Though the bureau confirmed the victim had been infected with the H5N1 avian virus no birds had been affected by the disease in the area recently.

Hao was admitted to Quan Hoa General Hospital last Thursday before being transferred to Thanh Hoa General Hospital in critical condition on Tuesday.

She was suffering from pleural and pericardial effusion and kidney failure at the time.

A team from the National Institute of Hygiene and Epidemiology and local health authorities failed to find any trace of bird flu in Thien Phu Commune, where Hao lived.

All four human bird flu cases in Vietnam this year have proved fatal.

Source: VNA