A brief history of malaria by London school
Malaria occupies a unique place in the annals of history. Over millennia, its victims have included Neolithic dwellers, early Chinese and Greeks, princes and paupers. In the 20th century alone, malaria claimed between 150 million and 300 million lives, accounting for 2 to 5 percent of all deaths (Carter and Mendis, 2002). Although its chief sufferers today are the poor of sub-Saharan Africa, Asia, the Amazon basin, and other tropical regions, 40 percent of the world’s population still lives in areas where malaria is transmitted.
Ancient writings and artifacts testify to malaria’s long reign. Clay tablets with cuneiform script from Mesopotamia mention deadly periodic fevers suggestive of malaria. Malaria antigen was recently detected in Egyptian remains dating from 3200 and 1304 BC (Miller et al., 1994). Indian writings of the Vedic period (1500 to 800 BC) called malaria the “king of diseases.” In 270 BC, the Chinese medical canon known as the Nei Chin linked tertian (every third day) and quartan (every fourth day) fevers with enlargement of the spleen (a common finding in malaria), and blamed malaria’s headaches, chills, and fevers on three demons—one carrying a hammer, another a pail of water, and the third a stove (Bruce-Chwatt, 1988). The Greek poet Homer (circa 750 BC) mentions malaria in The Iliad, as does Aristophanes (445-385 BC) in The Wasps, and Aristotle (384-322 BC), Plato (428-347 BC), and Sophocles (496-406 BC). Like Homer, Hippocrates (450-370 BC) linked the appearance of Sirius the dog star (in late summer and autumn) with malarial fever and misery (Sherman, 1998).
Malaria’s probable arrival in Rome in the first century AD was a turning point in European history. From the African rain forest, the disease most likely traveled down the Nile to the Mediterranean, then spread east to the Fertile Crescent, and north to Greece. Greek traders and colonists brought it to Italy. From there, Roman soldiers and merchants would ultimately carry it as far north as England and Denmark (Karlen, 1995).
For the next 2,000 years, wherever Europe harbored crowded settlements and standing water, malaria flourished, rendering people seasonally ill, and chronically weak and apathetic. Many historians speculate that falciparum malaria (the deadliest form of malaria species in humans) contributed to the fall of Rome. The malaria epidemic of 79 AD devastated the fertile, marshy croplands surrounding the city, causing local farmers to abandon their fields and villages. As late as the 19th century, travelers to these same areas remarked on the feebleness of the population, their squalid life and miserable agriculture (Cartwright, 1991). The Roman Campagna would remain sparsely settled until finally cleared of malaria in the late 1930s.
In India and China, population growth drove people into semitropical southern zones that favored malaria. India’s oldest settled region was the relatively dry Indus valley to the north. Migrants to the hot, wet Ganges valley to the south were disproportionately plagued by malaria, and other mosquito- and water-borne diseases. Millions of peasants who left the Yellow River for hot and humid rice paddies bordering the Yangtse encountered similar hazards. Due to the unequal burden of disease, for centuries, the development of China’s south lagged behind its north.
Although some scientists speculate that vivax malaria may have accompanied the earliest New World immigrants who arrived via the Bering Strait, there are no records of malaria in the Americas before European explorers, conquistadores, and colonists carried Plasmodium malariae, and P. vivax as microscopic cargo (Sherman, 1998). Falciparum malaria was subsequently imported to the New World by African slaves initially protected by age-old genetic defenses (sickle cell anemia, and G6PD deficiency) plus partial immunity gained through lifelong exposure. Their descendants, as well as Native Americans and settlers of European ancestry, were more vulnerable, however. Deforestation and “wet” agriculture such as rice farming facilitated breeding of Anopheles mosquitoes. By 1750, both vivax and falciparum malaria were common from the tropics of Latin America to the Mississippi valley to New England.
Malaria, both epidemic and endemic, continued to plague the United States until the early 20th century. It struck presidents from Washington to Lincoln, weakened Civil War soldiers by the hundreds of thousands (in 1862, Washington, D.C., and its surroundings were so malarious that General McClellan’s Army en route to Yorktown was stopped in its tracks), traveled to California with the Gold Rush, and claimed Native American lives across the continent. Until the Tennessee Valley Authority brought hydroelectric power and modernization to the rural South in the 1930s, malaria drained the physical and economic health of the entire region. Just as the United States was eradicating its last indigenous pockets of infection, malaria reclaimed Americans’ attention during World War II. During the early days of the Pacific campaign, more soldiers fell to malaria than to enemy forces. The United States’ premier public health agency—the Centers for Disease Control and Prevention—was founded because of malaria. By the time of the Vietnam War, the American military discovered that drug-resistant malaria was already widespread in Southeast Asia, a harbinger of the worldwide hazard it was destined to become.
But nowhere—past or present—has malaria exacted a greater toll than on Africa. A powerful defensive pathogen, it was a leading obstacle to Africa’s colonization. Portuguese traders who entered the African coastal plain in the late 1400s and early 1500s were the first foreigners to confront the killing fever. For the next 3 centuries, whenever European powers tried to establish outposts on the continent, they were repelled time and again by malaria, yellow fever, and other tropical scourges. By the 18th century, the dark specter of disease earned West and central Africa the famous epitaph, “the White Man’s Grave.”
Even stronger testimony to malaria’s ancient hold on Africa is the selective survival of hemoglobin S—the cause of the inherited hemoglobin disorder sickle cell anemia. Since individuals who inherit two copies of the hemoglobin S gene (one from each parent) are unlikely to survive and reproduce, the disease should be exceedingly rare. However, in those people who have inherited only one sickle cell gene (such individuals are sickle cell “carriers”—they suffer few if any complications of sickle cell disease), needle-shaped clumps of hemoglobin S within red blood cells confer strong protection against malaria (Bayoumi, 1987). Thus, the sickle cell gene is perpetuated in malarious regions by one set of individuals who reap its benefits while another set pays the price. In some parts of Africa, up to 20 percent of the population carry a single copy of the abnormal gene (Marsh, 2002).
In recent years, by virtue of climate, ecology, and poverty, sub-Saharan Africa has been home to 80 to 90 percent of the world’s malaria cases and deaths, although some predict that resurgent malaria in southern Asia is already altering that proportion.