Epidemiology of Noninfectious Diseases

Abstract

From the time of Hippocrates until the 1880s (see §8.2), epidemics had the meaning of diseases falling upon the people and affecting them simultaneously. No restriction to infectious diseases was implied because the idea of contagion was not accepted. In the years 1875 to 1925, many of the epidemics were shown to be caused by living agents, including bacteria, viruses, and parasites. “Epidemic” became identified with infectious diseases. There are, however, noninfectious diseases that appear as epidemics, for example, avitaminoses, environmental poisonings, and lung cancers in miners, and it seems quite proper to use the word epidemiology for their study. As the quotation from Burnet (1941) in §8.6 shows, there would have been great difficulty in the Middle Ages, say, in differentiating between diseases that were infectious in the modern sense and those that were not, even if the diseases had been clearly identifiable. These difficulties have persisted into recent times as is recounted below in the discussion on pellagra.