Four years ago, a Wisconsin couple and their 3-year-old daughter went to a pet “swap meet” in the town of Wausau. But instead of returning with a puppy or parakeet, they purchased two prairie dogs. Two days later, one of the dogs bit the girl. Within 10 days the child developed a fever and a pustulant skin lesion. Her parents took her to the hospital. Although the doctors couldn’t diagnose her disease, they treated the symptoms, and she recovered.