The Vietnamese government has increased efforts to suppress outbreaks of bird flu among ducks and chickens around the country because of concerns that the disease could spread widely during the winter.

Prime Minister Phan Van Khai instructed ministries and provincial governments last week to mobilize the military, militias and college students, and criticized emergency response to the virus so far at both national and local levels as "slow and lacking determination."

Since the start of this month, senior officials have declared new measures to confront the disease and prepare for a possible human pandemic almost daily.

"No matter what it costs, and even if we have to readjust the growth rate, the entire nation should try to fight the epidemic," Deputy Prime Minister Nguyen Tan Dung said last week in remarks quoted by the Thanh Nien newspaper.

International health specialists warn that the virus, confined mostly to poultry in Asia, could either alter or obtain genetic material that would allow it to spread more easily among humans and spark a global pandemic. So far the World Health Organization reports that 67 people have died from bird flu, with 130 human cases reported in Vietnam, Thailand, Cambodia, Indonesia and China. Only a few victims of bird flu are thought to have contracted the disease from other people, who were family members in nearly all cases.

About two-thirds of the people killed by the disease worldwide were Vietnamese. But the outbreak in humans and poultry subsided this summer and abruptly reemerged only last month, causing the death of tens of thousands of birds in at least 13 provinces and killing a 35-year-old Hanoi man who lived near a livestock market. He was the country's 42nd fatality from avian influenza since it broke out in late 2003 but the first confirmed human case in three months. Two other possible cases were under investigation.

Vietnam has also become the first country in Southeast Asia to reach agreement with Swiss pharmaceutical company Roche to manufacture Tamiflu, the most effective drug available for treating bird flu, according to Health Ministry and company officials. Roche said it would supply the raw material for local production.

Within the last six months, international health experts said, Vietnam has improved its monitoring of possible human cases. Hans Troedsson, WHO's chief representative in the country, said tests were being conducted at several hospitals where patients had exhibited influenza symptoms, even if bird flu had not been diagnosed, to determine whether any mild cases are being missed. After testing about 500 people, scientists found that very few cases appeared to have been overlooked, he said.

But health experts added that the local monitoring program was still spotty, citing a lapse last month involving two deaths in the central province of Quang Binh. After local officials initially said they suspected bird flu, the government ruled it out as the cause. Yet no tests were conducted on the patients, leaving international health experts skeptical about the diagnosis.

Nor has Vietnam provided as much detailed information about outbreaks as international experts say they need to track the disease and fashion a response. Peter Horby, a WHO epidemiologist, said the agency gets weekly updates about human outbreaks but is looking for specifics about the incubation period of the illness and its symptoms, personal details about the victims and possible sources of infection.

In June, WHO dispatched a specialized team of influenza investigators to Hanoi after learning of preliminary research appearing to show bird flu as being far more prevalent among Vietnamese than earlier thought. Fearing the disease was now spreading easily from one person to another, agency experts had prepared to sound a pandemic alert, which could have staggered Vietnam's economy, but decided first to confirm the findings.

That investigation found that the virus had not altered and was not moving readily among people. The conclusions spared Vietnam, demonstrating the merits of working closely with international scientists, Troedsson said.

For the last two years, the outbreak in both birds and people has peaked during colder months, when scientists say the virus can survive longer, for instance in poultry excrement, which is thought to be a primary source of infection.

Vietnamese officials now hope to finish vaccinating up to 150 million chickens and ducks before the onset of winter next month. This program is the centerpiece of the country's efforts to fight the virus in birds, and Vietnam had planned to complete it by now. But a delay in receiving vaccine shipments from China slowed the effort. About 90 million birds have now been immunized, officials said.

"It is working fairly well but there are difficulties. It is a massive logistical campaign," said Anton Rychener, the U.N. Food and Agriculture Organization's chief representative in Vietnam.

Luong Van Thanh, 51, carries 70 of his chickens for collection in Hanoi. Officials hope to vaccinate 150 million fowl before winter.