- September 10, 2025
- By Kimbra Cutlip
University of Maryland scientists and collaborators for the first time have identified specific risk factors for the spread of highly pathogenic avian influenza (HPAI) in the U.S., a disease now widespread among wild birds that is prompting the federal government to spend $1 billion yearly to protect the poultry industry.
In the study published last month in the journal One Health, UMD wildlife ecologist Jennifer Mullinax and postdoctoral associate Matthew Gonnerman compared environmental conditions and practices on farms with and without HPAI outbreaks to identify the most effective prevention measures. With coauthors including researchers from the U.S. Department of Agriculture (USDA) and U.S. Geological Survey (USGS), the team found that wild bird activity, combined with cold, wet winters, raises the risk of bird flu spreading to poultry. However, biosecurity measures like washing vehicles, using fresh or heat-treated bedding, and not sharing carcass disposal sites with other farms significantly lower the chance of the disease spreading to poultry.
The work was supported by funding from USDA, USGS and the National Science Foundation.
“Before this study, we had limited information describing the effectiveness of avian influenza biosecurity measures,” said Gonnerman, the lead author for the study, who is also a postdoctoral affiliate with USGS. “With this new research using information from the ongoing outbreak, we are finally able to start giving poultry farmers effective recommendations on how to combat HPAI.”
HPAI is a relatively new disease in the U.S., first detected in 2021. Since then, farmers have culled well over 100 million chickens and other commercially raised birds to head off the disease, and consumers have paid billions of dollars more in groceries because of soaring egg and poultry prices.
Understanding the factors that contribute to its spread, and what measures are effective at reducing its impact on the poultry industry, is critical to effectively managing outbreaks and prevention. This study provides evidence that specific measures reduce the risks and can save farmers the costs of culling an infected flock.
To develop their findings, Mullinax and her colleagues evaluated environmental data about wild waterfowl populations, weather and land use, along with surveys from farmers about biosecurity practices such as how waste is handled and whether vehicles are washed.
The study offers guidance on surveillance of HPAI in wild and domestic populations, identifying when and where the virus is likely to occur while also providing insights into how poultry farms can better protect themselves from risk.
“Biosecurity in the poultry industry is comprehensive,” Mullinax said. “Our work is helping to focus those specific defenses to prevent HPAI, while accounting for migrating waterfowl and the farm’s location.”