Avian Influenza Alert: How to Reduce Wild Bird Risks on Poultry Farms
Madhusudan Timilsina DVM, MS, and Mostafa Ghanem DVM, MS, Ph.D., Department of Veterinary Medicine, University of Maryland
As migratory birds traverse North America twice a year traveling south in late summer through fall and returning north in late winter through spring, they pose a significant risk of introducing and spreading avian influenza (bird flu). Waterfowls, shorebirds, gulls, and terns are natural hosts of avian influenza viruses, with their nesting and stopover sites serving as key areas where new virus variants emerge. Among the four major migratory flyways, the Atlantic Flyway, which stretches along the eastern coast of North and South America, plays a crucial role in the epidemiology of avian influenza. Maryland and other states in the Delmarva region, lie within the Atlantic Flyway. The spread of Eurasian lineage viruses has been linked to infected migratory birds crossing the Atlantic from Europe.
Rising Threats from Migratory Birds
The spring migration season, which typically begins in February, significantly increases the risk of highly pathogenic avian influenza (HPAI) outbreaks. Domestic poultry, including commercial flocks and backyard birds, face exposure risks through contaminated feed, equipment, and personnel carrying droppings and secretions from infected wild birds. The recent emergence and widespread detection of H5N1, which was prevalent in Europe and Asia before arriving in North America in late 2021, have heightened concerns. Additionally, the introduction of HPAI into South America, a region previously free of the disease, underscores the ongoing threat to poultry farmers, public health officials, and animal health professionals.
The ongoing HPAI outbreak, which began in February 2022, has become the largest in U.S. history, surpassing the 2014–2015 crisis. As of July 2024, the outbreak has affected 1,667 flocks and resulted in the loss of approximately 168.27 million birds across all 50 states and Washington, D.C. Commercial poultry operations have experienced the greatest losses due to high-density farming, while backyard flocks account for a significant number of infected premises. The Midwest, particularly Iowa and Minnesota, along with the Atlantic Flyway, remain major hotspots.
Unlike previous outbreaks that subsided with seasonal changes, HPAI H5N1 has persisted year-round, driven by continuous transmission in wild migratory birds. Additionally, recent detections of H5N1 in U.S. dairy cattle and increasing reports of human infections (70 confirmed or probable cases as of 2024 )highlight the need for vigilance. While no sustained human-to-human transmission has been reported, those working closely with poultry, dairy cattle, and culling operations remain at elevated risk.
Strengthening Biosecurity Measures
With the seasonal pattern of avian influenza, the risk of outbreaks is expected to rise. Implementing stringent biosecurity measures as outlined by the USDA’s Animal and Plant Health Inspection Service (APHIS) and the National Poultry Improvement Plan (NPIP) is crucial in preventing disease spread.
Key biosecurity steps include:
· Using clean clothing and footwear before entering bird areas
· Disinfecting vehicles, equipment, and tools before and after use
· Limiting farm visitors and restricting access to essential personnel only
· Implementing farm isolation zones and rapid culling protocols when necessary
Additionally, effective wildlife management practices can significantly reduce farm exposure to HPAI:
· Eliminate wildlife attractants: Remove standing water and manage ponds and basins to deter wild waterfowl.
· Minimize food sources: Secure feed storage areas and cover waste to prevent access by wild birds.
· Block entry points: Seal holes, remove perches, and use deterrents to discourage roosting.
· Utilize scare devices: Rotate and reposition deterrents frequently to maintain effectiveness.
Poultry growers concerned about wildlife access near their farms can contact USDA-APHIS Wildlife Services at 1-866-4USDA-WS (1-866-487-3297) for assistance. More information on avian influenza and biosecurity practices is available at www.usda.gov/avianinfluenza.
Surveillance and Reporting
Early detection is critical for controlling avian influenza outbreaks. Farmers should report any unusual illness or sudden deaths in domestic poultry, pet birds, game birds, or wild birds to local animal health authorities.
As of 2024, USDA and CDC continue monitoring flu activity in animals and humans through expanded surveillance and testing programs. Vaccines targeting H5N1 remain stockpiled for potential use if the risk to humans escalates.
By combining strong biosecurity measures with active surveillance and reporting, poultry growers can help mitigate the risk of avian influenza and protect their flocks from this devastating disease.
References and Additional Resources:
1. USDA APHIS Biosecurity for Birds https://bit.ly/3QQpXCc;
2. CDC Avian Influenza Information https://www.cdc.gov/flu/avianflu;
3. Live Tracking of the Bird Migration https://birdcast.info;
4. Managing Wildlife to Prevent HPAI https://bit.ly/ManageWildlifeToPreventflu;
5. Detections of Highly Pathogenic Avian Influenza in Wild Birds https://bit.ly/3FFyIfL;
6. Detection of HPAI in Commercial Flocks https://bit.ly/4l4MpoM
Back to Commercial Poultry News - April 2025