WHO said seven of 11 patients from Azerbaijan had tested positive for the deadly strain of bird flu in samples checked at a major laboratory in Britain. Five of the cases were fatal.
The new global total of confirmed deaths from H5N1 is 103, WHO said. Those deaths are part of the total 184 confirmed human cases of H5N1 since it broke out in Asia in 2003.
In Azerbaijan, six of the 11 cases occurred in a small settlement in southeastern Azerbaijan, the agency said.
The sources of infection are still under investigation, but they possibly were feathers from dead swans collected by young women, WHO said.
"The majority of cases have occurred in females between the ages of 15 and 20 years," it said. "In this community, the defeathering of birds is a task usually undertaken by adolescent girls and young women."
There so far was no indication of direct exposure to dead or diseased poultry in some of the cases. That has been the usual source of exposure for humans who caught bird flu, which remains a difficult disease for people to catch.
Experts fear, however, that the H5N1 virus could mutate into a form that spreads easily among people, sparking a human flu pandemic that could kill millions.
Bird flu has not yet reached North and South America, but scientists expect it to arrive soon along with birds migrating from Asia, outgoing Interior Secretary Gale Norton explained to CBS Evening News anchor Bob Schieffer.
However, Norton stressed that people should not be afraid to eat poultry, because cooking kills the virus.
She added that while the government is trying to plan for a pandemic, it is not possible to produce vaccines in advance. "Until the genetic mutation occurs that would make this a human to human transfer, they can't really do the final perfection of a vaccine," she told Schieffer.
"Hopefully that mutation never occurs," she added.
The Azerbaijan deaths come as Health and Human Services Secretary Mike Leavitt visited North Carolina as part of a nationwide tour to talk about a possible flu pandemic. The visits are meant to emphasize the need for state and local communities to begin preparing for a possibly serious threat.
During his speech, Leavitt announced that North Carolina will get $2.5 million of the $350 million President Bush has proposed giving states to help with preparedness and said more money will be coming. But he also warned that any community that relies only on the federal government to pay for its preparations will fall short.
"We simply have no way to respond to 5,000 communities at the same moment," Leavitt said.
But some states are saying that's not enough. "From a state perspective, I can tell you that that will not cut it," said Gov. Mike Easley of North Carolina. "It is going to take a bigger federal commitment."
Audrey Heffron is an instructor with Florida State University's Disaster Risk Policy Center told CBS News correspondent Trish Regan that federal, state and local officials are not the only people who need to plan for a pandemic. Corporations need to start thinking about it as well.
"What would we do if we only had 40 percent of our workforce at a given time? We can barely begin to get our minds around what could happen," she said.
But Regan reports that a new study shows that only 48 percent of American corporations are considering a plan for a pandemic, and only 15 percent actually have one. Government studies estimate that a human bird flu pandemic could cost American businesses $675 billion.
In Azerbaijan the victims were a 17-year-old girl, her cousins — a woman of 20 and a boy of 16 — and a close family friend, a 17-year-old girl, WHO reported.
Two more cases in the community — on Azerbaijan's Caspian Sea coast, south of the capital, Baku — are a 10-year-old boy, who has recovered, and a 15-year-old girl, who is hospitalized in critical condition.
The seventh confirmed infection was in a 21-year-old woman in the central western part of the country. She died on March 9, WHO said.
Two more people in the coastal area have been hospitalized with pneumonia symptoms, often associated with bird flu. Testing of these patients is under way, WHO said.
The agency said its experts and those from the Health Ministry were working closely together and that 90 teams were conducting house-to-house surveillance for cases of influenza-like illness.
After officials in Baku found a single case of a stray dog infected with bird flu they announced last week they would collect and kill stray cats and dogs because of fears that they might spread bird flu.
The outbreak in Azerbaijan was first detected last month in wild birds along the Caspian Sea coast. It has spread to the northeast and the southwest near the border with Iran.
Azerbaijan shares a short border with Turkey, where four children died recently of the disease.