Wings of Change: The Environment's Influence on Bird Flu
The Transport of Avian Influenza in Aquatic Environments
Low pathogenic avian influenza (LPAI) viruses naturally occur in wild birds and are rarely fatal. Highly pathogenic avian influenza (HPAI) viruses are highly contagious, spread rapidly, are often fatal to poultry, and have been responsible for worldwide outbreaks. Together, LPAI and HPAI are generally referred to as either avian influenza viruses (AIVs) or "the bird flu."
Current Outbreak
The current U.S. bird flu outbreak (HPAI H5N1) began in late December 2021 and has become the longest-recorded outbreak in the U.S., responsible for the loss of over 150 million poultry (USDA, 2024). This outbreak has killed more wild birds than ever before, including species of value such as bald eagles and California condors, and has also spread to dairy cattle and multiple mammalian species, including humans.
Overview
Birds can shed AIV in their feces, which can end up in surface water. This can lead to transmission of AIV through animals via a fecal-oral route. USGS leads research and monitoring of AIVs in the aquatic environment. Collaborating with Federal and university partners, the USGS is working to improve AIV early detection and exploring measures that reduce spread into domestic poultry, dairy cattle, and other livestock and potential occupational or recreational exposure to humans.
- Understanding environmental sources, reservoirs, and transport pathways of infectious viruses is critical to informing biosecurity practices and maintaining a healthy food supply.
- Environmental sampling for HPAI can provide early warning information for livestock production, neighboring farms, hobby farmers with backyard flocks, and zoos and bird reserves.
Current Research
USGS scientists are working to answer important questions to help maintain a healthy food supply such as:
- What is the environment's (water, manure, sediment, air, and animal vectors) role in presence, transmission, and persistence of infectious AIVs?
- What mitigation is necessary to reduce the spread of disease into domestic poultry and potentially to other terrestrial animals?
- What does detecting infectious low pathogenic AIV in water mean for HPAI risk?
- How does temperature and water chemistry influence virus survival?
- What practical ways are available to deactivate (or kill) the virus in the environment?
- What are the sources and transport of virus in the environment (water, manure, sediment, air, and animal vectors)?
- Can biosecurity practices limit environmental transport?
- Can we determine the presence and transmission potential of AIV in National Parks and if the threat of HPAI via contaminated water exists for species of concern, such as the Bald Eagle and California Condor?
This knowledge can inform farmers and public land managers and aid in minimizing the further spread of this viral outbreak.
Method Development
The USGS has been optimizing field and laboratory tools for detecting infectious AIV from surface water. USGS methods can:
- Detect and recover low levels of infectious AIV from surface water.
- Provide evidence that surface water can serve as a plausible medium for environmental transmission of AIVs among birds and mammals, including HPAI.
- Isolate AIV from water at relevant and potentially infectious concentrations.
AIV detected in Iowa Wetlands: An Example
The USGS documented the first detection of infectious HPAI in a U.S. waterbody. In April and May 2022, USGS scientists collected surface water from wetlands located near areas with confirmed HPAI detections in wild bird or poultry operations. Results indicated that all tested wetlands were positive for infectious AIVs, including one positive HPAI virus detection.
In the environment (in this case, water), infectious viruses have the potential to infect wildlife, livestock, and humans using these water resources. The infectious HPAI virus detected and recovered from these wetlands was the same strain found in migratory birds and other animals (including dairy cattle and humans) and continues to be of public, livestock, and wildlife health concern.
Future Directions
- Continue to investigate the importance and influence of the environment as a source, reservoir, and transport pathway for infectious AIV.
- Better understand how AIV in the environment is related to:
- Outbreaks affecting U.S. poultry production and backyard/hobby farms
- Outbreaks affected U.S. dairy cattle and the milk supply
- Species of value
- Migratory bird species
- Mammals, including humans
- Safety of waterbodies used for human recreation and economics for various agricultural industries
- Mitigation to reduce the spread of disease into domestic livestock and safeguard agricultural resources critical for food production and US water resources for human recreation.
Read More on How Avian Influenza Moves Through the Environment!
Development of a Large-Volume Concentration Method to Recover Infectious Avian Influenza Virus from the Aquatic Environment
Highlighting the complexities of a groundwater pilot study during an avian influenza outbreak: Methods, lessons learned, and select contaminant results
Influenza A viruses remain infectious for more than seven months in northern wetlands of North America
Evidence for interannual persistence of infectious influenza A viruses in Alaska wetlands
Infectivity of Wild-Bird Origin Influenza A Viruses in Minnesota Wetlands across Seasons
Low pathogenic avian influenza (LPAI) viruses naturally occur in wild birds and are rarely fatal. Highly pathogenic avian influenza (HPAI) viruses are highly contagious, spread rapidly, are often fatal to poultry, and have been responsible for worldwide outbreaks. Together, LPAI and HPAI are generally referred to as either avian influenza viruses (AIVs) or "the bird flu."
Current Outbreak
The current U.S. bird flu outbreak (HPAI H5N1) began in late December 2021 and has become the longest-recorded outbreak in the U.S., responsible for the loss of over 150 million poultry (USDA, 2024). This outbreak has killed more wild birds than ever before, including species of value such as bald eagles and California condors, and has also spread to dairy cattle and multiple mammalian species, including humans.
Overview
Birds can shed AIV in their feces, which can end up in surface water. This can lead to transmission of AIV through animals via a fecal-oral route. USGS leads research and monitoring of AIVs in the aquatic environment. Collaborating with Federal and university partners, the USGS is working to improve AIV early detection and exploring measures that reduce spread into domestic poultry, dairy cattle, and other livestock and potential occupational or recreational exposure to humans.
- Understanding environmental sources, reservoirs, and transport pathways of infectious viruses is critical to informing biosecurity practices and maintaining a healthy food supply.
- Environmental sampling for HPAI can provide early warning information for livestock production, neighboring farms, hobby farmers with backyard flocks, and zoos and bird reserves.
Current Research
USGS scientists are working to answer important questions to help maintain a healthy food supply such as:
- What is the environment's (water, manure, sediment, air, and animal vectors) role in presence, transmission, and persistence of infectious AIVs?
- What mitigation is necessary to reduce the spread of disease into domestic poultry and potentially to other terrestrial animals?
- What does detecting infectious low pathogenic AIV in water mean for HPAI risk?
- How does temperature and water chemistry influence virus survival?
- What practical ways are available to deactivate (or kill) the virus in the environment?
- What are the sources and transport of virus in the environment (water, manure, sediment, air, and animal vectors)?
- Can biosecurity practices limit environmental transport?
- Can we determine the presence and transmission potential of AIV in National Parks and if the threat of HPAI via contaminated water exists for species of concern, such as the Bald Eagle and California Condor?
This knowledge can inform farmers and public land managers and aid in minimizing the further spread of this viral outbreak.
Method Development
The USGS has been optimizing field and laboratory tools for detecting infectious AIV from surface water. USGS methods can:
- Detect and recover low levels of infectious AIV from surface water.
- Provide evidence that surface water can serve as a plausible medium for environmental transmission of AIVs among birds and mammals, including HPAI.
- Isolate AIV from water at relevant and potentially infectious concentrations.
AIV detected in Iowa Wetlands: An Example
The USGS documented the first detection of infectious HPAI in a U.S. waterbody. In April and May 2022, USGS scientists collected surface water from wetlands located near areas with confirmed HPAI detections in wild bird or poultry operations. Results indicated that all tested wetlands were positive for infectious AIVs, including one positive HPAI virus detection.
In the environment (in this case, water), infectious viruses have the potential to infect wildlife, livestock, and humans using these water resources. The infectious HPAI virus detected and recovered from these wetlands was the same strain found in migratory birds and other animals (including dairy cattle and humans) and continues to be of public, livestock, and wildlife health concern.
Future Directions
- Continue to investigate the importance and influence of the environment as a source, reservoir, and transport pathway for infectious AIV.
- Better understand how AIV in the environment is related to:
- Outbreaks affecting U.S. poultry production and backyard/hobby farms
- Outbreaks affected U.S. dairy cattle and the milk supply
- Species of value
- Migratory bird species
- Mammals, including humans
- Safety of waterbodies used for human recreation and economics for various agricultural industries
- Mitigation to reduce the spread of disease into domestic livestock and safeguard agricultural resources critical for food production and US water resources for human recreation.
Read More on How Avian Influenza Moves Through the Environment!
Development of a Large-Volume Concentration Method to Recover Infectious Avian Influenza Virus from the Aquatic Environment
Highlighting the complexities of a groundwater pilot study during an avian influenza outbreak: Methods, lessons learned, and select contaminant results
Influenza A viruses remain infectious for more than seven months in northern wetlands of North America
Evidence for interannual persistence of infectious influenza A viruses in Alaska wetlands
Infectivity of Wild-Bird Origin Influenza A Viruses in Minnesota Wetlands across Seasons
