It was showtime at the youth swine exhibition, and the pig barn was bustling. The competitors, ages 3 to 21, were practicing their walks for the show ring and brushing pig bristles into place. Parents were braiding children’s hair, adding ribbons and pig-shaped barrettes.
Dr. Andrew Bowman, a molecular epidemiologist at Ohio State University, was striding through the barn in waterproof green overalls, searching for swine snot. As he slipped into one pen, a pig tried to nose its way out, then started nibbling his shoelaces.
Dr. Bowman prefers not to enter the pens, he said, as he wiped gauze across the animal’s nose. He soon spotted a more appealing subject: a pig sticking its nose out from between the bars of its enclosure. “We have a total bias for snouts out,” he said. Later, back in the lab, Dr. Bowman and his colleagues would discover that several of the snouts snuffling around this busy barn in New Lexington, Ohio, were harboring influenza.
The world is emerging from a pandemic that killed at least 6.9 million people. It won’t be the last. Outbreaks of zoonotic diseases, which can spread between animals and humans, have become more frequent in recent decades, and animal pathogens will continue spilling over into human populations in the years ahead. To Americans, spillover might seem like a distant problem, a danger that dwells in places like the live animal market in Wuhan, China, that may have been the origin of the Covid-19 pandemic.