I don’t believe wild birds are spreading h5n1

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  • #3228
    imported_Martin
    Participant

    post I just made in response to a question on Agonist.org, may be of interest:

    In short, yes, I do believe

    Wild birds are not spreading bird flu

    – not h5n1 variant that we’re so concerned about. (But they carry plenty of flus; benign for vast vast majority, till farming gets them and transforms [into frankenflus – yikes!].)

    Bit longer: birds were claimed to be vectors during 2003/2004, when there was extensive spread in east and se Asia. But, nowhere did such claims look credible; instead, movements within poultry trade (including illegal, inc fighting cocks) looked way more likely. At Qinghai, I’m sure that birds spread the virus amongst each other at the colonies (eg geese defecating on grass, grazing on it). But whether any that survived will go on to become vectors remains to be seen.

    After a time, what will happen to h5n1 in wild birds – will there be some evolution, even recombination, to form that is less harmful to them, and us – even unable to cross species barrier to humans? [they might be fine mixing vessels for flus, with plenty of H’s and so on – but these are for great part benign, which is a lot why birders have been little concerned re bird flu till now] I think we should then look south, along the true migration routes from Qinghai; come later autumn and winter, Indian scientists and birders will surely watch for potential vectors, see what happens. (There’s already a nice web page with h5n1 info by an Indian birder, indicating interest.) Now, with spread to Russia, I’m not certain birds haven’t moved virus over significant distances, but I think here too there is major cause for doubt.

    Again, as 2003/04, timings of outbreaks go against migration routes/timings. Instead of figuring there are errors in these, maybe could look for another vector. I think the Chany Lake outbreak just might be from wild birds, but might also be that from poultry farms (run-off entering a shallow wetland, hence to food eaten/water drunk by waterfowl). [Again, timing indicates latter to me.]

    For spread between farms, I believe markets etc will be mixing sources. The wild birds dying at lake in Mongolia also a concern; I’m intrigued to hear reports from team inc Wildlife Conservation Society members who were reportedly going to investigate. It’s too bad that China is so secretive about bird flu; there, I’ve seen at least one official claim of wild birds being vectors that apparently had not a shred of evidence. Russia, so far, more open, which is good (how odd to be reading reports from Pravda, on the Internet, in English!). I’ve just been cc’d an email from WWF Russia, saying,

    Quote:
    The Ministry (Agriculture) has no information about bird flu in Kursk region. Additionally, the AI was not confirmed in Kalmykia: the death of domestic birds was caused by other stomach infection.

    Maybe of some interest. To me, just reported outbreak in Japan (yet) again is an outbreak fitting trade – which can also involve smuggled birds (as smuggled ducks to Quemoy some time ago, with h5n1).

    I’ve been in touch with/been cc’d emails from various conservation organisations, including Birds Korea, Wetlands International, Wildlife Conservation Society (international and Thailand program), WWF Hong Kong (now WWF Russia), Birdlife International, Birdlife Asia. All have similar views: wild birds can be victims, but not shown to be vectors of h5n1 (even though they – especially waterfowl – are reservoirs of flu viruses, which can become problematic thro evolution in poultry).

    Also just in, email trying to check species affected at Qinghai (again, Chinese authorities could be such a help here). Based on names in a macine translated news item [posted here??]; here giving widely known English names in brackets. Some at least already named on this thread; one or two still bit baffling; I’m about to recheck thread in case more names given. Looking at numbers, striking to me just how high the proportion of bar-headed geese is; again, as faecal to oral route simpler I guess. For the gulls, I wonder if at least partly thro scavenging carcasses of dead birds. Cormorants – I don’t know, but they certainly defecate a lot when sitting around (after feeding by swimming, diving for fish). spot headed geese 5412 (Bar headed Goose) brown headed gulls 641 cormorants 1151 fishing gulls 1064 (Pallas’s Gull) red beaked diving ducks 121 (Red-crested Pochard) red feet ducks 34 (Ruddy Shelduck???) ring neck birds 23 (Common Pheasant???) swallow gulls 12 (Terns) white-headed crane 6 (Hooded Crane – unlikely on range; probably young Black-necked) Phoenix headed bird 11 (Northern Lapwing???) black neck crane 2 (Blac-necked Crane) raincoat feather crane 1 (Demoiselle Crane)

    #3710
    Anonymous
    Guest

    Dear Dr Martin,

    I am new to your forum as a contributor but you have cited my review paper previously to support your views (Sims et al Vet Rec (2005) 157 159-164) on the routes of spread of H5N1 viruses other than wild birds.

    I am a veterinarian, not an ornithologist, and have been closely involved with the avian influenza outbreaks in Asia since 1997, while working for the government in Hong Kong (1993-2002) and subsequently as a veterinary consultant working for FAO in China, Mongolia, Viet Nam, North Korea and Thailand

    Firstly let me reiterate that the major route of spread of avian influenza is via infected poultry, poultry products and contaminated items associated with the industry. This is especially true once a virus is established in an area.

    I have long been a sceptic of claims relating to wild birds, especially in places where the viruses are endemic in poultry, especially those with many domestic waterfowl (known “silent’ excretors in countries where the virus is endemic), and poultry are sold through poorly regulated live bird markets, providing ample opportunities for spread of the viruses.

    However, there are some cases where spread via domestic poultry or trade in poultry appears extremely unlikely as the source of infection. The recent outbreak in wild birds in Mongolia, which has a tiny commercial poultry industry concentrated largely around Ulan Bator and very few “village-level” poultry, is the least convincing.

    In the Mongolian case there are few plausible explanations available for the outbreak other than introduction by a wild bird. However, this raises questions as to how this occurred, especially when the timing of the outbreaks do not match the movement of migratory birds, as you have argued previously and clinically healthy birds tested so far are virus negative.

    To explain this, the possibility of introduction of virus followed by silent amplification in some species for a period of time needs to be considered. Not all H5N1 viruses are uniformly fatal in ducks even though they are still highly pathogenic for other poultry (and perhaps other wild birds). Alternatively, low level mortalities in some sites could go unnoticed for a period of time and in less densely populated lakes spread would not necessarily be explosive.

    I have not visited the infected wild bird sites in Mongolia or Qinghai but from information I have seen on the latter, the density of birds there would provide an ideal environment for spread and amplification of an H5N1 avian influenza virus.

    All it would take for a virus to establish in such a population is the entry of one infected bird excreting virus.

    We know that experimentally infected mallards can excrete Asian H5N1 virus for up to 17 days and therefore the possibility of an asymptomatic short term carrier duck introducing the virus is a possibility.

    Why do we not find healthy wild birds excreting virus? Perhaps such birds are rare and our capacity to test is limited. A negative result on limited number of samples does not rule out this possiblity (e.g. if only 1 in 1000 birds were excreting virus you would need to test about 3000 birds from a population to be 95% confident that this population was free from infection). Also, if we are looking at places where virus was introduced some time ago then we may not find the original “carrier(s)”.

    All of this is still speculative but there is a genuine need to explain the origin of the outbreaks in wild birds in places such as Mongolia. The above explanation appears the most plausible after considerable thought on the issue.

    Finally I would like to add a few comments on vaccination of poultry, of which you have been critical.

    The situation in a number of countries in the region is such that vaccination is the only rational course of action to reduce the levels of viral excretion and contamination. This in turn reduces the likelihood of infection of wild birds.

    H5N1 is not going to be eradicated from Asia for a long time and we need to use all of the tools at our disposal. Vaccination will remain, in my view, the most valuable of these especially in places where there are large numbers of scavenging poultry forming a key part of village economies that cannot be reared in biosecure facilities.

    Kind regards,

    Les Sims

    #3711
    imported_Martin
    Participant

    Hi Les:

    Many thanks for your post; most welcome to have such informed comment.

    Yes, Mongolia lake is puzzling. I’ve seen more from Wildlife Conservation Soc team who investigated this, and they too aren’t certain what happened, tho wild bird flying some distance with h5n1 looks most plausible reason. (Mentioned that a US outbreak of HPAI [in poultry] was traced to empty poultry crates being transported some distance – surely not what’s happened here, but does indicate odd things can happen.)

    Timings indeed odd. I’d figure that whooper swans and bar-headed geese would be sedentary (breeding) by time the 2 swans and 1 goose died.
    So, maybe they were infected by virus that had lingered for a few weeks, maybe passed between a few birds.
    I read of ducks shedding for up to 17 days; but also that Qinghai variant (which may/may not be near identical to the one in Mongolia/Russia) was more lethal than h5n1 a Chinese team had previously tested – killing 8 of 8 chickens in 20 hours, so perhaps harder to have ducks survive and shed.
    There is some summer tourism to Erkhel; might outbreak be linked to this? No evidence; but just about plausible.
    Yet again, more info needed.
    But, h5n1 evidently hasn’t spread well in wild birds here; seems more like other known outbreaks in wild, except Qinghai.

    Qinghai rather odd; so many birds reportedly killed; and dearth of info afterwards, that I’ve seen anyway (how many birds survived?, say; not possible that some over-zealous officials opted for cull [tho later in outbreak, came reports that cull dediced against]?

    Thanks, too, for comments re vaccinations. I’d drawn my info from New Scientist, and some info on FAO site (FAO perhaps rather reluctantly agreed to more widespread vaccinations for h5n1?).
    Seems vaccination should be used sparingly, in cases as you note; but China (especially – I believe HK poultry, say, now vaccinated) now uses extensively.
    This, to me, could explain how the h5n1 traced back to 1996 domestic goose sample from Guangdong has stayed with us so long; other HPAI outbreaks, as H7N7 that killed [vet] in Netherlands evidently eradicated by slaughtering infected poultry. HK seemed successful at likewise slaughtering poultry to eradicate h5n1 in 1997, but it clearly survived elsewhere, inc S China [as you’ll well know; this info might be useful here lest others come across this thread].

    Martin

    #3712
    Anonymous
    Guest

    Wow. Where has this forum been? I found it by accident while arguing with a certain Dr elsewhere. The spread from Qinghai is so closley matched to the bike race there that I’m thinking that it’s one and the same. The more that I look at dates and number of people- including their geographical range – it appears that it is a part of the spread.

    I know about the initial infections before the race found in the Chany Lake area. That area is actually (for those who don’t know) made up of several hundred lakes and thousands of ponds. There are also more than one lake that shares Chany’s name. Chany is the largest lake.

    I believe that it’s mostly smuggling. People take for granted that I mean bird smuggling. Not at all, I’m talking about H5N1 smuggling in on wet items. Birds, shirts, tires and feet. Anything that took a run over infected feces or dead birds. H5N1 can remain viable for many months in a cold wet place.

    The rest is explained through plain economics in the farmer’s hands. One bird or your neighbor’s birds get sick, run far away and sell yours now. Maybe ask a far away cousin to keep them with their birds.

    I can explain this a hundred ways faster than I can a wild bird approaching a domesticated bird area. Have you ever seen dog approach another dog’s yard? Try that on a rooster or goose. Same result. A fight.

    That’s enough for now. Time to read…

    LMc

    #3713
    imported_Martin
    Participant

    Hi Lewis:

    Thanks for the post.

    Hmm, without more info such as on bike race route, timings and how these correlate with the outbreaks, I’d wonder about this.

    As for smuggling – seems possible to me. I’ve read that bird flu virus can survive up to 100 days in poultry excrement. Not sure, though, just what this in turn could be carried on.

    Martin

    #3714
    Anonymous
    Guest

    I know. I don’t explain myself very well. I meant that after the race, in that exact area where the die-off occurred – 750,000 to 1 million people left the area. Competitors from every single "new" area of H5N1 discovered in the next weeks was there at the race. Bike teams have huge support groups with many vehicles. It rained the last day of the race, and it was called off because of the cold. Mud, cold temps, travel to far away places, H5N1 found in those far away places – out of sync with normal migration cycles for those areas. Here’s some reference material trying to make my theory stick around from Canada on their report of avian flu:

    Feb 15, 2005 The movement of buyers from farm to farm in conducting egg pickup can lead to biosecurity breaches and inadvertent disease transmission to a flock. Transmission of contaminated manure from an infected premises to a separate susceptible flock can an occur through the movement of people, equipment and vehicles. Barn to barn movement constitutes the highest risk activity for transfer, while deposition of contaminated manure in the vicinity of asusceptible flock is categorized as of somewhat lesser risk. It is thought that a small amount of contaminated dust adhering to boots, clothing or equipment is sufficient to transmit the virusfrom an infected barn to a susceptible flock. Lewis Mc

    #3715
    imported_Martin
    Participant

    Thanks again, Lewis.

    Hadn’t realised the bike race was such a huge event.
    So, competitors from Russia, Kazakhstan and Mongolia I presume. But, from the locales with outbreaks – like Chany Lake, Erkhel (or nearby)?

    I still wonder; would these people really come into contact with poultry flocks in Qinghai area (seems wild bird outbreak restricted to reserve), or contact with infected material?
    (Or might there have been poultry/eggs at good prices?)

    Thanks for link to the Canada report – shows bird flu spread can be complex issue.
    Too bad that there’s so little info from the recent outbreaks.

    Happily, though, outbreaks ebbing – to me, further indicating wild birds aren’t key vectors.

    Martin

    #3716
    Anonymous
    Guest

    Les –

    For my view, I try to just ignore what emotion I read and pick out the facts and then come back to take the messages I read in context. People are surprised about the race because China is supposed to be straw hats and shanty villages. Qinghai is far from that. It is a large city with highrises and part of the 6 or 8 lane freeway going in that crosses over the borders there. I think it’s called the millineum highway. It’s going in because so many people go that way already – hence my belief in travel and not wild birds spreading H5N1.

    “Chaney Lake” is like saying Michigan lake. Oceanliners can cross there. It’s huge. Chaney lake is actually hundreds of lakes, several of which include the name Chaney. I’m not sure about ocean liners on Chaney :), but the point is that it’s a country sized lake surrounded by “smaller lakes” that you can’t see across because of the size.

    I am really trying to find out where these poeple lived, but it’s hundreds of people, and Mongolia isn’t known for it’s white pages online. I am not going to contact the race teams individually. They keep online diaries that should help.

    H5N1 at Qinghai was absolutely lethal to birds. Qinghai does not have 750,000 hotel rooms. You can see from the race pictures that people sat on the lake shore and probably camped there. Birds get fed here in the states by people, so that may have happend, its normal to assume that. Macroviewing scenarios is a bad thing to do though. I prefer to just point out the facts of the race crowd numbers, lack of hotel rooms, location of the race route, and where everyone went after the race. The weather was my best clue for H5N1 to survive leaving the area.

    Lewis Mc

    PS – It’s been 100 months since the first human H5N1 confirmed death. I was wondering when H5N1 was first discovered in birds?

    #3717
    imported_Martin
    Participant

    From all I’ve seen, the variants of H5N1 causing all concern now traced to sample from a Guangdong farm goose, 1996 – not long before the first human cases/deaths. (so, had it been circulating a while, undetected or unreported?)

    Martin

    #3718
    imported_Martin
    Participant

    A Reuters Alertnet item headedPoor Asian farmers are weak link in bird flu fight includes:

    Quote:
    "We need to realise that there is very little incentive for farmers to report suspected outbreaks," said Dr Shigeru Omi, WHO regional director for the Western Pacific, which covers 37 Asian and Pacific nations. "In fact, fear that their flocks might be culled without compensation is a pretty strong disincentive to report an outbreak," said Omi at the opening of the WHO Western Pacific annual conference in Noumea, capital of New Caledonia in the South Pacific.

    – which will help cloud the real situation with h5n1. (Add secrecy by at least some officials, and picture indeed pretty muddled. But, it seems wild birds always ready as scapegoats!)

    #3719
    imported_Martin
    Participant

    After WHO director (I think – Lee) seemed to casually blame wild birds for spreading potential pandemic all around – and making headlines for doing so – here’s a more considered, far less headline making view. Buried in a Reuters Alertnet story, World has slim chance to stop bird flu pandemic

    Quote:
    Dr Hitoshi Oshitani, the man who was on the frontline in the battle against SARS and now leads the fight against avian flu in Asia. "SARS in retrospect was an easy virus to contain," said Oshitani, the World Health Organisation’s Asian communicable diseases expert. … Avian flu has moved west from Asia and into Russia, with many fearing migratory wild birds will spread the virus to Europe and possibly the United States via Alaska. But Oshitani casts doubt on the impact migratory birds are having on the spread of avian flu, saying different sub-types of the H5N1 virus are in Asia and Russia. "There are so many uncertainties about the pandemic. We don’t know how it will start. We don’t know exactly how it is spreading," he said.
    #3720
    imported_Martin
    Participant

    Just come across article in French (in which I get a mention), re arguments against notion wild birds spreading h5n1.

    Grippe aviaire: interrogation sur le rôle des oiseaux migrateurs

    #3721
    Anonymous
    Guest

    Now the Silk Road has generated H5N1 in Turkey. You have to cross that part over the mountains before winter arrives.

    #3722
    Anonymous
    Guest

    How do Birds get onto an island? It must be by flying? http://www.guardian.co.uk/society/2005/oct/20/health.birdflu

    Taiwan today became the latest country to announce the discovery of bird flu. Authorities said the H5N1 virus was found among birds on a Panama-registered freighter that was stopped by the Taiwanese coast guard on October 14. Spokesman Sung Hua-tsung said the freighter was carrying 1,037 smuggled birds – consisting of 19 species – all of which originated in China.

    #3723
    imported_Martin
    Participant

    Thanks for this, Lewis; helps show that trade, inc illegal, can move this flu.

    S China Morning Post reports today include:
    8 of 46 birds tested in shipment of 1037 being smuggled to Taiwan from mainland China positive for H5N1. 19 species in all, for pet shop; inc hill mynahs, black-naped orioles and Pekin robins (red-billed leiothrix). [With the mynah rather restricted range in China, I wonder if some from se Asia originally?]

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