Plagues and Peoples by William H. McNeill Page A
Authors: William H. McNeill
Tags: 20th Century, Non-Fiction, European History, Plague, Medieval History, Biological History, Social History, Cultural History, v.5, disease, Medical History
Ads: Link
and their human hosts was (and is) still evolving very rapidly, in response to the altering circumstances and conditions of human life.
Searching historic records for evidence of when and where the ancestors of our modern childhood diseases first invaded human populations can be quite frustrating. First of all, ancient medical terminology cannot easily be fitted to modern classifications of disease. Symptoms alter, and undoubtedly have altered, so much as to be unrecognizable. At first onset, a new disease often exhibits symptoms that later disappear when the host population in question has had time to develop resistance.
The fulminating symptoms that syphilis initially exhibited in Europe is a familiar example of this phenomenon from the past. Similar episodes can be observed today whenever a new disease invades a previously isolated community for the first time. Symptoms can, indeed, be such that they completely disguise the nature of the disease from all but expert bacteriological analysis. Thus, for example, when tuberculosis first arrived among a tribe of Canadian Indians, the infection attacked organs of their bodies which remained unaffected among whites. Symptoms—meningitis and the like—were far more dramatic, and the progress of the disease was far more rapid, than anything associated with tuberculosis infections among previously exposed populations. In its initial manifestations, only microscopic analysis allowed doctors to recognize the disease as tuberculous. By the third generation, however, the tuberculosis infection tended to concentrate in the lungs, as mutual accommodation between hosts and parasites began to approximate the familiar urban pattern. 37
The process of adaptation between host and parasite is so rapid and changeable that we must assume that patterns of infection prevailing now are only the current manifestations of diseases that have in fact altered their behavior in far-reaching ways during historic times. Yet in view of the figure of half a million needed to keep measles in circulation in modern urban communities, it is noteworthy that a recent estimate of the total population of the seat of the world’s oldest civilization in ancient Sumeria comes out to exactly the same figure. 38 It seems safe to assume that the Sumerian cities were in close enough contact with one another to constitute a single disease pool; and if so, massed numbers, approaching half a million, surely constituted a population capable of sustaining infectious chains like those of modern childhood diseases. In subsequent centuries, as other parts of the world also became the seats of urban civilizations, ongoing infectious chains became possible elsewhere. First here, then there, one or another disease organism presumably invaded available humanhosts and made good its lodgment in the niche increasing human density had opened for it.
Person to person, “civilized” types of infectious disease could not have established themselves much before 3000 B.C . When they did get going, however, different infections established themselves among different civilized communities in Eurasia. Proof of this fact is that when communications between previously isolated civilized communities became regular and organized, just before and after the Christian era, devastating infections soon spread from one civilization to another, with consequences for human life analogous to, though less drastic than, what happened to rabbits in Australia after 1950.
Closer consideration of these events will be reserved for the next chapter. Here it seems only needful to reflect briefly about the general historical consequences of the establishment of these distinctively civilized sorts of diseases in a few centers of unusually dense human population between 3000 and 500 B.C .
First and most obvious: patterns of human reproduction had to adjust to the systematic loss of population that resulted from exposure to diseases that flourished under
Searching historic records for evidence of when and where the ancestors of our modern childhood diseases first invaded human populations can be quite frustrating. First of all, ancient medical terminology cannot easily be fitted to modern classifications of disease. Symptoms alter, and undoubtedly have altered, so much as to be unrecognizable. At first onset, a new disease often exhibits symptoms that later disappear when the host population in question has had time to develop resistance.
The fulminating symptoms that syphilis initially exhibited in Europe is a familiar example of this phenomenon from the past. Similar episodes can be observed today whenever a new disease invades a previously isolated community for the first time. Symptoms can, indeed, be such that they completely disguise the nature of the disease from all but expert bacteriological analysis. Thus, for example, when tuberculosis first arrived among a tribe of Canadian Indians, the infection attacked organs of their bodies which remained unaffected among whites. Symptoms—meningitis and the like—were far more dramatic, and the progress of the disease was far more rapid, than anything associated with tuberculosis infections among previously exposed populations. In its initial manifestations, only microscopic analysis allowed doctors to recognize the disease as tuberculous. By the third generation, however, the tuberculosis infection tended to concentrate in the lungs, as mutual accommodation between hosts and parasites began to approximate the familiar urban pattern. 37
The process of adaptation between host and parasite is so rapid and changeable that we must assume that patterns of infection prevailing now are only the current manifestations of diseases that have in fact altered their behavior in far-reaching ways during historic times. Yet in view of the figure of half a million needed to keep measles in circulation in modern urban communities, it is noteworthy that a recent estimate of the total population of the seat of the world’s oldest civilization in ancient Sumeria comes out to exactly the same figure. 38 It seems safe to assume that the Sumerian cities were in close enough contact with one another to constitute a single disease pool; and if so, massed numbers, approaching half a million, surely constituted a population capable of sustaining infectious chains like those of modern childhood diseases. In subsequent centuries, as other parts of the world also became the seats of urban civilizations, ongoing infectious chains became possible elsewhere. First here, then there, one or another disease organism presumably invaded available humanhosts and made good its lodgment in the niche increasing human density had opened for it.
Person to person, “civilized” types of infectious disease could not have established themselves much before 3000 B.C . When they did get going, however, different infections established themselves among different civilized communities in Eurasia. Proof of this fact is that when communications between previously isolated civilized communities became regular and organized, just before and after the Christian era, devastating infections soon spread from one civilization to another, with consequences for human life analogous to, though less drastic than, what happened to rabbits in Australia after 1950.
Closer consideration of these events will be reserved for the next chapter. Here it seems only needful to reflect briefly about the general historical consequences of the establishment of these distinctively civilized sorts of diseases in a few centers of unusually dense human population between 3000 and 500 B.C .
First and most obvious: patterns of human reproduction had to adjust to the systematic loss of population that resulted from exposure to diseases that flourished under
Similar Books
