Hanoi - A man suspected of being infected with the H5N1 avian flu virus is in critical condition at a hospital in northern Vietnam, health officials said Saturday.

Ly Tai Mui, 23, has been hospitalized since February 3 at Quang Ninh general hospital, 150 kilometres west of Hanoi. Mui, a member of the Dao ethnic minority, had eaten the meat of a sick chicken in his village in rural Quang Ninh province some days before falling ill.

"We suspect this patient is infected with the avian flu virus," said Nguyen Huy Nga, head of Vietnam's Preventive Health and Environment Agency. Nga said a definitive diagnosis would have to wait for the results of tests early next week.

Nguyen Van Trong of the Quang Ninh health department said Mui was in critical condition and was breathing with the help of an oxygen machine. Dr Phan Van Tan, the doctor in charge of Mui's case, said he was in an isolated room to prevent contagion.

Vietnam's Ministry of Health has sent experts from the National Institute of Hygiene and Epidemiology and the National Institute for Infectious and Tropical Diseases, both in Hanoi, to Quang Ninh to investigate the case.

The group will return to Hanoi to report to leaders at the Health Ministry and obtain their approval before officially announcing next week whether Mui has avian flu.

Vietnam's first human case of bird flu this year was reported in January when a 13-year-old girl from Thanh Hoa province, 150 kilometers south of Hanoi, tested positive for the virus.

The girl's older sister died on January 2 in Thanh Hoa after displaying symptoms consistent with bird flu, but doctors failed to test for the virus, and her body was not exhumed for testing because of religious reasons.

Avian influenza has infected 106 people in Vietnam and killed 52 since it first appeared in the country in late 2003.

The disease is usually spread by contact between sick birds and humans, but scientists fear that the virus could mutate into a form that is easily transmissible among humans and spark a global pandemic that could kill millions. (dpa)