Scientists fear bird flu could eventually mix with human flu

Bird flu was a "crisis of global importance", the organisations for animal health and food and agriculture said in a joint statement.

They stressed that the virus continued to circulate in eastern Asia and urged governments to take more action.

A case of human infection in Thailand this week sparked fresh fears.

The H5N1 strain of bird, or avian, flu has killed 20 people in Vietnam this year and nine in Thailand while millions of birds have been culled or vaccinated.

'Permanent threat'

The BBC's science correspondent, Richard Black, says the warning by the UN-affiliated bodies is unusually stark.

BIRD FLU 29 human deaths in Vietnam and Thailand in 2004 More than 100 million birds culled this year as precaution No confirmed case of human-to-human transmission

The UN Food and Agriculture Organization (FAO) and the World Organization for Animal Health (OIE) warned on Monday that bird flu was far from being eradicated.

Recent outbreaks in China, Vietnam, Cambodia, Malaysia and Thailand showed the virus continued to circulate in the region and would "not probably be eradicated in the near future", they said.

"A permanent threat to animal and human health continues to exist," the joint statement added.

The two organisations issued guidelines which stress the importance of surveillance and early detection, and accused Asian governments of not doing enough.

While stressing that culling was the best way to tackle the problem, they added that vaccination against bird flu could be used as a complementary measure.

Infection scare

Initial reports in Thailand suggested the latest known bird flu sufferer, a 32-year-old woman, may have contracted it from her sister or niece, who died from suspected bird flu earlier this month.

But the Thai government later said the infected woman had been in contact with dead birds - the usual means of infection - and there was no evidence she had caught the virus from human contact.

The condition of the woman, identified as Pranom, is said to be improving.