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The source of deadly Avian Influenza, popularly known as Bird Flu in North America has long been a subject of debate among scientists. But now, scientists with the U.S. Geological Survey (USGS), in collaboration with the U.S. Fish and Wildlife Service in Alaska and the University of Tokyo claim they have genetic evidence to prove the role of migratory wild birds in the transfer of avian influenza viruses between Asia and North America. The revelation was made by USGS scientists in an article published in the Molecular Ecology.
The team of scientists carried out multi-pronged research and made concerted efforts to understand the role of migratory birds in the transfer of bird flu virus across continents. The scientists now have genetic evidence to prove the movement of Asian forms of avian influenza virus to Alaska via the Northern Pintail Duck.
According to the scientists, the Northern Pintail Duck was chosen as the focus of the study as they are fairly common in both North America and Asia. These birds are also known to migrate between Asia and North America and are frequently found to be infected by low pathogenic bird flu virus.
It may be noted that the role of migratory birds in moving the highly pathogenic virus has for long been a subject of debate amongst scientists. Disagreements brew on how likely it is for H5N1 virus to disperse among continents via wild birds. Scientists found it imperative to clear the controversy and understand the role of wild birds in the spread of highly pathogenic form of avian influenza virus that spread across Asia to Europe and Africa over the past decade, causing the deaths of 245 people and raising concerns of possible human pandemic.
A dedicated team of scientists with the USGS, in collaboration with the U.S. Fish and Wildlife Service, state agencies, and Alaska native communities, obtained samples from more than 1,400 Northern Pintails from locations throughout Alaska. Samples containing viruses were then analyzed and compared to virus samples taken from other birds in North America and Eastern Asia where Northern Pintails are known to travel for winter. The scientists observed that nearly half of the low pathogenic avian influenza viruses found in wild Northern Pintail Ducks in Alaska contained at least one (of eight) gene segments that were more closely related to Asian than to North American strains of avian influenza.
The revelation made by the study was considered significant by the USGS scientists as some previous researches on the subject led to speculation that intercontinental transfer of avian influenza viruses from Asia to North America via wild birds is rare. Claiming the authenticity of their study, the scientists claim that previous researches studied bird species that are not transcontinental migrants or were from mid-latitude locales in North America, regions far removed from sources of Asian strains of avian influenza.
Validating the success of the research, John Pearce, a research wildlife biologist with the USGS Alaska Science Center says, this kind of genetic analysis using the low pathogenic strains of avian influenza virus commonly found in the wild birds can answer questions relating to the migratory movements of wild birds and also about the degree of virus exchange that takes place between continents. Pearce further added that it is important to sample the right species and geographic location to get the right result from the study.
The co-author of the study, Pearce further stated that the team’s research also corroborated the current surveillance sampling process for highly pathogenic avian influenza in Alaska and exhibits that genetic analysis can be used as an effective tool to further refine surveillance plans across North America.
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