New Scientist writer Deborah MacKenzie just blaming wild birds for spreading H5N1 to Europe, based on flimsy "evidence" (and fair dollop of Nimanism?):
HAS the H5N1 bird flu virus crossed Asia on the wings of migrating wild birds? Yes, say governments and UN agencies. Prove it, say many bird conservationists, who fear we are about to see an irresponsible and unjustified cull. "People have just accepted that migrant birds are carrying disease," charges Richard Thomas of Bird Life International in Cambridge, UK.
What is beyond dispute is that in May 2005, thousands of wild geese died of H5N1 at Qinghai Lake in China. A smaller outbreak in migrant geese and swans followed in Mongolia. Then in late July the disease cropped up in poultry near Novosibirsk in Siberia, before moving west to five more regions in Russia and to Kazakhstan by August, Romania and Turkey in October, and Ukraine in December.
Conservationists point out that these outbreaks are clustered along major long-distance transport routes. They say this shows that commercial poultry, not migrating wild birds, are the vectors of the infection. Virologists, however, tell a different story.
Aside from a single test on a grebe in Novosibirsk, no one has yet found a smoking gun: healthy migrant birds carrying H5N1. But we do know that H5N1 can be carried and spread by healthy domestic ducks, and therefore probably by wild ducks - experiments are under way to find out. Moreover there is circumstantial evidence that the outbreaks are consistent with migration pathways.
Ward Hagemeijer of the conservation group Wetlands International concludes that the best explanation for the outbreak of H5N1 in Mongolia is that it was carried by infected migrating birds heading north from Qinghai. The further outbreaks can be explained by birds flying from Qinghai to north Siberian nesting grounds, where they mingled with, and perhaps infected, ducks from wintering grounds across the breadth of Asia and Europe, including the Black Sea coast and south Siberia. Birds that failed to mate, says Hagemeijer, then headed south in July - just in time for the outbreaks in south Siberia and Kazakhstan. The Black Sea outbreaks followed the main migration in autumn.
Genetic studies support this idea. Every outbreak in east Asia tested since 2004 was caused by a strain of H5N1 known as the "Z genotype". But birds in Qinghai, and in outbreaks to the west, were infected by a slightly different strain, a hybrid of the Z genotype with its immediate ancestor. The virus in both wild and domestic birds across Russia was closely related to the Qinghai virus, while swans in Romania died from a virus most closely related to the one in the grebe in Novosibirsk.
If the disease was being transmitted through poultry carried out of China, then at least some of the western outbreaks should be the Z genotype that has dominated outbreaks in China. But not one bird in west Asia or Europe has been found with this strain. "We haven't sequenced everything," cautions Juan Lubroth of the UN Food and Agriculture Organization in Rome, Italy. "But the pattern does suggest that wild birds are introducing the virus to new areas."
That doesn't mean the answer lies in the wholesale slaughter of wild birds -which is conservationists' worst fear. The real problem for people is not the wild birds, but infected poultry. It has been obvious, everywhere the virus has been, that poor management of domestic flocks is what transmits the infection throughout a region once it has arrived. And people have overwhelmingly caught the virus from their backyard chickens not from passing wild ducks.
"What can we do about the wild birds? Nothing," says Lubroth - shooting them just scatters them, and anything they may be carrying. "What can we do about poultry? A lot."
As I've just emailed a group of people interested in H5N1 and conservation:
I think Henry Niman indeed has role here; recall seeing something in New Sci (lighter side), re them having earlier done piece noting all wild birds with H5N1 sick/ding, and Niman wrote to pillory them, mentioning this grebe.
Indeed ridiculous to build case for spread by wild birds on one purportedly healthy bird, with no further info (All seen earlier was a report saying a GCG "showing no clinical symptoms" had been found with H5N1. It gave no details about whether the bird was even dead or alive, nor whether it was HPAI H5N1. Maybe, like four birds in OIE report re Russia, it was hunted, say).
Likewise this assertion that should see more variety in H5N1 clades reaching eastern Europe seems highly dubious. There are huge holes in our knowledge, inc for nw China; Guan Yi - who unlike Niman, does massive testing, saying wild birds not to blame. But, Niman is indeed King of the Ridiculous; and here has found another willing messenger. (cf Stratis Times guy earlier, doing big piece about H5N1 and Ebola perhaps mixing in Sichuan: neither were present, but still, Niman found another to spread his nonsense)
Bizarre, too, to ignore facts that birds infected in eastern Europe not originating in areas known to have H5N1. Also re 75,000 - 100,000 other healthy birds tested, all H5N1 negative. And bizarre to ignore current lack of H5N1 in Asian waterfowl in Asia (ex-Russia). How can they spread to Europe when can't spread round Asia? - we have perhaps a hundred Great Crested Grebes wintering in Hong Kong's Deep Bay, yet no H5N1 evident there (and, happily, nothing further re H5N1 here since the recent magpie robin)
Who on earth is "Ward Hagemeijer of the conservation group Wetlands International"? Believe guy of same name earlier telling Nature wild birds likely to spread H5N1 to Africa.
What does "conservation group" mean here? And, does anyone know if Wetlands International has received a wad of money for studying relationship between wild birds and H5N1? [I'd be v curious to know this generally; how many conservation groups, ecologists, have money for such studies.]
I've emailed New Sci, with excerpts of the above; and - after re-read thro the piece - also sent Deborah MacK:
Further, re those ducks. Know they can carry a low path form of H5N1 without sickening; but excrete only small amounts, with most in respiratory tracts. Ducks not French kissing, nor prone to sneezing that I've noticed. So, how to spread this in wild?
Further, does it matter so much they can spread low path form? Isn't all the fuss about highly pathogenic H5N1, which also kills ducks?
Dead Ducks Don't Fly!
"Every outbreak in east Asia tested since 2004 was caused by a strain of H5N1 known as the "Z genotype". But birds in Qinghai, and in outbreaks to the west, were infected by a slightly different strain, a hybrid of the Z genotype with its immediate ancestor. "
- yet Nature paper by Guan Yi et al said the Qinghai virus was very similar to strains from se China poultry.
Post edited by: martin, at: 2006/01/28 03:50