February 25, 2005

 

 

Extensive research key to long-term bird flu control

 

Health and animal experts have said any long-term strategy for controlling bird flu must address the role of ducks and other waterfowl as major culprits in the spread of the deadly virus.

 

At an international conference in Ho Chi Minh City this week, officials said extensive research since the first major outbreak last year has confirmed that wild birds, particularly ducks, are primary reservoirs for the H5N1 virus, since they can carry it without falling ill.

 

Some experts have upheld the approach taken by Thailand to minimize infection risks - by reducing the virus load in ducks, fighting cocks through inoculating free-range poultry and waterfowl - should be taken as one model.

 

Lowering viral risk in birds translates to fewer human infections.

 

Earlier this week, Thailand approved a program to vaccinate free-range chickens, ducks, fighting cocks and tropical birds in a bid to ward off bird flu, reversing an earlier ban on the practice.

 

However, it is virtually impossible to fully eliminate the virus from the environment because it can stay hidden in ducks, health experts say. At the conference, Shigeru Omi, the Western Pacific regional director for the World Health Organization, said the public health implications of ducks as carriers are enormous.

 

"How can people avoid exposure to the virus when they don't know which ducks are infected and which ones are not?" he said.

 

Complicating the issue are traditional methods of farming in Asia that allow free-range ducks who roam from paddy to paddy to mix with chickens and other livestock.

 

In host country Vietnam, for example, there are an estimated 59 million ducks, geese and other waterfowl, most raised in open-air backyard farms, according to agriculture figures.

 

Vietnam has banned the breeding of ducks until June 30. Ho Chi Minh City has ordered a cull of all ducks this month.

 

However, not all experts agree that wild birds alone are responsible for dispersing the virus so widely.

 

Evidence suggests that trade in live poultry, mixing of bird species in farms and markets, and poor biosecurity in poultry production play a much bigger role than wild bird movements, said an expert with the UN Food and Agriculture Organization.

 

The agency "advises against the destruction of wild birds and their habitats" since it is unlikely to have a major impact on controlling the bird flu, he said.

 

The UN expert has urged the international community to spend at least US$100 million to combat bird flu -- five times more than the amount provided last year.

 

Countries last year gave only about US$18 million to fund an emergency response to the bird flu outbreak, which reflecting in part a lack of commitment.

 

Experts have warned that the H5N1 virus, which has ravaged the region's poultry industry and killed 45 people across Thailand, Vietnam and Cambodia, could well become even deadlier if the virus mutates into a form that is easily transmitted between humans.

 

So far there is no evidence of that, but health and animal experts say the longer it remains in the environment, the greater the chances of the virus changing and triggering a global pandemic that could kill millions.