Massive Contact, Massive Fall: Transportation and Disease in Agricultural and Modern Societies
By the sixteenth century CE, European nations were stretching their sails and exploring new territories. Doors to Asia, Africa and the Americas, formerly barred from European contact, were newly thrown open, exposing the wide-eyed Europeans to resources, trade and new peoples. Whether the journey was for settlement or religious conversion, the Europeans had predominantly adverse effects on the populations they encountered. Some may credit the Europeans with their superior technology for their surprising upper hand in foreign lands. However, the overwhelming advantage of most European voyagers was the threat of infectious diseases.
A startling (and paradoxical) example of European contact with the “new worlds” lies in the fate of the Aztecs of Mexico. Hernán Cortés and his crew arrived in 1519, the exact year that the deity Quetzalcoatl was to arrive on the shores of Mexico. Quetzalcoatl was said to have fair hair and skin, which matched this strange European man who had arrived on the Mexican shore. Accordingly, Cortés was greeted like a god. And so were his men who carried smallpox. (Ehrlich, Paul R., 253) The robust population of 22 million Aztecs was cut down to 2 million by the end of the century. (Stutz, Bruce) In this case, the might of Portuguese microbes equaled, if not surpassed, the might of their swords. The same results were repeated in the West Indies, where Christopher Columbus and his crew wiped out nearly half of the population (Stutz, Bruce), and in North America, American Indians suffered greatly from smallpox. (Ponting, Clive, 228)
In his book Guns, Germs and Steel, Jared Diamond poses an interesting question: why was the exchange of disease so one-sided? Sure, syphilis probably came from the Native Americans, but it certainly didn’t wipe out half of the European population. What gave Europe the upper hand? The answer is livestock. Diamond states in his chapter, aptly titled “The Lethal Gift of Livestock,” that most of the nastier diseases, such as “smallpox, flu, tuberculosis, malaria, plague, measles, and cholera,” evolved from animal diseases. (Diamond, Jared, 197) European societies had grown accustomed to living in close proximity to their animals. Diseases from animals mutated slightly through time, and, with the help of natural selection, eventually were able to pass on to humans. For the most part, diseases would infect a group of people, and those who survived the epidemic would gain immunity. (Ponting, Clive, 225) The peoples from Africa, Asia and the Americas had no such contact with livestock, and therefore no immunities whatsoever to diseases brought by the Europeans.
The correlation between increasing contact among societies and the spread of disease was far from a new phenomenon in the 16th century. For instance, in the 14th century, the bubonic plague spread from the Mongol empire to Asia, carried by rats infested with infected fleas. The plague quickly spread into Europe and killed between a third and a half of the entire population. (Ponting, Clive, 229) Intermittent outbreaks of the plague continued for centuries thereafter. Even in the 6th century CE, diseases carried by trade ships (most likely smallpox) caused relatively large-scale losses in the Mediterranean. (Ponting, Clive, 227)
In the early 16th century until the 19th century, humans were bound to oversea and overland transportation that was not only slow but also relatively small scale. Modern transportation, on the other hand, delivers massive amounts of people from continent to continent in a matter of hours. The increased exposure to various peoples has definitely increased the exposure to multitudes of diseases. Think of the design of a plane: upwards of hundreds of people crammed into a small tube for several hours. Even filters in the ventilation system cannot prevent the cold projected via sneeze from the man down the aisle.
Despite massive modern transportation, there has not been a disease that has had the effect of a bubonic plague. Humans on a whole live healthier than their counterparts in the 14th century. Waste is properly removed from the vicinity of homes, for example. Humans also generally eat better (and more) food than ever before. Modern medicine also accounts for vaccinations and preventative measures against diseases, even common diseases such as the flu. Granted, curing and preventing head colds seems rather trivial compared to the pandemic of the 21st century: HIV/AIDS. HIV/AIDS is fatal, and currently has no cure. Most importantly, the virus does not kill its victims immediately, which leaves plenty of time to transmit the disease widely, sometimes before symptoms are noticed. Global transportation has helped spread the virus around the world, by plane, or even “along truck routes and between towns and cities within [a] continent” ("The Origins of HIV & the First Cases of AIDS") Even though AIDS is spreading far and wide around the world, its current treatments and ever-increasing information about prevention could help curb the transmission rate.
Even today, many diseases are transmitted from animals to humans. For example, it is fairly well known that HIV more than likely started as a disease in primates. For much of the world, humans live in agrarian societies, which frequently puts them in contact with livestock. Avian influenza A is a perfect example of a modern disease that has made the jump from animals—birds, in this case—to humans. ("Avian Influenza: Current H5N1 Situation") “Bird flu” is highly contagious among birds, but not yet humans. Despite its rarity, the few human cases of avian influenza have shown high mortality rates, especially among children and the elderly. There have been waves of fear of a human strain of this flu that would be devastating to the population, mainly because of its difficulty to control. The same hype has surrounded SARS, anthrax and other pathogens.
Fears of massive outbreaks in modern society are completely justified. Transportation paired with high-density populations, especially in cities and other commercial areas, transmission of any disease would be quick and painful. Even more concerning is the tendency of society to over-immunize itself to the point of defenselessness. By being exposed to germs, humans gain immunities that can help prevent the gravity of illnesses. With hand sanitizer, vaccines and medicines to clean and “cure” disease, humans may be leaving themselves open for attack of a super virus. In September, 2007, Prevnar, a vaccine to prevent pneumonia in children, “along with the overuse of antibiotics, was having the unfortunate effect of promoting new superbugs that cause ear infections that are resistant to all antibiotic drugs approved for children.“ (Imus, Deidre) So the ever-hoped-for “cure to cancer” may turn out to be as detrimental as it would be helpful to our overly medicated bodies. If one disease carried overseas ravaged entire populations, what could a super virus do to today’s completely interdependent society? The toll of a massive outbreak would be enormous.
Certainly humans suffer the brunt of waves of disease, but epidemics have had grave effects on the environment as well. Unsurprisingly, massive death tolls create disruptions in societies and environments. Living humans naturally want to remove dead bodies from society. On a large scale, that means massive burials and burning. Dead organisms can contaminate groundwater if they are buried, and uncontrolled fires can cause serious damage to surrounding forests and fields. For the most part, animals and nature tend to affect each other in various ways. For instance, a virus that kills multitudes of people would force humans to readjust their living locations. This puts spatial pressure on other species. Combined with the contamination previously mentioned, other species of plants and animals could suffer greatly. History has shown that even a tiny droplet can cause an unexpected and large ripple in all walks of life. One thing is certain: if humans are actually walking down the path toward another plague, there will be huge repercussions for the environment and animals alike.
Sources:
"Avian Influenza: Current H5N1 Situation." CDC: Centers for Disease Control and Prevention. 15 June 2007. Department of Health and Human Services. 26 Mar. 2008 <http://www.cdc.gov/flu/avian/outbreaks/current.htm>.
Diamond, Jared, "Ch. 11: Lethal gift of livestock," in "Guns, Germs, and Steel" W.W. Norton & Co, 1997, ISBN 0-393-03891-2, pp. 195-214
Ehrlich, Paul R., "Ch.11: Gods, Dive-Bombers, and Bureaucracy" in "Human Natures: Genes Cultures, and the Human Prospect" Island Press, 2000, pp. 253-279.
Imus, Deidre. "Over Medicated and Over-Vaccinated: The Uninteded Consequences of Medicines Meant to Protect." The Huffington Post. Nov. 2007. 26 Mar. 2008 <http://www.huffingtonpost.com/deirdre-imus/over-medicated-and-overv_b_73300.html>.
"The Origins of HIV & the First Cases of AIDS." ADVERT. 26 Mar. 2008. 26 Mar. 2008 <http://www.avert.org/origins.htm>.
Ponting, Clive. Ch.11 from "A Green History of the World," St. Martins Press, NYC, 1991, pp. 224-239.
Stutz, Bruce. "Megadeath in Mexico." Discover. 12 Feb. 2006. 26 Mar. 2008 <http://discovermagazine.com/2006/feb/megadeath-in-mexico/article_view?b_start:int=1&-C=>.