“I swear I’ve never had a cough like this,” Dr. Jean McDonald said, catching her breath after a string of wheezy barks. “Would you mind doing a quick consult?” Summer was over, and back-to-school bugs were swirling among hospital workers like leaves in a squall. Still, something about that call bothered me. To pediatricians like Jean, coughs and colds were bread-and-butter medicine. It had to be serious if she asked for help. “No problem. I can meet you in the...