Plagues and Peoples (13 page)

Exact definition of disease balances is altogether impossible, even for the oldest and best-known of these centers, in the Middle East. Here the original irrigation core had been supplemented after about 2000
B.C
. by the establishment of cities and organized states on rain-watered land. Civilized patterns of social organization thereafter became endemic wherever good agricultural soil was to be found. A broad belt of civilized lands therefore arose on both the eastern and western flanks of Mesopotamia; a more slender fringe also expanded Egyptian influence into both eastern and northern Africa.

The ebb and flow of empires these circumstances permitted is well known. Akkadian, Babylonian, Kassite, Mittanian, Hittite, Egyptian, Assyrian, Chaldean, and Persian conquerors
succeeded one another amid tumultuous war and recurrent influxes of barbarians from the borderlands. Successive imperial structures tended to grow ever larger and better organized, expanding toward natural limits set by those conditions of soil and climate that restricted peasant agriculture. With the establishment of the Persian empire in the sixth century
B.C.
, these limits were approximately reached. By 500
B.C
., the borders of that empire—on the north, south, and east—abutted on steppe and desert lands where prevailing methods of cultivation would not have brought in lush enough crops to bear the cost of an expanded imperial administration.

To be sure, on the west a narrow Aegean gateway offered a prospect of expansion onto fresh and sufficiently fertile ground for supporting the imperial style of macroparasitism. But when Xerxes’ armies tried to make this possibility real, 480–479
B.C
., they met defeat, as much from difficulties of supply as from the valor of the leagued Greek cities that resisted the Persian invasion. A similar gateway existed far to the southeast in the Indian Doab, a fertile region between the up waters of the Indus and Ganges. The Persians made no recorded attempt to force this gate, however, and when Alexander of Macedón did try in 326
B.C
., his troops mutinied and refused to follow. As a matter of fact, a disease gradient that assured severe losses to any army invading from beyond the Himalayas was probably more effective in guarding this gateway than any merely human obstacle.

Can we also say that microparasitism achieved a kind of natural limit within the expanded circuit of Middle Eastern civilized society by about 500
B.C
.? Perhaps the forms of parasitism appropriate to irrigation farming and dependent on the specialized exposures to infection and infestation resulting from frequent wading in irrigation water had attained a fairly stable balance by 500
B.C
. Irrigation farming was at least 3,000 years old by then, and communication between its major centers in Egypt, Mesopotamia and the Indus Valley was sufficient to have permitted a thorough homogenization of parasitic organisms across the 2,000–3,000 years during
which these valleys had maintained contact with each other. Absence of evidence in written sources of any notable change in worm and related forms of infestation can scarcely be taken as confirmatory, since those who wrote paid practically no attention to the life conditions of the peasantry, and medical texts are completely opaque when it comes to translating ancient terms into modern disease classifications.

Written evidence does, however, clearly attest the appearance of epidemic diseases in the ancient Middle East. Among the disasters mentioned in the Babylonian
Epic of Gilgamesh
as preferable to the Flood was visitation from the god of pestilence, and an Egyptian text of about the same age (ca. 2000
B.C
.) compares fear of Pharaoh with fear of the god of disease in a year of pestilence.
¹
In China, too, the most ancient decipherable writings, dating back to the thirteenth century
B.C.
, show familiarity with infectious epidemic disease. “Will this year have pestilence and will it be deaths?” asked an ancient ruler of Anyang.
²
His expert diviners thereupon recorded the question in a form that modern scholars can read on the sheep’s shoulderblade used in ritually seeking an answer from the spirits.

Biblical texts are of substantially later date but may preserve oral traditions going back to about the same time. There may therefore well have been a historical basis for the plagues of Egypt described in the Book of Exodus. It is there stated that among the plagues Moses brought down upon Egypt were “sores that break into pustules on man and beast.”
³
Furthermore, a lethal visitation upon Egypt’s first-born in a single night left “not a house where there was not someone dead.”
⁴
One may also cite an epidemic visited on the Philistines as punishment for their seizure of the Ark; the pestilence that punished David’s sin of numbering the people, and killed, if the text of the Bible is to be believed, 70,000 out of 1, 300,000 able-bodied men in Israel and Judah; and the fatal visitation that “slew in the camp of the Assyrians one hundred and eighty-five thousand” overnight, and caused the Assyrian
king, Sennacherib, to withdraw from Judah without capturing Jerusalem.
⁵
,
⁶
,
⁷

Such passages make it certain that the writers of the Old Testament, when they put the text into its present form between 1000 and 500
B.C
., were quite familiar with the possibility of a sudden outbreak of death-dealing disease, and interpreted such epidemics as acts of God. Modern translators regularly used the term plague for such events, since the principal disease that continued to manifest itself in this catastrophic fashion in Europe until the eighteenth century was bubonic plague.
⁸
There is, however, no good reason for supposing these ancient epidemics were outbreaks of bubonic plague. Any of the familiar civilized infections—whether propagated via the respiratory tract, like measles, smallpox, and influenza, or via the alimentary canal, like typhoid and dysentery—could have produced the sort of sudden outbreak of mortality recorded in the Bible.
⁹

All one can properly conclude therefore is that diseases of this type were familiar to ancient Middle Eastern populations well before 500
B.C
. and must have played roles of some importance in reducing population density from time to time and in affecting the course of military events. But the ravages of such diseases clearly were not enough to disrupt armies regularly nor to keep population below levels necessary for empire-building. Otherwise the Assyrian and Persian empires could not have flourished as they did between the ninth and fifth centuries
B.C
. 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. In other words, from the point of view of the disease organisms, they were on the way to arriving at a mutually tolerable accommodation to their human hosts. Animal reservoirs (as with bubonic plague) may of course have played a role in allowing some infections to survive between epidemic outbreaks, but human populations of the ancient Middle East were certainly large enough to sustain
the ancestors of modern childhood diseases on a fluctuating endemic basis.

In a few major centers of population and communication, where human chains of infection had an optimal chance of becoming permanently established, some of these diseases were probably becoming common childhood afflictions according to the pattern familiar today. Epidemic outbreaks would then occur mainly in outlying regions, where population density was insufficient to sustain the infection on a long-lasting basis, but where unusual conditions (often connected with military operations) might trigger a sudden outbreak of infection, intense enough and sufficiently disastrous to human life to attract the attention of the learned priests and scribes who shaped the biblical texts in which such events are referred to.

If these deductions are correct, civilized infectious diseases were only a little behind the diseases incident to irrigation agriculture in achieving a balance with their host populations in the ancient Middle East. As the locus of the oldest civilizations of the earth and one of the largest concentrations of human population in the world as of 500
B.C
., the Middle East offered adequate time and opportunity for microparasitic as well as macroparasitic balances to approach stability within conditions defined by village and city life. More particularly: since the earliest surviving literary references to epidemic disease date back to about 2000
B.C
., there had been sufficient time by 500
B.C
. for some reasonably stable patterns of infectious diseases to establish themselves in the anciently civilized, much fought over, and densely populated regions of the Middle East.
¹⁰

By contrast, greater instability prevailed in fringe areas where three different natural environments—the Yellow River flood plain, the monsoon lands of the Ganges Valley, and the Mediterranean coastlantds—had all become capable of supporting civilized social structures much more recently than was the case in the Middle East. Accordingly, in 500
B.C
. ecological balances were still precarious in these regions, and
there is reason to suppose that disease patterns were far less firmly fixed than in the Middle East.

Ecological instability can be attested in the first place by the comparatively massive population growth that was under way in each of these environments both before and after 500
B.C
. Evidence is circumstantial but no less certain on that account. Without large-scale increase in human numbers the territorial expansion that each of these civilizations underwent would have been impossible. In each case, moreover, population growth was associated with far-reaching technical adjustments in patterns of agriculture and with appropriate elaboration of the respective macroparasitic political and cultural structures that gave each civilization an enduring and characteristic form throughout subsequent history.
¹¹

In the Far East, Chinese peasants began to make real progress in farming the flood plain of the Yellow River from about 600
B.C
. This involved extending agricultural operations beyond the semi-arid environment of the loess soils where earlier Chinese agriculture had been at home, and shifting from millet to rice as the staple crop. A vast labor of diking, draining, canalization, and reclamation of swamp and marsh had to be carried through before the vast flood plain could be transformed into an almost unbroken carpet of rice paddies, each with a regulated access to water. In addition, the cultivated area as a whole had to be defended against dangers of flood and drought by an extensive and elaborate system of engineering works designed to control the tumultuous waters of the Yellow River.

This stream is one of the most geologically active large rivers in the world. Recently (geologically speaking) it annexed important tributaries from other drainage systems, and in making its way through the loess country in its middle course, the river erodes vast quantities of soil, cutting its channel deeper every year. When silt-laden waters then debouch upon the almost flat flood plain, the current slows so that massive deposition succeeds the no less massive erosion upstream. As a result, in the flood plain the river builds up its bed rather
rapidly. This made for trouble when men started to restrain the stream with artificial dikes. To be sure, the dikes could be built a little higher each year to match the deposition in the river’s bottom. But the result was that soon the great river began to flow seaward across the fertile flood plain above the level of the surrounding land. Enormous human effort was required to keep it there, since any runlet finding a pathway through a dike could quickly grow into a rushing torrent if not checked in time. Even a few hours might suffice to tear a gaping hole in the dike; and whenever massive gaps did occur, the entire river spilled out from its artificial bed, seeking a new, lower channel for itself. Several times the great river has thus shifted course by hundreds of miles, debouching either north (as at present) or south of the Shantung highlands.
¹²

The geological instability of the Yellow River was exacerbated but not created by human activity; and it will take geologic time spans for the river to achieve a more stable adjustment of its flow. Other dimensions of the ecological instabilities affecting early China were nearer the human scale. At the political level, for instance, the enlarged food resources produced by rice paddy cultivation sustained centuries of warfare among rival princes, until in 221
B.C
. a single conqueror mastered the whole Yellow River flood plain as well as a broad band of adjacent territory both north and south of the river. After one brief bout of further civil war, a new dynasty, the Han, emerged to supremacy in 202
B.C
., and remained in at least nominal control of all China until
A.D
. 221.

Internal peace secured by an imperial bureaucratic administration probably diminished the costs to the peasantry inherent in earlier chronic warfare. Yet the Han peace also meant consolidation of a double layer of human macroparasites upon peasant rice (and millet) fields. Private landowners, who extracted rents, and official representatives of the Emperor, who extracted taxes, from the same peasant population obviously were in competition, yet they also supported each other most effectively. Their interests were basically the same, for in fact,
the members of the imperial bureaucracy were recruited in large part from the landowning rentier class.