Plagues and Peoples

A more robust written record informs McNeill’s study of disease patterns starting from 500 B.C. By this time, civilization flourished along several well-known and fertile river basins, but there were general rules to the limits of their expansion, many of them explained by disease. In the ancient Middle East, literary sources such as the “Epic of Gilgamesh” and the Old Testament reference familiarity with society-altering diseases, though only through modern deduction may it be determined which those diseases were, and what the real-world context for them might have been. The Assyrian and Persian empires flourished well before the period described in this chapter, and with any such flourishing, “it follows that epidemic diseases of the sort that attracted the attention of biblical writers were neither severe nor frequent enough to threaten the fabric of civilized society with disruption” (97). In such stable civilized disease environments, once-epidemic disease patterns become more fragile “childhood diseases,” analogous (and sometimes identical) to such modern-day diseases as measles and chicken pox.

Geography made a critical difference in the spread of disease, and McNeill focuses on three distinct geographical areas. Early civilization in the floodplain of the Yellow river in China found temperate and hospitable conditions starting at around 600 B.C., and the semi-arid weather meant disease was kept to a minimum. By the time of the reign of Emperor Wu-ti (140-87 B.C.), the bureaucratic structures required to tame the unpredictable river also served to maintain a “macroparasitic” balance in politics and warfare.

By contrast, the more southerly Yangtse river was host to a greater microparasitic threat. McNeill explains:

In other words, almost a thousand years elapsed from the time when the taming of the Yellow River flood plain got seriously underway before comparable development took place in the valley of the Yangtze River (101-02).

Contemporary Chinese historiographers like Ssu-ma Ch’ien (145-87 B.C.) attested to this “disease barrier” from the south of which, McNeill assumes, diseases like malaria and dengue fever comprised a major part.

The Ganges in India posed problems like those of other near-equatorial tropical climates. “As compared to China, however, both the political and the intellectual structures that arose in the Ganges region before and after 500 B.C. remained unstable, and never were consolidated into an enduring whole,” writes McNeill (107). The southern “disease barrier” protected the Ganges region from northern invasion but came at the cost of more fragile social and political structures. McNeill speculates that the rigors of Hinduism and the caste system derived from this fragile social atmosphere and diminished material wealth of the people.

The network of cities that formed around the Aegean Sea created a different sort of caste system—one in which civilized “citizens” were insulated by land and sea barriers from the “barbarian” producers who worked the land. This network was secured by robust and variegated trade. McNeill states:

The more open Mediterranean pattern of trade, in which most ranks of society participated, allowed multiple urban centers to form, wherever an exportable surplus of oil or wine or other valued commodity could be produced (113).

This led to more political instability, as a heterogenous body of separate city-states claimed their own interests and independence. Frequent war resulted.

Hippocrates (460-377 B.C.) was among the first writers to trace the course of disease in ancient Greece. He describes disease patterns interpretively consistent with malaria, mumps, diphtheria, and tuberculosis, though little of the measles and smallpox that later ravaged Roman civilization. Geographically distinct regions within the Aegean network also made for varied disease climates. Nevertheless, Greek, Roman, and Carthaginian society flourished and grew—most notably through the vast campaigns of the 4-300s B.C. that seized far-flung foreign lands. Such disruption had a less well-recorded generational pushback, and by 200 B.C. there were reports of “abandoned villages and empty countrysides [sic]” (119).

In the cases of Chinese, Indian and Mediterranean pre-Christian civilization, population size per city made a difference in disease transmission, though only Roman and Han China documents give a good idea of population estimates. Within these city centers, occasional epidemics are recorded, but McNeill assumes that generally, a microparasitic balance was formed through herd immunity. The spread of disease from city centers out to less populated centers depended on speed of travel; disease did not carry well by land but quickly spread through the busy trade routes of shipping though the Aegean. As long trade routes became established, however, such as that between China and Syria, an accompanying infrastructure was left behind which better facilitated the spread of disease.

Still, such trade benefitted Roman merchants leading up to and past the beginning of the Christian Era such as to spark the growth of the Roman Empire. Two great Roman plagues are well-recorded, though the Antonine plague of A.D. 165-80 (repeated in A.D. 251 to 266) remains little understood. Contemporary doctor and writer Galen described the plague as a disease producing rashes and respiratory ailments—though his lens involved an outdated theory of medical humors which serve to obscure the nature of the disease to contemporary researchers. Its effect severely limited the impressive spread of Roman civilization up to that point.

During this time, Christianity rose as a meaningful alternative to Roman paganism. “Another advantage Christians enjoyed over pagans was that the teaching of their faith made life meaningful even amid sudden and surprising death,” writes McNeill (136). Later, Procopius would describe the plague of Justinian (542-43) with such exactitude that later researchers could identify it as bubonic, which corresponds to an increasing prevalence of rats brought over in ships from foreign military campaigns. McNeill cites the devastation of this cycle of disease added to Rome’s already attenuated infrastructure, as putting an end to the Empire.