Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Laidback Al · Apr 29, 2013

Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

In an article entitled, Epidemiological and risk analysis of the H7N9 subtype influenza outbreak in China at its early stage published in the Chinese Science Bulletin, Chinese researchers review the case data on human A(H7N9) infections and conclude that there is high risk of A(H7N9) causing a pandemic. They speculate that such a pandemic would be severe and have a higher mortality rate than the recent 2009 H1N1 pandemic.

From the article:

In light of the above considerations, we think that the H7N9 outbreak is severe, and it is likely to become very or extremely severe in the future, highlighting the emergent need of forceful scientific measures, such as building enough stockpile of H7N9 vaccine for human use in case the pandemic really occurs. . . .We do not exclude completely the possibility that the H7N9 will disappear naturally, or maintain its low pathogenicity in birds and limited transmission ability in humans for a long period, without forceful scientific control measures. However, such a mild scenario of the outbreak evolution is of less possibility than the very or extremely severe scenario describe above. The main reason is that some random mutations leading to the improved adaption of the virus to humans will emerge naturally during its long existence in humans, as the virus usually evolves rapidly. These mutants will become dominant by natural selection as they are more adaptive in humans. They thus may spread in humans rapidly and can spark a deadly pandemic. Similarly, the H7N9 virus of low pathogenicity in birds is more likely to become highly pathogenic through natural selection. . .

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Giuseppe · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

It was noted earlier that a very high case fatality ratio could not result an efficient and sustained human-to-human transmission.

The time-frame of the predicted circulation of this new virus, reported in the paper, would likely span through a decade.

But if the risk is considered impending, and signals of an efficient interhuman transmission proven, there would not be the time for a such degree of mutation described above.

In other words, the construction behind the conclusion drawn by the Authors lacks of solid scientific basis and should be taken with extreme caution.

Shannon Bennett · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

I must respectfully disagree. My rationale is based on the high number of cases we know of in the short period of a few months. I believe there are more-possibly many more cases that have not been reported. We still do not know what the real

vector is. While chickens undoubtedly play a role they are not implicated in at least 20% of the known cases. Wet markets may also be hotspots for contageon but again, many of those infected never went to a wet market. I believe that

something that flies or crawls in and out of wet markets as well as parks and balconies is our villian. If the culprit is a tiny bird or even a rodent then eradicating all of the species locally would be an impossible task. Add to the equation, the virus

has been found within or close to mega cities. The opportunity to explode if and when the virus adapts to humans is astounding. The other constant is the number of travelers in and out of these mega cities and, the speed in which they arrive at

their final destinations.

As for the CFR, we are a dead end for the virus in any case. If the flu killed off every human on earth (I don't believe this will happen!) then the virus would go on anyway, infecting its primary hosts- birds. Eventually all human flu virus mutate to a

less virulent strain but that takes time. That time would involve at least months. In past societies that traveled at a slower pace an out break might have been controlled. Today with modern air travel and a 4/10 incubation period we have no

hope of limiting the initial spike in readily transmitted cases. Therefore, if you have what appears atm to be a strain that has a very high cfr, thousands of flights in and out of China in a day, and a virus that suddenly mutates to a more completely

human adapted strain you have pandemic. Even if the CFR were to take a nosedive you would still be left with a novel bird flu in the human population. We know from 1918 and H5N1 that humans do not adjust well to these varients.

So while I am not utterly convinced that a pandemic is a certainty, I do believe the possibility definitly exists. We should do everything in our power to limit the scope and vacines are a good place to start. Especially as it may take more than one

jab to initiate a good response to infection. And to give us time to perfect the vax so we don't have the problems we did with H1N1 vacines in Europe.

sharon sanders · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

What do we have proof of that we can see in the threads on this site?

1) There is an epidemic of H7N9 influenza virus in the Eastern part of China.

2) It is infecting people of all ages.

3) It can cause severe respiratory and organ failure.

4) Some weird wet market phenomena has been blamed for the spread to humans.

5) It might be able to spread to another human being in a close contact situation.

What conclusions do I draw from this?

1) I am not traveling to China because I think their explanation for the cause of this disease is extremely lacking in the facts.

2) I will not be eating any poultry, pig, wild bird products from China until the Chinese identify the source of this disease.

3) Everyone in China should employ virus avoidance techniques to prevent the H7N9 virus from making them sick.

Laidback Al · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

The general points made by the authors of this paper are correct. However, as Giuseppe notes, the time frame for such mutations and or reassortments are not known. The H7N9 pandemic strain could be developing in the index case this very minute. Or, it could take years for the process to unfold. Or this strain could die out as quickly as it originated.

A(H5N1) provides an analogy. It is virulent when it infects humans, but it has been infecting people since 1997 and we have not yet experienced an H5N1 pandemic. We need a better understanding of how viruses change and how they spread before we can predict which virus will cause the next pandemic and more importantly, when the next pandemic will occur.

Shannon Bennett · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Ah but Al this virus is already better adapted to humans than H5N1 ever was. It might take years but it also might take months.
The virus has billions of humans to experiment with, all living in close proximity to whatever it is that is infecting them. But your comments still beg the question of whether this virus will become a severe pandemic. The possibility exists........as to when?

Ronan Kelly · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

To me, the line that raises the most questions is - "we think the virus can also infect pigs". Why do you think that? Are there as yet unreleased positive pig results that are not common knowledge? Are pigs being "test infected"? ...

sharon sanders · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Ronan Kelly said:
To me, the line that raises the most questions is - "we think the virus can also infect pigs". Why do you think that? Are there as yet unreleased positive pig results that are not common knowledge? Are pigs being "test infected"? ...

I agree.

Treyfish · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

:tiphat: Pretty strong article ya got goin there. Have mercy, they don't cut any slack in it. We see what is happening and the water is gettin hot!

..From the toll increase trend, we think that the H7N9 outbreak will become a Grade IV (very severe) outbreak at the end of this April, because the toll will
exceed 100 at that time... Uh that's in a couple days. I wonder what they are thinking nowadays

...Eighthly, the probable long existence of the H7N9 virus
in humans will provide the driving force to the virus to
adapt to humans through mutations. The virus may thus
obtain human-to-human transmission, and may spark a pandemic influenza thereafter. The possible pandemic should
likely be very dangerous with the consideration that the virus
has showed highly pathogenicity in the first 91 cases.
Some experts thought that the H7N9 outbreak was not
that serious. They mainly analyzed the present status rather
than its future development. Additionally, some people may
think that the possible H7N9 pandemic influenza should not
be that deadly, as we have just passed through the pandemic influenza caused by the novel swine H1N1 influenza virus
emerging in 2009. However, influenza pandemics caused by
different virus strains may be of different severity [13]. The
H1N1 influenza pandemic in 2009 was mild mainly because
seasonal H1N1 influenza viruses had widely circulated in
humans for decades before the pandemic, which resulted in
some immunity in humans against the novel pandemic
H1N1 virus, especially in the elderly (so their infections
were much fewer, as showed by Figure 1). In contrast, H7
subtype influenza virus has never widely circulated in humans, and thus persons of all ages are likely susceptible to
the virus infection. Therefore, the future possible H7N9
pandemic will be likely more severe than the pandemic
H1N1 influenza in 2009

gsgs · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

so many Chinese scientists ... are these creditworthy ?

zero hits for reassortment in the paper, did they check the reassortment
studies ?

as for H5N1 ... only recently we figured out what it may need
to go pandemic. Just give us some more time, we might finally
succeed to create one

sharon sanders · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

gsgs said:
so many Chinese scientists ... are these creditworthy ?

zero hits for reassortment in the paper, did they check the reassortment
studies ?

as for H5N1 ... only recently we figured out what it may need
to go pandemic. Just give us some more time, we might finally
succeed to create one

Those scientists are from a top facility in China:

China Animal Health and Epidemiology Center in Qindao

http://www.dwws.moa.gov.cn/

Catbird · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Ronan Kelly said:
To me, the line that raises the most questions is - "we think the virus can also infect pigs". Why do you think that? Are there as yet unreleased positive pig results that are not common knowledge? Are pigs being "test infected"? ...

That also struck me as being very significant. Not only do we not know if pigs are being tested, we also don't know if any other mammals have been tested.

I'd like to add a couple of facts to the list that Sharon made.

6. We know that there can be asymptomatic carriers (4 yr. old boy in Beijing)

7. We know that there are both mild and virulent forms.

8. We know that China is continuing to use throat swabs as the testing standard for "close contacts" (see xhttp://www.jx.xinhuanet.com/news/focus/2013-04/28/c_115577857.htm) in spite of the evidence of the case in Taiwan who had 2 negative throat swabs even though he was infected.

My personal theory is similar to Shannon's. There is something that exists in or passes through wet markets. IF the data from China is accurate, and they haven't found any trace of the virus in poultry farms, then the poultry are being infected en route or while IN the wet markets.

sharon sanders · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Isn't it really odd that Ministry of Agriculture scientists have published a paper about a disease which is NOT in animals (except a couple of pigeons)?

Something is really off here.

gsgs · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

chickens aren't animals in China ?

sharon sanders · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

They say all of the H7N9 positive samples from chicken are from markets NOT farms.

There is some mystery market contagion.

Diane Morin · Apr 29, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

How this document may it have been submitted to the Chinese Science Bulletin on April 11 and present data on 19 April?

Giuseppe · Apr 30, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

--->@MarionKoopmans --->@Crof A yesterday chinese paper doi: 10.1007/s11434-013-5880-5
suggested high degree of panic among readers.What's your op?

@MarionKoopmans ---> @ironorehopper --->@Crof

''i do not see new info in the paper, prediction is speculation. The severity score is quite crude and influenced by CFR ''

09:06 AM - 30 Apr 13

mbeltran · Apr 30, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Laidback Al said:
Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

In an article entitled, Epidemiological and risk analysis of the H7N9 subtype influenza outbreak in China at its early stage published in the Chinese Science Bulletin, Chinese researchers review the case data on human A(H7N9) infections and conclude that there is high risk of A(H7N9) causing a pandemic. They speculate that such a pandemic would be severe and have a higher mortality rate than the recent 2009 H1N1 pandemic.

From the article:

How many asymptomatic cases circulating in silence?
Perhaps these researchers know of things not published. ?

sharon sanders · Apr 30, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Giuseppe Michieli said:
--->@MarionKoopmans --->@Crof A yesterday chinese paper doi: 10.1007/s11434-013-5880-5
suggested high degree of panic among readers.What's your op?

@MarionKoopmans ---> @ironorehopper --->@Crof

''i do not see new info in the paper, prediction is speculation. The severity score is quite crude and influenced by CFR ''

09:06 AM - 30 Apr 13

I understand but look at who wrote this paper: The Ministry of Agriculture of China. A very interesting development.

Farmer · Apr 30, 2013

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Diane Morin said:
How this document may it have been submitted to the Chinese Science Bulletin on April 11 and present data on 19 April?

The date discrepancy could be explained by the standard publication process for peer-reviewed reports.

For example:

The report was received by the journal on April 11.

The report returned to the authors with reviewer comments (if any). The authors may change and update the text at that time.

The final version was accepted April 23. Additional minor changes to the proof may be effected before publication.

Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

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