At first glance, the house sparrow may not seem all that intimidating. But now that highly pathogenic avian influenza (HPAI) is endemic in the wildlife waterfowl population, this tiny bird could become a huge problem for U.S. livestock producers, USDA’s David Marks said at the 2025 American Association of Swine Veterinarians annual meeting in San Francisco in March.
“Ducks and geese waterfowl are a reservoir for highly pathogenic avian influenza (HPAI),” says Marks who serves on the staff of USDA Animal and Plant Health Inspection Services (APHIS) Wildlife Services (WS). “They brought it over here in 2022 from Europe and Asia, and now it is circulating in waterfowl. HPAI is a foreign animal disease in North and North America, but now it’s endemic in wildlife. It’s not a good situation.”
Peri-domestic birds like the house sparrow and the American robin are attracted to the same water sources as these ducks and geese, which can result in peri-domestic birds carrying the disease back to the livestock barns, Marks explains.
“Keep your farms tight,” he says. “HPAI is mixing and reassorting in our waterfowl. Every time it gets in these birds, it’s mutating. Over 85% of positive farms now are from wildlife introductions.”
When it comes to managing wildlife disease threats, there are basically three options: manage the site itself, manage the wildlife, or install a barrier to keep wildlife out.
How Big of a Problem Do We Have?
Since the outbreak in poultry in 2022, APHIS has worked with state animal health officials to identify and respond to detections and mitigate the virus’ impact on U.S. poultry production and trade. Marks says more than 105.2 million birds in 1,197 flocks in 48 states have been affected by the virus since then. In response to this current outbreak, USDA has spent over $1 billion, paying for indemnity, cleanup and disinfection of facilities, diagnostics and other aspects related emergency response.
“More than 75% of infections have been directly related to new introductions of virus of wildlife origin and not related to lateral transfer between facilities, employees and equipment as in previous HPAI outbreaks,” Marks says.
WS developed the Midwest Wildlife Biosecurity Assessment Pilot Project in response to the continued outbreaks of HPAI across the country. Four states (Iowa, Minnesota, North Dakota and South Dakota) were selected as the focus for this project based upon the high number of infections and re-introductions of facilities during calendar year 2022 from within this area.
Earlier this month, USDA announced it is expanding the availability of its biosecurity assessments to commercial poultry producers.
“These assessments, which were previously available on a limited basis have been extremely successful in improving biosecurity on individual premises and preventing the introduction or spread of avian influenza,” USDA Secretary Brooke Rollins said.
The goal of the assessments is to take a proactive approach to managing potential disease transfer and improve the wildlife biosecurity of commercial poultry facilities in the U.S., thus reducing the number of facilities that become infected with HPAI and other diseases of concern to the poultry industry, Marks explains.
Wildlife biosecurity assessments are through evaluations of all buildings, external operations and wildlife population use and movements that occur on and near commercial poultry facilities. These reports are directly provided to facility managers and include long-term management recommendations for mitigating any identified risks related to wildlife.
The formal WBA process is comprised of three main components: Wildlife hazard identification surveys, wildlife abundance surveys, and in most cases, direct control and continued monitoring for attractants, hazards, and wildlife.
Step 1: Wildlife Abundance Surveys
What species are there in the first place? Marks says wildlife abundance surveys (WAS) simply determine what wildlife species one could expect and that one finds on an operation.
“A farm in northwest Iowa might be different than a farm in southeast Iowa or Texas,” he points out. “WS conducts WAS at different times during the day (morning, midday, evening, and night) to understand the different species present in and around the facilities at these times.”
After establishing multiple survey points to represent all habitats and cover the perimeter, WS conducts standardized wildlife point counts at each survey point and revisits those monthly to create population trend data. These maps show areas of wildlife activity for each facility.
Step 2: Wildlife Hazard Identification Surveys
Wildlife hazard identification survey (WHIS) take place at all facilities as they enter the program, he says. These reports provide a detailed list of all the wildlife biosecurity hazards found within the perimeter buffer area of the facility, and categorizes hazards into three tiers, with tier 1 being of the greatest concern. Examples of Tier 1 hazards include holes in barn exterior walls, exclusionary netting, or other breaches that would allow direct contact with wildlife and poultry.
Lower Tier hazards include wildlife attractants and potential sources for indirect transmission routes, such as standing water and food sources. WS conducts the first WHIS during an initial facility site visit and generates the report for the producer shortly after. WHIS reports contain photographs of all hazards identified and their locations represented on an aerial photo. WS designs the reports so producers can quickly identify and mitigate any hazards found.
WS personnel conduct subsequent WHIS quarterly to monitor progress. They also monitor for additional hazards continuously while on site, and any additional hazards found are recorded and relayed to producers in real time. Formal quarterly WHIS reports help track hazards and mitigation over time.
Step 3: Direct Control
The next step is to develop a plan for routine direct control actions. This includes both lethal (removal) and nonlethal (habitat management, exclusion, harassment) management of wildlife present at the facility, Marks explains.
“WS records all direct control activity results, along with wildlife observations while on site,” he says. “These are not standardized data, but over time are very valuable in showing trends and we expect a direct inverse correlation to result from wildlife abundance surveys (ie, the more wildlife managed, the lower the wildlife abundance on site). Similar to wildlife abundance data, direct control trend data can be depicted on a map of a facility to show areas of wildlife activity.”
After the first six months of participation in the program, WS generates a comprehensive report for the facility, which summarizes all WS personnel activities.
While on site, WS personnel collect samples from wildlife species for HPAI testing, he adds. Sampling strategies focus on facilities that have recently become positive for HPAI because of the increased likelihood of the virus being present in non-reservoir species. WS processes samples and submits them to the diagnostic lab for analysis, and all influenza A detections are forwarded to the USDA National Veterinary Services Laboratory for confirmation and genomic sequencing. Additionally, WS collects samples from a subset of wildlife collected from non-infected facilities.
What Can You Do Now?
Although the biosecurity assessments and audits are offered to poultry producers only at this time, WS does offer financial support to help dairy producers enhance biosecurity and offset costs associated with Influenza A testing, veterinary expenses, personal protective equipment purchases, milk disposal and milk losses.
“The wildlife exclusions and barn setups are similar between swine and poultry facilities,” Marks says. “Biosecurity is a critical tool for disease prevention for all species.”
USDA encourages all producers to review their biosecurity plans and take action now to prevent disease from reaching their herds. While the actual assessments may not be available to pork producers right now, USDA does offer biosecurity resources for swine producers here.
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