HO CHI MINH CITY, Vietnam -- As Vietnam reported 27 new outbreaks of bird flu, public health officials called for a massive transformation in poultry farming throughout Southeast Asia to stem the epidemic.
The biggest challenge will be to reform the practices of millions of subsistence farmers who share living space with their chickens, ducks, and other animals.
Scientists said such conditions created a hot house for mutations within the flu virus that could eventually allow it to pass easily between people -- a precondition for a possible pandemic.
US officials, for their part, said they were nearing the start of a large clinical trial of an experimental avian flu vaccine that could help suppress the virus if it spread beyond Southeast Asia.
The "backyard farmers" of Vietnam -- the country that has borne the brunt of the latest outbreak -- raise about 90 percent of the country's poultry, said Cao Duc Phat, the nation's agriculture minister, at a news conference during a three-day meeting in Ho Chi Minh City convened by the World Health Organization.
Among other recommendations, officials urged that chickens and other fowl be kept out of homes, that different species of birds be segregated on farms and in markets to limit spread of the virus, and that domestic fowl be kept penned up so they can't mingle with the wild ducks that are thought to be a natural reservoir for the virus, formally known as H5N1.
Changing farming practices and monitoring the spread of the disease, which has killed 45 people in the past year -- 13 in the past month -- and devastated the poultry industry in parts of Southeast Asia, will require massive infusions of aid from rich nations, officials said.
"The world is now in the gravest possible danger of a pandemic" that would dwarf SARS in its lethality, scope, and economic cost, Shigeru Omi, the WHO's top Asia-Pacific official, told delegates from more than two dozen nations.
Some changes have already begun, and they have had an major economic impact. In Ho Chi Minh City, few birds are in evidence because of a recently enacted ban.
Nguyen Thi Le, a nearby fish seller, said the ban was an overreaction that cost many jobs and depressed local businesses. "Many people, since they cannot sell chicken, had to go back to their home villages," she said.
In the United States, officials at the Centers for Disease Control and Prevention said yesterday that the government would soon begin testing a vaccine against avian flu and that the agency had stockpiled 2 million doses of the vaccine as well as substantial quantities of antiviral drugs in preparation for a potential outbreak.
The French pharmaceutical company Sanofi Pasteur has prepared two batches of 4,000 doses each -- in two concentrations -- that will be shipped to the National Institute for Allergy and Infectious Diseases for clinical trials.
The vaccine will be tested in New York, Missouri, Maryland, and Texas to ensure its safety and to determine the optimum dose in various groups, including children and the elderly.
Sanofi also prepared 2 million doses of the vaccine under a potential commercial process to allow them to more easily scale up to full production if an emergency arises.