The highly pathogenic H5N1 avian influenza seems to have become endemic in central Asia. Over the past week, the virus was confirmed as the source of outbreaks in Kazakhstan and Siberia, and it is suspected in outbreaks in Mongolia and Tibet, according to information given by the countries involved to the World Organization for Animal Health (OIE).
Earlier this year, the H5N1 virus, previously only seen in east and southeast Asia, was reported in China's western Qinghai and Xinjiang regions (ScienceNOW, 13 June). All of these areas border one another in north-central Asia. Most avian influenza experts believe the virus is spread primarily by trading in domestic poultry and the movement of crates and trucks unknowingly carrying contaminated droppings or other materials. But there is still a possibility that wild birds may be spreading the virus over long distances. This is causing heightened concerns with the approach of the fall migration season, particularly since there is only a rudimentary understanding of many migration routes.
Noureddin Mona, the representative of the United Nations' Food and Agricultural Organization (FAO) in Beijing, says that local authorities have taken appropriate steps to contain each outbreak--culling infected flocks, disinfecting affected farms, trying to prevent movements of poultry, and vaccinating poultry in surrounding areas to prevent infection. But still, "the virus is jumping from place to place, and surrounding countries should be alarmed," Mona says.
Alex Thiermann, a veterinarian at OIE, Paris, says there is reason to hope that if the virus does spread to Europe, the impact may be less than it has been in Asia. Throughout southeast Asia, the widespread practice of rural families raising small flocks of chickens in their backyards brings wild birds into close contact with domestic poultry, which are in close contact with humans. "The way poultry are raised in Europe is very different," he says. But this doesn't mean Europe can be complacent. "It is important that measures are taken so there is no chance commercial poultry operations will get exposed to the virus," Thiermann adds.
The OIE's daily H5N1 update