Until the beginning of the twentieth century, infectious diseases were by far the most important causes of mortality; they took their greatest toll among infants and children. Indeed, if individuals managed to survive to the age of twenty, they could for the most part look forward to an additional forty years or more of life. High rates of infant and child mortality (as well as fertility) meant that the number of aged persons in the population would be correspondingly small. Hence, chronic and long-term diseases—many related to advancing age—were less important causes of mortality. To emphasize the significance of infectious diseases, however, is not to imply that their impact on populations was constant. Infectious diseases appeared and disappeared and were often dependent on the interaction of social, economic, behavioral, and environmental factors. Nowhere is this better illustrated than in the history of health and disease in late-eighteenth and early-nineteenth-century America.
The first settlers who came to the North American continent in the seventeenth century faced a strange and unfamiliar environment. In the initial stages of settlement, there were extraordinarily high death rates from dysentery, typhoid fever, a variety of enteric diseases, and respiratory infections. Nutritional diseases, inadequate housing, contaminated water supplies, and deficient disposal of organic wastes further compounded health risks. New England and the mid-Atlantic or middle colonies adjusted to their new environment relatively quickly, and mortality rates declined rapidly. The rural character of these colonies also minimized the spread of epidemic and endemic infectious diseases. The environment of the Chesapeake and southern colonies, by contrast, was far more threatening to human life. In addition to gastrointestinal disorders, the presence of infected individuals and insect vectors made malaria one of the gravest health problems in these areas. High mortality rates made it difficult for the white population to sustain itself through natural growth. The overwhelming majority of individuals who lived through the vicissitudes of infancy and childhood and reached the age of twenty rarely survived to the age of fifty. Unlike their neighbors to the north, the residents of the Chesapeake and southern settlements continued to face an environment that posed severe health risks.
The native Indian population was hardest hit by the movement of Europeans to the Americas. During the seventeenth and eighteenth centuries, their numbers declined rapidly because of the impact of imported diseases. Having never been exposed to many of the diseases common in England and Europe, they constituted a highly vulnerable population. High mortality from infectious diseases (notably smallpox), periodic famines, and the social dislocations that accompanied these crises also reduced fertility to such low levels that population recovery became impossible. From a high of three thousand in the late seventeenth century, the Indian population on Nantucket had fallen to twenty by 1792. Much the same was true for many other East Coast tribes.
After the dangers posed by a new environment were surmounted, population began to grow rapidly. Between 1700 and 1770 there was a ninefold increase from 250,000 to an estimated 2.15 million. Health indicators in the Northeast and middle colonies improved dramatically during these decades. Nevertheless, increasing population density, the expansion of internal and external trade and commerce, the development of new forms of agriculture, and the transformation of the landscape began to alter health patterns. Toward the end of the eighteenth century, there was an increase in mortality from a variety of infectious diseases, particularly among infants and children and residents of larger towns and urban port areas. In the seventeenth century the rural character of colonial society inhibited the spread of infectious epidemic diseases that had such a dramatic impact on societies in Europe, Asia, and the Middle East. In the eighteenth century, by contrast, colonial port communities began to experience the ravages of infectious epidemic diseases. Although small if not infinitesimal by modern standards, they contained larger numbers of people living in close quarters. The maritime character of Boston, New York, Philadelphia, and Charleston—the most important colonial ports—brought their residents into contact with each other and, more important, with Europe, the Caribbean, and Africa. These ports were also the entry points for both sailors and immigrants. Such population movements became the means of transporting a variety of pathogens capable of causing epidemic outbreaks. Moreover, the physical environment of port villages—crowded living conditions, crude sewage disposal, and stagnant or contaminated water—facilitated periodic epidemics. Many residents were susceptible to the invading pathogens and hence lacked antibodies that prior exposure would have produced. The large number of susceptible individuals facilitated the rapid spread of infectious diseases.
During the eighteenth century periodic smallpox epidemics became common in New England and the middle colonies. Despite efforts at containment, it was difficult to prevent the spread of the disease. The movement of people in trade and commerce provided a convenient means of transporting the virus. The war with the French in the 1760s merely exacerbated the problem. In Philadelphia, smallpox was the single largest cause of mortality during the third quarter of the eighteenth century. The disease was less significant in the Chesapeake and South because a more dispersed population and an agricultural economy inhibited the spread of the virus (which can only survive in human tissue). South Carolina was an exception, since Charleston was an important seaport and commercial center with links to the interior. It therefore served as a port of entry for infectious diseases. In 1760, 6,000 of 8,000 residents were infected with smallpox, and estimates of mortality ranged from a low of 730 to a high of 940.
Smallpox was by no means the only imported disease. Yellow fever (a viral disease) was another. Transmitted by an insect vector biting an infected individual, it flourished in moist tropical areas. During the first two-thirds of the eighteenth century, there were at least twenty-five outbreaks. The interruption of trade during the Revolutionary crisis caused the disease to disappear. But with the return of peace, yellow fever returned. In 1793 Philadelphia experienced an epidemic that threatened its very existence. A slave rebellion in French Saint Domingue (later Santo Domingo) brought two thousand refugees to the city, some of whom were infected. A hot and humid summer provided ideal conditions for the proliferation of the mosquito population. Perhaps half of the fifty-one thousand residents fled the city during the outbreak. Of those that remained, a large number became ill and between 9 and 12 percent perished. Nor was Philadelphia the only city to experience an epidemic. Between 1793 and 1822 yellow fever was also present in Baltimore, Boston, and New York. After the latter year it disappeared from New England and the mid-Atlantic states, where the climate was not conducive to the insect vector, while appearing periodically in the South, notably New Orleans, which had five epidemics between 1804 and 1819.
Spectacular periodic smallpox and yellow fever epidemics tended to overshadow other diseases that played a more important role in shaping population development. Indeed, the health advantages enjoyed by seventeenth-and early-eighteenth-century settlements, once the period of adjustment passed, slowly began to diminish. In the eighteenth century infectious diseases traditionally associated with infancy and childhood became common. Many of these diseases were not indigenous to the Americas. When imported they affected the entire population, since adults as well as children were susceptible. Measles, for example, struck New England and the mid-Atlantic colonies; the Chesapeake and South were less affected. Mortality from measles was extraordinarily high, equaling modern death rates from cancer and cardiovascular diseases. Other infectious diseases, including diphtheria, scarlet fever, pertussis (whooping cough), and chickenpox, also resulted in high mortality.
Despite high mortality rates associated with periodic epidemics, certain endemic diseases—notably dysentery and malaria—took a far higher toll. In general, sporadic and spectacular outbreaks of epidemic diseases produced much greater fear than did endemic diseases that had a much greater demographic impact. Dysentery was undoubtedly the most significant disease in eighteenth-century America. Outbreaks were especially common in such towns as Boston, New York, Philadelphia, and Charleston. These ports were the entry points for ships bringing thousands of immigrants to the colonies. Conditions aboard vessels were conducive to outbreaks of dysentery, and infected immigrants disseminated the causative pathogens upon their arrival. Infants and children were especially vulnerable, since there was no understanding that dehydration could lead to rapid death. Local data revealed that during an epidemic, perhaps half of a community's population would become infected and that one of every six or seven would perish.
Malaria had the same endemic characteristics as dysentery. Although important south of the Mason Dixon line, it had its greatest impact in South Carolina, where the cultivation of rice and indigo created ideal conditions for the breeding of the anopheles mosquito. The colony acquired a deserved reputation as a graveyard. High mortality among whites provided a rationale for the introduction and spread of slavery, since they believed that Africans were better equipped physiologically to labor in a sunny, hot, and humid climate.
Most eighteenth-century respiratory disorders were endemic and seasonal in character. But the growth of population and expansion of trade rendered the colonies somewhat more vulnerable to influenza pandemics and epidemics. By the time of the American Revolution, the newly independent colonies had become part of a larger disease pool. In 1781-1782 and 1788-1789, influenza appeared in pandemic form, affecting millions of people in both Europe and America. Nevertheless, case fatality rates remained low, although it did pose a mortal threat to elderly and chronically ill persons.
During these decades, tuberculosis and other pulmonary disorders also emerged as important causes of mortality. They were most prevalent in more densely populated areas, although rural areas were affected as well. The critical element was not total population, but household size. Many households contained from seven to ten inhabitants, thus permitting the dissemination of the tubercle bacillus and other pathogens. Moreover, relatively inefficient heating led inhabitants to seal windows and doors. Behavioral patterns thus facilitated the spread of the infection within households.
Nowhere was the complex relationship between pathogens, humans, and the environment better illustrated than during war. In the American Revolution a large number of recruits came from rural areas and had never been exposed to many common communicable diseases. Crowded camp quarters and contaminated water supplies from both human and animal wastes, inadequate diets, and the absence of personal hygiene provided ideal conditions for the spread of infectious diseases. Perhaps 200,000 served in the military (comprising the total of all American armed forces, including militia). About 7,100 were killed in military engagements, 10,000 died in camps, and 8,500 perished as prisoners of war. Deaths in camps and among prisoners resulted from a variety of diseases, notably dysentery and respiratory disorders. A similar situation prevailed during the War of 1812. About two and half times as many soldiers perished from disease or accident as were killed in battle.
Toward the end of the eighteenth century, mortality from infectious diseases began to increase. In New England and the mid-Atlantic regions, this increase did not appreciably affect population growth. Mortality, however, was not equally distributed. After 1760 health indicators improved among the white middle and upper classes. Among the poor—both white and black—mortality rose. Philadelphia—a center of commerce and immigration—proved to be a dangerous place. Its mortality rates, particularly among recent immigrants, exceeded many European cities. Despite high fertility, Philadelphia's growth was made possible only because of migration from rural areas and immigration of younger people.
Mortality rates in the South remained excessive even by the standards of that age. South Carolina presented the greatest risks to life; the Chesapeake region and North Carolina followed. Without a constant supply of immigrants to replenish a population devastated by extraordinary mortality rates, these areas would not have developed economically and their very survival as societies would have become dubious. Neither wealth nor status conferred a distinct advantage insofar as survival was concerned. Mortality rates, admittedly unequally distributed, remained high among all groups, both white and black.
By the beginning of the nineteenth century, the health advantages that Americans had enjoyed after the initial period of adjustment had begun to diminish. Rapid population and economic growth created conditions conducive to the spread of infectious diseases. In succeeding decades, health indicators would begin to fall. Ironically, the increase in mortality and decline in life expectancy occurred at a time when the standard of living was rising.
Although the United States was still a predominantly rural nation, cities were growing in number, size, and importance. Their growth, together with the simultaneous acceleration in economic activity, magnified the risks from infectious diseases. Municipal governments moved relatively slowly in protecting health. There was little provision for safe and accessible water supplies or removal of wastes. Because horses were used for transportation, streets were covered with manure. Housing standards were virtually unknown; there were no provisions for drainage or ventilation in most structures. The accumulation of organic wastes and rising odors caused inhabitants to keep their windows shut, thus preventing the circulation of fresh air and facilitating the dissemination of infectious organisms. The movement of large masses of immigrants and susceptible individuals from rural areas only served to magnify the impact of infectious diseases.
In these urban areas, tuberculosis and pulmonary diseases took a high toll. Nearly a quarter of all deaths in Boston between 1812 and 1821 were due to "consumption" (a generic category that included tuberculosis and other pulmonary diseases). Native-born whites had the lowest mortality rate, African Americans the highest, and foreign-born individuals fell between the two. The circumstances of urban life—crowding and the absence of facilities to bathe and wash clothes, among other things—led to the emergence of such infectious diseases as typhus, which at times could result in a mortality rate of 50 percent in adult populations. Other infections—diarrheal and respiratory diseases, diphtheria and croup, measles, whooping cough, and scarlet fever—added to the burden of disease. Mortality was largely a function of age: infants and children were at highest risk. In 1830, 1,974 deaths were recorded in Baltimore. Of these, 406 were under the age of 1 and 932 under 10. Suicide, homicide, accidents, and occupational diseases also contributed to total urban mortality. To emphasize that infectious diseases were the major element in urban morbidity and mortality patterns is not to suggest that such chronic and long-duration diseases as cancers, cardiovascular and renal diseases, and diseases of the central nervous system were absent. Their incidence and prevalence, however, were low, because high mortality rates among the young meant that the older cohort constituted a relatively small percentage of the total population.
Rural areas had lower mortality rates than their urban counterparts. For the nation as a whole in 1830, about 54 percent of those alive at age 5 survived to 60. In rural areas the figure was 5 7.5 percent, as compared with 43.6 in such small towns as Salem, Massachusetts, and New Haven, Connecticut, and 16.4 in the large cities of Boston, New York, and Philadelphia. Nevertheless, the increase in mortality that set in toward the end of the eighteenth century was not confined to cities; the same occurred in rural areas.
Aggregate data reveal the magnitude of the decline. In the period from 1800 to 1809, a white male and female age 20 could expect to live an additional 46.4 and 47.9 years, respectively; by 1850 to 1859 the comparable figures were 40.8 and 39.5. Declining life expectancy was also accompanied by a decline in height as well. By the American Revolution, Americans had achieved heights not fundamentally different from their twentieth-century successors; during and after the 1820s heights declined, reflecting a comparable decline in health. In these decades the standard of living rose, calling into question the familiar generalization that health indicators rise with increasing affluence.
What accounts for the declining health of Americans, a decline that lasted beyond the Civil War and was not reversed until the end of the nineteenth century? The answer to this question remains somewhat murky. Whatever the reasons, it is clear that economic development negatively affected health. The beginnings of a national transportation network increased both internal migration rates and interregional trade and thus contributed to the movement of pathogens from urban to rural and semirural regions where more susceptible populations resided. The movement across the Appalachian Mountains after the War of 1812 enhanced the significance of such debilitating and fatal diseases as malaria and various forms of dysentery, to say nothing about the health risks in a new and undeveloped environment. The rise of artisan workshops and factories concentrated employees in surroundings conducive to the spread of infectious diseases. The advent of large-scale migration of poor immigrants exacerbated the prevailing disease environment, particularly in urban areas. Fundamental changes would be required to alter an environment in which infectious diseases flourished.