Although the current problems facing industrialized societies are the “diseases of civilization” which are linked to the alteration of our diet and our new patterns of living, the spread of infectious diseases has been the major health factor throughout most of human history (Ponting, 225).

            With the acceptance of agriculture and the advent of settled societies, humans exposed themselves to a whole new range of communicable diseases that would have been impossible within the lifestyle of a hunter-gather. People were now coming into contact with each other more than ever before. As a result of the greater concentration of population, waste disposal, which had not been a problem in a settlement of one hundred, became a major factor within city planning. One body of water was usually dedicated to this purpose and became a flourishing ground for intestinal parasites. Humans were not merely living closer together with each other, however; they were also existing with, and in most cases, living with their animals, which exposing them to new diseases like smallpox which had formerly only infected animals (Ponting, 225, 226). These diseases were no longer limited to a small population, however; as a result of new technologies in ship building and travel, trade between cities and countries was made easier and more profitable than ever before. Seemingly incidental contacts between people traveling to other countries or contact with the animals or artifacts that they brought back, intentionally or otherwise, could result in the transmission of an old disease into a new population without any immunity.

            Some of these diseases evolved into epidemics. An epidemic is defined as a disease that quickly infects the whole population as the germs rapidly spread from infected people to healthy ones rather than merely impacting a small number of people over a longer period of time. These are normally acute illnesses that result in either a quick death or a series of anti-bodies that could potentially provide a lifelong immunity from the disease. As the remaining population slowly becomes resistant to the disease, the germs must wait until a new group of babies is born that has no defense against the disease or be spread by other means to effect a new population that has never been exposed to the disease and thus remains vulnerable to it (Diamond, 202-203).

            One of the most destructive examples of an epidemic was the Black Plague, which killed one-quarter of Europe’s population between 1346 and 1352 (Diamond, 202).  England’s population alone was 50% lower than it would have been if the plague had not occurred and the average life expectancy of a medieval man was reduced from 32-35 years to 18 years by the late 14th century (Raleigh). The disease was characterized by the swelling of the lymphatic glands as well as other secondary swellings and caused fever, vomiting, delirium and death within a few days. While the plague in its pneumonic form was one hundred percent fatal, the variations with the disease itself meant that overall ten percent of infected individuals were able to survive (Ponting, 229). Yet many cities were left with death tolls of up to seventy percent as the disease swept through the population, causing terrible pain and social dislocation as people fled the city and unwittingly infected the population of the countryside (Diamond, 202; Ponting, 229).

            The disease was spread across Eurasia in the year 1200 as trade routes across the steppes of central Asia were opened for the first time after foundation of the Mongolian Empire. As a result of the new trade routes the burrowing rodents of the steppes were able to spread into China, carrying the bubonic plague and a legion of infected fleas. The plague began in China in 1331, although it quickly spread up the Mediterranean to Crimea in 1346 (Ponting, 229). While in previous centuries the disease might have been localized in Asia, the innovations within shipbuilding that were developed in Europe in the thirteenth and fourteenth centuries meant that Europeans were able to travel farther and trade more than they ever had before using navigational instruments to find new markets and making major modifications within the rigging and the hull in order to get them there (Adas, 23). They brought back more than just silks and tea from China, however; their ships were also carrying rats that were infected with what came to be known in Europe as the Black Death (Ponting, 229).

            Human beings were forced to confront their helplessness in the face of nature as they watched all of the people that they knew die horribly around them from causes that they couldn’t understand. While the bubonic plague had catastrophic effects on every group that it came into contact with it left a particular series of social scars upon Europe in particular. Their vulnerability to disease was sharply highlighted in their experiences with the plague along with their powerlessness in the face of the natural forces of the world (Adas, 23). Yet Europe’s population ultimately regained and substantially increased their presence on the continent. Moreover, further advancements were made to the travel technologies that had almost inadvertently resulted in the destruction of their society as the need for profit overcame any qualms about contact with outsiders and possible endemics.

Therefore, with improved ships and a sense of destiny, the Europeans headed out to the New World, bringing with them a slew of diseases that would prove to be far more catastrophic to the population of the New World than the Black Death. This time, however, they would be the infected carriers rather than victims. Like the rats that snuck onto European ships in the Middle Ages, the Europeans would quickly infect those they came into contact with smallpox, measles and a host of other diseases; however, the real impact would be felt far from the coasts and the presence of the Europeans themselves. The diseases would sneak up the Americas, following the trade routes from the Aztec and Inca civilizations to the Mississippi Valley civilizations and beyond, leaving over 90 percent of Native American population dead and the rest of their people severely demoralized (Diamond, 211). While the European population was able to recover and even flourish after the plague as a result of the decreased population, which left more opportunities for the survivors who remained as agricultural land was made available again, the Native American population was never given the chance to rebuild. The impact of the disease was combined with the European presence on their continent and ultimately led to the collapse of their major civilizations.

If they had been forced to choose, even the most materialistic of medieval Europeans might have said that all of the trade brought back from China wasn’t worth the death and the suffering that resulted from the exposure between the two cultures. Watching the Native people of a continent that they believed was theirs die horribly was no problem at all, however; in fact, they often did everything they could to spur it on. Governments weakened by disease were easily collapsed and dead people no longer needed the goods that they had collected for sale or the land that they had formerly occupied. Moreover, watching the Native people die around them further enhanced the Europeans sense of destiny within the New World, cementing the ideal of their divine providence. Travel and disease, in this case, proved to be the making of several European civilizations rather than the destruction of them, although only at the expense of another equally vibrant culture.    

Works Cited

Adas, Michael. Machines as the Meaure of Men: Science, Technology, and Ideologies of Western Dominance. Cornell UP, 1989. 1-35.

Diamond, Jared. Guns, Germs, and Steel. W.W. Norton and Co, 1997. 195-214.

Ponting, Clive. A Green History of the World. NYC: St. Martin\'s P, 1999. 224-239.

Raleigh, Veena S. "Trends in World Population: How Will the Millenium Compare with the Past." Human Reproduction Update (1999): 500-505.