Avian Influenza Active
Avian influenza is a viral disease caused by various strains of avian influenza viruses that can be classified as low pathogenic avian influenza (LPAI) or highly pathogenic avian influenza (HPAI). It remains a global disease with potential high consequence with the potential to threaten wildlife, agriculture, and human health.
The USGS National Wildlife Health Center (NWHC) in collaboration with multiple partners conducts research into the ecology of avian influenza virus and surveillance for highly pathogenic avian influenza (HPAI) viruses leading to several significant findings towards early detection and response to HPAI.
Avian Influenza (AI) is a global disease with potential high consequence. Wild birds, in particular certain species of waterfowl and shorebirds, are considered to be the natural reservoirs for avian influenza viruses. These subtypes that naturally occur in wild species usually cause little or no disease. In domestic birds, however, some AI viruses can be more pathogenic and mutation or recombination of a virus acquired from wild birds can increase disease potential. In recent years, spill-back has occurred negatively affecting wild birds.
Avian influenza viruses (AIV) are classified by a combination of two groups of proteins found on the surface of the virus: hemagglutinin proteins (H), of which there are 18 (H1-H18), and neuraminidase proteins (N), of which there are 11 (N1-N11). Additional information on avian influenza viruses are available in the Field Manual of Wildlife Diseases.
AI strains are divided into two groups based on the pathogenicity of the virus, or the ability of the virus to produce disease. Most AI strains are classified as low pathogenic avian influenza (LPAI) and cause few clinical signs in infected birds. LPAI generally does not pose a significant health threat to humans. However, LPAI is monitored because two strains of LPAI— the H5 and H7 strains–can mutate into highly pathogenic forms. On the other hand, highly pathogenic avian influenza (HPAI) strains frequently fatal to birds and easily transmissible between susceptible species.
Avian Influenza Movement in the Atlantic
Highly pathogenic avian influenza outbreaks in domestic poultry cause large economic losses to the U.S. economy. It has been thought that Eurasian strains of avian influenza viruses enter the United States through the Pacific Flyway (Alaska to Baja California) and that this route is the most likely avenue for emerging Eurasian AIV strains to enter North America. However, AIV also frequently infects domestic poultry and wild ducks in Europe and Africa and migrating wild birds that use the east Atlantic flyway may also risk introducing Eurasian strain viruses to North America via this route. With the on-going European outbreaks of HPAI there is a risk of moving these viruses to North America as well.
The USGS National Wildlife Health Center, in collaboration with the National Institutes of Health Centers of Excellence for Influenza Research and Surveillance (CEIRS), the University of Iceland, and other partners, has explored the ecology and movement of AI viruses in the North Atlantic region since 2010. This research has demonstrated the importance of the migratory bird flyways in this region to the intercontinental movement of viruses between Europe and North America. AI viruses from both continents, as well as recombinations of both strains, were isolated in Iceland, sometimes from within a single flock of birds, showing that this region is a hotspot of virus movement and genetic reassortment. These studies also demonstrated the longer-term persistence of portions of these viruses within the North Atlantic avian community.
Highly pathogenic AI viruses have been frequently found in wild and domestic European birds, significantly in 2006, and annually since then. This continued European epizootic increases the risk of HPAIV being transported from Europe to North America as bird populations migrate through the North Atlantic to breeding sites in Greenland and Canada, and highlights the importance of these studies. Stakeholders include federal and state agencies, North Atlantic and European countries, and commercial poultry businesses who have an interest in protecting wildlife and/or domestic animals by identifying the risks of HPAIV entering the United States through North Atlantic wild bird flyways. Significant findings from this research in the North Atlantic include:
- Gulls and marine birds are an integral component of AIV ecology in this region;
- Genetic sequence data revealed frequent mixing of North American and Eurasian AIV lineages in the North Atlantic;
- Icelandic viruses were discovered to have genetic relationships with viruses causing seal mortalities in Europe; and
- No HPAIV has been identified, however, viruses with genetic relationships to HPAIV H5N1 viruses have been detected in Iceland.
HPAI and other influenzas circulate in freshwater waterfowl. It is also possible that sea ducks, which regularly move between continents, could play a role in how HPAI moves and evolves around the world. In collaboration with CEIRS, State Wildlife Agencies, Ducks Unlimited, and hunting guides, the NWHC has conducted surveillance in wild sea ducks in the Northeastern United States, Alaska, Canada, and Iceland over the past 6 years. This research has shown that sea duck avian influenzas often differ from those carried by freshwater ducks. This research is currently defining environmental factors that affect AI transmission in marine environments.
Quantitative Applications in Disease Ecology
Human, agricultural, and wildlife health depend on each other. Therefore, risk assessment, prediction, and management of wildlife diseases are important for our nation’s health and economy. However, monitoring and evaluating wildlife health is difficult and expensive. This leads to incomplete and biased datasets that are difficult to analyze with traditional methods. A project is underway to develop new statistical and mathematical techniques and package them into user-friendly tools. Some examples of new tools in development are the ability to analyze and interpret complex data, assess risk of future or ongoing disease outbreaks, estimate the effects of disease on individuals, populations, and ecosystems, and evaluate potential management solutions. This project, performed in partnership with the Department of Statistics at the University of Wisconsin-Madison, is broadly applicable to a variety of wildlife diseases, but is currently working on new statistical methods for predicting virus isolation of avian influenzas.
Minor Spillover of Avian Influenza Between Wild and Domestic Birds
In another study, NWHC reserachers also analyzed the genomes of HPAIV that spread in the United States during 2014-2015 and resulted in over $3 billion in losses to the U.S. poultry industry. As infection and transmission of pathogens in wild birds are difficult to measure during a fast-moving outbreak, the NWHC used cutting-edge modeling techniques to analyze genetic similarity between HPAIVs infecting wild birds and poultry. Analyses indicated that even though the viruses likely evolved in Asia, they easily infected and spread among North American wild birds. The viruses were also able to spread between domestic and wild birds (i.e., spillover). However, the rate of spillover was minor, and the poultry outbreak persisted without need for ongoing transmission from wild birds. Techniques used in this study can also be used to examine transmission and adaptation of avian influenza within waterfowl populations and between waterfowl and poultry.
Avian Influenza Surveillance
The USGS National Wildlife Health Center is a member of the U.S. Interagency Steering Committee for Surveillance for Highly Pathogenic Avian Influenza in Wild Birds. The NWHC performs both passive and active surveillance for the detection and monitoring of avian influenza. Check out the Avian Influenza Surveillance page to learn more.
Below are multimedia items related to avian influenza.
Below are publications related to avian influenza.
Intercontinental spread of asian-origin H5N8 to North America through Beringia by migratory birds
The dynamics of avian influenza in western Arctic snow geese: implications for annual and migratory infection patterns
Novel H5 clade 2.3.4.4 reassortant (H5N1) virus from a green-winged teal in Washington, USA
Novel Eurasian highly pathogenic avian influenza A H5 viruses in wild birds, Washington, USA, 2014
Cyclic avian mass mortality in the northeastern United States is associated with a novel orthomyxovirus
Evidence for seasonal patterns in the relative abundance of avian influenza virus subtypes in blue-winged teal (Anas discors)
Avian influenza virus ecology in Iceland shorebirds: intercontinental reassortment and movement
Respiratory transmission of an avian H3N8 influenza virus isolated from a harbour seal
Avian influenza virus antibodies in Pacific Coast Red Knots (Calidris canutus rufa)
North Atlantic migratory bird flyways provide routes for intercontinental movement of avian influenza viruses
Sampling strategies and biodiversity of influenza A subtypes in wild birds
Genomic analysis of avian influenza viruses from waterfowl in Western Alaska, USA
Below are news stories related to avian influenza.
Below are FAQs related to avian influenza.
What is Avian Influenza?
Avian influenza (AI) is caused by an influenza type A virus that can infect poultry such as chickens, turkeys, pheasants, quail, domestic ducks, geese, and guinea fowl. It is carried by wild waterfowl (ducks and geese) and shorebirds. Learn more: USGS Avian Influenza
Below are partners associated with avian influenza projects.
- Overview
Avian influenza is a viral disease caused by various strains of avian influenza viruses that can be classified as low pathogenic avian influenza (LPAI) or highly pathogenic avian influenza (HPAI). It remains a global disease with potential high consequence with the potential to threaten wildlife, agriculture, and human health.
The USGS National Wildlife Health Center (NWHC) in collaboration with multiple partners conducts research into the ecology of avian influenza virus and surveillance for highly pathogenic avian influenza (HPAI) viruses leading to several significant findings towards early detection and response to HPAI.
Avian Influenza (AI) is a global disease with potential high consequence. Wild birds, in particular certain species of waterfowl and shorebirds, are considered to be the natural reservoirs for avian influenza viruses. These subtypes that naturally occur in wild species usually cause little or no disease. In domestic birds, however, some AI viruses can be more pathogenic and mutation or recombination of a virus acquired from wild birds can increase disease potential. In recent years, spill-back has occurred negatively affecting wild birds.
Avian influenza viruses (AIV) are classified by a combination of two groups of proteins found on the surface of the virus: hemagglutinin proteins (H), of which there are 18 (H1-H18), and neuraminidase proteins (N), of which there are 11 (N1-N11). Additional information on avian influenza viruses are available in the Field Manual of Wildlife Diseases.
AI strains are divided into two groups based on the pathogenicity of the virus, or the ability of the virus to produce disease. Most AI strains are classified as low pathogenic avian influenza (LPAI) and cause few clinical signs in infected birds. LPAI generally does not pose a significant health threat to humans. However, LPAI is monitored because two strains of LPAI— the H5 and H7 strains–can mutate into highly pathogenic forms. On the other hand, highly pathogenic avian influenza (HPAI) strains frequently fatal to birds and easily transmissible between susceptible species.
Avian Influenza Movement in the Atlantic
Highly pathogenic avian influenza outbreaks in domestic poultry cause large economic losses to the U.S. economy. It has been thought that Eurasian strains of avian influenza viruses enter the United States through the Pacific Flyway (Alaska to Baja California) and that this route is the most likely avenue for emerging Eurasian AIV strains to enter North America. However, AIV also frequently infects domestic poultry and wild ducks in Europe and Africa and migrating wild birds that use the east Atlantic flyway may also risk introducing Eurasian strain viruses to North America via this route. With the on-going European outbreaks of HPAI there is a risk of moving these viruses to North America as well.
The USGS National Wildlife Health Center, in collaboration with the National Institutes of Health Centers of Excellence for Influenza Research and Surveillance (CEIRS), the University of Iceland, and other partners, has explored the ecology and movement of AI viruses in the North Atlantic region since 2010. This research has demonstrated the importance of the migratory bird flyways in this region to the intercontinental movement of viruses between Europe and North America. AI viruses from both continents, as well as recombinations of both strains, were isolated in Iceland, sometimes from within a single flock of birds, showing that this region is a hotspot of virus movement and genetic reassortment. These studies also demonstrated the longer-term persistence of portions of these viruses within the North Atlantic avian community.
Highly pathogenic AI viruses have been frequently found in wild and domestic European birds, significantly in 2006, and annually since then. This continued European epizootic increases the risk of HPAIV being transported from Europe to North America as bird populations migrate through the North Atlantic to breeding sites in Greenland and Canada, and highlights the importance of these studies. Stakeholders include federal and state agencies, North Atlantic and European countries, and commercial poultry businesses who have an interest in protecting wildlife and/or domestic animals by identifying the risks of HPAIV entering the United States through North Atlantic wild bird flyways. Significant findings from this research in the North Atlantic include:
- Gulls and marine birds are an integral component of AIV ecology in this region;
- Genetic sequence data revealed frequent mixing of North American and Eurasian AIV lineages in the North Atlantic;
- Icelandic viruses were discovered to have genetic relationships with viruses causing seal mortalities in Europe; and
- No HPAIV has been identified, however, viruses with genetic relationships to HPAIV H5N1 viruses have been detected in Iceland.
HPAI and other influenzas circulate in freshwater waterfowl. It is also possible that sea ducks, which regularly move between continents, could play a role in how HPAI moves and evolves around the world. In collaboration with CEIRS, State Wildlife Agencies, Ducks Unlimited, and hunting guides, the NWHC has conducted surveillance in wild sea ducks in the Northeastern United States, Alaska, Canada, and Iceland over the past 6 years. This research has shown that sea duck avian influenzas often differ from those carried by freshwater ducks. This research is currently defining environmental factors that affect AI transmission in marine environments.
Quantitative Applications in Disease Ecology
Human, agricultural, and wildlife health depend on each other. Therefore, risk assessment, prediction, and management of wildlife diseases are important for our nation’s health and economy. However, monitoring and evaluating wildlife health is difficult and expensive. This leads to incomplete and biased datasets that are difficult to analyze with traditional methods. A project is underway to develop new statistical and mathematical techniques and package them into user-friendly tools. Some examples of new tools in development are the ability to analyze and interpret complex data, assess risk of future or ongoing disease outbreaks, estimate the effects of disease on individuals, populations, and ecosystems, and evaluate potential management solutions. This project, performed in partnership with the Department of Statistics at the University of Wisconsin-Madison, is broadly applicable to a variety of wildlife diseases, but is currently working on new statistical methods for predicting virus isolation of avian influenzas.
Minor Spillover of Avian Influenza Between Wild and Domestic Birds
In another study, NWHC reserachers also analyzed the genomes of HPAIV that spread in the United States during 2014-2015 and resulted in over $3 billion in losses to the U.S. poultry industry. As infection and transmission of pathogens in wild birds are difficult to measure during a fast-moving outbreak, the NWHC used cutting-edge modeling techniques to analyze genetic similarity between HPAIVs infecting wild birds and poultry. Analyses indicated that even though the viruses likely evolved in Asia, they easily infected and spread among North American wild birds. The viruses were also able to spread between domestic and wild birds (i.e., spillover). However, the rate of spillover was minor, and the poultry outbreak persisted without need for ongoing transmission from wild birds. Techniques used in this study can also be used to examine transmission and adaptation of avian influenza within waterfowl populations and between waterfowl and poultry.
Avian Influenza Surveillance
The USGS National Wildlife Health Center is a member of the U.S. Interagency Steering Committee for Surveillance for Highly Pathogenic Avian Influenza in Wild Birds. The NWHC performs both passive and active surveillance for the detection and monitoring of avian influenza. Check out the Avian Influenza Surveillance page to learn more.
- Multimedia
Below are multimedia items related to avian influenza.
- Publications
Below are publications related to avian influenza.
Filter Total Items: 79Intercontinental spread of asian-origin H5N8 to North America through Beringia by migratory birds
Phylogenetic network analysis and understanding of waterfowl migration patterns suggest the Eurasian H5N8 clade 2.3.4.4 avian influenza virus emerged in late 2013 in China, spread in early 2014 to South Korea and Japan, and reached Siberia and Beringia by summer 2014 via migratory birds. Three genetically distinct subgroups emerged and subsequently spread along different flyways during fall 2014 iAuthorsDong-Hun Lee, Mia Kim Torchetti, Kevin Winker, Hon S. Ip, David E. Swayne, Chang-Seon SongThe dynamics of avian influenza in western Arctic snow geese: implications for annual and migratory infection patterns
Wild water birds are the natural reservoir for low-pathogenic avian influenza viruses (AIV). However, our ability to investigate the epizootiology of AIV in these migratory populations is challenging, and despite intensive worldwide surveillance, remains poorly understood. We conducted a cross-sectional, retrospective analysis in Pacific Flyway lesser snow geese Chen caerulescens to investigate AIAuthorsMichael D. Samuel, Jeffrey S. Hall, Justin D. Brown, Diana R. Goldberg, Hon S. Ip, Vasily V. BaranyukNovel H5 clade 2.3.4.4 reassortant (H5N1) virus from a green-winged teal in Washington, USA
Eurasian (EA)-origin H5N8 clade 2.3.4.4 avian influenza viruses were first detected in North America during December 2014. Subsequent reassortment with North American (AM) low-pathogenic wild-bird-origin avian influenza has generated at least two reassortants, including an EA/AM H5N1 from an apparently healthy wild green-winged teal, suggesting continued ongoing reassortment.AuthorsMia Kim Torchetti, Mary-Lea Killian, Robert J. Dusek, Janice C. Pedersen, Nichole Hines, Barbara L. Bodenstein, C. LeAnn White, Hon S. IpNovel Eurasian highly pathogenic avian influenza A H5 viruses in wild birds, Washington, USA, 2014
Novel Eurasian lineage avian influenza A(H5N8) virus has spread rapidly and globally since January 2014. In December 2014, H5N8 and reassortant H5N2 viruses were detected in wild birds in Washington, USA, and subsequently in backyard birds. When they infect commercial poultry, these highly pathogenic viruses pose substantial trade issues.AuthorsHon S. Ip, Mia Kim Torchetti, Rocio Crespo, Paul Kohrs, Paul DeBruyn, Kristin G. Mansfield, Timothy Baszler, Lyndon Badcoe, Barbara L. Bodenstein, Valerie I. Shearn-Bochsler, Mary L. Killian, Janice C. Pederson, Nichole Hines, Thomas Gidlewski, Thomas J. DeLiberto, Jonathan M. SleemanCyclic avian mass mortality in the northeastern United States is associated with a novel orthomyxovirus
Since 1998, cyclic mortality events in common eiders (Somateria mollissima), numbering in the hundreds to thousands of dead birds, have been documented along the coast of Cape Cod, Massachusetts, USA. Although longitudinal disease investigations have uncovered potential contributing factors responsible for these outbreaks, detecting a primary etiological agent has proven enigmatic. Here we identifAuthorsAndrew B. Allison, Jennifer R. Ballard, Robert B. Tesh, Justin D. Brown, Mark G. Ruder, M. Kevin Keel, Brandon A. Munk, Randall M. Mickley, Samantha E. J. Gibbs, Julie C. Ellis, Amelia P.A. Travassos da Rosac, Hon S. Ip, Valerie I. Shearn-Bochsler, Matthew B. Rogers, Elodie Gheldin, Edward C. Holmes, Colin R. Parrish, Chris P. DwyerEvidence for seasonal patterns in the relative abundance of avian influenza virus subtypes in blue-winged teal (Anas discors)
Seasonal dynamics of influenza A viruses (IAVs) are driven by host density and population immunity. Through an analysis of subtypic data for IAVs isolated from Blue-winged Teal (Anas discors), we present evidence for seasonal patterns in the relative abundance of viral subtypes in spring and summer/autumn.AuthorsAndrew M. Ramey, Rebecca L. Poulson, Ana S. González-Reiche, Benjamin R. Wilcox, Patrick Walther, Paul Link, Deborah L. Carter, George M. Newsome, Maria L. Müller, Roy D. Berghaus, Daniel R. Perez, Jeffrey S. Hall, David E. StallknechtAvian influenza virus ecology in Iceland shorebirds: intercontinental reassortment and movement
Shorebirds are a primary reservoir of avian influenza viruses (AIV). We conducted surveillance studies in Iceland shorebird populations for 3 years, documenting high serological evidence of AIV exposure in shorebirds, primarily in Ruddy Turnstones (Arenaria interpres; seroprevalence = 75%). However, little evidence of virus infection was found in these shorebird populations and only two turnstoneAuthorsJeffrey S. Hall, Gunnar Thor Hallgrimsson, Kamol Suwannanarn, Srinand Sreevatsen, Hon S. Ip, Joshua L. TeSlaa, Sean W. Nashold, Robert J. DusekRespiratory transmission of an avian H3N8 influenza virus isolated from a harbour seal
The ongoing human H7N9 influenza infections highlight the threat of emerging avian influenza viruses. In 2011, an avian H3N8 influenza virus isolated from moribund New England harbour seals was shown to have naturally acquired mutations known to increase the transmissibility of highly pathogenic H5N1 influenza viruses. To elucidate the potential human health threat, here we evaluate a panel of aviAuthorsErik A. Karlsson, Hon S. Ip, Jeffrey S. Hall, Sun W. Yoon, Jordan Johnson, Melinda A. Beck, Richard J. Webby, Stacey Schultz-CherryAvian influenza virus antibodies in Pacific Coast Red Knots (Calidris canutus rufa)
Prevalence of avian influenza virus (AIV) antibodies in the western Atlantic subspecies of Red Knot (Calidris canutus rufa) is among the highest for any shorebird. To assess whether the frequency of detection of AIV antibodies is high for the species in general or restricted only to C. c. rufa, we sampled the northeastern Pacific Coast subspecies of Red Knot (Calidris canutus roselaari) breeding iAuthorsJames A. Johnson, Lucas H. DeCicco, Daniel R. Ruthrauff, Scott Krauss, Jeffrey S. HallNorth Atlantic migratory bird flyways provide routes for intercontinental movement of avian influenza viruses
Avian influenza virus (AIV) in wild birds has been of increasing interest over the last decade due to the emergence of AIVs that cause significant disease and mortality in both poultry and humans. While research clearly demonstrates that AIVs can move across the Pacific or Atlantic Ocean, there has been no data to support the mechanism of how this occurs. In spring and autumn of 2010 and autumn ofAuthorsRobert J. Dusek, Gunnar T. Hallgrimsson, Hon S. Ip, Jón E. Jónsson, Srinand Sreevatsan, Sean W. Nashold, Joshua L. TeSlaa, Shinichiro Enomoto, Rebecca A. Halpin, Xudong Lin, Nadia Federova, Timothy B. Stockwell, Vivien G. Dugan, David E. Wentworth, Jeffrey S. HallSampling strategies and biodiversity of influenza A subtypes in wild birds
Wild aquatic birds are recognized as the natural reservoir of avian influenza A viruses (AIV), but across high and low pathogenic AIV strains, scientists have yet to rigorously identify most competent hosts for the various subtypes. We examined 11,870 GenBank records to provide a baseline inventory and insight into patterns of global AIV subtype diversity and richness. Further, we conducted an extAuthorsSarah H. Olson, Jane Parmley, Catherine Soos, Martin Gilbert, Neus Latore-Margalef, Jeffrey S. Hall, Phillip M. Hansbro, Frank Leighton, Vincent Munster, Damien JolyGenomic analysis of avian influenza viruses from waterfowl in Western Alaska, USA
The Yukon-Kuskokwim Delta (Y-K Delta) in western Alaska is an immense and important breeding ground for waterfowl. Migratory birds from the Pacific Americas, Central Pacific, and East Asian-Australasian flyways converge in this region, providing opportunities for intermixing of North American- and Eurasian-origin hosts and infectious agents, such as avian influenza virus (AIV). We characterized thAuthorsAndrew B. Reeves, John M. Pearce, Andrew M. Ramey, Craig R. Ely, Joel A. Schmutz, Paul L. Flint, Dirk V. Derksen, Hon S. Ip, Kimberly A. Trust - News
Below are news stories related to avian influenza.
- FAQ
Below are FAQs related to avian influenza.
What is Avian Influenza?
Avian influenza (AI) is caused by an influenza type A virus that can infect poultry such as chickens, turkeys, pheasants, quail, domestic ducks, geese, and guinea fowl. It is carried by wild waterfowl (ducks and geese) and shorebirds. Learn more: USGS Avian Influenza
- Partners
Below are partners associated with avian influenza projects.