5N8 or H5N2 raising serious surveillance concerns. Moreover, neither Canada nor the US has released any H5N2 or H5N8 sequences with Fujian H5.
These surveillance concerns are also present in European countries reporting H5N8 in commercial farms, but no reports in wild birds (England and Italy) as well as neighboring countries who have not reported H5N8 cases.
The recent report of HPAI H5 in Nigeria also raises concerns that H5N8 has migrated to Africa in the absence of any reports for eastern Europe, the Middle East, or northeast Africa.
Release of sequences and enhanced surveillance would be useful.
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