However, given the dearth of reliable information that comes out of Yangon, as well as the junta's dubious track record with the truth, many international observers are worried about a cover-up of potentially global significance.

The fear is that the virus will infect birds in Myanmar then -- either through a cover-up or a lack of monitoring in remote or rebel-run areas -- will remain undetected for long enough to mutate, "go human" and unleash a killer flu pandemic on the world.

"Would they admit to it if it was here? That's the big question, since they deny everything left, right and centre," said one Yangon-based diplomat.

Another said some of the ruling generals appeared to have grasped the seriousness of the threat, but given the dire lack of infrastructure -- annual health spending amounts to a few dollars per person -- doubted whether anything could or would be done.

"I think there's an assumption that if it isn't already, then it will be a problem here, but you're lacking capacity and you're lacking will," the second diplomat said.

Myanmar is spurned by most of the international community due to its human rights record and detention of democracy icon Aung San Suu Kyi, but where bird flu is concerned, sanctions, isolation and strong rhetoric are in nobody's interest.

Bringing that problem into focus is this week's "front line" bird flu trip by US Health Secretary Michael Leavitt, who is going to Thailand, Cambodia, Laos and Vietnam -- but not Myanmar, which Washington has branded an "outpost of tyranny".

DRAFT PLANS

Officials at the Food and Agriculture Organisation (FAO) treat Myanmar's assurances it has never had bird flu with a degree of scepticism, especially since it is situated on the path of migratory birds which could be spreading the virus.

"If you consider the flight paths, and the fact the disease is spreading westwards, infection in Myanmar may be likely now or in the future," an FAO spokesman in Bangkok told Reuters.

However, they are loath to accuse the junta of lying, noting among other things that after the Indian Ocean tsunami, Myanmar announced a death toll only in double figures -- an estimate derided at the time but which later turned out to be accurate.

On the ground, the FAO says cooperation with government veterinary officials is good, and that bird flu reports from overseas dissident groups are in all likelihood Newcastle disease, a bird illness which poses no major risk to humans.

"I trust them," said Tang Zhengping, the FAO's representative in Yangon.

Under FAO auspices, Myanmar has been able to test samples for bird flu since April by sending them to Australia for analysis, although Tang said none had been sent either there or elsewhere.

No human or animal testing is available inside the country.

International health experts say the Health Ministry has drawn up a draft bird flu management strategy, including plans to educate Myanmar's 45 million people about it, as well as disease surveillance and victim treatment plans.

It has even identified special "bird flu hospitals", including one at an infectious diseases centre near Yangon which is equipped with isolation wards, said one expert, admitting nevertheless that much concrete action needed to be taken.

"Developing a national plan is already a big step. If the government is building a plan, I see that as a sign of political will," the expert said.

"But obviously, the Minister of Health will need resources in case something happens. Whether he will get those resources -- that's another story."

Even though years of mismanagement have crippled the economy, the expert said Myanmar still had a relatively large number of overseas-qualified doctors, unlike other impoverished nations in the bird flu firing line such as Cambodia.