In the final chapter of The Hot Zone, Richard Preston describes Kinshasa Highway as the “AIDS highway,” noting that the rapid spread of the AIDS virus was made possible through the paving of the once dirt road. No longer used by the occasional car, the road now “carried a continual flow of vehicles. The overlanders were mixed up with pickup trucks and vans jammed with people and the road reeked of diesel smoke” (383). Preston argues that if the road had never been paved to create a convenient travel route through the middle of Africa, the AIDS virus would not have been able to travel from town to town with such ease.
In his book Plagues & Poxes: The Impact of Human History on Epidemic Diseases, author Alfred Jay Bollett notes, “Some infectious diseases that have caused the most devastating mass mortality in human history can trace their origin and mode of spread to human activity and behavior. Many other diseases . . . have been caused and spread by technological changes that benefited society as a whole, but had serious side effects that resulted in epidemic disease.” The Kinshasa Highway is just one example of human advancement that inadvertently contributed to the spread of disease, with other examples including animal domestication, exploration, and trade.
The origins of measles, tuberculosis, and smallpox can all be traced back to the first agriculturalists who domesticated wild animals after abandoning the hunter-gatherer lifestyle. Influenza and whooping cough can be similarly connected to diseases in domesticated animals such as pigs, dogs, and chickens. As these animals began to live in close proximity with humans, their diseases eventually modified until they could also affect humans. The advancement of agriculture also created some diseases due to nutritional deficiencies. As communities became more settled, the human diet shifted from mostly meat to mostly grains and vegetables, which resulted in severe iron deficiencies among many members of the population.
While exploration is hailed as a crucial part of the advancement of human history, it was also a key factor in the spread of disease between North America and Europe. When Spanish conquistadors traveled to the New World in the search of gold, they brought smallpox and measles with them. While the explorers themselves had been exposed to the diseases from an early age and were largely immune, the native population had no previous exposure and was decimated. However, the conquistadors suffered equal exposure at the hands of the native population and brought syphilis back to Europe with them.
Many of the outbreaks of the bubonic plague can be connected directly to exploration through trade, as both seafaring vessels and caravans on the Silk Road often contained rats that carried infected fleas. Just as the AIDS virus can be traced along the Kinshasa Highway, the Black Death can be traced to main port cities and caravan routes in the Middle East and Europe in the 14th century. By merely following the trade routes of the time period, it is possible to connect the dots from outbreak to outbreak, starting with Constantinople and leading to Britain, Spain, Italy, Scandinavia, and Russia. The Black Death alone contributed to the deaths of 25 million people, or approximately one-third of the world’s population, between 1348 and 1350.
Although the AIDS virus has not yet reached the impact of the bubonic plague during the Middle Ages, it is clear that human development goes hand in hand with the spread of infectious disease. Yet, as technology becomes more advanced, it also has the potential to prevent and even cure the viruses that it may promote. While a single paved road was enough to begin an epidemic in Africa, we can only hope that further human advancement will be enough to stop it.