from New Scientist, 30 May 2006:
Wild birds have helped transmit the deadly H5N1 bird flu across Eurasia, a meeting of 300 scientists at the UN Food and Agriculture Organisation (FAO) concluded on Wednesday. But killing them to prevent further spread of the disease is not the answer, they warn.
I wrote an article about this in Audubon this spring, concluding from the divided and tenuous opinions and facts then that wild birds almost certainly did help spread avian flu. Since then, opinion among scientists has swung a couple of times as the evidence bounced about. The appearance of infected birds in Africa this winter encouraged many to think the birds were spreading H5N1 — a notion the subsequent failure of significant summertime spread to Europe cast into doubt. And some of the most convincing evidence in favor of a spread theory showed holes. For instance, the death from bird flu of hundreds of gulls at a highly isolated lake on the Tibetan plateau last winter seemed firm evidence that wild birds were spreading the flu, since no poultry farms were known to be nearby. Then a few weeks ago it came out that there were poultry farms nearby.
Last week the UN FAO conference, after sorting through such variables and ambiguities, concluded that wild birds are playing a significant role in spreading H5N1. It concluded, reports New Scientist, that
while poultry has dominated the spread of the disease, wild birds have also played a role, particularly in transmitting the H5N1 virus long distances across Eurasia during migration.
The FAO’s chief vet, Juan Lubroth, says “we don’t need prime ministers to come out and say, ‘we’ll cut off the tops of trees or drain the wetlands’ [to kill the carriers]". Instead, scientists at the meeting called for increased research to see which species carry the virus, whether it can persist in wild bird populations, and to where the birds migrate.
Given how uncertain we remain about how this is spreading, this seems a good idea.