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Tuesday, February 4, 2014

JX346

They isolated the virus and dubbed it A/Jiangxi-Donghu/346/2013(H10N8), or JX346 for short...


Genetic findings

The authors' genomic analysis of the virus showed that its hemagglutinin (H) protein was most closely related to that of a 2012 H10N3 duck isolate from Hunan province and that the neuraminidase (N) protein was most closely related to that of an H10N8 virus from a mallard in Korea.

All six of JX346's internal genes were closely related to those of H9N2 poultry viruses currently circulating in China, the authors found. But the internal genes were significantly different from those of previously reported H10 and N8 subtype viruses and were in different subclades from those of known H7N9 viruses.
Only two H10N8 viruses have been reported previously in China, one from a lake and the other from a poultry market, the report notes.

"H9N2 virus provided the internal genes not only for the H10N8 virus, but also for H7N9 and H5N1 viruses," the report says. "This relation should be studied further to understand the mechanism of how the internal genes of H9N2 virus transfer to viruses that infect people, and how the avian influenza virus transfers between species."
The authors say the findings suggest that JX346 might have originated from multiple reassortments between different avian flu viruses.

Senior author Yuelong Shu, PhD, of the Chinese Center for Disease Control and Prevention commented in a Lancet press release, "The H10 and H8 gene segments might have derived from different wild bird influenza viruses [that] reassorted to give rise to a hypothetical H10N8 virus in wild birds, which infected poultry and then reassorted with H9N2 viruses in poultry to give rise to the novel reassortant JX346 (H10N8) virus."
In other observations, the researchers say the patient's chronic medical conditions could have played a role in her death. But they found that the novel virus was "overwhelmingly dominant" in her tracheal specimens, which indicates that it was involved in her demise.

In addition, they found a mixture of glutamic acid and lysine at residue 627 in the virus's PB2 protein, a mutation that is associated with adaptation to, and can increase virulence in, mammals.
Further, the authors report that the novel virus preferentially binds avian-like alpha2,3-linked sialic acid receptors, which are "dominant in human lung tissue," suggesting a potential for the kind of lung damage found in human H5N1 infections....

http://www.cidrap.umn.edu/news-perspective/2014/02/study-h10n8-virus-first-human-case-novel-strain