Potential Intercontinental Movement of Influenza A(H7N9) Virus into North America by Wild Birds: Application of a Rapid Assessment Framework

Abstract

A critical question surrounding emergence of novel strains of avian influenza viruses (AIV) is the ability for wild migratory birds to translocate a complete (unreassorted whole genome) AIV intercontinentally. Virus translocation via migratory birds is suspected in outbreaks of highly pathogenic strain A(H5N1) in Asia, Africa and Europe. As a result, the potential intercontinental translocation of newly emerging AIV such as A(H7N9) from Eurasia to North America via migratory movements of birds remains a concern. An estimated 2.91 million aquatic birds move annually between Eurasia and North America with an estimated AIV prevalence as high as 32.2%. Here, we present a rapid assessment to address the likelihood of whole (unreassorted)-genome translocation of Eurasian strain AIV into North America. The scope of this assessment was limited specifically to assess the weight of evidence to support the movement of an unreassorted AIV intercontinentally by migratory aquatic birds. We developed a rapid assessment framework to assess the potential for intercontinental movement of avian influenzas by aquatic birds. This framework was iteratively reviewed by a multidisciplinary panel of scientific experts until a consensus was established. Our assessment framework identified four factors that may contribute to the potential for introduction of any AIV intercontinentally into North America by wild aquatic birds. These factors, in aggregate, provide a framework for evaluating the likelihood of new forms of AIV from Eurasia to be introduced by aquatic birds into North America. Based on our assessment, we determined that the potential for introduction of A(H7N9) into North America through aquatic migratory birds is possible, but the likelihood ranges from extremely low to low.

Nomenclature updates resulting from the evolution of avian influenza A(H5) virus clades 2.1.3.2a, 2.2.1, and 2.3.4 during 2013–2014

“…The spread of H5N1 viruses to Europe in 2005–2006 and subsequent years following wild bird outbreaks in Qinghai Lake, China, has been extensively documented. The recent detection of HPAI A(H5) gs/GD/96 lineage viruses in wild ducks in Canada and the western seaboard of the USA is not unprecedented considering previous evidence of gene flow between the Eurasian and American low pathogenicity avian influenza gene pools and overlapping migratory bird flyways . H5N8 and H5N2 viruses have also recently been detected in poultry, and H5N2 viruses have been identified in wild birds from the central and Mississippi flyways of North America .…”

“…The recent detection of HPAI A(H5) gs/GD/96 lineage viruses in wild ducks in Canada and the western seaboard of the USA is not unprecedented considering previous evidence of gene flow between the Eurasian and American low pathogenicity avian influenza gene pools and overlapping migratory bird flyways. 32 H5N8 and H5N2 viruses have also recently been detected in poultry, and H5N2 viruses have been identified in wild birds from the central and Mississippi flyways of North America. 15,33,34 It remains to be seen whether these viruses become established in North America or what affect they may have on the influenza virus gene pool of aquatic bird populations worldwide.…”

Identification of migratory bird flyways in North America using community detection on biological networks

“…A related concern is the continued threat of introduction of other emergent highly pathogenic, Asian strains of avian influenza (Miller et al. ), which often originate from a combination of wild bird and domestic poultry strains (Gao , Kageyama et al. , Liu ).…”

Predicting the initial spread of novel Asian origin influenza A viruses in the continental USA by wild waterfowl

“…The use of band‐recovery data to predict potential movement of influenza A viruses in North America has been previously proposed (Doherty et al., ; Miller et al., ) but never implemented in an emergency‐response situation. Despite being a reactive approach to quickly respond to the initial outbreak of clade 2.3.4.4 H5 viruses in North America, our analyses demonstrated that the approach worked well in identifying areas where wild birds were likely to further spread clade 2.3.4.4 H5 viruses to high density poultry production areas, such as the Sacramento Valley in California, which is one of the top 10 poultry production areas in the USA (National Agricultural Statistics Service, ).…”

“…Thus, an underlying assumption in using band-recovery data is that areas and seasons for waterfowl hunting also correspond to waterfowl concentration areas (Buhnerkempe et al, 2016;Farnsworth et al, 2011). Although imperfect, these data represent the best available large-scale movement data for waterfowl over both time and space and are useful for rapid risk assessment situations at regional and national scales (Miller, Sweeney, Akkina, & Saito, 2015).…”