China says it has eradicated bird flu, after culling nine million birds in the seven weeks since the first case.
Nine million birds were destroyed as China tackled the disease
A ministry of agriculture spokesman said the last isolation orders had been lifted and there had been no new infections in almost 30 days.
But Jia Youling warned that the disease could break out again when the weather warms up.
Thailand reported its eighth death from bird flu on Tuesday, after tests on a woman who died on 12 March.
The 39-year-old factory worker from Prathumthani province died after a visit to her family home in Ayutthaya in central Thailand, Dr Charal Trinvithipong, director general
of the Communicable Disease Control Department, said.
It is suspected that she contracted the disease from chickens in a
neighbour's house, where 20 birds had died of bird flu.
Along with the eight people who have died from bird flu in Thailand an additional 21 are suspected of being infected with the virus, a senior official said.
The disease killed at least 23 people in Vietnam and Thailand, though no human cases were reported in China.
Bird flu is still circulating in other parts of the world.
United Nations health experts in Geneva had warned of potentially serious effects if bird flu combined with the human influenza virus, triggering fears that the region was in for a crisis on the scale of the Sars outbreak.
Severe Acute Respiratory Syndrome, which killed some 300 people in China and about 800 worldwide, caused widespread damage to tourism and service industries.
At that time China, where the disease first emerged, was accused of covering up the true extent of the outbreak.
When the first cases of bird flu were reported, the respected British magazine the New Scientist suggested the outbreak had begun as long as a year ago in southern China, when vaccines used by farmers masked the symptoms of the disease.
But Mr Jia said the country's last case of bird flu had been in 1996 and that any cover-up would be against the law.
In fact the BBC's Beijing correspondent, Louisa Lim, says that China's proclamation of early victory against this outbreak of bird flu has been tempered by a note of caution.
"The situation is still grave for disease prevention and control," Mr Jia said. "We may suffer a relapse of bird flu unless preventive measures are intensified."
There are fears that as the weather warms up the disease could be spread by wild fowl migrating north.
Other potential risks included a spread of the virus from other countries or by long-distance transport of poultry, Mr Jia added.