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 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
Sources/Usage: Public Domain.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.
Sources/Usage: Public Domain.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
- News
- 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...