Indonesian officials covered up and then neglected a spreading bird flu epidemic for two years until it began to sicken humans this summer, posing a grave threat to people well beyond the country's borders, according to Indonesian and international health experts.

Unlike Southeast Asian countries that began to see human cases almost as soon as avian influenza was identified in their poultry, Indonesia had a generous head start to prevent an outbreak among people. But since July, it has registered more human cases than any other country, including three deaths confirmed by international testing. Influenza specialists agree that the actual number of human cases is higher and expect it to rise with the approach of the rainy season.

Health experts say the Indonesian epidemic started in commercial poultry farms, spread among the tens of millions of free-range chickens raised in back yards across the country and then finally infected people. At each step, the Indonesian government failed to take measures that could have broken the chain, while discouraging research into the outbreak.

As a result, specialists are concerned that the cases in Indonesia pose a worldwide threat if the bird flu virus changes and becomes contagious among humans.

"If the government had acted sooner to stamp it out, there would be no outbreak. They have wasted so much time," said Chairul A. Nidom, an Indonesian microbiologist who first identified the virus in this country's birds. "What terrifies me is that it just won't affect Indonesia."

In recent days, the virus has killed birds in Turkey, Romania and possibly Greece, for the first time presenting a danger to European poultry. Russia on Wednesday reported that preliminary tests, conducted after hundreds of birds died south of Moscow, showed the presence of the virus, according to news services. And China reported a fresh outbreak of bird flu in its northern grasslands, where 2,600 birds have died of the disease.

The U.N. Food and Agriculture Organization warned that the chances were increased that avian flu would move to the Middle East and Africa.

Health experts stress, however, that a human pandemic is still most likely to erupt in East Asia. Bird flu is already deeply entrenched among Asian poultry. Moreover, many countries in the region lack both basic agricultural safeguards to prevent the disease from spreading to humans and health care systems able to contain the virus if it does.

Since 2003, at least 60 people in Southeast Asia have died of the illness. U.N. health officials warn the threat could multiply if bird flu develops into a form easily passed among humans, potentially setting off a plague killing tens of millions of people worldwide.

Indonesia, in particular, is a worry to U.N. and other international experts, partly because it has Southeast Asia's largest population of both people and poultry. The country also has an impoverished health care system that has deteriorated significantly since the 1997 Asian financial crisis and the weakening of central government authority following the 1998 ouster of the longtime dictator Suharto.

In an interview with The Washington Post this spring, Tri Satya Putri Naipospos, Indonesia's national director of animal health, first disclosed that officials had known chickens were dying from bird flu since the middle of 2003 but kept this secret until last year because of lobbying by the poultry industry. She also revealed that the government had not set aside any money this year to vaccinate poultry against the virus though officials had trumpeted this as the centerpiece of their strategy to contain the disease.

Naipospos repeated her allegations late last month, but this time in Indonesian in an interview with the influential local newspaper Kompas.

A day after the article was published, the Agriculture Ministry fired her.

U.N. officials complained that her dismissal had set back efforts to fight the virus, faulting the government for ousting what they call its most respected animal health expert at the height of a crisis.

Naipospos alleged that bird flu has never been a priority in the Agriculture Ministry. Until recent months, she added, the ministry was even unwilling to tap its $3 million emergency account to pay for disease control measures.

"They could not see the potential threat until there was an actual threat," she said in an interview with The Post last week. "I talked to the minister about it many times. He said a disease outbreak is not a national emergency, not a disaster."

Agriculture Minister Anton Apriyantono said the Indonesian government considers bird flu a matter of great concern. Every morning, he said, he files a report with President Susilo Bambang Yudhoyono on efforts to battle the disease.

"That means our attention is very high on how to address this problem," the minister said in an interview. "The thing is, we don't want to publicize too much about bird flu because of the effect on our farms. Prices have dropped very drastically."

Apriyantono said he fired Naipospos because he was not happy with her handling of bird flu and her working relationship with top ministry officials.

When the virus first appeared in Indonesia in the summer of 2003, government officials were divided over whether the sudden death of hens on a commercial farm on Java island was caused by bird flu or a less virulent ailment, Newcastle disease. Nidom, a professor at Indonesia's Airlangga University, was called in. Within two months, he said, his laboratory research had determined that the ailment was indeed bird flu and was genetically related to a strain found seven years earlier in southern China.

But the owners of major poultry companies, who have personal ties to senior Agriculture Ministry officials, insisted that any containment efforts be done secretly, Naipospos recalled. These eight farming conglomerates, which handle 60 percent of the country's poultry, feared that publicity would harm sales of chicken and eggs. Offering new details in her interview last week, Naipospos said owners even lobbied Indonesia's president at the time, Megawati Sukarnoputri.

"They said, 'It's better to do it with confidentiality. Do a hidden, silent operation,' " Naipospos recounted. "I said, 'It won't work if you do a silent operation. This is a disease that can't be hidden. It's too risky.' "

In late January 2004, Nidom broke ranks and announced his findings to the Indonesian news media. A day later, the Agriculture Ministry confirmed the bird flu outbreak. But already the disease had spread across Java and on to Bali and Sumatra islands.

"It was too late. The virus was everywhere," Nidom recalled.

Last fall, with human cases mounting in Vietnam and Thailand, Nidom was growing increasingly nervous about the prospect of the epidemic spreading to Indonesians. He arranged an October conference at his university to examine bird flu and invited four of the world's premier influenza researchers, from the United States, Japan, Hong Kong and mainland China.

Shortly before its scheduled start, a senior agriculture official contacted Yoes Prijatna Dachlan, the head of Nidom's institute, and demanded that foreign participants and all media be banned, Dachlan said. Dachlan, chairman of the university's Tropical Disease Center, said he rejected the conditions and canceled the gathering. Nidom said officials threatened to have police break it up if it proceeded.

Apriyantono said in the interview that he was unfamiliar with the incident but that Indonesia was open to foreign researchers.

Through this summer, avian flu continued to spread, often unreported, and containment efforts remained unfunded. The disease reached two-thirds of the country's provinces. Then in July, a father and two daughters in an affluent Jakarta suburb died of respiratory disease. The father tested positive as the country's first bird flu victim. Health investigators concluded that his daughters likely died of the same cause.

Responding to public anxiety, Apriyantono went on television to oversee the culling of several dozen pigs and ducks on a farm 10 miles away. But when the cameras left, the campaign stalled. Officials backed away from a vow to kill about 200 swine in the area. Thousands of chickens, identified by health experts as the leading suspects in the outbreak, escaped slaughter.

As suspected human cases mounted last month, government officials said they would take extraordinary measures. Apriyantono said he was changing course and would order a mass slaughter of poultry in any area declared highly infected.

But one month later, Apriyantono acknowledged that he has yet to define such an area. As a result, he has now directed that culling be limited to the specific property where an infection is detected and that neighboring birds be spared.

Special correspondent Yayu Yuniar contributed to this report.

A worker cleans chickens at a small slaughterhouse in Jakarta. Experts say Indonesia covered up the spread of bird flu in poultry until it had begun to sicken humans.