The Avian Influenza Transmission Risk Model web application depicts the intricate connections between 16 layers of administrative, environmental, and economic data in an application that runs inside a web browser. To view and manipulate the full web application, please visit http://www.pwrc.usgs.gov/ai.
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 produce disease in chickens: highly pathogenic avian influenza (HPAI) or low pathogenic avian influenza (LPAI).
- HPAI viruses cause high mortality in poultry and occasionally high death rates in certain species of wild birds.
- LPAI viruses can cause a variety of outcomes in poultry ranging from no apparent clinical signs to moderate death rates. LPAI viruses usually cause little to no signs in wild birds.
H5 and H7 LPAI viruses have the potential to mutate or evolve into HPAI viruses and are closely monitored by animal health officials.
Learn more: USGS Avian Influenza
Related Content
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
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...
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...
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...
What is chronic wasting disease?
Chronic wasting disease (CWD) is a fatal, neurological illness occurring in North American cervids (members of the deer family), including white-tailed deer, mule deer, elk, and moose. Since its discovery in 1967, CWD has spread geographically and increased in prevalence locally. CWD is contagious; it can be transmitted freely within and among cervid populations. No treatments or vaccines are...
What is White-nose Syndrome?
White-nose syndrome is an emergent disease of hibernating bats that has spread from the northeastern to the central United States at an alarming rate. Since the winter of 2007-2008, millions of insect-eating bats in at least 40 states and eight Canadian provinces have died from this devastating disease. The disease is named for the white fungus, Pseudogymnoascus destructans , that infects skin of...
Does White-nose Syndrome pose a risk to human health?
Thousands of people have visited affected caves and mines since White-nose Syndrome (WNS) was first observed, and there have been no reported human illnesses attributable to WNS. We are still learning about WNS, but we know of no risk to humans from contact with WNS-affected bats. However, we urge taking precautions and not exposing yourself to WNS. Biologists and researchers use protective...
Avian Influenza Transmission Risk Model Web Application Virtual Tour
The Avian Influenza Transmission Risk Model web application depicts the intricate connections between 16 layers of administrative, environmental, and economic data in an application that runs inside a web browser. To view and manipulate the full web application, please visit http://www.pwrc.usgs.gov/ai.
Kenai River during the personal use dipnet fishery for sockeye salmon.
Gulls using beach at the mouth of Kenai River during the personal use dipnet fishery for sockeye salmon; photo taken during sampling trip in July 2016.
Gulls using beach at the mouth of Kenai River during the personal use dipnet fishery for sockeye salmon; photo taken during sampling trip in July 2016.
Blue-winged teal in Texas. Inset shows avian influenza virus
Blue-winged teal in Texas. Inset shows avian influenza virus
Blue-winged teal in Texas. Inset shows avian influenza virus
Sampling Forster’s Tern Chicks for Avian Influenza Study
Scientists sampling Forster's Tern chicks for avain influenza during salt pond restoration work in south San Francisco Bay salt ponds.
Scientists sampling Forster's Tern chicks for avain influenza during salt pond restoration work in south San Francisco Bay salt ponds.
What are the differences between low pathogenic and highly pathogenic avian influenza viruses and how are influenza viruses grouped?
linkListen to hear the answer.
Testing for Avian Influenza
A USGS scientist takes a sample from a northern pintail duck (Anas acuta) to be tested for avian influenza.
A USGS scientist takes a sample from a northern pintail duck (Anas acuta) to be tested for avian influenza.
Related Content
- FAQ
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
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...
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...
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...
What is chronic wasting disease?
Chronic wasting disease (CWD) is a fatal, neurological illness occurring in North American cervids (members of the deer family), including white-tailed deer, mule deer, elk, and moose. Since its discovery in 1967, CWD has spread geographically and increased in prevalence locally. CWD is contagious; it can be transmitted freely within and among cervid populations. No treatments or vaccines are...
What is White-nose Syndrome?
White-nose syndrome is an emergent disease of hibernating bats that has spread from the northeastern to the central United States at an alarming rate. Since the winter of 2007-2008, millions of insect-eating bats in at least 40 states and eight Canadian provinces have died from this devastating disease. The disease is named for the white fungus, Pseudogymnoascus destructans , that infects skin of...
Does White-nose Syndrome pose a risk to human health?
Thousands of people have visited affected caves and mines since White-nose Syndrome (WNS) was first observed, and there have been no reported human illnesses attributable to WNS. We are still learning about WNS, but we know of no risk to humans from contact with WNS-affected bats. However, we urge taking precautions and not exposing yourself to WNS. Biologists and researchers use protective...
- Multimedia
Avian Influenza Transmission Risk Model Web Application Virtual Tour
The Avian Influenza Transmission Risk Model web application depicts the intricate connections between 16 layers of administrative, environmental, and economic data in an application that runs inside a web browser. To view and manipulate the full web application, please visit http://www.pwrc.usgs.gov/ai.
The Avian Influenza Transmission Risk Model web application depicts the intricate connections between 16 layers of administrative, environmental, and economic data in an application that runs inside a web browser. To view and manipulate the full web application, please visit http://www.pwrc.usgs.gov/ai.
Kenai River during the personal use dipnet fishery for sockeye salmon.Gulls using beach at the mouth of Kenai River during the personal use dipnet fishery for sockeye salmon; photo taken during sampling trip in July 2016.
Gulls using beach at the mouth of Kenai River during the personal use dipnet fishery for sockeye salmon; photo taken during sampling trip in July 2016.
Blue-winged teal in Texas. Inset shows avian influenza virusBlue-winged teal in Texas. Inset shows avian influenza virus
Blue-winged teal in Texas. Inset shows avian influenza virus
Sampling Forster’s Tern Chicks for Avian Influenza StudyScientists sampling Forster's Tern chicks for avain influenza during salt pond restoration work in south San Francisco Bay salt ponds.
Scientists sampling Forster's Tern chicks for avain influenza during salt pond restoration work in south San Francisco Bay salt ponds.
What are the differences between low pathogenic and highly pathogenic avian influenza viruses and how are influenza viruses grouped?What are the differences between low pathogenic and highly pathogenic avian influenza viruses and how are influenza viruses grouped?
linkListen to hear the answer.
Testing for Avian InfluenzaA USGS scientist takes a sample from a northern pintail duck (Anas acuta) to be tested for avian influenza.
A USGS scientist takes a sample from a northern pintail duck (Anas acuta) to be tested for avian influenza.
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