Michael Radonich remembers the day he got Lyme disease: It was late August 2012, the beginning of his first semester at the Wharton School in Philadelphia. He and his classmates had boarded buses for a day of ropes courses and bonding activities at a campground in the Pennsylvania woods.
About two weeks later, Radonich suddenly awoke to shooting pains in his scalp, as if someone had clipped electrodes to his temples. His heart rate began fluttering between 60 and 140 beats per minute. His experienced severe double vision, and then the left side of his body went numb. He was 28 years old, much too young to be having a stroke.