Vietnam has said a 27-year-old man has died from bird flu, bringing to 19 the number of deaths from the illness sweeping Asian poultry.
Millions of chickens have been slaughtered across Asia
The man is believed to have caught the disease at his family's chicken farm.
All confirmed human infections and deaths from the H5N1 bird flu have been registered in Vietnam and Thailand.
The virus has so far only jumped from poultry to humans, and one possible case of human-to-human transmission has now been proved a false alarm.
Health experts are worried that if the virus mixes with a regular human influenza strain, it might create a mutant form that was able to pass between humans, triggering a human flu pandemic.
Fourteen people have died of the disease in Vietnam while five have died in Thailand.
AVIAN FLU ALERT
First jumped "species barrier" from bird to human in 1997
In humans, symptoms include fever, sore throat, and cough
Types which threaten humans are influenza A subtypes H5N1 and H9N2
The latest man to die from the illness came from Vietnam's southern Binh Phuoc province.
Health officials have also reported a new infection in Vietnam - a 23 year old man from central Lam Dong province is in hospital in Ho Chi Minh City in a stable condition.
In other developments:
- Experts are waiting for test results from a Cambodian woman who died in a Vietnamese hospital - if she is confirmed to have had the disease she would be the first victim from Cambodia
- Malaysia is still free of bird flu after a suspected case in a bird shop owner in Kelantan state near the Thai border proved to be a false alarm.
- The World Health Organization (WHO) said that tests had shown that two Vietnamese sisters feared to have caught the disease from human to human transmission had not in fact done so
- Several Asian countries have suspended imports of US chicken as details of an outbreak of bird flu in the state of Delaware are investigated.
Tens of millions of chickens and ducks have already been slaughtered across South East Asia as the outbreak also hit Vietnam, China, South Korea, Cambodia, Taiwan, Indonesia, Pakistan, Laos and Japan.