The USGS National Wildlife Health Center (NWHC) conducts surveillance in wild birds to facilitate early detection and situational awareness for high consequence pathogens, including highly pathogenic avian influenza (HPAI) viruses.
Investigating Avian Influenza in U.S. Wildlife
In addition to investigating wildlife mortality events since our founding in the 1970s, the NWHC conducts research to better understand processes and environmental factors that influence spread, distribution, and transmission of HPAI in wild birds and poultry. Surveillance activities conducted by NWHC, in support of national HPAI surveillance objectives, provide critical information regarding avian influenza strains currently circulating in the U.S. and enhance our understanding of disease impacts on wild birds. Wild bird surveillance also provides early warning for the agricultural sector and helps inform the need for increased biosecurity at poultry facilities.
The NWHC routinely tests samples from wild birds for avian influenza viruses. In December 2014, the NWHC detected HPAI viruses of Asian origin in wild waterfowl in the state of Washington (Ip et al. 2015). By the end of 2015, losses associated with this HPAI outbreak exceeded 50 million poultry, resulting in over $3 billion dollars in economic impacts.
Between 2016 and 2021, the NWHC tested over 3,400 wild-bird carcasses and over 12,400 swab samples from healthy wild birds for the presence of avian influenza viruses. While HPAI was not detected in any of these samples, over 2,600 low pathogenicity avian influenza viruses were identified and characterized, providing critical information to wildlife and agricultural officials regarding the spatial distribution and strains of avian influenza viruses circulating in our nation’s wildlife.
HPAI Surveillance Update 2021-22
Highly pathogenic avian influenza has been detected in North American wild birds for the first time since 2015. Initial detections occurred in Canada (Newfoundland and Labrador) and the United States (South Carolina) in December 2021. Additional detections in the United States are reported online by the U.S. Department of Agriculture and a map of confirmed detections in North America is available from the NWHC.
Interagency Partnerships
The NWHC serves on the U.S. Interagency Steering Committee for Surveillance for Highly Pathogenic Avian Influenza in Wild Birds and conducts morbidity and mortality event investigations in support of the Interagency Strategic Plan for Early Detection and Monitoring for Avian Influenzas of Significance in Wild Birds. The NWHC also serves as an affiliate member of the National Animal Health Laboratory Network (NAHLN) and collaborates with the U.S. Department of Agriculture's National Veterinary Services Laboratory on diagnostic testing of samples collected from wild birds for avian influenza surveillance.
Additional Resources
- Distribution of Highly Pathogenic Avian Influenza in North America, 2021/2022 (Map)
- Avian influenza (USDA)
- Information on Avian Influenza (CDC)
- Implementation Plan for Avian Influenza Surveillance in Waterfowl in the United States
- NWHC Wildlife Health Bulletins
- Status and Response to Detections of Highly Pathogenic Avian Influenza H5N1 in North America – February 2022
- Detection of Highly Pathogenic Avian Influenza H5N1 in an Exhibition Farm in Newfoundland and Labrador, Canada - December 2021
- Winter 2021 Update on Highly Pathogenic Avian Influenza Viruses Circulating Globally in Wild Birds - December 2021
More Information on Avian Influenza
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), which refers to a specific virus’ capability to cause mortality in domestic poultry. It remains a high consequence global disease with the potential to threaten wildlife, agriculture, and human health. Check out the main Avian Influenza page to learn more.
Learn about other NWHC work on avian influenza.
Avian Influenza
Below are publications related to avian influenza surveillance.
Global dissemination of Influenza A virus is driven by wild bird migration through arctic and subarctic zones
Spatiotemporal changes in influenza A virus prevalence among wild waterfowl inhabiting the continental United States throughout the annual cycle
Maintenance and dissemination of avian-origin influenza A virus within the northern Atlantic Flyway of North America
Ecological divergence of wild birds drives avian influenza spillover and global spread
Highly pathogenic avian influenza is an emerging disease threat to wild birds in North America
Highly pathogenic avian influenza virus H5N2 (Clade 2.3.4.4) challenge of mallards age appropriate to the 2015 midwestern poultry outbreak
Genesis and spread of multiple reassortants during the 2016/2017 H5 avian influenza epidemic in Eurasia
Serosurvey of coyotes (Canis latrans), foxes (Vulpes vulpes, Urocyon cinereoargenteus) and raccoons (Procyon lotor) for exposure to influenza A viruses in the USA
Avian influenza virus prevalence in marine birds is dependent on ocean temperatures
Artificial intelligence and avian influenza: Using machine learning to enhance active surveillance for avian influenza viruses
Aerosol transmission of gull-origin Iceland subtype H10N7 influenza A virus in ferrets
Predicting the initial spread of novel Asian origin influenza A viruses in the continental USA by wild waterfowl
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
How do scientists study avian influenza in wild birds?
To learn more about the impacts of avian influenza on wild birds and the role wild birds may play in the spread of the virus, experts from government agencies have gathered samples from hundreds of thousands of live-captured, apparently healthy wild birds, hunter-harvested birds, and dead wild birds of all species. Testing methods include analyses of fecal samples and swabs of the bird’s trachea...
How is avian influenza spread?
State and federal government experts continue to evaluate how Highly Pathogenic Avian Influenza (HPAI) viruses can spread and impact wild and domestic birds. The global spread of HPAI subtype H5N8 has been driven in large part by migratory waterfowl. Knowledge about migratory patterns and intercontinental associations of waterfowl, as well as genetic analyses of viral strains support the...
Can people get avian influenza?
While rare, human infections with avian influenza viruses have occurred. The Centers for Disease Control and Prevention considers the risk to the general public from HPAI H5 infections in wild birds, backyard flocks, and commercial poultry, to be low. To date, no humans or other mammals have shown signs of disease from the HPAI viruses found in North America but field personnel handling live or...
Can wild birds spread avian influenza to domestic poultry?
Although it is possible for domestic poultry to become infected with avian influenza from direct contact with wild birds, it is more likely that avian influenza viruses are spread indirectly to poultry on contaminated feed, clothing, and equipment. Agricultural agencies encourage producers to prevent wild birds and other wildlife from coming into direct contact with their poultry, and to avoid...
What are the different types of avian influenza?
Avian Influenza (AI) type A viruses are divided into subtypes based on two proteins on the surface of the virus: Hemagglutinin (HA), of which there are 16 subtypes (H1-H16) Neuraminidase (NA), of which there are 9 subtypes (N1-N9) Many combinations of HA and NA proteins are possible (i.e., H5N1, H5N2, H7N2, H7N8, etc). AI viruses are also classified into two groups based on their ability to...
What is the difference between low pathogenic and highly pathogenic avian influenza?
The designation of low or highly pathogenic avian influenza refers to the potential for these viruses to kill chickens. The designation of “low pathogenic” or “highly pathogenic” does not refer to how infectious the viruses may be to humans, other mammals, or other species of birds. Most strains of avian influenza are not highly pathogenic and cause few signs of disease in infected wild birds...
What is the meaning of the numbers next to the “H” and “N” in avian influenza designations?
Avian influenza (AI) viruses are classified by a combination of two groups of proteins: hemagglutinin or “H” proteins, of which there are 16 (H1 to H16), and neuraminidase or “N” proteins, of which there are nine (N1 to N9). Many different combinations of “H” and “N” proteins are possible. Each combination is considered a different subtype and can be further broken down into different strains. AI...
- Overview
The USGS National Wildlife Health Center (NWHC) conducts surveillance in wild birds to facilitate early detection and situational awareness for high consequence pathogens, including highly pathogenic avian influenza (HPAI) viruses.
Investigating Avian Influenza in U.S. Wildlife
USGS biologists swab a hen mallard duck for avian influenza in Rio Grande County, Colorado. In addition to investigating wildlife mortality events since our founding in the 1970s, the NWHC conducts research to better understand processes and environmental factors that influence spread, distribution, and transmission of HPAI in wild birds and poultry. Surveillance activities conducted by NWHC, in support of national HPAI surveillance objectives, provide critical information regarding avian influenza strains currently circulating in the U.S. and enhance our understanding of disease impacts on wild birds. Wild bird surveillance also provides early warning for the agricultural sector and helps inform the need for increased biosecurity at poultry facilities.
The NWHC routinely tests samples from wild birds for avian influenza viruses. In December 2014, the NWHC detected HPAI viruses of Asian origin in wild waterfowl in the state of Washington (Ip et al. 2015). By the end of 2015, losses associated with this HPAI outbreak exceeded 50 million poultry, resulting in over $3 billion dollars in economic impacts.
Between 2016 and 2021, the NWHC tested over 3,400 wild-bird carcasses and over 12,400 swab samples from healthy wild birds for the presence of avian influenza viruses. While HPAI was not detected in any of these samples, over 2,600 low pathogenicity avian influenza viruses were identified and characterized, providing critical information to wildlife and agricultural officials regarding the spatial distribution and strains of avian influenza viruses circulating in our nation’s wildlife.
Distribution of Highly Pathogenic Avian Influenza H5 and H5N1 in North America, 2021/2022. Updated October 16, 2022. HPAI Surveillance Update 2021-22
Highly pathogenic avian influenza has been detected in North American wild birds for the first time since 2015. Initial detections occurred in Canada (Newfoundland and Labrador) and the United States (South Carolina) in December 2021. Additional detections in the United States are reported online by the U.S. Department of Agriculture and a map of confirmed detections in North America is available from the NWHC.
Interagency Partnerships
The NWHC serves on the U.S. Interagency Steering Committee for Surveillance for Highly Pathogenic Avian Influenza in Wild Birds and conducts morbidity and mortality event investigations in support of the Interagency Strategic Plan for Early Detection and Monitoring for Avian Influenzas of Significance in Wild Birds. The NWHC also serves as an affiliate member of the National Animal Health Laboratory Network (NAHLN) and collaborates with the U.S. Department of Agriculture's National Veterinary Services Laboratory on diagnostic testing of samples collected from wild birds for avian influenza surveillance.
Additional Resources
- Distribution of Highly Pathogenic Avian Influenza in North America, 2021/2022 (Map)
- Avian influenza (USDA)
- Information on Avian Influenza (CDC)
- Implementation Plan for Avian Influenza Surveillance in Waterfowl in the United States
- NWHC Wildlife Health Bulletins
- Status and Response to Detections of Highly Pathogenic Avian Influenza H5N1 in North America – February 2022
- Detection of Highly Pathogenic Avian Influenza H5N1 in an Exhibition Farm in Newfoundland and Labrador, Canada - December 2021
- Winter 2021 Update on Highly Pathogenic Avian Influenza Viruses Circulating Globally in Wild Birds - December 2021
More Information on Avian Influenza
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), which refers to a specific virus’ capability to cause mortality in domestic poultry. It remains a high consequence global disease with the potential to threaten wildlife, agriculture, and human health. Check out the main Avian Influenza page to learn more.
- Science
Learn about other NWHC work on avian influenza.
Avian Influenza
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. - Multimedia
- Publications
Below are publications related to avian influenza surveillance.
Filter Total Items: 43Global dissemination of Influenza A virus is driven by wild bird migration through arctic and subarctic zones
Influenza A viruses (IAV) circulate endemically among many wild aquatic bird populations that seasonally migrate between wintering grounds in southern latitudes to breeding ranges along the perimeter of the circumpolar arctic. Arctic and subarctic zones are hypothesized to serve as ecologic drivers of the intercontinental movement and reassortment of IAVs due to high densities of disparate populatAuthorsJonathan D. Jr. Gass, Robert J. Dusek, Jeffrey S. Hall, Gunnar Thor Hallgrimsson, Halldór Pálmar Halldórsson, Solvi Runar Vignisson, Sunna Bjork Ragnarsdottir, Jón Einar Jónsson, Scott Krauss, Wong. Sook-San, Xiu-Feng Wan, Sadia Akter, Srinand Sreevatsan, Nidia S. Trovão, Felicia B. Nutter, Jonathan A. Runstadler, Nichola J. HillSpatiotemporal changes in influenza A virus prevalence among wild waterfowl inhabiting the continental United States throughout the annual cycle
Avian influenza viruses can pose serious risks to agricultural production, human health, and wildlife. An understanding of viruses in wild reservoir species across time and space is important to informing surveillance programs, risk models, and potential population impacts for vulnerable species. Although it is recognized that influenza A virus prevalence peaks in reservoir waterfowl in late summeAuthorsCody M. Kent, Andrew M. Ramey, Josh T. Ackerman, Justin Bahl, Sarah N. Bevins, Andrew S. Bowman, Walter Boyce, Carol Cardona, Michael L. Casazza, Troy D. Cline, Susan E. W. De La Cruz, Jeffrey S. Hall, Nichola J. Hill, Hon S. Ip, Scott Krauss, Jennifer M. Mullinax, Jacqueline M. Nolting, Magdalena Plancarte, Rebecca L. Poulson, Jonathan A. Runstadler, Richard D. Slemons, David E. Stallknecht, Jeffery D. Sullivan, John Y. Takekawa, Richard J. Webby, Robert G. Webster, Diann J. ProsserMaintenance and dissemination of avian-origin influenza A virus within the northern Atlantic Flyway of North America
Wild waterbirds, the natural reservoirs for avian influenza viruses, undergo migratory movements each year, connecting breeding and wintering grounds within broad corridors known as flyways. In a continental or global view, the study of virus movements within and across flyways is important to understanding virus diversity, evolution, and movement. From 2015 to 2017, we sampled waterfowl from breeAuthorsDiann Prosser, Jiani Chen, Christina Ahlstrom, Andrew B. Reeves, Rebecca L. Poulson, Jeffery D. Sullivan, Daniel McAuley, Carl R. Callahan, Peter C. McGowan, Justin Bahl, David E. Stallknecht, Andrew M. RameyEcological divergence of wild birds drives avian influenza spillover and global spread
The diversity of influenza A viruses (IAV) is primarily hosted by two highly divergent avian orders: Anseriformes (ducks, swans and geese) and Charadriiformes (gulls, terns and shorebirds). Studies of IAV have historically focused on Anseriformes, specifically dabbling ducks, overlooking the diversity of hosts in nature, including gull and goose species that have successfully adapted to human habiAuthorsNichola J. Hill, Mary Anne Bishop, Nidia S. Trovao, Katherine Ineson, Anne Schaefer, Wendy B. Puryear, Katherine Zhou, Alexa Foss, Dan Clark, Ken McKenzie, Jonathan D. Jr. Gass, Laura Borkenhagen, Jeffrey S. Hall, Jonathan A. RunstadlerHighly pathogenic avian influenza is an emerging disease threat to wild birds in North America
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 typicallAuthorsAndrew M. Ramey, Nichola J. Hill, Thomas J. DeLiberto, Samantha E. J. Gibbs, M. Camille Hopkins, Andrew S. Lang, Rebecca L. Poulson, Diann Prosser, Jonathan M. Sleeman, David E. Stallknecht, Xiu-Feng WanHighly pathogenic avian influenza virus H5N2 (Clade 2.3.4.4) challenge of mallards age appropriate to the 2015 midwestern poultry outbreak
BackgroundThe 2015 highly pathogenic avian influenza virus (HPAIV) H5N2 clade 2.3.4.4 outbreak in upper midwestern U.S. poultry operations was not detected in wild birds to any great degree during the outbreak, despite wild waterfowl being implicated in the introduction, reassortment, and movement of the virus into North America from Asia. This outbreak led to the demise of over 50 million domestiAuthorsJeffrey S. Hall, Daniel A. Grear, Scott Krauss, Patrick Seiler, Robert J. Dusek, Sean Nashold, Robert G. WebsterGenesis and spread of multiple reassortants during the 2016/2017 H5 avian influenza epidemic in Eurasia
Highly pathogenic avian influenza (HPAI) viruses of the H5 A/goose/Guangdong/1/96 lineage can cause severe disease in poultry and wild birds, and occasionally in humans. In recent years, H5 HPAI viruses of this lineage infecting poultry in Asia have spilled over into wild birds and spread via bird migration to countries in Europe, Africa, and North America. In 2016/2017, this spillover resulted inAuthorsSamantha Lycett, Anne Pohlmann, Christoph Staubach, Valentina Caliendo, Mark Woolhouse, Martin Beer, Thijs Kuiken, Steven van Borm, Andrew Breed, Francois-Xavier Briand, Ian Brown, Adam Dan, Thomas J. DeLiberto, Sophie von Dobschuetz, Ron A. M. Fouchier, Marius Gilbert, Sarah Hill, Charlotte Kristiane Hjulsager, Hon S. Ip, Marion Koopmans, Lars Erik Larsen, Dong-Hun Lee, Mahmoud Mohamed Naguib, I. Monne, Oliver Pybus, Andrew M. Ramey, Vladmir Savic, Kirill Sharshov, Alexander Shestopalov, Chang-Seon Song, Mieke Steensels, David Swayne, Edyta Swieton, Xiu-Feng Wan, Siamak ZohariSerosurvey of coyotes (Canis latrans), foxes (Vulpes vulpes, Urocyon cinereoargenteus) and raccoons (Procyon lotor) for exposure to influenza A viruses in the USA
We tested coyote (Canis latrans), fox (Urocyon cinereoargenteus, Vulpes vulpes), and raccoon (Procyon lotor) sera for influenza A virus (IAV) exposure. We found 2/139 samples (1 coyote, 1 raccoon) had IAV antibodies and hemagglutination inhibition assays revealed the antibodies to the 2009/2010 H1N1 human pandemic virus or to the 2007 human seasonal H1N1 virus.AuthorsMarit A. Bakken, Sean Nashold, Jeffrey S. HallAvian influenza virus prevalence in marine birds is dependent on ocean temperatures
Waterfowl and shorebirds are the primary hosts of influenza A virus (IAV), however, in most surveillance efforts, large populations of birds are not routinely examined; specifically marine ducks and other birds that reside predominately on or near the ocean. We conducted a long-term study sampling sea ducks and gulls in coastal Maine for IAV and found a virus prevalence (1.7%) much lower than is tAuthorsJeffrey S. Hall, Robert J. Dusek, Sean Nashold, Joshua L. TeSlaa, Bradford R. Allen, Daniel A. GrearArtificial intelligence and avian influenza: Using machine learning to enhance active surveillance for avian influenza viruses
Influenza A viruses are one of the most significant viral groups globally with substantial impacts on human, domestic animal and wildlife health. Wild birds are the natural reservoirs for these viruses, and active surveillance within wild bird populations provides critical information about viral evolution forming the basis of risk assessments and countermeasure development. Unfortunately, activeAuthorsDaniel P. Walsh, Ting Fung Ma, Hon S. Ip, Jun ZhuAerosol transmission of gull-origin Iceland subtype H10N7 influenza A virus in ferrets
Subtype H10 influenza A viruses (IAVs) have been recovered from domestic poultry and various aquatic bird species, and sporadic transmission of these IAVs from avian species to mammals (i.e., human, seal, and mink) are well documented. In 2015, we isolated four H10N7 viruses from gulls in Iceland. Genomic analyses showed four gene segments in the viruses were genetically associated with H10 IAVs tAuthorsMinhui Guan, Jeffrey S. Hall, Xiaojian Zhang, Robert J. Dusek, Alicia K. Olivier, Liyuan Liu, Lei Li, Scott Krauss, Angea Danner, Tao Li, Wiriya Rutvisuttinunt, Xiaoxu Lin, Gunnar T. Hallgrimsson, Sunna B. Ragnarsdottir, Solvi R. Vignisson, Josh TeSlaa, Sean Nashold, Richard Jarman, Xiu-Feng WanPredicting the initial spread of novel Asian origin influenza A viruses in the continental USA by wild waterfowl
Using data on waterfowl band recoveries, we identified spatially explicit hotspots of concentrated waterfowl movement to predict occurrence and spatial spread of a novel influenza A virus (clade 2.3.4.4) introduced from Asia by waterfowl from an initial outbreak in North America in November 2014. In response to the outbreak, the hotspots of waterfowl movement were used to help guide sampling for cAuthorsAlan B. Franklin, Sarah N. Bevins, Jeremy W. Ellis, Ryan S. Miller, Susan A. Shriner, J. Jeffrey Root, Daniel P. Walsh, Thomas J. DeLiberto - 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
How do scientists study avian influenza in wild birds?
To learn more about the impacts of avian influenza on wild birds and the role wild birds may play in the spread of the virus, experts from government agencies have gathered samples from hundreds of thousands of live-captured, apparently healthy wild birds, hunter-harvested birds, and dead wild birds of all species. Testing methods include analyses of fecal samples and swabs of the bird’s trachea...
How is avian influenza spread?
State and federal government experts continue to evaluate how Highly Pathogenic Avian Influenza (HPAI) viruses can spread and impact wild and domestic birds. The global spread of HPAI subtype H5N8 has been driven in large part by migratory waterfowl. Knowledge about migratory patterns and intercontinental associations of waterfowl, as well as genetic analyses of viral strains support the...
Can people get avian influenza?
While rare, human infections with avian influenza viruses have occurred. The Centers for Disease Control and Prevention considers the risk to the general public from HPAI H5 infections in wild birds, backyard flocks, and commercial poultry, to be low. To date, no humans or other mammals have shown signs of disease from the HPAI viruses found in North America but field personnel handling live or...
Can wild birds spread avian influenza to domestic poultry?
Although it is possible for domestic poultry to become infected with avian influenza from direct contact with wild birds, it is more likely that avian influenza viruses are spread indirectly to poultry on contaminated feed, clothing, and equipment. Agricultural agencies encourage producers to prevent wild birds and other wildlife from coming into direct contact with their poultry, and to avoid...
What are the different types of avian influenza?
Avian Influenza (AI) type A viruses are divided into subtypes based on two proteins on the surface of the virus: Hemagglutinin (HA), of which there are 16 subtypes (H1-H16) Neuraminidase (NA), of which there are 9 subtypes (N1-N9) Many combinations of HA and NA proteins are possible (i.e., H5N1, H5N2, H7N2, H7N8, etc). AI viruses are also classified into two groups based on their ability to...
What is the difference between low pathogenic and highly pathogenic avian influenza?
The designation of low or highly pathogenic avian influenza refers to the potential for these viruses to kill chickens. The designation of “low pathogenic” or “highly pathogenic” does not refer to how infectious the viruses may be to humans, other mammals, or other species of birds. Most strains of avian influenza are not highly pathogenic and cause few signs of disease in infected wild birds...
What is the meaning of the numbers next to the “H” and “N” in avian influenza designations?
Avian influenza (AI) viruses are classified by a combination of two groups of proteins: hemagglutinin or “H” proteins, of which there are 16 (H1 to H16), and neuraminidase or “N” proteins, of which there are nine (N1 to N9). Many different combinations of “H” and “N” proteins are possible. Each combination is considered a different subtype and can be further broken down into different strains. AI...