Asian Wild Bird Study To Provide Data on H5N1 Transmission
Washington File Staff Writer
Washington – Somewhere in the skies over Eurasia, wild swans are soaring on their annual migratory routes, carrying with them the hopes of an international research team.
The birds are the test subjects of wildlife scientists from the U.S. Geological Survey (USGS), the Food and Agriculture Organization of the United Nations (FAO), the Mongolian Academy of Sciences and the nongovernmental Wildlife Conservation Society (WCS).
The creatures have been equipped with solar-powered satellite transmitters that will convey signals to the scientists, allowing them to track the birds on their migratory journey.
"We are marking swans with very small GPS [global positioning system] transmitters that are similar to navigation systems on cars,” said John Takekawa with the USGS Western Ecological Research Center in California, “but that also transmit the data through weather satellites so we can track their movements."
The project, part of the Wild Bird Global Avian Influenza Network for Surveillance (GAINS) program, is designed to create a better understanding of how wild birds might play a role in the intercontinental transmission of viruses, according to a joint USGS-FAO press release issued September 6.
GAINS, funded by the U.S. Agency for International Development, has been carried out as the highly pathogenic H5N1 avian influenza virus has traveled from Southeast Asia to more than 50 countries in Europe, Africa and the Middle East.
"We are working to understand the role wild birds may play in the spread of H5N1," said Scott Newman, international wildlife coordinator for avian Influenza for FAO.
"Although poultry and bird trade are probably the primary routes of movement,” he added, “migratory birds are likely involved in some areas."
THE SPREAD OF H5N1
The whooper swans of Mongolia and Western China are considered likely suspects in that transmission process because of a significant die-off in their flocks in 2005-2006. When the dead birds were discovered, testing revealed that some were infected with avian influenza.
No domestic flocks are nearby in the remote area, eliminating the possibility that the wild swans could have been infected by sick poultry. That finding suggests the wild flocks could be a natural reservoir for the virus, serving as vehicles to transport the lethal strain as they move on their migratory routes.
The virus might be transmitted to domestic flocks through shared watering places or through the droppings and shed feathers of the wild birds.
H5N1 has reached pandemic proportions among birds in Asia since its appearance in late 2003. More than 200 million domestic birds have been killed by the virus itself, or destroyed to avert its further spread.
More than 240 humans also were infected by sick birds as the disease has spread, resulting in 141 deaths.
People do not have a natural immunity to this particular flu strain, so international health authorities fear that it could become the spark for a global flu pandemic among humans.
Previous human pandemics, which also have been triggered by viruses originating in animals, have taken millions of lives and have been accompanied by serious social and economic consequences.
The international team captured whooper swans in early August on the grassland steppe of far eastern Mongolia, near the borders of Russia and China.
Each year, swans molt their feathers after the breeding season. During that flightless period, biologists in boats and on foot captured the birds.
Small, 70-gram solar-powered transmitters were affixed on 10 of the 8-kilogram swans with backpack harnesses. The harnesses are made of Teflonâ ribbon that deteriorates and will fall off the birds within a few years.
Takekawa said satellite tracking data will help scientists better understand and document links between wild birds and the spread of avian influenza. In addition, the data are expected to enhance conservation efforts by determining the ranges of birds and the mechanisms involved in long-distance migration.
The GPS transmitters are made by a wildlife specialty company and can provide information on a bird’s location with an accuracy of within 10 meters. That data can provide information that never before has been available on migrating birds and use of their habitats.
The birds’ locations are recorded every two hours and stored in the transmitter memory before being sent to the research team by e-mail through weather satellites every two days.
The need for a better understanding of the connections between animal and human health has been one outcome of the H5N1 spread. Pursuit of that goal has been affirmed at a number of international conferences over the past year. (See related article.)
The United States also has been a key partner in building international collaboration in the effort to contain and control avian influenza and avert pandemic. (See related article.)
The United States has pledged more than $360 million to assist developing nations most severely affected by avian influenza.
The full text of the joint USGS-FAO press release is available on the USGS Web site.
For ongoing coverage of avian influenza and efforts to combat it, see Bird Flu.