Tracking the next pandemic: Avian Flu Talk |
H7N9 more likely to transmit among humans |
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Strategos
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Posted: May 18 2013 at 5:11pm |
EdwinSm,
Moderator Joined: April 03 2013 Status: Offline Points: 24065 |
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From the article:
"Besides, the WHO offered the Chinese government several suggestions, including staying alert despite the virus' seasonal weakening during the summer," "weakening" is different from the standstill that we are seeing in the non-reporting from China. Are they leaving the door open for more cases to be reported 'when the weather turns cold again'? Or is this a message from WHO China saying "we believe that there are still more cases - you can suddenly go from 4 new cases a day to 2 a week and then nothing." |
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Strategos
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Either way, I believe h7n9 isn't standing still, maybe laying off a little, but never standing still. Also remember that the first wave of the 1918 pandemic was mild, but the second wave was killer. Also remember that the second wave didn't hit until four years later, I do believe.In any case, h7n9 isn't off the scope for me, nor is the h5n1.
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jacksdad
Executive Admin Joined: September 08 2007 Location: San Diego Status: Offline Points: 47251 |
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Strategos - the first wave appeared in January of 1918, and the second wave hit in August of the same year.
And I agree that we shouldn't forget our old nemesis, H5N1. With H7N9 infecting humans it provides yet another opportunity for H5N1 to pick up the genetic material necessary to go H2H. |
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"Buy it cheap. Stack it deep"
"Any community that fails to prepare, with the expectation that the federal government will come to the rescue, will be tragically wrong." Michael Leavitt, HHS Secretary. |
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CStackDrPH
Valued Member Joined: April 21 2013 Status: Offline Points: 2308 |
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This is a good read on H7N9 and H2H issues: http://annals.org/article.aspx?articleid=1686101
I'm not very concerned about reassortment of H7N9 with H5N1 as both are essentially avian viruses, and these would require extensive mutation in order to effectively transmit from human host to human host. However, there are still many strains of influenza in circulation including H1N1 "swine flu," H3N2 and others. The chances of H7N9 reassorting in a human host with one of these is not insignificant, nor is it inconceivable that H7N9 might yet co-infect swine in China or other Asian countries. I'm taking this far more seriously than many of my peers in the US public health system seem to be taking it.
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CRS, DrPH
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Strategos
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I stand corrected. (:
What I meant to say was that the strain that eventually gave way to the 1918 pandemic was believed to occur, or began to emerge, 4 years earlier or about that time. At least this is what I have come to understand based on this information I discovered on Wikipedia when I researched the subject a few years back. This is the info I read. Please tell me what you think? Is this what that is saying? Spanish flu researchMain article: Spanish flu research Centers for Disease Control and Prevention as Dr. Terrence Tumpey examines a reconstructed version of the 1918 flu. The origin of the Spanish flu pandemic, and the relationship between the near-simultaneous outbreaks in humans and swine, have been controversial. One hypothesis is that the virus strain originated at Fort Riley, Kansas, in viruses in poultry and swine which the fort bred for food; the soldiers were then sent from Fort Riley around the world, where they spread the disease.(Harvard Open Collections) Similarities between a reconstruction of the virus and avian viruses, combined with the human pandemic preceding the first reports of influenza in swine, led researchers to conclude the influenza virus jumped directly from birds to humans, and swine caught the disease from humans.[73][74] Others have disagreed,[75] and more recent research has suggested the strain may have originated in a nonhuman, mammalian species.[76] An estimated date for its appearance in mammalian hosts has been put at the period 1882β1913.[77] This ancestor virus diverged about 1913β1915 into two clades (or biological groups), which gave rise to the classical swine and human H1N1 influenza lineages. The last common ancestor of human strains dates to between February 1917 and April 1918. Because pigs are more readily infected with avian influenza viruses than are humans, they were suggested as the original recipients of the virus, passing the virus to humans sometime between 1913 and 1918. An effort to recreate the 1918 flu strain (a subtype of avian strain H1N1) was a collaboration among the Armed Forces Institute of Pathology, Southeast Poultry Research Laboratory and Mount Sinai School of Medicine in New York City. The effort resulted in the announcement (on 5 October 2005) that the group had successfully determined the virus's genetic sequence, using historic tissue samples recovered by pathologist Johan Hultin from a female flu victim buried in the Alaskan permafrost and samples preserved from American soldiers.[78] On 18 January 2007, Kobasa et al. reported that monkeys (Macaca fascicularis) infected with the recreated strain exhibited classic symptoms of the 1918 pandemic, and died from a cytokine storm[79]βan overreaction of the immune system. This may explain why the 1918 flu had its surprising effect on younger, healthier people, as a person with a stronger immune system would potentially have a stronger overreaction.[80] On 16 September 2008, the body of British politician and diplomat Sir Mark Sykes was exhumed to study the RNA of the flu virus in efforts to understand the genetic structure of modern H5N1 bird flu. Sykes had been buried in 1919 in a lead coffin which scientists hoped to have helped preserve the virus.[81] However, the coffin was found to be split because of the weight of soil over it, and the cadaver was badly decomposed. Nonetheless, samples of lung and brain tissue were taken through the split, with the coffin remaining in situ in the grave during this process.[82] In December 2008, research by Yoshihiro Kawaoka of the University of Wisconsin linked the presence of three specific genes (termed PA, PB1, and PB2) and a nucleoprotein derived from 1918 flu samples to the ability of the flu virus to invade the lungs and cause pneumonia. The combination triggered similar symptoms in animal testing.[83] In June 2010, a team at the Mount Sinai School of Medicine reported the 2009 flu pandemic vaccine provided some cross-protection against the 1918 flu pandemic strain.[84] One of the few things known for certain about the influenza in 1918 and for some years after was that it was, out of the laboratory, exclusively a disease of human beings.[85] |
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jacksdad
Executive Admin Joined: September 08 2007 Location: San Diego Status: Offline Points: 47251 |
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I agree - it's not yet as widespread as H1N1 or the other influenza viruses currently circulating and the odds of reassortment are consequently statistically lower, but if H7N9 continues to spread in a geographical area already well known for H5N1 infections, the possibility still exists for them to undergo antigenic shift, although obviously not to the extent that an H7N9/H1N1 reassortment could potentially take place. In a few decades we've moved from a situation where one dominant flu virus was circulating to having several now able to infect humans and exist side by side, most likely because of inherently unsafe and irresponsible livestock practices. Probabilities aside, I honestly think anything could happen right now, in much the same way that a triple assortment avian virus just blindsided everyone and appeared out of nowhere in China.
It's the avian viruses (particularly H5 and H7) that worry me because of the severity of the disease they cause in humans. Dr Robert Webster's "nasty bastards" indeed. |
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"Buy it cheap. Stack it deep"
"Any community that fails to prepare, with the expectation that the federal government will come to the rescue, will be tragically wrong." Michael Leavitt, HHS Secretary. |
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jacksdad
Executive Admin Joined: September 08 2007 Location: San Diego Status: Offline Points: 47251 |
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Happened to me far more times than I care to remember... |
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"Buy it cheap. Stack it deep"
"Any community that fails to prepare, with the expectation that the federal government will come to the rescue, will be tragically wrong." Michael Leavitt, HHS Secretary. |
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Strategos
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Well, when you gots it wrong you gots it wrong lol. You live, you learn. And I to agree with you on the assessment of our current situation. I just know that these types of viruses, in what ever form they come in, have a way of fading away for awhile only to come charging back with a vengeance. If anything, this was more of the point I was trying to make in the first place. In any case, thanks for keeping me straight on this. (:
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ISee
advanced Member Joined: May 13 2013 Status: Offline Points: 30 |
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I work as clinician within several health agencies and the "taking seriously" topic is my question today. Preparing within agencies I assume comes in small steps.
I would expect a trajectory of "preparedness" to look like this: First, introducing the awareness amongst the worker bees from administration. Second, an accounting of materials to handle a potential threat. That is the pandemic plan is reviewed of personnel, count ventilators, enact communication to clinicians of the CDC diagnostic algorithm. Third, perhaps a practice drill scheduled several months in advance if situation determines the need. When do these steps occur? When are policies dusted off and actually used for an influenza threat? You folks are in tune and critical thinkers. Very appreciated. |
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