ZKEA

Emerging Diseases : Biological Terrorism : Biological Warfare

Summary

The plague began to spread in ancient times. Incited by ecological disruption of the grasslands and following the trade routes west and south, it appears that the plague first reached Europe in about 2,500 years ago. Unfortunately, the taboos did not spread with the bacterium; ancient people had no notion of where the disease came from or how to deal with it. This, along with their high urbanization, was a recipe for disaster.

Athens was hit in the summer of 430 BCE. Thucydides recorded its dire effects, and suffered from it himself. The plague devastated the city and was a major contributing factor in its defeat by Sparta. (Note: it's not completely certain that the epidemic of 430 BCE was, in fact, plague. Not all the symptoms line up, in particular the evident direct spread person-to-person. Even so, the best guess is that it was plague, perhaps the pneumonic form)

But there is no doubt that plague then hit Rome in the subsequent centuries. And plague was instrumental in the empire's eventual downfall. Among other things, the army was depopulated, leading to increasing reliance on barbarian mercenary troops. And the elite was also badly hit, even thought the plague originally started in the roman slums and initially primarily affected poorer parts of the population.

Indeed, Rome was particularly vulnerable to highly infectious diseases of this sort. By ancient standards the city was huge. For a long time the urban population exceeded one million people. Further, even by ancient standards, most of this population lived in crowded and sub-standard conditions. Tenements were usually crowded and badly constructed, with poor light and even worse sanitation. A survey in 50 CE found over 3,500 such buildings within the urban core. Even worse, the Roman population was famously diverse and mobile. As the historian Tacitus famously observed, Rome "that great reservoir and collecting ground for every kind of depravity" welcomed people from all over the world. No wonder the city was a hotzone for disease.

Because of this the wealthy usually preferred their rural manors. It was well-known that a man lived far longer and healthier if he avoided Rome and spent as much time as possible in his country estate.

Bubonic plague receded, not to be seen again until the Black Death. But over the intervening centuries Europe was hit by a number of other plagues. Given Europe's geographical position (exposed to migrations and invasions from both Asia and Africa) and its high-density urban environments and trading culture, European populations suffered heavily from epidemic disease. Smallpox, in particular, was very devastating. Other diseases also had impact. Measles, whooping cough (pertussis) and typhoid fever all inflicted great mortality. Some other diseases killed fewer people and yet left more profound scars on the collective consciousness. Hansen's Disease (leprosy) is a good example. This disfiguring bacterium probably originated in Egypt, spreading to India by 600 B.C. But leprosy was apparently unknown in Europe until the return of Alexander the Great's armies from India in 326 B.C. Starting in Greece the bacterium rapidly spread throughout the continent. By the time of the Roman Empire leprosy was already considered ancient and was widely feared and discussed. The Bible mentions it no less than 56 times.

Interestingly, leprosy appears to have become less lethal over time. This pattern is not uncommon. As evolution proceeds it is often the case that pathogens and their hosts become more tolerant of each other. Even though the pathogenic microorganism remains, it exhibits less disease and lethality. Modern Europeans are largely immune to leprosy whereas populations which have had less historic exposure - such as Asians - suffer from it to a greater extent.

Thus while destructive of countless lives through history, this constant exposure to novel pathogens did grant Europeans one advantage: they eventually built relative immunity to many of the great epidemic diseases that afflicted our species. Thus, as European colonial powers moved outward after the 15th century, they usually introduced new diseases to non-European populations, rather than the reverse. Since the non-European populations did not have natural immunity to these new diseases, the result was often a demographic disaster.

Syphilis was the great exception. Brought back to Europe after the Columbus expeditions, it ravaged Europe for centuries. Like leprosy, however, it gradually diminished in severity as the human population and the virus co-evolved some level of tolerance. Today syphilis remains a serious disease, but is not nearly as lethal as it was a few centuries ago.

Link: Plague Fatally Weakens Rome
Link: Thucydides Primary Report On The Athenian Plague
Link: History Of Infectious Disease
Link: Examples of How Disease Altered History
Link: Bacterial History
Link: The Effects Of The Black Death On Europe Link: The History Of Leprosy
Link: The Columbian Exchange - And Syphilis Emerges In Europe.