Jiangxi Province – Credit Wikipedia – Site of 2 H10N8 Cases
# 8268
Last night Robert Roos, editor of CIDRAP NEWS, wrote a detailed piece on a study that appeared yesterday in The Lancet, on the recently detected human infection from H10N8 in China. Overnight, a number of other media outlets have picked up on this report, along with an embedded warning from the author’s that this virus – like H5N1 and H7N9 – needs to be watched closely for signs of spread and adaptation.
Over the past couple of months I’ve blogged several times on the emergence of this novel virus, including:
Since I’m unlikely to produce anything as clear and concise as Robert already has, I’ll direct you to his piece and a link to the study/abstract, after which I’ll be back with a bit more.
Study: H10N8 virus in first human case is novel strain
Robert Roos | News Editor | CIDRAP News
Feb 04, 2014
CDC / Erskine L. Palmer & M. L. Martin
Highly magnified view of influenza virus structure.
Chinese scientists reported today that the first human infection with an H10N8 avian influenza virus involved a new strain that carries genes from H9N2 viruses and has a mutation associated with adaptation to mammals.
Writing in The Lancet, the scientists detailed the results of their genomic analysis of the virus, which was isolated from a 73-year-old Chinese woman who died Dec 6. Her illness was the first known human case involving that strain.
A second human case in China was reported by the country's government news agency on Jan 27. "The pandemic potential of this novel virus should not be underestimated," the Lancet authors warn.
The Lancet article may be accessed here:
Chen H, Yuan H, Gao R, et al. Clinical and epidemiological characteristics of a fatal case of avian influenza A H10N8 virus infection: a descriptive study. Lancet 2014 (published online Feb 4) [Abstract]
See also:
Feb 4 Lancet press release
Feb 4 Lancet commentary on the study
Of considerable interest is the fact that H9N2 – an avian flu virus that is commonly found across much of Asia – contributed six of H10N8’s internal genes. A contribution very similar to that which H9N2 has made to other emerging avian viruses over the years, including H5N1 and H7N9.
As I wrote last month in Viral Reassortants: Rocking The Cradle Of Influenza, we continue to see new, emerging, `reassorted’ flu viruses from many places around the world, but particularly from Southeast Asia.
Reassorted viruses can result when two different flu strains inhabit the same host (human, swine, avian, or otherwise) at the same time. Under the right conditions, they can swap one or more gene segments and produce a hybrid virus.
While most of these reassortant viruses are evolutionary failures, and are unable to compete with the existing wild viruses, every once in awhile a new one appears that is a genuine contender.
Which is why we watch novel influenza viruses – even those that appear only rarely, carefully.
Last year we saw the emergence of H7N9 in Eastern China, along with previously unrecognized lineage of the H7N7 virus (see Nature: Genesis Of The H7N9 Virus). Last December, Hong Kong reported a rare case of avian H9N2 infection - imported from Shenzhen - and last May, Taiwan reported a never-seen-before human H6N1 infection.
And it is likely that other, novel reassorted viruses were produced last year – and may even have infected humans - without being detected. Since surveillance for novel viruses is limited, we honestly don’t know how often this happens.
But it is probably more common than we know.
The good news is that pandemic viruses only appear rarely. The bad news is that nature’s laboratory is open 24/7, and it is constantly trying to produce the next `successful’ virus.
All of which highlights the need for continual and enhanced surveillance of humans, livestock, and wild birds for emerging viral threats. Because it isn’t a question of if another pandemic will emerge.
It’s only a matter of when.
