Definition
Although the definitions of the terms “epidemic” and “pandemic” remain inexact, authorities mostly agree that the difference between the two words is subtle and hinges on the geographical scale of the disease and the number of populations afflicted. Generally, an epidemic is a frequent, severe, and widespread outbreak of a specific disease, whereas a pandemic is a recurring epidemic that affects a very large area of the world.
Epidemics Before the Seventeenth Century
Civilization’s earliest written records periodically include accounts of devastating epidemics of unknown origin, epidemics that killed huge numbers of people and left behind disruption and despair. In 430 BCE, the city of Athens, Greece, was faced with a four-year epidemic known as the plague of Athens that appeared during the Peloponnesian War and reduced the Athenian population by 30 to 35 percent. Greek historian Thucydides, afflicted by a then-unknown disease, described its effects upon people, suggesting that it was not bubonic plague but, more likely, smallpox. Thought to have originated in Africa, smallpox was unknown to Athenians; consequently, Athens was likely a virgin-soil area.
Although by the fifth century BCE in ancient Rome, malaria was endemic to certain low lying areas, reaching epidemic proportions during late summer and fall, no evidence suggests how it affected the population. However, a series of epidemics swept through the Roman Empire, one of the most deadly being the plague of the Antonines, which struck Rome in 166 CE and lasted about fifteen years. The famous Greco-Roman physician Galen, who lived during this time, recorded descriptions of those stricken that imply the disease was smallpox. Estimates of this disaster (from nineteenth and early twentieth century writings) insist that one-half the Roman Empire population died, but later research suggests a loss of 10 percent of the population.
In the eighth century, smallpox epidemics ravaged Japan, and attacks of
leprosy (Hansen’s disease) in Europe between 1000 and about
1350 led to the construction of institutions for isolating lepers. Thought by
medieval Christians to be divine punishment for sin, and by physicians to reflect
an imbalance in the four humours (blood, phlegm, yellow bile, and black bile) that
are believed to inhabit the body, ideas about leprosy were influenced by medieval
attitudes. People of the time believed that epidemics resulted from God’s anger,
especially the deadly epidemic known as French disease, or syphilis,
which was spread through Europe by soldiers. Pustules appeared on infected bodies,
which soon seemed to rot. Response to this disease included the first prepared and
marketed remedy: mercuric ointment.
The encroachment of French disease into virgin-soil areas of Europe also was
similar to the vast sixteenth century American epidemics originating with Spanish
explorers and slaves who unwittingly spread microorganisms among the indigenous
peoples (who had no previous exposure). Spreading from the Caribbean region to
Mexico, in about 1520, smallpox took a huge toll on the Aztecs, on the peoples of
Panama, and on the Incas in South America, therefore reducing the indigenous
resistance to the Spanish conquerors. The later part of the century saw renewed
outbreaks of smallpox, measles, and typhus.
Epidemics: Seventeenth to Twenty-first Centuries
Few methods of disease exposure were more effective than war, particularly the Thirty Years’ War, which involved vast numbers of people in a large area of central Europe. Most battles raged through the Germanic areas, with many areas losing one-half their populations between 1618 and 1648. This century’s battles illustrated the interaction between war and epidemic disease that characterized armies in centuries to come. Wars carried diseases of influenza, typhus, and plague, yet, war’s chaos prevented any response to the diseases.
Also in the seventeenth century, a sequence of disasters, including famines,
floods, and epidemics that may have involved several different diseases (such as
typhus, typhoid
fever, malaria, dysentery, and bubonic and pneumatic
plague), ravaged China between 1635 and 1644. Much conjecture pertains to the
political implications of the losses of populations in certain areas and to
whether the crop failures associated with disasters contributed to dietary
deficiencies in a population more likely to succumb to disease.
In its devastation of huge areas of the world, smallpox attacked Iceland between 1707 and 1709, claiming the lives of one-quarter of the population. In 1721, Boston fell victim to a smallpox epidemic, leading to controversy between religion and science with regard to inoculation. The argument concerning inoculation continued during the eighteenth century smallpox rampage through European cities, with children being the most susceptible to the disease.
A severe late-eighteenth century epidemic of yellow fever
thwarted the efforts of British soldiers trying to take over Saint Domingue (now
Haiti) and ultimately facilitated the island’s bid for independence by its former
slaves. Another yellow fever epidemic farther north afflicted Philadelphia and was
possibly caused by fleeing Haitian refugees. As the capital of the new United
States, Philadelphia’s wresting with a deadly epidemic led to limitless political
speculation. In 1853, yellow fever struck New Orleans, a site of frequent
outbreaks, with its worst epidemic, leading to one-half of the recorded deaths in
that city in 1853.
In 1916, the United States sustained the world’s first major poliomyelitis epidemic, in the environs of New York City, striking mostly young children. Twenty-seven thousand Americans were afflicted by poliomyelitis and six thousand died from the disease. This epidemic initiated hysteria about poliomyelitis, whose numbers rose drastically between 1945 and 1955, and then declined spectacularly. In the 1980s, the number of diagnosed AIDS (acquired immunodeficiency syndrome) cases in the United States reached more than 160,000, soon declining significantly. Tuberculosis, sometimes connected with AIDS, is one of the most prevalent diseases in the world, as is malaria, whose death toll in the twentieth century varies between one and two million cases, most of these in Africa.
An epidemic of Ebola, with its first officially recorded case occurring in March 2014, was eventually sourced to an initial case in a small village in Guinea in late 2013. Over the following year, outbreaks of the virus began occurring rapidly in other West African countries, including Liberia, Sierra Leone, and Nigeria, resulting in the largest Ebola epidemic in history. According to the World Health Organization (WHO), by late 2015, the epidemic had led to the deaths of more than eleven thousand people, and the first case had been declared in the United States shortly after a Liberian man had flown to the country to visit family in September 2014. After worldwide panic, the WHO had finally declared Liberia, Sierra Leone, and Guinea free of Ebola by the end of 2015.
Pandemics: Plague and Cholera
The first plague pandemic began spreading from obscure origins in 540 BCE, moving through the Roman Empire into Asia in waves of disease for two hundred years. Although modern estimates of mortality vary widely, descriptions of those afflicted verify that the disease was bubonic plague. Thought to be sent by a vengeful God, the plague prompted changes in populations hitherto discussed only speculatively; however, recent archaeological discoveries have suggested more indirect answers.
The second plague pandemic began with the Black Death that originated in 1346 in southern Russia and spread, following trade routes, to the most densely populated areas in Europe, destroying more than one-third of its population by 1353. As the Black Death began to wane, other random but widespread outbreaks occurred in the next four hundred years, targeting Italian cities in the 1630s, London in 1665, Marseilles in 1721–22, and Moscow in 1771; it remained in northern Africa until 1844. Before the second plague pandemic was extinguished in Asia, another disease site took hold in China that would expand into the third plague pandemic. This third plague pandemic continued in Asia and then into Africa and the United States in the twentieth century. An estimated thirteen million people perished in the third plague pandemic, with most deaths between 1894 and 1912.
All seven cholera pandemics that afflicted vast areas of the world began in Bengal, India, in the Ganges River delta, where cholera had long been endemic. The first pandemic began in Calcutta in 1817 and spread into Thailand, the Philippines, Asia, Japan, the Persian Gulf, Syria, and Persia; by 1823, it had spread to the Russian Empire. The second cholera pandemic spread from Bengal in 1827 into Russia and continued westward to, for the first time, Europe and North America in 1832. Americans were suspicious of the immigrant poor, while many Parisians believed the cholera pandemic was an elitist plot to rid Paris of the poor. In 1839, the third cholera pandemic began in paths that moved from Bengal to other parts of the world, some of which had never seen cholera. The disease reappeared in Europe and North America, spreading widely into areas of the Caribbean and South America, where a shocking number of deaths occurred in Brazil and in Latin America. These deaths initiated inquiries about the connection between cholera and race.
The fourth cholera pandemic, beginning in 1863, traveled around the world and convinced many that cholera moved with “human traffic.” The fifth pandemic, beginning in 1881, extended across the Mediterranean to Italy, France, and Spain, then across the world to Argentina, Japan, and the Philippines. During this pandemic, Robert Koch, a German microbiologist, discovered a germ that is primarily in water (and in some food) and was responsible for cholera; but, as doubts and uncertainties reigned, positive response to his findings was slow in coming. The sixth cholera pandemic (1899) made less progress because of the growing insistence upon clean water supplies; and, the seventh cholera pandemic (1961), attacking Europe, Africa, Latin and Central America, and Mexico, left cholera endemic to some parts of the world.
Pandemics: Influenza and AIDS
In 1781–82, a massive pandemic of influenza spread from Russia into Europe and afflicted an estimated three-fourths of the population of Europe. Despite its high morbidity rate (the number of ill persons), the mortality rate was relatively low, as the disease proved fatal mostly to the elderly. A second influenza pandemic (1889–90), also beginning in Russia, extended worldwide by way of steamship and railroad travel. Morbidity was uncommonly high, calculated to be between one-third and one-half the world’s population. Historian David Patterson has estimated that this pandemic killed between 270,000 and 360,000 people in Europe.
The third influenza pandemic (1918–19) became the most extensive disease event in recorded history, with an estimated death toll of fifty million people. The pandemic traveled in three waves. The first one began in March of 1918 in Fort Riley, Kansas, and, following US troops to battle in World War I, appeared in western Europe in April. It then moved to China, India, Australia, and Southeast Asia. The second wave of the influenza pandemic, experiencing a resurgence in France and crossing the Atlantic, entered Boston in October of 1918 and moved westward to the Pacific Coast. Mortality rates in the United States were estimated at 5.2 per 1,000 persons. Another surge of the second wave progressed from France, to the Mediterranean areas, and to Scandinavia, Great Britain, Germany, eastern Europe, and Russia. The second wave, far more lethal than the first, was especially harsh for young adults between the ages of eighteen and thirty-five years. Also, the populations in Asia, Africa, and India were at greater risk of death, suffering disastrous mortality rates that were twelve times greater than those of Europe and North America. The pandemic’s third wave was milder than the second, raising the number of cases moderately as the disease was in decline.
After becoming known in the United States in 1981, AIDS began to spread worldwide within ten years, and by the end of the century, more than 25 million people had died in the pandemic. The region most affected by AIDS was Africa, with Zimbabwe, Zambia, and Malawi exceeding 500 cases per 100,000 persons. The number of persons in South Africa who are infected with the human immunodeficiency virus (HIV) reached 5.3 million by 2004. According to the charity organization AVERT, that number had risen to 6.3 million in 2013. In many African states, life expectancy has fallen below age forty years, as the disease strikes age groups between fifteen and forty-five years, and has increased the death rate of orphaned children. Also, the economic aspects are dire because the targeted age group is the most productive group of the African population.
In April 2009, a worldwide pandemic of H1N1 influenza effectively began with two cases in southern California (with cases possibly having occurred even earlier in Mexico). By June, the new, highly contagious version of the virus had spread to several other countries and the WHO had officially declared the situation a pandemic. By the time that the WHO had announced that the pandemic had ended in August 2010, thousands of people had died—and one of the most concerning statistics became the large percentage of the dead who were under the age of sixty-five, which was a departure from previous influenza strains. The WHO reported 18,500 laboratory-confirmed deaths, but this number was later believed to have been grossly underestimated; additional studies indicated that the true number of deaths may have been as high as 280,000.
Impact
Knowledge of major epidemics and pandemics from the beginning of recorded history provides insight into the beliefs and mind-sets peculiar to times that were unable to combat catastrophic diseases. With the gradual realization that epidemics demand responses from the medical community, world societies began to understand the need for clean water, antibiotics, vaccines, and quarantines. This knowledge also raises serious questions about the future of epidemics and pandemics from the standpoint of population shifts and growth, primarily in dense urban populations in warm climates, and about mass migration and the aging or younger populations who are especially at risk. Other serious considerations include the cost of public health measures, the effect of certain political imperatives, and the possibilities that those without money would be disregarded.
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