Avian Influenza and Wetlands: Complex Interactions

[gsgs]

Re: Avian Influenza and Wetlands: Complex Interactions

I speculate :


In wild birds LP is evolutionary more fit and thus prevalent.
Then wild birds introduce it to poultry and it often mutates
to HP in poultry (while apparantly it never mutates back to LP).
Then the HP usually dies or is wiped out.
That didn't work so well with H5N1 which persists in wild birds and poultry.

We don't know whether H5N1 was already HP when it emerged in poultry
in 1996, but no LP H5N1 was observed. However no HP H5N1 was observed in birds
in China before 1996 either. The H5 is similar to LP-H5 from Hongkong,Japan,Italy
but not H5N1.
That particular combination/reassortment of segments which first formed
H5N1 in China, was presumably LP. But the new combination was a dramatic change
which might have caused the HP-mutation as well as many subsequent
reassortments with all sorts of serotypes. Then that virus went to the goose-farm in 1996.

Or...

Some LP-H5Nx was already present on some Guangdong poultry farm.
Then some wild bird brought a new virus with N1, H5N1-LP was formed
by reassortment, and after some time it mutated to HP

 

[Mamabird]

Re: Avian Influenza and Wetlands: Complex Interactions

Right on gsgs. Most of the literature would support this view.

More precisely, an H5 virus apparently reassorted with H9N2 and H6N1 as they mixed in live bird markets in Hong Kong, producing an H5N1 variant. That virus likely turned highly pathogenic in poultry as many of the H7 and H5 viruses are prone to do, and it has been HP ever since 1996 spreading rapidly on the wings of migratory birds that cannot be controlled.

 

[HenryN]

Re: Avian Influenza and Wetlands: Complex Interactions

I speculate :


In wild birds LP is evolutionary more fit and thus prevalent.
Then wild birds introduce it to poultry and it often mutates
to HP in poultry (while apparantly it never mutates back to LP).
Then the HP usually dies or is wiped out.
That didn't work so well with H5N1 which persists in wild birds and poultry.

We don't know whether H5N1 was already HP when it emerged in poultry
in 1996, but no LP H5N1 was observed. However no HP H5N1 was observed in birds
in China before 1996 either. The H5 is similar to LP-H5 from Hongkong,Japan,Italy
but not H5N1.
That particular combination/reassortment of segments which first formed
H5N1 in China, was presumably LP. But the new combination was a dramatic change
which might have caused the HP-mutation as well as many subsequent
reassortments with all sorts of serotypes. Then that virus went to the goose-farm in 1996.

Or...

Some LP-H5Nx was already present on some Guangdong poultry farm.
Then some wild bird brought a new virus with N1, H5N1-LP was formed
by reassortment, and after some time it mutated to HP

What does any of the above have to do with H5N1 in Asia since 1996 (or any H5N1 positive country west of China since 2005)?

 

[HenryN]

Re: Avian Influenza and Wetlands: Complex Interactions

Right on gsgs. Most of the literature would support this view.

More precisely, an H5 virus apparently reassorted with H9N2 and H6N1 as they mixed in live bird markets in Hong Kong, producing an H5N1 variant. That virus likely turned highly pathogenic in poultry as many of the H7 and H5 viruses are prone to do, and it has been HP ever since 1996 spreading rapidly on the wings of migratory birds that cannot be controlled.

The H5N1 in Hong Kong in 1997 was quite distinct from the H5N1 currently in circulation. It had wild bird (H9N2 and H6N1) internal genes but that constellation is not widespread (limited to a few more recent isolates from eggs in Vietnam).

The HPAI H5N1 in circulation now has been divided into something like 10 clades. Of these, clade 1 and 2 have been reported to cause human disease and were actually more closely linked to early isoaltes from NORTHERN China than the Hong Kong isolates.

Moreover, the first post on this thread is a propaganda piece focused on wild birds as victims, which has NOTHING to do with the current version of H5N1 in circulation (other than a possible role a decade ago).

 

[mixin]

Re: Avian Influenza and Wetlands: Complex Interactions

.....Moreover, the first post on this thread is a propaganda piece focused on wild birds as victims, which has NOTHING to do with the current version of H5N1 in circulation (other than a possible role a decade ago).

Did you even read this article?

The message I took away was that people, poultry, wild birds, etc could all end up being victims of Avian Influenza if more appropriate steps in its prevention weren't taken in the future. I truly don't see an argument with that.

 

[gsgs]

Re: Avian Influenza and Wetlands: Complex Interactions

not so attractive to read long articles without abstract or summary.

wetlands = mainly the large west sibirian wetlands ?

> HP was rare before H5N1 came along

HK'97 was different, but in HA it was not so different,
we can see the evolution of H5N1-HA separately.

When there are dramatic changes, then reassortment
tries to compensate for occurring problems.

New strains need some time to find their stable points

 

[HenryN]

Re: Avian Influenza and Wetlands: Complex Interactions

Did you even read this article?

The message I took away was that people, poultry, wild birds, etc could all end up being victims of Avian Influenza if more appropriate steps in its prevention weren't taken in the future. I truly don't see an argument with that.

The LPAI data had NOTHING to do with pandemic H5N1. The article was a snow job.

 

[HenryN]

Re: Avian Influenza and Wetlands: Complex Interactions

not so attractive to read long articles without abstract or summary.

wetlands = mainly the large west sibirian wetlands ?

> HP was rare before H5N1 came along

HK'97 was different, but in HA it was not so different,
we can see the evolution of H5N1-HA separately.

When there are dramatic changes, then reassortment
tries to compensate for occurring problems.

New strains need some time to find their stable points

The polybasic cleavage site has been around (and in MANY H5N1 clades and sub0clades) since 1996. No poultry required to go from LPAI to HPAI since 1996 in Asia (and now clade 2.2 in Europe, the Middle East, and Africa).