Strange New Disease Outbreaks-- Click the picture:
Posted on 10/23/2005 9:07:56 PM PDT by Termite_Commander
In the upcoming Virology paper "Evolution of the receptor binding phenotype of influenza A (H5) viruses, Gambaryan et al screen H5 isolates for affinity for human Sia2-6Gal (human-like) receptors. Two isolates, A/Hong Kong/212/2003 and A/Hong Kong/213/2003 were identified. Both isolates had the S227N polymorphism.
These two isolates were from bird flu patients who had returned from a visit to Fujian province, The daughter had died in China with bird flu symptoms. The two isolates were from her brother and father. The father subsequently also died. Thus, the change in receptor binding was associated with a familial cluster that probably involved human to human transmission.
Although the S227N change requires a simple G/A transition, it is rare. This is similar to another polymorphism E627K in PB2. The change is also encoded by a A/G transition, but is strictly conserved. E was exclusively in avian H5N1 isolates and K was found in all human isolates. The conservation could be explained by selection which may have been further restricted by opportunities for recombination. The conservation was broken at Qinghai Lake, where all 16 avian isolates contained the human E627K polymorphism.
Similarly, the lack of S227N in H5N1 may be related to a lack of recombination opportunities. As H5N1 expands its global reach via spread by long range migratory birds, the potential for new recombination targets generating novel genetic changes increases.
A search of the Los Alamos flu database using a 10 nucleotide probe representing the S227N polymorphism identified 42 exact matches. All were in HA and all isolated after 1998 were in the Middle East in chickens, turkeys, geese, and an ostrich.
H9N2 has become endemic in Israel and millions of migratory birds will be passing through the area in the upcoming days. Thus, the potential for dual infections by H9N2 and H5N1 is high. The 10 nucleotides of identity offers an opportunity for homologous recombination that would create the S227N polymorphism and increase the efficiency of H5N1 human transmission.
Efforts to limit the exposure of H9N2 infected birds to H5N1 infected wild birds should be aggressively pursued.
Isolates with donor sequences for S227N acquisition:
AY575869 A/Hong Kong/212/03 2003 H5N1
AB212054 A/Hong Kong/213/03 2003 H5N1
ISDN38262 A/Hong Kong/213/2003 2003 H5N1
AY575870 A/Hong Kong/213/2003 2003 H5N1
AY738456...
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[Follow link for the rest of the isolates]
Now, just an aside that Mr. Niman is more on the tinfoil hat side of things when it comes to bird flu, but many of his predictions have come to pass, so don't dismiss it offhand.
The method& quickness in which Avian flu is nation spreading, just in the last week, (migratory Autumn season) Mr. Niman's overview should be reviewed.
uh-oh ping
BFL
"Quite technical, but it's an interesting point."
Uh, could I impose on you for a brief translation/summary?
Could one of you ping me if there is a translation into simple layman's language?
Thanks.
In layman's terms it means that they have found a strain of the H5N1 virius that has acquired a polymorphism (genetic coding) from the H9N1 virius that would make it possible to transmit the virius human to human. Since viriuses recombine with similiar viriuses, Mr. Niman's concern about two populations of birds co-mingling infected with H5N1 and H9N1 is justified. There are two things to rememeber in all of this: Other than a "handful" of humans, no one alive today has been exposed to a H5 flu, and two, currently the H5N1 flu kills +50% of those who come down with it. We're talking Black Death time if the virus acquires a polymorphism that allows it to go human to human. Do the math. The predictions are 50% of the population will get infected (in 1918 the Spanish flu reached EVERY corner of the globe with the one exception of a small island off the coast of Brazil. And that was without global jet travel) Even if the lethality is cut by a factor of ten (5%), we're looking at tens of millions upon tens of millions dead in the space of a year or two. In the United States we could be looking at 7.5 million (2.5% of the population). Care to speculate on the effects of that on our political, economic and social structures?
Strange New Disease Outbreaks-- Click the picture:
If both people and birds can carry this, I don't see how, say, China could escape either.
Send scarecrows to Israel? Verrrrrrry interesting that the Holy Land might be the site of origination of a plague of biblical proportions.
China would probably consider it to be a fortuitous population control tool, and a provider of employment for the survivors -- mortuary work.
Wal-Mart will be suffering.
If the US found methods to cut the lethality, how would we determine who received the medications? Wouldn't we have to distribute them according to Preferred Minority Status? Perceived inequities here could result in serious civil unrest.
China has it already. There have been massive bird kills.
bump
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