In the first days of the new year, on the marshy coastal edge of South Carolina’s Lowcountry, a hunter shot an American widgeon, a rusty-fronted duck with a pale beak and a brilliant green stripe. This was not a big deal; the state’s duck hunting season runs from Thanksgiving through the end of January. Neither was what happened next: Before taking it home, the hunter let a wildlife biologist affiliated with a government program swab the carcass for lab analysis.
But what happened after that was a big deal indeed. After the sample went through its routine check at Clemson University, it made an unusual second stop at a federal lab halfway across the country, in Iowa. The news of what was in the sample percolated through a pyramid of agencies, and on January 14 the US Department of Agriculture revealed why it had attracted so much scrutiny: The South Carolina duck was carrying the Asian strain of H5N1 avian influenza, the first sighting of that pathogen in the continental US in years.
But not the last. Just a few days later, the USDA disclosed that two more birds shot by hunters also carried the same pathogen: a teal, shot in the same South Carolina county, and a northern shoveler shot in the far northeast corner of North Carolina, about 400 miles away. The virus in all three was what is known as highly pathogenic—meaning it could cause fast-moving, fatal disease in other bird species, such as poultry, though it was not making the ducks ill.
Three birds out of the millions that American hunters shoot each year might seem like nothing—but the findings have sent a ripple of disquiet through the community of scientists who monitor animal diseases. In 2015, that same strain of flu landed in the Midwest’s turkey industry and caused the largest animal-disease outbreak ever seen in the US, killing or causing the destruction of more than 50 million birds and costing the US economy more than $3 billion. Human-health experts are uneasy as well. Since 2003, that flu has sickened at least 863 people across the world and killed more than half of them. Other avian flu strains have made hundreds more people ill. Before Covid arrived, avian flu was considered the disease most likely to cause a transnational outbreak.
It is far too soon to say whether the arrival of this virus in the US is a blip, an imminent danger to agriculture, or a zoonotic pathogen probing for a path to attack humanity. But it is a reminder that Covid is not the only disease with pandemic potential, and of how easy it is to lose focus when it comes to other possible threats. The possibility of a human- or animal-origin strain of flu swamping the world once seemed so imminent that back in 2005 the White House wrote a national strategy for it. But researchers say the surveillance schemes that would pick up its movement have since been allowed to drift.
“In wildlife disease surveillance, we’re always chasing a crisis,” says David Stallknecht, director of the Southeastern Cooperative Wildlife Disease Study, a research institute housed at the University of Georgia. “And as soon as the crisis is over, the interest goes down. It’s difficult to keep going long-term. People are here to do the work, but the money isn't there to support it.”