a1 The Picower Institute for Medical Research
Most communicable diseases are caused by infectious agents that are not visible to the naked eye, which led earlier societies to believe in miasmas and control by quarantine. Although microscopes revealed the agents in the eighteenth century, they were not associated with disease syndromes until the late nineteeth century. Today, vaccines are the most cost-effective means of control.
Kenneth S. Warren, MD, The Picower Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA