Highly pathogenic avian influenza is an emerging disease threat to wild birds in North America

Abstract

Prior to the emergence of the A/goose/Guangdong/1/1996 (Gs/GD) H5N1 influenza A virus, the long‐held and well‐supported paradigm was that highly pathogenic avian influenza (HPAI) outbreaks were restricted to poultry, the result of cross‐species transmission of precursor viruses from wild aquatic birds that subsequently gained pathogenicity in domestic birds. Therefore, management agencies typically adopted a prevention, control, and eradication strategy that included strict biosecurity for domestic bird production, isolation of infected and exposed flocks, and prompt depopulation. In most cases, this strategy has proved sufficient for eradicating HPAI. Since 2002, this paradigm has been challenged with many detections of viral descendants of the Gs/GD lineage among wild birds, most of which have been associated with sporadic mortality events. Since the emergence and evolution of the genetically distinct clade 2.3.4.4 Gs/GD lineage HPAI viruses in approximately 2010, there have been further increases in the occurrence of HPAI in wild birds and geographic spread through migratory bird movement. A prominent example is the introduction of clade 2.3.4.4 Gs/GD HPAI viruses from East Asia to North America via migratory birds in autumn 2014 that ultimately led to the largest outbreak of HPAI in the history of the United States. Given the apparent maintenance of Gs/GD lineage HPAI viruses in a global avian reservoir; bidirectional virus exchange between wild and domestic birds facilitating the continued adaptation of Gs/GD HPAI viruses in wild bird hosts; the current frequency of HPAI outbreaks in wild birds globally, and particularly in Eurasia where Gs/GD HPAI viruses may now be enzootic; and ongoing dispersal of AI viruses from East Asia to North America via migratory birds, HPAI now represents an emerging disease threat to North American wildlife. This recent paradigm shift implies that management of HPAI in domestic birds alone may no longer be sufficient to eradicate HPAI viruses from a given country or region. Rather, agencies managing wild birds and their habitats may consider the development or adoption of mitigation strategies to minimize introductions to poultry, to reduce negative impacts on wild bird populations, and to diminish adverse effects to stakeholders using wildlife resources. The main objective of this review is, therefore, to provide information that will assist wildlife managers in developing mitigation strategies or approaches for dealing with outbreaks of Gs/GD HPAI in wild birds in the form of preparedness, surveillance, research, communications, and targeted management actions. Resultant outbreak response plans and actions may represent meaningful steps of wildlife managers toward the use of collaborative and multi‐jurisdictional One Health approaches when it comes to the detection, investigation, and mitigation of emerging viruses at the human‐domestic animal‐wildlife interface.

Exploring surface water as a transmission medium of avian influenza viruses – systematic infection studies in mallards

“…In 1996, a flock of domestic geese in the Chinese Guangdong province was identified to be infected with HPAIV termed A/goose/Guangdong/1/1996 (H5N1) [ 6 , 7 ]. Descendants of this virus later became known as the Goose/Guangdong (gs/GD)-lineage [ 8 ].…”

Maintenance and dissemination of avian-origin influenza A virus within the northern Atlantic Flyway of North America

“…Our study contributes a unique look at wild waterfowl migratory connectivity paired with genetic analyses to assess persistence and dissemination of influenza A viruses within the Atlantic Flyway of North America. Although important for migratory waterfowl as well as poultry production in the U.S., this flyway has been generally less sampled for wild bird-origin IAV as compared to the Pacific Flyway despite evidence for virus exchange with Europe through direct movements or shared breeding grounds in regions such as Greenland and Iceland [ 37 , 50 – 52 ]. Such virus exchange has proven ecologically and economically relevant as exemplified by frequent HPAI H5N1 detections in North America beginning in late 2021 [ 39 , 41 ].…”

Epidemiology and Ecology of Influenza A Viruses among Wildlife in the Arctic

“…All human influenza pandemics that can be traced to their origins (1918, 1957, 1968, 2009) emerged from wild birds, often facilitated by intermediate hosts such as swine and poultry [ 26 , 27 ]. Amplification of IAVs has been well characterized at the domestic animal–human interface; however, much less is understood about how interfaces between wild birds, other wildlife species, and environmental sources of transmission maintain animal infections in the natural world [ 28 , 29 , 30 , 31 , 32 ].…”