Which microbe was responsible for the Antonine Plague remains unclear, though most specialists believe that the likeliest culprit is an ancestor of the smallpox virus. The Antonine Plague is one example of a broader lesson that becomes clear in the study of human disease: Many of the most vicious microbes of human history are not altogether very old. They emerged and evolved on human time scales, in recent millenniums and centuries — and in response to the opportunities we inadvertently presented them. A second lesson is that human health and animal health are inseparable. Our relationship with the environment reverberates back upon us, sometimes with destructive force.
The smallpox virus is less than 2,000 years old. The Antonine Plague may well represent an early stage of its evolution as a human pathogen. Like many viruses, the agent of smallpox belongs to a family many of whose representatives infect small mammals, like rodents. As human societies expand, and become more interconnected, we collide with animals and their diseases. Evolution relentlessly experiments with adaptations to new hosts, and some of these experiments unfortunately prove successful.
The Antonine Plague was such an experiment. Even without understanding the microbiology of the disease, the Romans knew that the Antonine Plague had come from without, that it was something new that had appeared with terrific fury. They believed that the pestilence had been unloosed by their own soldiers on campaign beyond Roman borders, inside what is now Iraq. More likely, the germ simply spread along the bustling trade routes that connected virtually the entire Old World. The Romans carried on a vigorous commerce with East Africa, the Near East and India and China beyond. As it happens, the first documented direct contact between Rome and China fell in the very year the Antonine Plague broke out under Marcus Aurelius. Though nothing compared with our “flat” world, the Romans lived through one of the most important phases in the long history of globalization. Then as now, exposure to disease was one of its unintended consequences.
Author(s): Kyle Harper
Publication Date: 15 February 2021
Publication Site: NYT