This subject involves a discussion of the early and present pandemics, cardinal features of the viability and dissemination of Bacillus pestis and the transmission of plague.
While indefinite statements regarding plague are found in the earliest writings, no definite knowledge of this disease has been found until the writings of Rufus of Ephesus regarding plague in Egypt in the second century B. C. At this time the disease was present in lower Egypt, spread along the coast of the Mediterranean and existed as a pandemic for an unknown period. Numerous detailed accounts give positive data that this pandemic was the same disease as that now known as bubonic plague. During this period war, drought and famines were prevalent throughout the world. During the centuries following this pandemic, numerous references to plagues are found, but each is too indefinite to warrant a diagnostication of bubonic plague.In the Justinian
CALVERT WJ. SOURCES OF PLAGUE.. JAMA. 1904;XLII(3):142-145. doi:10.1001/jama.1904.92490480004001a