Avian influenza has been circulating for centuries. What concerns epidemiologists about the latest iteration of the virus is its remarkable ability to spread across multiple animal species, including humans.
“It's spilled over into not just bird species, but so many different mammal species — from marine mammals along shorelines to dairy cattle that are part of our food source,” said Dr. Sharon Deem, wildlife veterinarian and epidemiologist. “It should be on all our minds right now.”
Human-designed systems have helped to increase bird flu’s ability to move between wild and domesticated animal populations over recent years, said Deem, who studies the links between human health and that of other animal species as director of the St. Louis Zoo Institute for Conservation Medicine.
Many Midwestern poultry farms were built on former wetlands that tens of millions of migratory birds fly over each year. With densely packed flocks of tens of thousands to millions of birds, these facilities create good conditions for pathogens to spread.
“The ability for wild birds to mix with domestic birds, and share these viruses, makes a virus happy in many ways [and] helps with mutations that change a once lowly pathogenic little virus into a highly pathogenic one,” she said. “These systems that we as a society, as a species, have reached for to feed the 8.2 billion humans on the planet have created some real health challenges.”
Deem spends a lot of time thinking about how everyday people can advocate for changes to systems upheld by powerful, moneymaking industries. That includes animal agriculture in the U.S., where poultry producers made more than $67 billion in 2023. She said she sees potential for change through consumer purchasing power.
“What we put on our dinner tables has this ripple global effect for conservation,” she said. “Thinking [about] how what I eat, what my family eats, may be playing into some of these questions of pandemics — I think it's up to all of us to be aware of that, think about it and think how [our] actions may be able to put some things in place that help us reimagine our food systems today.”
Despite the global, daunting challenges facing conservationists and epidemiologists alike, Deem said she has hope that younger generations will better understand and act on the interconnectedness of humans, animals and the environments they share. She also believes that increasing pressure on the planet makes positive change more likely.
She likens the planet to a patient with a medical emergency.
“As a human, you need a heart attack before you're going to listen to your doctor — before you're going to slow down on drinking or smoking or eat better,” she said. “I would argue we're at that planetary heart attack point. That might not sound hopeful, but just like that single human patient, we as a community are seeing this — and it takes a heart attack, a crisis, for people to move into action. And that gives me hope.”
To learn more about how human health is dependent on animal health — including ways antibiotic use in agriculture has contributed to antibiotic resistance, as well as recent efforts that have brought several species back from the brink of extinction — listen to St. Louis on the Air on Apple Podcasts, Spotify, YouTube or click the play button below.
“St. Louis on the Air” brings you the stories of St. Louis and the people who live, work and create in our region. The show is produced by Miya Norfleet, Emily Woodbury, Danny Wicentowski, Elaine Cha and Alex Heuer. Jada Jones is our production assistant. The audio engineer is Aaron Doerr.
