Dr. Snow never did discover the cause of the cholera epidemic, but he didn't need to. Although he couldn't treat it, he could prevent it and stop its spread by interrupting its transmission. Many of the great scourges of history, including cholera, malaria, tuberculosis, and typhoid fever were vastly diminished by changes made in human environments, even before the cause of the disease was known or effective drugs and vaccines were available. It is far more efficient to prevent the transmission of a communicable disease than to provide treatment following exposure and infection. Prevention typically involves precautions to limit exposure and transmission, enhancement of a population's nutrition to increase their resistance to infection, and, when a vaccine exists, immunization.
Prevention is the most effective method for controlling communicable viral disease.
Prevention should be our first line of defense. Recognizing evil as infectious disease unleashes this powerful tool to prevent and treat some of our oldest problems. It is time to begin a scientific investigation of evil. We already study biological virology and electronic virology. It is time to make a science of behavioral virology, to map this disease, develop, test, and implement new means of prevention and treatment.