ABSTRACT
Humankind’s journey through the ages has been diffi cult. Our primordial ancestors faced threats to their survival in a hostile environment. Wild carnivorous animals abounded and natural disasters such as forest fi res and fl oods surely presented grievous challenges to our ancestors. Over time the nature of the environmental hazards changed as humans passed from a nomadic, tribal existence to a more communal lifestyle in small villages and, later, large cites. As humans huddled together in increasingly large numbers, health problems magnifi ed in both numbers and severity of disease. Perhaps no greater health calamity has befallen humankind than the bubonic plague (also called the Black Death). There were three major pandemics of the plague, occurring in the sixth, fourteenth, and seventeenth centuries. The death toll approximated 137 million victims. The pandemic of the fourteenth century was particularly devastating, causing the death of 25 million people. Ultimately, the plague killed about one-third of Europe’s population over a fi ve-year period, beginning in year 1347. The plague was eventually found to be caused by the bacterium Yersinia pestis, which is spread by fl eas that infest animals such as the black rat [1]. The plague, an example of an extreme environmental health problem, illustrates the importance of environmental hazards as a public health concern.
