Epidemics and epidemiology in the western medical tradition: past, present, future

Abstract

In current medical language, "epidemic" means an outbreak of disease, which, for a limited period of time, a significantly greater number of people in a community or region suffers than is normally the case; or, in other words, "a temporary íncrease in [dísease] prevalence". In its medical sense, for centuries the term was only applied to any communicable or infectious disease, namely, the kind of illness nowadays defined as "caused by the transmission of a specific infectious agent or its products from an ínfected person or animal to a specific host, either directly or indirectly". Yet, from the mid twentieth century, the word "epidemic" has also been applied to non-infectious diseases (cancer, heart disease, obesity, and so on), whenever an illness affects "a large number of people, with a recent and substantial increase in the number of cases". And, needless to say, mass media currently apply the term "epidemic" to many events that are neither disease conditions (e.g., famine, drug abuse, and accidents), nor subject to the attention of public health authorities (e.g., computer viruses). In this work provide a brief historical outline of the western medical construction of "epidemic" as a concept, and of "epidemiology" as a discipline in order to stimulate reflection on the present and future of epidemiological thought and practices.