The Highly Pathogenic Avian Influenza, or bird flu, has resurged across Pennsylvania in recent weeks, causing significant bird mortality — particularly in wild geese.

First detected in Pennsylvania in 2022, the bird flu appears to be on the rise, according to Dr. Andrew DiSalvo, Pennsylvania Game Commission wildlife veterinarian.

“It’s scary stuff,” DiSalvo told agency commissioners during a recent board meeting.

In late December, more than 200 sick or dead snow geese with the virus were reported at quarries in Lehigh and Northampton counties. A little over a week ago, the commission reported that 5,000 geese had been impacted, with the commission having to depopulate the area and having a contractor remove and dispose of them.

“Since then, we have had a blossoming of reports of detections of high-path HPAI, mainly in the Southeast Region,” which includes the counties of Berks, Bucks, Chester, Dauphin, Delaware, Lancaster, Lebanon, Lehigh, Montgomery, Northampton, Philadelphia and Schuylkill, DiSalvo said.

The commission, he said, believes it is “just the tip of the iceberg.”

“It will likely become more widespread in the coming weeks to months,” he said.

The commission, he said, urges anyone who spots sick or dead wildlife to contact the commission at 833-PGC-WILD.

Signs of infection in wild birds may include neurological dysfunction such as circling, head tilting and difficulty flying.

In the past three weeks, DiSalvo said, the commission has received and confirmed more than 400 reports of the bird flu in the Southeast Region alone.

And while folks might not be seeing sick or dead birds in their area, DiSalvo said it’s been reported across the state and nation.

DiSalvo said the bird flu presents many challenges for wildlife management agencies. “For starters, it reservoirs in an abundant wildlife resource that freely moves across the landscape at peak density,” DiSalvo said.

When the birds gather for migration, he said, they have “a mixer of sorts” and the highly pathogenic strains emerge.

DiSalvo spoke about Middle Creek Wildlife Management Area in Lancaster, an annual stopping point for migrating snow geese. At any given time in late February or early March, he said, 100,000 snow geese are present.

Mallards and Canada geese, which also can carry the virus, are evenly distributed across Pennsylvania.

“So it’s challenging,” he said.

DiSalvo said management strategies are limited, since vaccination of wild birds is out of the question.

Despite the challenges, wildlife agencies continue to record locations where bird flu has been detected and the types of species it is infecting.

The majority of reports are in snow geese, but other waterfowl, avian scavengers like crows and vultures, and raptors have also tested positive for the virus.

When the bird flu was detected in Pennsylvania in 2021, DiSalvo said officials were hoping it would resolve as it has in the past.

“I’m here with you in 2025 because that did not work out as we hoped,” he said. “Things smoldered throughout the entire year in 2022, carried through 2023 and into 2024.”

It also impacts commercial poultry but rarely impacts humans. Despite the low risk, however, a Louisiana man recently succumbed to the virus.

“The risks exists. You’re never going to say it’s a zero risk,” DiSalvo said.

The commission asks that people view wildlife from a safe distance, avoid wildlife feces and never handle sick or dead birds.

The agency is working with Pennsylvania Department of Agriculture, U.S. Department of Agriculture, Pennsylvania Department of Health and Wildlife Futures Program at the University of Pennsylvania School of Veterinary Medicine, and the Pennsylvania Animal Diagnostic Laboratory System to monitor for HPAI in wild and domestic bird populations throughout the commonwealth.

DiSalvo’s update to the agency’s commissioners is available on the Game Commission’s YouTube channel.