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Researchers to explore the role of wild birds in the spread of avian flu viruses

last modified Jun 06, 2013 04:10 PM
Cambridge researchers are working with leading Georgian scientists to address key questions about the ecology and evolution of avian flu.
Researchers to explore the role of wild birds in the spread  of avian flu viruses

Alphabetic Tower, Batumi, Georgia

A new initiative to study the spread of avian flu by wild bird populations launched today at Ilia State University in Georgia. The three-year international collaboration will examine the ecology and evolution of avian influenza viruses in their natural hosts, waterfowl.

Influenza A viruses have been isolated from many host species, including a wide range of domestic and wild birds.  However, these viruses can sometimes infect other animals such as pigs and humans, potentially resulting in an epidemic or even a pandemic because the new host species doesn’t have immunity to these avian flu viruses. Aquatic birds are the natural reservoir for all avian influenza A viruses (AIVs). Most are of low pathogenicity and cause mild or subclinical infections in aquatic birds. However, since the emergence and westward spread of high pathogenic H5N1 from SE-Asia, one of the outstanding questions is the role wild birds, particularly long distance migrants, might play in the dissemination of AIV from SE-Asia to other geographic regions.

This ever-present risk means it is important to understand what flu viruses circulate in wild birds, and what risk these viruses might pose to other animal species. In addition, occasionally when avian flu viruses infect poultry they can mutate into a more deadly form of flu. This highly pathogenic strain of avian flu is not only more deadly in birds than other avian flu viruses but is also more deadly than the common seasonal human flu if it infects people.

Despite widespread surveillance, little is still understood about the spatial, temporal and ecological role of the host populations in defining the genetic structure of AIVs. However, sharing a common waterbody, whether for breeding, migration stop-off or on wintering grounds offers the opportunity for mixing and the potential for AIV transmission.

 

This work provides the basis for a significant scientific contribution over the next three years to the field of avian influenza research, building on the strong surveillance base provided by the previous project, and the expectation that this contribution will be translated from the current international collaboration to a self-sustaining scientific effort from the Georgian partners.

Integral to this scientific output is the training component which will produce a molecular biology qualified workforce which could be utilized for science in the CPHRL, exercise the local diagnostic laboratories in on-going surveillance for an important pathogen and transfer state-of-the-art analytical techniques to Georgians to enable them to apply for sustainable science-based funding in the future.

The information and data obtained will develop integrated approaches to understanding the prevalence of AI in wild birds. This project will enhance surveillance and epidemiological analytical capabilities in Georgia using tools such as phylogenetics, geographic information systems, and population genetics.

Since the emergence and westward spread of the highly pathogenic A/H5N1, one of the unanswered questions is what role wild birds, particularly long-distance migrants, play in the dissemination of influenza A viruses from Southeast Asia to other geographic regions. As Georgia bridges Western Asia and Eastern Europe and is home to wild water birds from many different parts of Eurasia during migration and winter, it is an ideal location to undertake the research.

To find out more about how the viruses spread, the researchers will map circulating avian flu strains in birds in the region as well as studying the movements and population structure of the birds themselves as currently, very little is known about the migratory routes wild birds take to reach breeding and overwintering grounds.

Dr Nicola Lewis, lead researcher on the project from the University of Cambridge, said: “Three migratory flyways converge in the Caucasus region so avian flu viruses that had been infecting birds in one part of Asia might get the opportunity to spread to birds flying in from other regions, and we think that this is most likely to happen in places such as Georgia, where birds from many different parts of Eurasia mix in large numbers during migration and during the winter.

“Knowing where bird populations fly will ultimately allow us to assess what risk might be for an avian flu virus, particularly a deadly one, in one region being taken by a wild bird as it migrates to another region in Asia.”

The Cambridge researchers will be working with leading Georgian scientists to address these key questions about avian flu viruses in wild water birds.

Lewis added: “By understanding how these avian flu viruses evolve in wild birds and the risk wild birds might pose in spreading infectious diseases, this international scientific collaboration will inform both global animal and public health.”

As well as improving avian influenza virus surveillance in the region, the project will also increase the diagnostic and scientific expertise in Georgia by training local Masters students, academics and laboratory staff to use state-of-the art infectious disease analyses. Integrating Georgia more fully into the international scientific influenza community will provide a much more comprehensive picture of the spread of avian flu.

The collaboration includes the University of Cambridge, the Animal Health and Veterinary Laboratories (AHVLA) in the UK, Ilia State University, the Georgian National Centre for Disease Control and Public Health, the Laboratory of the Ministry of Agriculture of Georgia and the Richard G. Lugar Center for Research in Tbilisi, Georgia.