UN: Migratory birds not major cause of flu transmission
12 November 2006

www.chinaview.cn 2006-11-02 23:28:35

NANCHANG, Nov. 2 (Xinhua) -- UN officials on Thursday said migratory birds do not play a major role in the transmission of the highly pathogenic avian influenza H5N1.

They made the remarks at the first international Living Lakes Conference in this capital of east China's Jiangxi Province.

Dr. Vincent Martin, an official with the Food and Agriculture Organization of the United Nations (UNFAO), said the spread of bird flu is mainly the result of the world's fast and unregulated development of animal production to meet the increased demand for animal protein.

Highly concentrated domestic poultry production systems, especially in Asia, are still using centuries-old practices that place humans and poultry in close proximity, he said. Meanwhile, the constantly evolving nature of the virus has provided the ideal conditions for the emergence of new pathogenic strains of avian influenza.

Evidence indicates wild migratory birds play a minor role in the long-distance spread of the virus, he said, adding that the main causes of the deadly disease are the trade of poultry and poultry products.

Marco Barbieri, executive secretary of Convention on Migratory Species (CMS) of the United Nations Environment Program (UNEP), said the spread of bird flu receives a lot of attention in the media yet there remains widespread misunderstanding of the issue.

Misinformation has led to wild birds being automatically blamed, the official said. "This creates political pressure for ill-advised and disproportionate policies such as the culling or harassment of wild birds and the destruction of wetland habitats."

According to Barbieri, other modes of transmission, such as the trade in poultry and poultry products, the trade in caged birds and human movements may well play a far more significant role in the spread of the bird flu.

In some cases, these modes of transmission have been underestimated and do not receive proportionate exposure in the media, he said. "We need to present an accurate and balanced view which acknowledges that there are a number of factors whose relative importance can change, depending on the area or outbreak concerned."

On the role of wild birds in transmission of the bird flu, Barbieri said it is clear that trade in domestic poultry has been a crucial factor, even in transmitting avian influenza over long distances and across continents.

However, numerous species of wild birds, especially water fowl, have been proven to be susceptible to infection by H5N1, he pointed out. The loss of wetlands around the globe has forced many wild birds onto alternative sites like farm ponds and paddy fields, bringing them into closer contact with chickens, ducks, geese, and other domestic fowl.

A long term solution would be to separate poultry operations and wetlands used by wild birds in order to avoid shared access and cross-contamination, the UN officials suggested.

Wild birds and poultry in the same region should not have direct contact with each other, and runoff from domestic poultry operations must not pollute wetlands used by wild birds.

"Farmers can help to reduce the risks of direct transmission of poultry and cross-infection between wild and domestic birds by improving hygiene and bio-security standards in farms and during the transportation of birds, said Barbieri.

Scientists should synthesize information on the routes and timing of water bird migration, especially of poorly known intra-African migrants, and birds using Central Asian, Asia-Pacific and Neotropical flyways.

"We need to strengthen bird research worldwide, especially in areas where little or no ringing and counting schemes have operated in the past," he said.

The official urged all countries to strengthen field surveillance of wild birds and enhance the understanding of wild bird migration and use of important sites during migration.

They must avoid unjustified and counter-productive measure such as culling of wild birds and destruction of the natural habitats on which they depend, such as wetlands, he said.

"The governments should also work with site management and veterinary authorities to ensure regular and effective site monitoring, aimed at rapid detection and reporting of any potential H5N1 outbreak," he added.