Asia’s deadly bird flu will persist for many years and a global effort is needed to stop the virus from spreading and prevent a human pandemic, the U.N. food agency said on Wednesday.

“There is an increasing risk of avian influenza spread that no poultry-keeping country can afford to ignore,” Samuel Jutzi, a senior official at the Food and Agriculture Organization (FAO), told bird flu experts gathered in Vietnam for a 3-day conference.

Jutzi said in a speech prepared for delivery to the conference that the virus, which has killed 46 people in Asia since it arrived in late 2003 “will persist for many years to come in some countries that had disease outbreaks.”

To prevent it spreading to other parts of the world, rich nations and donors must back efforts to control and contain the highly contagious disease “at the source,” he said.

The conference in Ho Chi Minh City, near the Mekong Delta where Vietnam is battling its latest outbreaks, will review how Asian governments have fared against the stubborn virus and plot a battle plan for the future.

Nearly 140 million birds have been slaughtered or died in the Asian epidemic so far, and the financial cost is already up to $10 billion, according to some estimates.

But new outbreaks have reinforced fears that the deadly H5N1 strain could mutate into a form that could spread through a world population with no immunity to it.

Minimising poultry infections and keeping humans free of avian influenza would help prevent that nightmare scenario from happening, Jutzi said.

“STOP DRINKING BLOOD”

But one year on, many countries lack diagnostic tools and surveillance systems to detect and respond quickly to outbreaks.

Stricter measures throughout the poultry production chain are also needed, he said.

Wild birds, especially ducks, are natural hosts of the virus and they are often blamed for its spread.

But Jutzi said the evidence suggests that trade in live poultry, the mixing of species on farms and at bird markets, and poor farming practices “contribute much more to disease spread than wild bird movements.”

Public awareness campaigns about the health risks of bird flu are running in several affected countries.

But Jutzi noted traditional practices, such as drinking the raw blood of ducks, still go on and must be discouraged.

Host Vietnam, the hardest-hit country where 13 people have died in the latest outbreaks, has clamped down on the poultry trade in Ho Chi Minh City in recent weeks, boosted surveillance and imposed other tough measures.

But Vietnam and other affected countries will need “hundreds of millions of dollars” from donors to sustain a prolonged fight against the disease, an FAO official said.

The countries are expected to outline their technical and financial needs at the conference, which ends on Friday.