FAO/OIE conference to tackle bird flu controversy

Role of wild birds a key issue

25 May 2006, Rome – How far wild birds are to blame for spreading highly pathogenic avian influenza (HPAI), or bird flu, will be the key issue at a scientific conference organized here on May 30-31 by FAO and OIE, the World Organisation for Animal Health.

Some 300 scientists from over 100 nations will attend the two-day meeting to try to shed light on one of the most controversial aspects of the H5N1 crisis: just what is the role played by wild birds, as against domestic poultry, in propagating bird flu.

The FAO and OIE International Scientific Conference on Avian Influenza and Wild Birds will also discuss such issues as the ecology and virology of HPAI, surveillance, risk analysis and disease management.

But almost three years after HPAI first broke out in Southeast Asia, scientists are still searching for a vital piece of the puzzle as they strive to check the disease. “There is a fundamental piece of information missing,” says Joseph Domenech, FAO’s Chief Veterinary Officer.

The main problem, according to Domenech, is that no one knows for sure whether wild birds can act as long-term reservoirs of HPAI viruses such as H5N1.

“Where they are not reservoirs but only victims of contamination from poultry, then prevention has to remain at the domestic bird level,” he says. “But where they are, we have to find out which birds are involved and where they migrate to in order to prevent other wild birds and poultry being infected.”

While it has been demonstrated that migrating birds can carry the virus over long distances – in Siberia, Eastern and Western Europe for example – it is not clear where the infection originated. However, most scientists point the finger at domestic fowl.

In the early spring, it was feared that there would be large-scale outbreaks of HPAI in Africa. And though bird flu did hit six African countries, this was less than expected and there was no evidence to link the outbreaks with wild birds.

Similarly, widespread new cases were feared in Europe but largely failed to materialize. “Lots of questions remain without answers,” says Domenech. “We therefore need to increase research and surveillance to better understand the epidemiology of the disease.”

FAO and OIE lead role

The conference is expected to confirm FAO and OIE’s lead role with respect to HPAI-related migrating bird research and monitoring. “It is clear, however, that we cannot do this alone and will continue to work in close partnership with other UN agencies and specialized NGOs such as Wetlands International,” said Jan Slingenbergh, Senior Animal Health Officer.

Surveillance and monitoring of H5N1 in wild birds is a major technical and scientific undertaking involving satellite tracking and assembling information from ornithologists, ecologists, virologists and epidemiologists, he added.

Slingenbergh said he believed there would be no clear conclusion as to whether wild birds or domestic poultry were responsible for HPAI introduction into new areas. “The answer is it’s a mix,” he said.

“In Europe, we know that in most countries where the virus has appeared, it’s been with the wild birds,” he said. In East and Southeast Asia the disease was arguably spread by a combination of domestic and wild birds, while in Africa it appeared that poultry trade and traffic was essentially responsible, he added.

Since the first outbreaks of HPAI in Southeast Asia at the end of 2003, H5N1 has killed 124 humans, nearly all of them infected by domestic fowl. Over 200 million poultry have died of the disease or have had to be culled so far.