People’s risk of getting bird flu is currently low, but avian flu experts told Pennsylvania lawmakers it is critical to continue tracking the spread of the virus and how it mutates in order to keep animals and humans safe.
Since 2022, more than 7 million chickens, ducks and other fowl in Pennsylvania have been affected by avian flu. More than 2 million birds were struck in the last 30 days, according to data from the U.S. Department of Agriculture. Since Feb. 6, more than 136,000 birds in Lancaster County have been affected by the avian flu.
Bird flu is killing wild birds and mammals, too
Louise Moncla, assistant professor of pathobiology at the University of Pennsylvania School of Veterinary Medicine, was part of a panel of experts who testified last week to a joint hearing of the state House committees on agriculture and health.
Moncla’s lab is tracking the avian flu virus. She said the virus causing the outbreak that started three years ago is harder to contain than viruses from previous outbreaks. In 2015, she said the U.S. culled about 50 million domestic birds and halted a bird flu outbreak. This time around, more than 160 million birds have been euthanized, and the virus is still spreading.
Moncla said past avian flu outbreaks were mainly spread by birds on farms. But now, it’s wild birds that are responsible for the spread of the flu.
“Because these wild birds are migratory, these viruses can be spread very far geographic distances very rapidly when these birds migrate,” she said.
The state Game Commission found thousands of snow geese dead from suspected avian flu in the Lehigh Valley this winter. As a precaution to prevent the virus’s spread, the popular snow geese-viewing site Middle Creek Wildlife Management Area closed some areas to the public.
There are many low-severity varieties of avian flu circulating in wild birds, Moncla said. Different viruses can get mixed together, making new viruses that can increase the risks for agriculture and for humans.
If the virus reaches cattle, which it has in other states, it’s hard to stop it from spreading, Moncla said. That leads to human exposure risk. She said Pennsylvania is doing well in monitoring for bird flu in cattle and milk.
“Pennsylvania is doing a really great job of testing individual cows as well as bulk tank milk to try to figure out if our cows here have these viruses and currently we don’t,” Moncla said.
Risk to humans
The risk to people right now is low, said Scott Hensley, a professor of microbiology at Penn’s Perelman School of Medicine.
He said there have been 69 human infections of avian flu nationwide, but the vast majority happened in people who worked with or handled infected animals.
A mutation in the virus could increase the chance that people get infected, Hensley said.
“This process of mutations happens all the time. You’re infected with a seasonal flu virus today – the virus is going to be turning out random mutations. It’s like playing the lottery,” he said.
The dean of Penn Vet, Andrew Hoffman, warned avian flu is an issue around the world, so it will take global cooperation, communication, coordination to get it under control.
On the first day of his second term, President Donald Trump signed an executive order to withdraw the U.S. from the World Health Organization, which responds to emerging health threats around the world.
“The more we withdraw ourselves as a nation from those cooperative agencies, we’re going to know less and less about what’s going on,” Hoffman said.
The Trump Administration has also moved to dramatically cut or freeze federal spending, including at the USDA.
Hoffman said if the federal government defunds research efforts, it may be up to private industry or state governments to support research and monitoring efforts to protect against bird flu.
Hensley said he and members of his lab are nervous about decisions being made at the federal level about avian flu surveillance and potential vaccination.
“I would be lying to you if I were to tell you that we aren’t all sweating,” Hensley said.
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