Sunbeams through the windows illuminate floating dust motes—and, imperceptibly, microdroplets of mucus carrying the measles virus, expelled from an infected but asymptomatic child who is hopping and ...

Little T.J. was a monster. There's no other way to say it. Extremely hyperactive, the toddler ran around in circles, destroying everything in his path. He choked the cat and dragged it by its tail. He ...