# 1523
Not since the `Tastes Great, Less Filling' wars has there been a subject with as much controversy as the argument over whether H5N1 is spread primarily by migratory birds or by the poultry trade.
Both sides have their proponents.
Today, Scott Newman, international wildlife coordinator for avian influenza at the U.N.'s Food and Agriculture Organization (F.A.O.) presented his views on the subject. He lays the blame primarily at the feet of poultry traders and smugglers.
Others still point their fingers at migratory birds.
The debate over the role of wild birds in the spread of the H5N1 virus probably won't end with this presentation at the 2008 International Conference on Avian Influenza in Bangkok, Thailand.
Don't blame wild birds for H5N1 spread: expert
BANGKOK (Reuters) - There is no solid evidence that wild birds are to blame for the apparent spread of the H5N1 virus from Asia to parts of Europe, Africa and the Middle East, an animal disease expert said on Wednesday.
There was also no proof that wild birds were a reservoir for the H5N1 virus, Scott Newman, international wildlife coordinator for avian influenza at the U.N.'s Food and Agriculture Organization, said at a bird flu conference in Bangkok.
After H5N1 was found in 2005 in a huge lake in central China where it killed over 10,000 wild birds, it turned up in parts of Europe, Africa and the Middle East, leading some experts to believe migratory birds may be to blame.
But Newman said there was no good reason for thinking so.
"We know that some wild birds have probably moved short distances carrying viruses and then they died, but we have not been able to identify carriage of H5N1 across large scale spatial distances and then resulting in spread to other birds and mortality in poultry flocks," Newman told Reuters.
He said fecal tests on some 350,000 healthy birds worldwide had to date only yielded "a few" positive H5N1 results.
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He stressed the need to focus attention on the poultry trade, and particularly smuggling, adding that these factors may instead be spreading and sustaining the deadly disease.
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3 comments:
Migratory birds *must* be the cause of long-distance contagion, because the odds of identical strains arising over long distances is remote. Many of the first birds affected in new areas are wild birds, not domestic poultry.
Local spread is via illegal smuggling and also through innocent trade - that is why so many affected birds are in backyards, in certain countries.
Tell me, what percentage is 350 thousand, of the billions of wild birds (many dozens of species affected)?
Gap your fingers very closely now. It's a very, very small sample.
If the strain is virulent, you do not need a large number of infected carriers.
Since I don't have a bird in this fight, I don't have an agenda.
Seems perfectly logical to me that Migratory birds AND the poultry trade are both spreading the virus.
Asymptomatic waterfowl have been found in many areas.
I suspect they are perfectly capable of flying long distances and spreading the virus.
The central argument of the naysayers seems to rest on the quality of the ornithological data from two previous studies suggesting the linkage between wild bird migration and spread of H5N1 to local domestic birds. But we know that ducks can and do harbor bird flu with minimal signs of illness. They are not 'healthy', but they are not terminally ill, either. The problem is that migration dramatically affects physiology, and it differs between bird groups in a distance- and migration-style dependent fashion.
While you have seen this article at FluWiki, it might be useful reading for others new to this argument.
Ecologic Immunology of Avian Influenza (H5N1) in Migratory Birds
CDC journal, Emerging Diseases
http://www.cdc.gov/eid/content/13/8/1139.htm
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