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Commentary
Fujian H5N8 Diversity Raises Surveillance
Concerns
Recombinomics Commentary
January 1, 2015 12:00
This geographic difference suggested that the spread may have taken a more northern route, which was supported when Russia reported H5N8 in a healthy Eurasian wigeon shot in northeastern Russia on September 25, but tested in December. The H5 and N8 sequences, A/wigeon/Sakha/1/2014, were closely related to the sequences in Europe as well as the initial sequences in Japan (A/duck/Chiba/26-372-48/2014 and A/duck/Chiba/26-372-61/2014). All formed a sub-clade which had evolved from the sequences in South Korea and Japan isolated in early 2014 and was most closely related to A/broiler duck/Korea/Baun2/2014.
However, more recent sequences from Japan (A/crane/Kagoshima/KU1/2014 and A/chicken/Miyazaki/7/2014) were in a sub-clade that linked to a subset of the sequences, which included ,A/chicken/kumamoto/1-7/2014, A/Baikal teal/Korea/H41/2014, A/bean goose/Korea/H53/2014, A/Baikal teal/Korea/H66/2014, A/breeder duck/Korea/H128/2014, A/broiler duck/Korea/H145/2014, A/broiler duck/Korea/H48/2014, A/broiler duck/Korea/H49/2014, A/bean goose/Korea/H40/2014, signaling co-circulation of three distinct sub-clade. Moreover, a recent sample from water from roost of Kagoshima cranes, A/environment/Kagoshima/KU-ngr-H/2014, matched the larger subclade from Europe/Russia/Chiba, reinforcing the diversity in a small area collect 8 days apart, which suggested similar diversity may be present in North America, where H5N8 was reported in a wigeon near Wiser Lake in Washington, as well as a backyard farm in Winston, Oregon, and H5N2 was found on 12 commercial and backyard farms in British Columbia, as well as a northern pintail at Wiser Lake.
Although none of the North American sequences have been released, the USDA noted the most closely related sequences for each of the three Fujian H5s. Both the H5 from Oregon and the H5 from H5N2 in Washington were most closely related to A/bean goose/Korea/H40/2014 indicating they were distinct from the larger series linked to A/broiler duck/Korea/Baun2/2014, and instead were linked to the smaller sub-clade noted above. Moreover, the percent identity for A/bean goose/Korea/H40/2014 was 99.3% for Oregon and 98% for Washington signaling divergence between these two H5s.
Similarly, the H5 from the H5N8 in Washington was most closely related to A/coot/Korea/H81/2014, which was distinct from the larger sub-clade in Europe/Russia/Chiba, as well as the sub-clade(s) of the two other US sequences, indicating co-circulation of 3 distinct sub-clades in the US, raising surveillance concerns.
Although the US has reported three different isolates in two states, there have been no reports of outbreaks in commercial farms. Similarly, although Canada has reported H5N2 in 12 farms in British Columbia, there have been no reports of H5N8 anywhere, and no reports of any Fujian H5 in wild birds.
These absences raises serious concerns about the level of surveillance and the true distribution of H5N8 and H5N2 in North America.
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