Bird flu killed a 22-year-old man in central China, state media reported Monday.

It was the 18th fatality linked to the H5N1 bird flu virus in China, which raises more poultry than any other country. Beijing has vowed to aggressively fight the virus, which has killed at least 227 people worldwide, according to the World Health Organization.

The man, identified only by his surname Li, died Jan. 24 after developing fever and headache eight days earlier, Xinhua News Agency said, citing the Ministry of Health.

Li tested positive for the deadly H5N1 bird flu virus strain, according to the Center for Disease Control and Prevention, the report said. It did not say how he contracted the disease or explain the delay in reporting the death.

Li lived in Jianghua county of Hunan's Yongzhou City. People who came into close contact with Li were put under medical observation, and none of them has showed signs of bird flu, Xinhua said, citing the Health Ministry.

Bird flu remains hard for humans to catch, but experts worry that outbreaks in poultry may cause the virus to mutate into a form easily transmitted among humans, potentially igniting a pandemic. Most human cases have been traced to contact with infected birds.

Last month, Chinese authorities confirmed a father and son who were sickened with bird flu were the country's first infections within the same family, but said their cases showed no evidence that the virus has changed into a form that can easily be passed between humans.

The 24-year-old son from the eastern city of Nanjing died Dec. 2.

Meanwhile, a 3-year-old Indonesian boy has died of bird flu, an Indonesian health official said Saturday, announcing the country's second death from the illness in one day. The two cases, which were apparently unrelated, brought Indonesia's bird flu death toll to 105.

The latest victim was identified only as Han, a 3-year-old boy from the southern part of the capital, Jakarta, radio El-Shinta reported. It said he died Friday at a hospital in the city.

Senior Health Ministry official Nyoman Kandun confirmed the report and said laboratory tests confirmed the boy had the dangerous H5N1 strain of the bird flu virus. It was not clear how he was infected, and Kandun gave no further details.

Earlier Saturday, the Health Ministry said a 16-year-old Indonesian boy from Central Java province died of bird flu. The boy, whose name was not disclosed, became ill on Feb. 3 with a cough and other respiratory symptoms, according to the Health Ministry's Web site.

He died a week later in a hospital in the city of Solo about 280 miles southeast of Jakarta, said Sumardi, a ministry spokesman. Like he many Indonesians, he goes by one name.

Tests confirmed the boy had H5N1, the ministry's Web site said.

The 16-year-old victim's neighbors had sick chickens on their property and the boy apparently slaughtered some of them before he became ill, the ministry said.

Indonesia has regularly recorded human deaths from bird flu since the virus began ravaging poultry stocks across Asia in 2003.

Bird flu remains hard for people to catch, but health experts worry the virus could mutate into a form that passes easily among humans and trigger a pandemic. So far most human cases have been linked to contact with infected birds.

Scientists have warned that Indonesia, which has millions of backyard chickens and poor medical facilities, is a potential hot spot for a global bird flu pandemic.

More than 225 people have died worldwide from the virus, according to the World Health Organization's Web site.