A man in Thailand has died of bird flu, the first human casualty in the country since the disease re-emerged in Asia in July, officials said Thursday.

Tests confirmed that the death on Wednesday of an 18-year-old man in Prachinburi province was caused by the H5N1 bird flu (search) virus, said Dr. Charal Trinvuthipong, director-general of the Health Ministry's Department of Communicable Disease Control.

"This case is not unexpected," Dr. Kumara Rai, the acting World Health Organization (search) representative to Thailand, told The Associated Press. "As the WHO has been reminding its member countries, as long as the virus is circulated by birds it is a matter of time before a human is infected."

The victim, who raised fighting cocks, was admitted to a hospital in Prachinburi, 60 miles northeast of Bangkok, on Sept. 4, four days after falling ill.

The victim, who was not identified, was in the habit of sucking out blood and other fluids from the mouths of his roosters when they were injured during fighting, a common practice in the sport, said a Public Health Ministry spokeswoman who asked not to be identified.

She said all the chickens in a one-mile radius of the victim's house have been culled. A 15-year-old assistant of the victim has been quarantined even though he did not show any symptoms, she said.

The death raised the number of people killed by avian influenza in Thailand this year to nine and in Asia to 28. Eight people died in Thailand and 16 in Vietnam in the first outbreak in January, which devastated poultry stocks and led authorities to cull tens of millions of birds.

The disease re-emerged in July and claimed three more lives in Vietnam.

Nearly 300,000 birds have been slaughtered since early July in Thailand.

Experts from the U.N. Food and Agriculture Organization (search) and other groups have warned that the virus cannot be easily or quickly eradicated, especially since evidence has accumulated that it is spread by migratory birds.

Rai said Thailand has done a good job of surveillance and detection.

"Since Thailand has experienced the first wave of bird flu, it is much more prepared to deal with it now," he said.