Old Diseases
It is very difficult to trace precisely the historical development of particular epidemic diseases in China. First, traditional Chinese medical terminology is based on a system hardly translatable into modern Western terms.
Second, not only the concepts of disease, but the diseases themselves have changed, so much so that it is impossible to determine whether an ancient classical term meant the same thing when used in premodem texts, or to find the exact modem counterpart of a disease discussed in old texts.Only during the second half of the nineteenth century did diseases in China begin to be scrutinized by Western medical practitioners, and as late as the early twentieth century, it was difficult to construct a complete picture because “there were classes of disease that were rarely brought for treatment to modem doctors” (Polunin 1976).
One principal feature of the traditional Chinese medical system (a system that achieved classical form by the second century) that makes it difficult to identify individual epidemic diseases in premodem China is the ancient categorization of both epidemic and endemic diseases along with other afflictions into a large group labeled shanghan (“affection by cold,” although today it is the modem term for typhoid fever). Ge Hong, one of China’s most important early medical thinkers, specified in the early fourth century A.D. that the Shanghan diseases included not only those caused by winter cold but also those caused by spring warmth and by seasonal Iiqi (epidemic “breath”). However, he conceded that differences among the origins of the three types of diseases were slight and they should therefore be grouped into a single category. This ambiguous conception of epidemic “fevers” as part of a more general category of “cold fevers,” despite some minor modifications, remained relatively unshaken in Chinese medical thought until the seventeenth century (late Ming and early Qing dynasties).
Widespread epidemics during the late Ming dynasty (Dunstan 1975) induced certain medical thinkers to reject the entire shanghan theory because most of the diseases they were called on to treat were found not to be caused by winter cold.
The most representative of these pioneer thinkers was Wu Youxing, a seventeenth-century native of the epidemic-stricken eastern Jiangsu region. His work Treatise on Warmth Epidemic Disease, written in 1642, put forward the theory that seasonal epidemics were caused by deviant qi (“ether”) in the atmosphere (Dunstan 1975). The “warm factor” was now favored over the “cold factor” as cause for the disease. Even diseases such as smallpox that had traditionally been considered manifestations of the body’s internal “fire” or “poison” were now grouped with communicable diseases caused by external qi.Even this important development in understanding the etiology of epidemic diseases in premodem China does not help us understand all diseases in this period in Western terms. Insufficient descriptions of the symptoms of diseases in medical texts as well as in local gazettes and dynastic histories where most of the information on epidemics can be found constitute the main obstacle to such understanding. Moreover, China’s vast size implies regional differences in disease history that are still grossly unappreciated. At the present stage of research, with the exception of a few diseases that are easily identifiable, the best guesses as to the identity of most remain highly hypothetical.