Deadly spectre of bird flu returns to Vietnam

The World Health Organisation (WHO) said further tests were needed to see if three other people who have died over the past fortnight in the communist nation from a similar illness had also been infected with avian influenza.

The latest confirmed deaths take the number of Vietnamese victims of the disease this year to 19, according to the Ministry of Health. Eight people have also died in Thailand but the last death there occurred on March 12.

Vietnamese health authorities said the H5 virus had been detected in samples taken from the three latest victims but that further tests were needed to determine if the virus belonged to the deadly H5N1 strain.

The H5N1 is the only strain of the H5 subtype known to pass from infected poultry and cause illness in humans.

The WHO described their deaths as a worrying development that "confirmed the continuing ability of the virus to transmit to humans".

"Every human case raises the risk of avian and human viruses mingling, and the development of a pandemic strain," Peter Cordingley, spokesman for the WHO's Western Pacific Office in Manila, told AFP.

"Outbreaks in poultry are not under control. The virus is widespread in the environment and will take concentrated efforts over a long period to remove it."

Vietnam was widely criticised for acting prematurely and recklessly when it announced on March 30 that the country was free of the disease.

The WHO urged all Asian governments to exercise maximum caution and surveillance.