Image: Ellen F. O’Connell/Hazleton Standard-Speaker via AP
Since a strain of the H5N1 virus—a type of avian influenza—was introduced to North America in 2021, it appeared in U.S. dairy cattle for the first time last March and has since affected more than 900 livestock herds. The virus has infected dozens of people in the country and this January killed one, a person who had been exposed to sick birds. There has yet to be any reported human-to-human transmission.
Human infections have mostly been relatively mild, “and that’s because this H5N1 virus doesn’t bind well to human cells,” says Scott Hensley, a professor of microbiology at the Perelman School of Medicine. “The problem is flu viruses change all the time, and we know that the virus is only one or two mutations away from being able to latch onto human cells much more effectively.”
Hensley says he doesn’t know if or when this virus would cause a pandemic, “but the worst thing we can do is be flat-footed and unprepared, because this virus does represent a true pandemic risk, with a potential to cause an incredible amount of disease.”
He and Drew Weissman, Roberts Family Professor in Vaccine Research at Penn Medicine and a Nobel Prize winner, have developed a vaccine against the virus, using the same mRNA technology as the COVID vaccines, while School of Veterinary Medicine faculty and students are researching transmission dynamics and assisting the Pennsylvania Department of Agriculture and the Pennsylvania Game Commission with disease surveillance.
Hensley and Weissman published a study last May showing their vaccine elicited a strong response in mice and ferrets. They are now vaccinating chickens and will soon be launching a small study in dairy cattle with Penn Vet’s Gary Althouse, professor of reproduction and swine health, at New Bolton Center in Kennett Square. “If we can reduce the amount of virus in birds and cattle, we’re ultimately reducing the chance that this virus has of infecting humans,” Hensley says.
“At Penn, we really pride ourselves on interdisciplinary teaching, research, and practice, and all of those are on display right now with Penn’s role in supporting the state’s response to avian influenza,” says Michael Smith, senior director of commonwealth relations for Penn. “That’s in keeping with our strategic framework, In Principle and Practice. This is a clear demonstration of Penn’s commitment to being an anchored, interwoven, engaged institution that is creating and deploying inventive solutions to real public problems.”
In addition to working on vaccine development, Penn is a partner in the Pennsylvania Animal Diagnostic Laboratory System (PADLS), along with the Pennsylvania Department of Agriculture and the Pennsylvania State University. The PADLS lab at New Bolton Center has tested more than 20,000 samples from domestic birds, wild birds, and wild mammals since the highly pathogenic avian influenza (HPAI) outbreak began in the United States, says Penn Vet assistant pathobiology professor Eman Anis, section head of molecular diagnostics and avian serology at the lab.
Following earlier detections of the virus in dairy cattle in other parts of the U.S., the lab began running tests on milk samples from Pennsylvania, she says. And in response to the recent deaths of snow geese in Lehigh County from bird flu, the lab has collaborated with Penn Vet’s Wildlife Futures Program to prioritize timely testing of wild bird samples. New Bolton Center’s lab performed the testing that identified infections among a 50,000-bird commercial chicken flock in Lehigh County.
“The implications of this outbreak extend beyond animal health,” Anis says. “The economic impact of this virus on the poultry and dairy industries is particularly concerning. This virus has been circulating in the U.S. for over three years, leading to the culling of millions of birds. Also, the disease has been associated with decreased milk production in infected dairy cattle.”
Read more on Penn Today!
