Wild birds spreading H5N1 in Asia

Wild birds whose migration patterns have been tracked by satellite may be spreading the H5N1 avian influenza to Mongolia from India or Tibet when they fly north in the spring, which may explain past outbreaks.

Mongolia has reported several H5N1 outbreaks since its first in August 2005, including one in 2006, one in 2009 and one in May of this year. The satellite tracking may explain these re-infections, CIDRAP News reports.

In the November 16 issue of FAO AIDE, a study was published detailing the findings after tracking waterfowl that frequent Qinghai Lake in China. Over 6,000 wild bids died of H5N1 in 2005 at Qinghai Lake, CIDRAP News reports. The study included fitting GPS transmitters on 525 waterfowl in 11 countries and tracking their migratory patterns.

Bar-headed geese, a species that made up half of the birds that died in the 2005 Qinghai Lake outbreak, spend their winters in the Lhasa region of India or Tibet and come into contact with domestic poultry during that time, the study found. It is believed that this allowed the virus to spread between domestic and wild birds.

“If this is so, wild waterfowl on the eastern portion of the Central Asian Flyway may in fact be helping spread H5N1 HPAI [highly pathogenic avian influenza] into Mongolia each spring as they cross the Qinghai-Tibetan plateau to the north and east,” the FAO article says. “[However, the information] suggests that wild birds are not the primary spreader of H5N1 HPAI but that human movement of virus through trade, marketing and fomites likely account for significant spread of the virus.”