The story is all over NewsNow this morning: the spread of H5N1 doesn't match with migratory bird patterns, which means the real vector is us.
The argument seems to have originated with a Netherlands-based conservation organization, Wetlands International, which has this to say on its avian-flu page:
Wild migrating waterbirds are seen as one of the causes of the spread of the flu. However the evidence for this is weak. Millions of waterbirds flew already from Asia to the Middle East and Africa. However, the flu didn't travel with them, so far. An explanation for this might be that contaminated birds die quickly. The global trade in millions of chickens and other poultry might be a much bigger risk. Wetlands International calls for additional attention for the risks of the bio-industry and the global trade of poultry.
Revere at Effect Measure thinks the evidence does point to wild birds. A forum run by Dr. Martin Williams offers a page of expert citations questioning migratory birds as H5N1 vectors—including Dr. Guan Yi, the Hong Kong virologist who's been so critical of Beijing's response to avian flu.
Dr. Williams has held this position for a long time, and his forum is also a haven for critics of Dr. Henry Niman. I've chosen to avoid the controversy on the safe grounds of being too ignorant to have an opinion worth reading.
But avian flu is a scientific issue that merits scientific analysis. We know the migratory paths of wild bird species that are known to carry H5N1. We know the spread of H5N1 in domestic poultry. We ought to know the trade routes on which both wild and domestic birds are bought and sold. How much evidence supports the theory of wild birds as vectors, and how much supports the theory of humans as vectors?
As Dr. Guan observes, if wild birds are the cause of the spread of H5N1, then governments are off the hook. If it's the poultry business itself that's causing the spread, then governments have a really awful political problem on their hands.