A v curious opinion piece just out by New Scientist writer Debora MacKenzie, who has done news items on wild birds supposedly spreading H5N1 - including a piece in which "New Scientist can reveal" wild ducks carried H5N1 to Nigeria, even though this was pure speculation, and evidence showed poultry smuggling - or even transfer via vets - was responsible.
This is lopsided piece, based on flimsy evidence - wild ducks that survive H5N1, for which only tiny evidence - and ignoring much, including absence of H5N1 in migratory birds in east Asia since last summer. (In an email to me, DM suggested can' t prove absence, which is a v curious notion; likewise, can't prove beings from outer space haven't been involved in spreading H5N1, etc.)
Here's the piece; below it, a couple of emails I'd earlier sent DM - for yes, I'm among the bird conservationists who had emailed her. Arguments in these remain valid, seems she - like so many Tooth Fairy Bird Believers - has her story, and is sticking to it no matter the facts.
Bird lovers in denial It's clear that wild birds are spreading the H5N1 virus, so why do some bird experts still refuse to acknowledge it, asks Debora MacKenzie
MOST of us, at some time in our lives, have refused to believe something we don't want to believe despite considerable evidence that it is true. Such denial is understandable; the truth can be painful. But there are times when denial can also be dangerous. The reluctance of some ornithologists, conservationists and other members of the birding community to accept the role of wild birds in spreading HSN1 bird flu is a striking example.
Since I wrote in this magazine some eight months ago that wild birds appeared to be carrying the H5N1 flu virus, I have received dozens of critical, sarcastic, even vicious emails from such people. How can you spread this ludicrous theory, they ask. Why is New Scientist protecting the poultry industry? Where's the evidence that wild birds have been helping the virus spread?
Let's summarise the evidence. The H5N1 virus emerged and acquired its nastiness in poultry; there's no dispute about that. The trade in poultry is also overwhelmingly responsible for H5N1's spread in east Asia. It was a different story, however, when the virus, having killed wild geese at Qinghai Lake in China, spread across Russia and into Turkey, Ukraine and Romania. The strain found in all these places is identical to the one first seen at Qinghai, never in east Asian poultry, which strongly suggests that it was not carried west by poultry. Maps of the outbreaks look a lot like the migration maps of dabbling ducks - long-distance migrators that tolerate the virus. [See below: e Asian poultry not fully sampled; migration routes don't fit; evidence dabbling ducks tolerate the virus not so strong or straightforward, evidence they can transmit to others is lacking - indeed, evidence fron wild is to contrary. Note absense in e Asian migrants recently.]
Since then the evidence has become even clearer. There have been outbreaks in western Europe almost exclusively in wild birds, and in all cases of bird flu west of Qinghai the virus is identical, suggesting it has found a carrier where it is more stable than in chickens. Yet the critics refuse to listen. They tend to start with the conclusion that wild birds must never be blamed, and then marshal "evidence" to support their case, ignoring any that doesn't. Wild birds are being made scapegoats for a disease that evolved on battery farms, they say; they're the victims, not the vector - ignoring the fact that they can be both. Or they invoke alternative explanations and demand they be disproved: the virus found in birds in a German nature reserve could have got there in Turkish chicken waste used as fertiliser, rather than ducks migrating from Siberia. [Notion of a "stable" virus that kills its hosts is contradictory; here, shows DM hasn't the slightest inkling of natural selection and diseases: evolutionary biology]
Some have come round to the idea that the virus is being carried by wild birds, but others are still in denial. This month we heard hopeful claims that because the spring migration across the northern hemisphere has not been accompanied by an explosion of bird flu, no wild birds are carrying the virus. Yet everything scientists know about bird flu epidemiology indicates that this is not surprising: it's likely that a few infected birds have arrived at their summer locations, that over the coming months they will infect others, and that prevalence will peak in the autumn. [a "few infected birds"? why is this likely?]
I am not the only one concerned about all this. "The ornithology community has been slow to acknowledge that wild birds might be playing some role," says one senior European virologist. A top American virologist who himself resisted the evidence about wild birds admitted: "It's a political debate, not science." A UN official told me: "They aren't speaking from evidence." [a supposedly respectable magazine quoting only anonymous sources? Ornithology community not slow to acknowledge; some readily acknowledged, but over time, increasing belief wild birds not key vectors H5N1. If not about science, why so many facts ignored in this opinion piece?]
Their attitude could have consequences for how we tackle the spread of H5N1. We need birding experts to predict where the virus might migrate next, rather than deny that it will. The influence of birders is said to underlie the British government's decision not to force poultry farmers to keep their birds inside. If nothing else, wild birds are indeed victims of this virus, and their advocates should be fighting to protect them from it, not denying it is there.
Ask birders why they are scared of implicating wild birds and they'll say it encourages people to cull them and undermines conservation efforts. It's true that some people worried about bird flu have threatened to shoot birds or destroy wetlands, but as far as I have been able to discover nothing much has materialised.
I'm sceptical that this is the real reason. A clue as to what this might be emerged in April at the first, hastily arranged World Migratory Bird Day in Nairobi, Kenya, which was described by its conservationist organisers as happening "at a time when migratory birds are being unfairly portrayed solely as the harbingers of death and disease" - an absurdly exaggerated claim. Another critic said: "The real question is not, are wild birds to blame, but why are wild birds being blamed?" In other words, this isn't about evaluating evidence, it's about building conspiracies. [Bizarre!]
The only reason I can think of for all this is that we are dealing with a community acting more on faith and emotion than reason. For them, birds are, by definition, innately pure and transcendent - too pure to carry anything as mundane or dirty as a virus. Given this attitude you can understand their denial, but they are doing neither wild birds nor humans any favours.
I've tried emailing Debora MacKenzie several times.
Here's one example, after she had tried rebutting arguments by Nial Moores and me:
Thanks for the email; glad you are willing to look at this in some detail.
However, your argument is not solid. And, curiously, you ignore the absence of H5N1 across a swathe of land, from Iran east to Japan, where most of north Asia's waterbirds winter, yet there are no outbreaks in migratory wetland birds. Hong Kong is a notable site here: has some 50,000 waterbirds, including pintail (garganey pass through on migration): not one healthy wild bird has tested positive, among over 16,000 [by some reports; PNAS for some reason gives 13,000 I think, without re-checking.] Currently getting H5N1 in birds, inc poultry; maybe after higher poultry demand at Chinese New Year; and mentioning this, seen report that Nigerian smuggling can increase around Hajj. Hong Kong is at a crossroads for migrants in southern China, right at the epicentre of H5N1 outbreaks. Had H6N1 in birds, inc two urban parks (ornamental waterfowl, at least 2 wild little egrets, which likely residents). So, blithely ignoring not easy.
Further, PNAS paper is overall strongly counter to ideas wild birds spread H5N1. Witness regional forms of H5N1: if wild birds could indeed carry and introduce to poultry (and do so readily), why do we see these?
It seems curious logic to say poultry trade spreads over short distances, but wild birds over long range. There is long distance trade, inc smuggling - cf large batch of smuggled poultry from China arriving in Italy.
"one detects the presence of the virus chiefly because it causes outbreaks in poultry if the wild birds contact them" - wild birds contact poultry? Where? [maybe it does happen in Nigeria - but people hunt waterbirds there, so might figure wild birds avoid humans as much as possible]
"The ducks themselves, at least those that made it through migration, dont die of it, so you wont see it that way." - questionable; are ducks that die of it, plus can get significant death rates - very high in Qinghai - in birds sharing wetlands with them.
"A very low prevalence of sampling, if there is even that, cannot prove absence," No need for sampling at Qinghai - the virus made its presence very clearly known. Elsewhere, it is scarce or rare in wild; get some die-offs but need monitoring to find them..
"Flu is highly contagious. It spreads from bird to bird." Ah, now here's an important one. You refer to "flu" - and make this rather casual statement. Regular wild bird flus do indeed seem highly contagious, among waterbirds (with caveats; seasonal changes, can get variations depending on bird type). But, evidence is that H5N1 in wild birds is not highly contagious. Qinghai the exception. But otherwise, we don't see H5N1 readily spreading among wild birds. Hong Kong again - has had dead waterbirds found at/near wetland with the waterbirds, but no spread. (Just lately, a dead little egret a few km from Deep Bay.) Mongolia's Erkhel - "the disease appeared self-limiting in wild birds", researchers had to look hard to find it., and then o only in dead birds Thailand openbill storks - only few amongst large numbers of birds Romania: infected swans on ponds did not infect other waterbirds sharing ponds (this by lack of deaths, also as several of these birds tested) Romanian swans excreting low amounts of virus. Webster's ducks with H5N1 that didn't readily kill them likewise excreted low amounts; High amounts respiratory tracts - but ducks not prone to sneezing/French kissing.
"Selling their birds off at market is what they are reportedly doing even now." - so, do you think others with infected birds, or near infected birds, might have sold them off at markets? To people from non-infected areas. Nigeria had banned poultry imports; yet domestic demand surely still there. Surely tempting to smuggle in birds at bargain prices.
"especially the Z genotype that has been responsible for virtually all commercial poultry outbreaks in east Asia" - This is the Z genotype. One of its variants, but it's Z.
" birds at Poyang Lake in southeast China in March, some of which migrated to Qinghai." - Which ones migrated this way? I know of none that migrate Poyang to Qinghai. I've studied some of the Poyang winter birds on migration along east coast of China (can be certain re Siberian cranes) - a long way from Qinghai. [I've asked Guan Yi and Robert Webster just which species they say migrated; so far, just told "migratory ducks". Detail is important with virology; also important here re wild birds.]
"timing of the outbreaks in Siberia, Turkey, the Black Sea and Nigeria exactly fit the known movements of some species" Not so with the timing of the outbreaks in Siberia. Link from Qinghai to Siberia doesn't work: especially timing, in July, when birds from Qinghai not migrating north [many of geese flightless at this time]
"They are kicking birds around because they are rural people, that is how that culture treats animals," - how astonishingly patronising. I have seen rural people interacting with wild birds; maybe hunt n trap and so on, but never this. New Scientist not read there, perhaps, but New Sci taken as authoritative, reaches newspapers and other media
"Were there geese, which do die of this virus, at Poyang as there were at Qinghai?" - Yes, many thousands, including much of world population of swan goose. Also geese, cranes etc. All sharing shallow wetlands, at high densities.
"the Poyang and Qinghai viruses differ from any that have ever been seen in poultry in China." By no means all poultry in China have been tested. Witness PNAS - north China, inc between Poyang and Qinghai, just a blank on the map. I've asked Guan Yi; they lack data. So, you are only making guesses re virus in poultry n China. The team found 4 distinct forms in mainland China (seen Guan mention 250 strains); how to be certain a form in north isn't as per Qinghai?
"The commercial transport of poultry should transport genotypes pretty much at random - smugglers dont genotype infected birds before they ship" - Why at random? If birds from n China to Russia/Kazakhstan, and then onwards by transport links such as railway - and the timings indeed fit this pattern too - would be same strain.
"the only spread long distance so far has coincided with migratory pathways, " Not so; has been spread to Indonesia, Tibet (one case traced to poultry shipped 1500km, Lanzhou to Lhasa), more recently the spread to Russia and so on. Again, it baffles me why this notion re long distance spread by wild birds, short distance within poultry trade. This is not borne out by bulk of PNAS paper - notice re an introduction to Vietnam, evidently by transport from China. But, convenient for officials. [cf with foot n mouth; reached continent from UK - but there, no flying cows as convenient scapegoats]
followed - after some more correspondence, inc as DM asking for ideas re bird species that may be impacted by H5N1 (her idea: by disease; my view is fear of the flu is more dangerous) by:
Firstly, these "reservoir species" are mythical if considering wild species. I know you write of them; yet rather like the Tooth Fairy and so forth.
(I spoke w Malik Peiris over phone here yesterday. Yes, his team has details re virology, but little more than arm-waving - as one of my lecturers would call it - re wild birds. Why should virus stay basically the same if spread by wild birds, especially when it kills so many of them? Instead, shouldn't this lead to evolution? Whilst rapid spread by transport could surely lead to same virus strain being transported, and yet to evolve regional forms - Peiris acknowledged this is possible too.)
Proven reservoir is poultry industry. We have loads of dead wild birds with h5n1, hardly any apparently healthy ones with it. When something is so hard to find, and leaves so little evidence of its presence, indeed Tooth Fairy like.
Huge extrapolation from a few birds - which at Poyang were six ducks with two genotypes; I'd love to know what bird flu situation in surrounding poultry was. Also re the dead wild birds there. And re H5N1 across north China. Yes, also ducks with antibodies to - probably - H5N1, but not so sure as to exactly what strain/genotype. And, experimental ducks; but shedding little when they recovered.
>>> Again: it's clearly hard to get wide spread of H5N1 amongst wild birds; it's too lethal. (I know the European swans are scattered over wide area, but yet to see at any one place re massive deaths. [Caspian Sea???]) Qinghai the prime case where many deaths, and there, no known survivors. [why so many deaths? was there culling?]
Seems that for H5N1 itself to kill wild birds in numbers at any one place, need exceptional circumstances. - Perhaps considerable introduction of virus (at Qinghai, by poultry - perhaps manure into fishponds?). - also, birds packed together, maybe at a colony, as Qinghai.
cf openbill storks in Thailand, which I think were killed during nesting season; I've seen them nesting in huge colony, where they go out to feed in rice fields. I believed a horrific situation could unfold. Yet, turned out only around 8 that died and confirmed to have H5N1. Again, virus kills fast, dies away fast.
As to wintering/migrating waterbirds, Poyang is among examples of virus being very hard to spread amongst wild birds. Those very few ducks found, yet no mass deaths reported, despite tens of thousands of waterbirds including variety of duck species, geese, swans, cranes, gulls, avocets...
Hong Kong another example. Tens of thousands of waterbirds pack into small bay each winter; a few cases of H5N1, but no spread. And where is H5N1 at the wetland? Birds can - supposedly - miraculously be reservoirs of this disease, carry it west to Europe; yet, it is not present at wetland here on south coast of China. (Not just because 2000 healthy birds tested there this winter proved negative; also no unusual deaths - and H5N1 is not given to lurking quietly in the wild.)
Yes, songbirds dying of it, eg here in Hong Kong. But how they did they get infected? Here, quite possible all songbirds were from captivity - esp given main dates just around and after Chinese New Year.
How to transmit the virus among songbirds, say? I can understand with waterfowl, especially grazers such as geese, some ducks, swans. But for many other birds will be harder to get and sustain transmission.
- it doesn't matter, then, that it can kill mesias etc, if they can't readily catch and transmit it in the wild.
Not surprisingly then, in Hong Kong, songbird deaths by H5N1 seem over. Now to crows/magpies.
So yes, with crows and magpies dying in a few places, indeed appears scavengers are susceptible. But, if they don't have something with H5N1 - like dead chickens - to scavenge, they won't get H5N1.
Birds of prey, too. Peregrines - 1 or 2, both from illegal captivity - in Hong Kong have died. As these are bird hunters, including ducks, should surely be resistant to flu, yet H5N1 kills them.
>>>> Meanwhile, are indeed threats arising from action taken as a result of Fear of the Flu. If Russia indeed takes widespread measures to prevent birds nesting this spring/summer, could have serious impact on wild birds. Other impacts, too, which Nial and I have sent to you.
Qinghai virus described as Z genotype in one of papers (Chen et al I think). Yes, it's a distinguishable strain; one of several strains of Z known. [DM had for some reason alleged the strain spread westwards was not Z; later backtracked saying a distinguishable form of Z]
Post edited by: martin, at: 2006/05/23 00:52