Infectious Diseases

A Geographic Guide

Eskild Petersen, Lin Hwei Chen, Patricia Schlagenhauf-Lawlor, Eskild Petersen, Lin Hwei Chen, Patricia Schlagenhauf-Lawlor

• Publisher: Wiley-Blackwell
• Year: 2017
• ISBN:
  9781119085744
• Edition: 2
• Topic: Medicine
• Subtopic: Infectious Diseases

The second edition of this concise and practical guide describes infections in geographical areas and provides information on disease risk, concomitant infections (such as co-prevalence of HIV and tuberculosis) and emerging bacterial, viral and parasitic infections in a given geographical area of the world.

• Geographic approach means that its the only book to guide the health care worker towards a diagnosis based on the location of symptoms and travel history by encouraging the question where have you been?
• New content covering MERS, Ebola, Zika, and infections transmitted during air and maritime travel
• Covers the major infectious disease outbreaks framed in their geographic setting such as H7N9 bird flu influenza, H1N1, Ebola, and Zika
• Outstanding international editor team with vast experience on various international infectious disease and as journal editors and key leaders in infection surveillance

Chapter 1
Historical overview of global infectious diseases and geopolitics

Francis E.G. Cox^† and Frank J. Bia¹

¹Department of Internal Medicine, Infectious Disease Section, Yale School of Medicine, New Haven, Connecticut, USA

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Following the migration of Homo sapiens out of Africa, our species interbred with other archaic humans while spreading through present‐day Europe, Africa, Asia, and Australia, ultimately arriving in the New Worlds of current‐day North and South America. Over subsequent millennia, national boundaries have largely been shaped by discrete populations of our human species, through the retention or acquisition of strategically important land areas necessary to satisfy their needs for resources such as food, settled agriculture and trade. Wars and conquest, for which we have only relatively recent information covering the past few millennia, have played important roles in these events. However, a number of infectious diseases, including cholera, leprosy, typhoid, typhus, plague, tuberculosis, measles, smallpox, yellow fever, and malaria, have also played significant roles in important historical events that we know of. This chapter highlights ways in which infectious diseases have influenced the course of recent human history and often changed political maps of the world.

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Introduction

Superimposed upon physical maps of the world are political maps that show not only natural boundaries, but also boundaries created by humans through their acquisition of territories by conquest and colonization or subjugation by force. Geopolitics, a term that has had many meanings, some politically extreme, is concerned with “… power relationships in international politics including, inter alia, the acquisition of natural boundaries, the control of strategically important land areas and access to sea routes” – Kjellén’s original definition that will be adopted here [1,2].

The present‐day political maps of the world have been determined largely by earlier human migrations, and ultimately both military successes and failures. Throughout history, civilian casualties and deaths have been regarded as unfortunate consequences of conflicts. The role played by disease among both armies and civilians is seldom acknowledged despite the fact that in virtually all wars, morbidity and loss of life from disease have massively exceeded losses caused by weapons [3,4]. It can, therefore, be argued that disease within civilian populations, during and as an aftermath of conflict, has been as important in shaping the political maps of the world as military successes or failures [5].

Most anthropologists agree that our species, Homo sapiens, emerged in Africa about 150–200 000 years ago and from c.70 000 BC dispersed in waves throughout the world until by the end of the last ice age, c.10 000 BC, we had occupied most of the inhabitable planet except New Zealand and some other isolated islands [6]. The world’s population of modern humans was then about 1 million, but increasing and discrete populations began to covet territory that others already occupied, thus leading to conflict and occupancy – the beginnings of geopolitics. Acquisition of territory became more important as the population of the world grew to about 10 million by 3000 BC and nearly 500 million by AD 1500 when the political world as we know it today began to take shape [7]. Nearly all that we know about the epidemiology and effects of infectious diseases dates from about 1500.

The most important diseases in the past, as now, were those caused by microbial pathogens (broadly speaking, viruses, bacteria and protozoa) that multiply within their hosts, causing an immediate threat unless brought under control by an immune response. Individuals differ in their degree of susceptibility or resistance to infection and, over time, as more susceptible individuals die out, those who are more resistant pass on their genes. Thus whole populations develop “herd immunity” which protects them against diseases prevalent in their particular environment and communities [8]. When such individuals move into areas where there are infections to which they have not developed herd immunity, they rapidly succumb and, conversely, spread their own infections among susceptible local inhabitants. This is an oversimplification that takes no account of such factors as the role of nutrition, which markedly affects an individual’s capacity to resist infection. It has been argued that improvements in nutrition have, over the centuries, enabled populations to withstand diseases that would have killed their ancestors [9]. This is a study in itself and will not be considered further in this chapter,

Of approximately 150 common infectious diseases, 28 that are caused by viruses, 35 by bacteria and six by protozoa are the most serious [10,11]. Of these, cholera, leprosy, typhoid, typhus, plague, tuberculosis, measles, smallpox, yellow fever, and malaria in particular have, in turn, markedly affected the course of history [12]. Region by region, the following sections will discuss ways in which some of these diseases exerted profound changes upon the history of the world. The topics covered are, of necessity, selective and for more information, particularly regarding the background, the reader is referred to the following references: [2,5,9,10,13–24], for historical continuity [25–27], and for more information on disease and geopolitics [28].

The Near East and North Africa

Human civilizations emerged somewhere between 12 000 and 10 000 years ago in this region and by 2000 BC there were great cities and populations that stretched over Mesopotamia, Egypt, North Africa and the Mediterranean. For nearly 30 centuries, great empires including Babylonian, Phoenician, Persian, Greek, and Roman came and went until the rise of Islam in the seventh century AD. We know both from military and civilian records and archaeological evidence that several infectious diseases, including tuberculosis, leprosy (brought from India by the troops of Alexander III), typhus, typhoid, and malaria, existed in the region, but there appear to have been no epidemics that could have significantly altered the course of history. There is, however, one intriguing possibility. Alexander III (the Great), having amassed a great empire and having conquered the Greek, Persian, Syrian, Phoenician, and Egyptian empires, was on the brink of bringing much of Asia and parts of Europe under his control when he died suddenly in 323 BC. He had successfully led his Macedonian troops in conquests but died following an 11‐day illness contracted after sailing down the Euphrates River, while inspecting marshlands near the Arabian border. Although most commentators believe that he was poisoned, some feel that he died of typhoid or malaria [10,29]. Because he experienced continuous fevers during the illness, it is more compatible with typhoid. After Alexander’s death, his empire was divided among his generals and began its terminal decline. If this decline resulted from Alexander’s death caused by an infection, this could be the earliest documented example of an infectious disease changing the course of history. There is a need for some caution here because many historians believe that his death merely accelerated an historical process that would have inevitably occurred within the next decade or two.

The rise of Islam in the seventh century might also be traced back to the effects of an infectious disease. By 632 AD most of the Arab world had converted to Islam and the next target for conversion was the Byzantine empire, the successor of the Roman West (see below), and its capital, Damascus, which fell after a siege in 634. The origins of this defeat can be traced back to 542 when the “Justinian Plague” (see below) frustrated plans to reunite the Roman empire after which neither the Roman nor Byzantine armies ever recovered. By 634 each was so weakened that Damascus surrendered with hardly a fight. What followed was an Islamic golden age during which Islam spread throughout the Mediterranean area and into Spain and southern France. It is tempting to speculate that if the fall of Damascus can be traced back to the Justinian Plague of 542, and had Damascus not fallen, the advance of Islam might have been halted.

Europe

By 7000 BC, farming was established in Europe and for the next 6000 years people lived in small tribes on farms or within small villages. Several infectious diseases must have been prevalent but, because of the scattered nature of the population, it is unlikely that there were any significant epidemics. This situation changed with the development of the first city states which brought people together in large numbers and witnessed the growth of military expeditionary forces. The first European city state, Athens, emerged as a major power in about 750 BC and flourished until it was defeated by its rival, Sparta, in the Peloponnesian wars (431–405 BC), after which it fell into decline [30].

The outcome of the wars was determined less by superior military achievements than by the arrival from Africa, via Egypt, Libya, and Persia, of the “Plague of Athens” that killed an estimated one‐quarter to one‐third of the population of Athens. Pericles, then ruler of Athens, attempted to hold back his troops and sit out a siege by the Spartans until they requested a truce. Having fortified and protected Athens, along with its port of Piraeus, inside wooden walls, the Athenians experienced an unexpected influx of refugees from the countryside as the Spartans advanced. The city rapidly became overcrowded, setting the stage for the oldest epidemic ever recorded. It was documented by Thucydides and included the loss of both Pericles and about a quarter of the Athenian frontline troops and cavalry [10]. The cause was possibly louse‐borne typhus, for which besieged Athens’ crowded and humid conditions were ideal. Measles and smallpox have also been suggested but the actual cause will probably never be known [31]. We do know, however, that the Spartans were spared.

The next great power to emerge in Europe was the Roman empire. By the third century AD, its dominance had spread until it included nearly all of Western Europe, North Africa and the Near East [32]. Under a series of ambitious military emperors, however, the empire grew so large that it became almost ungovernable and by the beginning of the fourth century it had split into the West, centered on Rome, and the East, centered on Constantinople. By the end of the fifth century, the empire had begun to disintegrate. Most of the West had succumbed to the invading Visigoths, while the East became the precursor of the Byzantine empire. In 540, one final abortive attempt to restore the old Roman empire was begun by the Emperor Justinian. By then he had regained most of the former Mediterranean possessions and hoped to retrieve the more important Eastern section. He was, however, stopped in his tracks by the arrival of the “Plague of Justinian” (541–2). Because we have the writings of Procopius of Caesarea and his detailed descriptions of its signs and symptoms, most experts agree that this was bubonic plague that had spread from Alexandria to Constantinople, where it killed an estimated 5–10 000 people every day. This may have been the first epidemic of bubonic plague in Europe that continued for 200 more years. Because of the “plague” Justinian could not raise the armies required for his campaign and was forced to abandon his ambitious plans. This eventually led to the terminal decline of the Roman empire. The estimated overall death toll in the two empires is estimated to have been 100 million [10].

Bubonic plague spread through Western Europe, beginning in 547, and continued to recur sporadically for the next 200 years until it virtually disappeared there for 600 years. However, plague returned with a vengeance in 1347 as the “Black Death.” The origins of this epidemic are obscure, but it appears to have emerged around 1300 along the Caspian Sea and spread to both the Crimea and Constantinople by 1346–7. On the Black Sea, while the Tartar army was laying siege to Kaffa in the Crimea, it was caught up in the plague pandemic. The invaders catapulted the bodies of plague victims into the city – perhaps one of the first examples of germ warfare [33,34]. Beginning inconspicuously with the arrival of infected Genoese merchants from the Black Sea at the port of Messina, Sicily, the infection spread with amazing rapidity throughout Europe. In less than 10 years, it had reduced Europe’s population from about 75 million people to less than 50 million. The plague was particularly hard on the populations of great cities such as Venice, Florence, Genoa, London, Paris, and Barcelona, some of which lost half their population. Plague also affected even the most remote rural areas, taking with it princes, clergy, and peasants, leaving Europe in a state of chaos. Agriculture failed and millions who had survived the plague died of starvation. As a result of plague, the former feudal system fell into abeyance; a shortage of labour occurred and peasants realized that labourers were worth their wages – with implications that lasted for centuries. Other long‐lasting effects included the irrevocable loss of whole villages, migration to larger conurbations and a diminution of the authority of Church and state which could not control the disease [34].

The cause of plague was unclear and the Church had very little to offer ...