Bird 'Flu Epidemiology

[Badly Shaved Monkey]

Aside from the question of whether the apostrophe in 'flu (and the one at the end has died already) can survive this epidemic, has anyone here looked into the epidemiology properly yet? I'm a vet and I should know, but I don't and I was wondering if anyone has any quick answers.

I am confused by these apparent facts.

1. H5N1 is highly contagious.
2. H5N1 is present in wildfowl reservoirs, some of which are asymptomatic
3. H5N1 has spread with migrating birds
4. H5N1 has killed birds in Europe having spread from the Far East where it first appeared about 8 years ago.

But, if 1, 2 and 3 are true it should be almost ubiquitous by now. If we're only picking up the occasional dead birds, where did they get it from? Either there really isn't much of it about, in which case 1 is false, or there's loads of it about already and we're only picking up the tiny tip of the iceberg.

All this leads to this thought, if H5N1 exists in wild reservoirs already, aren't we better off if it hurries through the bird population and burns itself out? If current policy cannot control it in the wild reservoirs then our attempts to stall its spread in wild reservoirs will simply give it a longer opportunity to mix with human-compatible 'flu viruses and potentially acquire mutations?

So, shouldn't we want it to hurry through the wild birds while at the same time closing off contact of domestic birds and people with those wild reservoirs?

I asked around our vets' meeting this morning and no one had clear answers including the vet whose partner is in the avian veterinary industry, so my ignorance may be worrying, but it is not unique.

 

[Soapy Sam]

I've been wondering too. An airborne (ie wing-borne) highly infectious virus in wildfowl is bound to infect free range chickens sooner or later. Is it not best to accept that and breed frominfected but immune birds?

 

[Rolfe]

Does it burn out? Guy on the radio this morning was saying that once we've got it in this country it's here for the long haul - either enzootic or sporadic. So management has to take years into account, not just measures which can be kept up for a couple of months.

(Actually he didn't say "enzootic", he said "endemic", which is driving me nuts. It didn't matter with FMD because that isn't transmissible to man anyway, so that was "department of we know what you mean". But since "endemic" means present in the human population, and "epidemic" means sweeping through the human population, and "pandemic" means felling the human population in great swathes, then it's not to my mind a good idea to use the terms when specifically referring to infeciton in the non-human population. I've already come across people very confused about news reports referring to an "epidemic" of bird flu. OK, the equivalent words for animal infections (enzootic, epzootic and panzootic) might not be well understood by the general public at the moment, but if they were used by the news media then they'd soon become understood, and discussion would be much clearer and more precise.)

Rolfe.

 

[brettDbass]

Does this help answer some of the questions?

{snip}

the virus .. appeared in wild birds at Qinghai Lake in north-west China last spring, and then spread across Siberia to the Black Sea coast and Turkey.

All outbreaks so far have been near wintering spots for ducks that spend the summer in Siberia, where there were multiple cases of the Qinghai strain last year.

According to http://www.newscientist.com/channel/health/mg18925392.900.html

 

[Badly Shaved Monkey]

Does it burn out? Guy on the radio this morning was saying that once we've got it in this country it's here for the long haul - either enzootic or sporadic. So management has to take years into account, not just measures which can be kept up for a couple of months.

But what is the "it"? Bird flu as a whole? H5N1?

I thought it was epizootic (point taken) in birds as well.

It may be a matter of how you defined these things. Seasonal flu is people is epidemic in the UK, but is it more like endemic in its breeding grounds in SE Asia?

Having started this thread, I've done some Googling and I'm not seeing good answers to these questions.

 

[Rolfe]

I thought it was epizootic (point taken) in birds as well.

I thought that too. Until there was this virologist on the Today programme. I don't think he was specifically a veterinary virolologist, but I imagine he knew what he was talking about. I got the impression it was specifically H5N1 he was referring to.

Rolfe.

 

[Soapy Sam]

Something of a side issue, but I suspect most people are unaware of the term "epizootic" and the related terms Rolfe mentions. In this case- where public interest interects with medical / veterinary terminology, I feel we must accept some loss of precision and live with the fact that "epidemic in animals" is the term most people will inevitably use.
(I remember a futile attempt to use the word "Selenology" instead of the oxymoronic "Lunar Geology" years ago. It was a pointless attempt.)

Incidentally , "epidemic" can be both noun and adjective. I can see "epizootic" as adjective, but is it also used as a noun?

 

[Rolfe]

Yes.

(I still think it would be worth a try. "Lunar geology" may be silly, but again it's "department of we know what you mean". Unless they are really going to take care to say "epidemic in animals" every time, which they don't, there is real confusion here.)

Rolfe.

 

[Dymanic]

But, if 1, 2 and 3 are true it should be almost ubiquitous by now.

http://www.curevents.com/vb/showthread.php?t=39480

Confirmed - 36 countries

-- Austria (B) 2-14-06
-- Azerbaijan (B) 2-9-06
-- Belgium (B) 10-?-05
-- Bosnia/Herzegovina (B) 2-17-06
-- Bulgaria (B) 2-11-06
-- Cambodia (B) 1-24-04 (H) 2-?-05
-- China (B) ? (H) 2-4-03
-- Croatia (B) 10-26-05
-- Cyprus (B) 1-30-06
-- Egypt (B) 2-16-06
-- Ethiopia (B)
-- France (B) 2-18-06
-- Germany (B) 2-14-06
-- Greece (B) 2-11-06
-- Hungary (B) 2-15-06
-- India (B)
---- Maharashtra (B) 2-18-06
-- Indonesia (B) 2-2-04 (H) 7-?-05
-- Iran (B) 2-14-06
-- Iraq (B) (H) 1-2-06
-- Italy (B) 2-11-06
-- Japan (B) 1-?-04
-- Kazakhstan (B) 8-2-05
-- Kuwait (B) 11-11-05
-- Laos (B) 1-27-04
-- Libya (B) 10-9-05
-- Malaysia (B) 8-?-04
-- Mongolia (B) 8/12/05
-- Nigeria (B) 2-8-06
----- Sokoto (B)
----- Katsina (B)
----- Kano (B)
----- Yobe (B)
----- Kaduna (B)
----- Bauchi (B)
----- Plateau (B)
----- Nassarawa (B)
----- Abuja (B)
----- Kogi (B)
----- Lagos (B)
-- Reunion Island (H?)
-- Romania (B) 10-15-05
-- Russia (B) 7-23-05
-- Saudi Arabia (B)
-- Slovenia (B) 2-12-06
-- South Korea (B) 12-19-03
-- Taiwan (B) 10-?-05
-- Thailand (B) Tigers 1-23-04 (H) 9-?-04
-- Turkey (B) 10-13-05 (H) 1-1-06
-- UK (finches in quarantine) (B) 10-?-05
-- Ukraine (B) 12-5-05
-- VietNam (B) 1-8-04 (H) 12-?-04


Suspected - 17 countries

-- Albania (B)
-- Bulgaria (H) 2-18-06
-- Chad (B) from post, not news article
-- Greece (H) 2-15-06
-- India (H) 2-18-06
-- Macedonia (B) 2-15-06
-- Mauritania (B) 2-17-06
-- Morocco (B)
-- Netherlands (B) 2-16-06
-- Niger (B) 2-15-06
-- Poland (B) 2-15-06
-- Serbia & Montenegro (B) 2-16-06
-- Spain (B)
-- Sweden (B) 2-16-06
-- Taiwan (B?) if the UK finches were from Taiwan, then they should be listed
-- UK (B) 2-17-06 (swans)

 

[Dymanic]

I was wondering if anyone has any quick answers.

I'm not seeing good answers to these questions.

Certainly there are plenty of quick answers. Good answers are a little harder to come by. There aren't any good, quick answers.

Is it not best to accept that and breed from infected but immune birds?

Aquired immunity isn't passed on to offspring, unfortunately. As long as the virus is endemic (ok, ok, enzootic) in wild birds, preventing domestic poultry from contracting it will be difficult, at best. Don't count on it "burning out".

The WHO:
"It is considered unusual for an avian influenza virus causing outbreaks in birds to remain this genetically stable over so many months. This finding raises the possibility that the virus -- in its highly pathogenic form -- has now adapted to at least some species of migratory waterfowl and is co-existing with these birds in evolutionary equilibrium, causing no apparent harm, and travelling with these birds along their migratory routes.

If further research verifies this hypothesis, re-introduction of the virus or spread to new geographical areas can be anticipated when migratory birds begin returning to their breeding areas.

The recent appearance of the virus in birds in a rapidly growing number of countries is of public health concern, as it expands opportunities for human exposures and infections to occur. These opportunities increase when the virus spreads from wild to domestic birds, especially when these birds are kept as backyard flocks in close proximity to humans"

 

[Badly Shaved Monkey]

http://www.curevents.com/vb/showthread.php?t=39480

Confirmed - 36 countries

-- Austria (B) 2-14-06
-- Azerbaijan (B) 2-9-06
-- Belgium (B) 10-?-05
-- Bosnia/Herzegovina (B) 2-17-06
-- Bulgaria (B) 2-11-06
-- Cambodia (B) 1-24-04 (H) 2-?-05
-- China (B) ? (H) 2-4-03
-- Croatia (B) 10-26-05
-- Cyprus (B) 1-30-06
-- Egypt (B) 2-16-06
-- Ethiopia (B)
-- France (B) 2-18-06
-- Germany (B) 2-14-06
-- Greece (B) 2-11-06
-- Hungary (B) 2-15-06
-- India (B)
---- Maharashtra (B) 2-18-06
-- Indonesia (B) 2-2-04 (H) 7-?-05
-- Iran (B) 2-14-06
-- Iraq (B) (H) 1-2-06
-- Italy (B) 2-11-06
-- Japan (B) 1-?-04
-- Kazakhstan (B) 8-2-05
-- Kuwait (B) 11-11-05
-- Laos (B) 1-27-04
-- Libya (B) 10-9-05
-- Malaysia (B) 8-?-04
-- Mongolia (B) 8/12/05
-- Nigeria (B) 2-8-06
----- Sokoto (B)
----- Katsina (B)
----- Kano (B)
----- Yobe (B)
----- Kaduna (B)
----- Bauchi (B)
----- Plateau (B)
----- Nassarawa (B)
----- Abuja (B)
----- Kogi (B)
----- Lagos (B)
-- Reunion Island (H?)
-- Romania (B) 10-15-05
-- Russia (B) 7-23-05
-- Saudi Arabia (B)
-- Slovenia (B) 2-12-06
-- South Korea (B) 12-19-03
-- Taiwan (B) 10-?-05
-- Thailand (B) Tigers 1-23-04 (H) 9-?-04
-- Turkey (B) 10-13-05 (H) 1-1-06
-- UK (finches in quarantine) (B) 10-?-05
-- Ukraine (B) 12-5-05
-- VietNam (B) 1-8-04 (H) 12-?-04


Suspected - 17 countries

-- Albania (B)
-- Bulgaria (H) 2-18-06
-- Chad (B) from post, not news article
-- Greece (H) 2-15-06
-- India (H) 2-18-06
-- Macedonia (B) 2-15-06
-- Mauritania (B) 2-17-06
-- Morocco (B)
-- Netherlands (B) 2-16-06
-- Niger (B) 2-15-06
-- Poland (B) 2-15-06
-- Serbia & Montenegro (B) 2-16-06
-- Spain (B)
-- Sweden (B) 2-16-06
-- Taiwan (B?) if the UK finches were from Taiwan, then they should be listed
-- UK (B) 2-17-06 (swans)

That's sort of what I was meaning. Lots of places, but apparently not very prevalent in any of them.

 

[Jorghnassen]

OK, the equivalent words for animal infections (enzootic, epzootic and panzootic) might not be well understood by the general public at the moment, but if they were used by the news media then they'd soon become understood, and discussion would be much clearer and more precise.

Oh I understand the difference perfectly. I just think epizootic (pan- and en-) really isn't a nice sounding word. It's just wrong. An inspired poet, supported by Pegasus, would have found a nice christian name for it. That or a cunning linguist.

/obscure, deeper and not so out of the blue as it appears
//still, somebody should've come up with something better

 

[Dymanic]

That's sort of what I was meaning. Lots of places, but apparently not very prevalent in any of them.

I favor the "tip of the iceberg" hypothesis. Since sampling of wild bird populations has been limited primarily to the counting of dead birds, "not apparent" doesn't automatically mean "not ubiquitous". The cautious approach would be to assume that the virus "has adapted to at least some species of migratory waterfowl and is co-existing with these birds in evolutionary equilibrium, causing no apparent harm, and travelling with these birds along their migratory routes". There are, undeniably, significant economic consequences for adopting such an approach -- but justified in my view, considering the stakes.

 

[Rolfe]

Oh I understand the difference perfectly. I just think epizootic (pan- and en-) really isn't a nice sounding word. It's just wrong. An inspired poet, supported by Pegasus, would have found a nice christian name for it. That or a cunning linguist.

The one I really find impossible is "epizootiology". Fortunately, most of the time one can get away with simply writing it....

Rolfe.

 

[Mojo]

In Ben Goldacre's column in this Saturday's Grauniad, he says that there isn't yet a vaccine for the current variety of bird flu. On the BBC news this morning (on the telly) there were repeated references to vaccinating domestic fowl. Is there a vaccine for this available for birds but not people, or have the BBC fallen into the same pitfall as the people mentioned in the column?

 

[rustytunes]

I keep my eye on a Homeopath egroup - noticed this posting today:

Dear Members,
My Name is A.SAMPATH KUMAR from India I am working in the field of
Homeopathic Medicines Manufacturing and Research & Development of new
combinations past 16 years in India.
I have recently formulated one ANTI-PYRETIC Oral Liquid and We have
tried this one under clinical trial among common flu patients (Human
beings)
We found that this Oral Liquid is working very good.
I wish to inform you that any interested Homeopath can cantact me in
this regard.
I will ready to give this combination to any bird flu infected person
in this world.
I need the assitance of interested homeopaths all over the world.
Thanks
A.SAMPATH KUMAR
INDIA

Looks like there is a bird flu vaccine!

 

[Capsid]

In Ben Goldacre's column in this Saturday's Grauniad, he says that there isn't yet a vaccine for the current variety of bird flu. On the BBC news this morning (on the telly) there were repeated references to vaccinating domestic fowl. Is there a vaccine for this available for birds but not people, or have the BBC fallen into the same pitfall as the people mentioned in the column?

There is a potential candidate for humans. I don't see why this vaccine couldn't be used on domestic fowl, but the logistics of vaccinating millions of birds that have a rather short life is both daunting and perhaps not appropriate.

 

[Mojo]

Looks like there is a bird flu vaccine!

But from a homoeopath called Kumar...

 

[Badly Shaved Monkey]

In Ben Goldacre's column in this Saturday's Grauniad, he says that there isn't yet a vaccine for the current variety of bird flu. On the BBC news this morning (on the telly) there were repeated references to vaccinating domestic fowl. Is there a vaccine for this available for birds but not people, or have the BBC fallen into the same pitfall as the people mentioned in the column?

Intervet have the bird vaccine. I don't know whether it should be readily usable in people (subject to licensing hurdles).

 

[kellyb]

I favor the "tip of the iceberg" hypothesis. Since sampling of wild bird populations has been limited primarily to the counting of dead birds, "not apparent" doesn't automatically mean "not ubiquitous". The cautious approach would be to assume that the virus "has adapted to at least some species of migratory waterfowl and is co-existing with these birds in evolutionary equilibrium, causing no apparent harm, and travelling with these birds along their migratory routes". There are, undeniably, significant economic consequences for adopting such an approach -- but justified in my view, considering the stakes.

That's pretty much what I think, too.

Here's an interesting article on the possibility of what it's doing in people.
http://www.iht.com/articles/2006/01/10/news/flu.php