1 Departments of Epidemiology and Public Health, and Pediatrics, Yale University School of Medicine, New Haven, Connecticut
Time Was when measles, rubella, scarlet fever, and the "fourth disease" were the infections to he considered when dealing with puzzling rashes. Events in the past generation have changed the problem considerably and complicated it to an extraordinary degree. This is due largely to the discovery in the late 1940's and early 1950's of several whole new families of viruses, including the Coxsackie, echo-, and adenoviruses. In the subsequent two decades the pathogenic potential and diverse clinical associations of these agents, which number close to 100, have gradually emerged. One of the most striking features has been an uncovering of an etiologic relationship to the so-called "summer exanthems."l,2