Vietnam confirmed a new case of bird flu (search) Friday, heightening the sense of urgency as an international conference on fighting the deadly virus ended with calls for concerted action to prevent a possible global pandemic.

Health and animal experts said the long-term strategy for battling the disease must focus on minimizing the risks of infection to poultry and people by a virus now firmly established within flocks of wild birds in the region, beyond hope of quick eradication.

"The threat is real and the potential is very high" for a human epidemic, said Dr. Samuel Jutzi, with the U.N.'s Food and Agriculture Organization. "The longer the virus circulates in the poultry production system the higher the probability of exposure to humans."

Underscoring the threat, Vietnam confirmed on Friday that a 21-year-old man from northern Thai Binh province tested positive for the deadly H5N1 strain of the bird flu virus. He was admitted to a hospital Monday with a high fever, a serious lung infection, breathing difficulties and liver failure, said Nguyen Thi Tuong Van of Bach Mai Hospital in Hanoi.

His 14-year-old sister is also suspected of having the disease. Her tests were pending Friday.

Since Dec. 30, 13 people have died in Vietnam from the bird flu, while four others recovered from the virus. A total of 45 people from Thailand, Vietnam and Cambodia have died over the past year from the bird flu.

Meanwhile, a growing number of experts are warning of an imminent global pandemic if the bird flu is not contained, noting the H5N1 virus could become far more lethal if it mutates into a form that can be easily transmitted among humans.

The reemergence of outbreaks this year indicated the virus is entrenched in many parts of Asia, including Cambodia, Thailand, China, and Indonesia. Ducks and other migratory waterfowl have been pinpointed as culprits in spreading the disease because they carry the virus without falling sick.

Complete eradication of bird flu from the region is unlikely, but it is still possible to effectively control the H5N1 virus at its source, if people and farm animals in Asia are sealed off from infected wild bird carriers, U.N. officials said.

It will take a sizable investment. At a minimum, about $100 million would be needed at the outset for monitoring the disease and providing animal vaccines. Precautions would include penning up poultry in cages and separating chickens from ducks and other water fowl on farms and in markets. Several hundred million more dollars would be needed for poultry restocking, compensation for farmers or restructuring farming practices.

The 28 countries represented at the conference said the world community would have to help. Vietnam, which has been the hardest hit, is thus far the only nation to have publicly asked for assistance.

U.N. officials have criticized the lackluster response from affected countries and donors when the H5N1 strain surfaced last year. Donors gave only about $18 million to fund an emergency response. Jutzi called this a "glaringly insufficient" amount compared with the magnitude of the threat.

Conference delegates agreed one key to controlling the virus in the long-term will be difficult — revamping practices at Asia's myriad mom-and-pop poultry farms, where farmers often live in close, usually unsanitary quarters with their birds.