I have noticed a few recent news clips out of Vietnam, Cambodia, Egypt and Indonesia all stating that investigators were locating chickens and ducks that harbored H5N1 (were positive for the virus) yet were not showing symptoms of the disease (yet).This seems contrary to much of what we were initially hearing about H5N1, that in Asia, Europe and Africa it is all HP-“high path”.
In the Americas, they are quick to point out that all the birds that have been found recently have tested positive for H5N1 but they claim it is the “low path” type, not like the asian strains, because the birds were not dead or the chickens nearby didn’t die. How can they say this righ toff the bat when it appears that the mortality of the birds is no longer a “given”? They announce these findings well before any sequencing can determine what strain the birds have. And then, the sequences don’t appear for review anyway… “since it is LP (as announced previously), the sequences really aren’t important to publish anyway, right?” -or so we are led to believe.
I have a theory…
The virus has strains developed now that are less pathogenic in different bird species, but it is the same virus. -Just as we see different CFR rates in humans throughout the world based on the strain caught. I believe the America’s version is just a different strain of the same virus.
Maybe the Americas’ clade gave birth to the Asian clade back in the 80′s and it has since mutated to somethign very different. Maybe the other way around. Afterall, hasn’t H5N1 been around in some documented form for over 100 years?
When they say a virus is Highly Pathogenic, it doesn’t mean that it has to be pathogenic to the bird from which it was isolated. It only means that it shows the characteristic molecular features, ie a series of basic amino acids in the cleavage site of the HA protein, which allows it to cause severe systemic disease in birds that are susceptible.
Low Path H5N1 would not have this signature feature.
So how can they declare HP or LP without having done sequencing?
TreasureIslandGal – at 11:08 So how can they declare HP or LP without having done sequencing?
PCR, presumably?
I especially remember when the PEI birds got sick… They claimed it “had to be” LP because chickens nearby didn’t get sick. -even though the birds that did get it died quickly.
We are seeing cases overseas where even chickens in the same flocks are not showing symtoms while others die and yet others aren’t positive.
And what a shame, they weren’t able to recreate the virus for sequencing. -and the college must have been wrong in their earlier testing. *rolling eyes
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