for National Geographic News
The deadly H5N1 strain of bird flu could hit North America during the fall snow goose migration, experts warned early this month.
In a March 8 press conference at the United Nations headquarters in New York City, David Nabarro, the UN's lead spokesperson on bird flu, predicted that the virulent strain will arrive in the United States and Canada within 6 to 12 months.
"And who knows? We've been wrong on other things. It might be earlier," the Associated Press reported him as saying.
Ken Rosenberg, director of conservation science at Cornell University's ornithology laboratory, agrees with this prediction.
The disease is now on three continentsAsia, Africa, and Europeand "seems to be showing up in far-flung places," he said.
Alaska (see map) is the disease's most likely point of entry into the Americas. That's because many birds migrate to Alaska from Asia via the Aleutian Islands.
In Alaska infected birds from Asia could mingle with their North American counterparts, such as snow geese, which could then carry it south during their fall migrations.
Fearing such an intercontinental transfer, bird experts last year began testing Alaska's migratory birds for the disease.
But there are other routes by which bird flu could reach the Americas.
Some gulls, for example, follow the Arctic Ocean shoreline from the Russian region of Siberia to Alaska, Canada, and Scandinavia.
There are also species that fly from Scandanavia to Greenland (see map), where they mingle with other birds that migrate between Greenland and North America.
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