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…