Dr. David Nabarro, the UN's bird flu coordinator, speaking in a news briefing, said the disease is estimated to spread beyond the Atlantic in two stages. The first sees wild birds migrating from Africa to the Arctic regions in a few months and the second enables the virus to reach North and South America six months later."
"Maybe even before that," Nabarro added.
In Europe, Norway is testing two ducks for the lethal H5N1 strain of bird flu after finding 12 birds dead in the same area, the Norwegian Food Safety Authority said yesterday.
Sweden already reported cases of the H5N1 avian flu last month but Norway has found no cases despite dozens of tests. Wednesday's discovery in Jaeren, in southwest Norway, was the largest discovery of dead birds in one place.
However, all of the birds did not die at roughly the same time as might be typical in a flu outbreak. Only two of the ducks had died recently enough to be tested for the virus, officials said.
"Last night two dead and one sick duck were found," the Food Safety Authority said in a statement. "Nearby there were relatively fresh remains of 10 other birds."
"We'll have the first test results today, and that will give us a good indication. But it takes up to 24 hours to confirm if the birds had the aggressive variant, H5N1," Eivind Lien, a senior adviser at the agency, told reporters.
Meanwhile, the World Health Organization (WHO) denied this week it was exaggerating the risk of a human influenza pandemic, while China reported a 10th person had been diagnosed with the potentially fatal bird flu virus.
WHO director-general Lee Jong-Wook said the threat of a pandemic was a genuine one.
"Concern has been expressed that we are overplaying this threat. We are not," Lee said in an opening speech to the WHO's executive board, holding a week-long meeting in Geneva. "We can only reduce the devastating human and economic impact of a pandemic if we all take the threat seriously now and prepare thoroughly. This is a global problem."
The United Nations agency has predicted between two and 7.4 million people could die if a pandemic sweeps the world.
A 29-year-old woman from southwest China was diagnosed with the H5N1 virus, the Chinese health ministry said. She was in critical condition in hospital. The woman ran a shop in a farm goods market in Jinhua Town in Sichuan Province. Six of the 10 known victims of bird flu in China have died.
At least a dozen people are being treated for the lethal virus in Indonesia. The WHO has confirmed bird flu as the cause of death of a young brother and sister in Indonesia this month, taking the death toll to at least 82 since the virus reemerged in late 2003.
U.S. Federal, state and local health officials may test as many as 100,000 birds for the virus this year, mainly in Alaska, said Frank Quimby, a spokesman for the U.S. Interior Department.
The rate of H5N1 infections in humans has increased this year as the virus spread to more parts of Asia, and to Africa, Europe and the Middle East. The virus has killed at least 96 of 175 people infected since late 2003. It is reported to have infected an average of three people a week this year, killing an average of two a week. Last year, 23 cases, including 14 fatalities, were reported in the first 10 weeks.