How a Tiny Parasite Helped Shape History

Last weekend, the mosquitoes emerged from the narrow stream that trickles by our house outside Baltimore, flitting around the ankles of my 9-year-old son, skipping stones with his pants rolled up to his knees.

These days, it's just a benign sign of warmer months to come, but it wasn't always so. Not too long ago, the local Anopheles mosquitoes -- like dozens of mosquito species around the world today -- were just as likely to slip in a few Plasmodium parasites with their itchy bites, roiling their victims with the chills and fever named after the Italian for bad air, mal'aria. The stories of how malaria and yellow fever impeded European colonization of Africa and the building of the Panama Canal (surveyed by the Spanish in 1534, unsuccessfully attempted by the Scots in the seventeenth century and the French in the late nineteenth) are familiar. Less known is how malaria's tide sculpted our own landscape, too.

English settlers from the malarious low-lying counties around the Thames brought vivax malaria to the Chesapeake Bay colonies in the seventeenth century, and by the eighteenth, European colonists in the Americas had introduced the killer falciparum malaria too, carried in the bodies of enslaved Africans. Malaria-plagued families of 18th-century South Carolina endured the deaths of a third of their children before their fifth birthdays, most during the August-November malaria season. Those who could fled to the highlands during the late summer and fall; medical authorities warned them not to return until after the first killing frost.

During the Civil War, Union troops suffered 1.3 million cases of malaria, and as the infected troops returned home, they spread the scourge northwards. Madison Square, Washington Square, and Tompkins Squares in Manhattan became "dangerous hot-beds of disease and death" as the New York Times put it in 1877. Every man, woman, and child in the neighbourhoods of Dutch Kills and Ravenswood in Long Island, it seemed to a New York Times reporter that year, had been "poisoned" with malaria. "There has been so much malarial fever that it amounts almost to an epidemic," the Times reported. The schools were emptied of students and half the police force was "unfit for duty." Residents fled the island en masse, "to let" signs fluttering on their abandoned homes.

In Bound Brook, New Jersey, not a single family escaped malarial infection. "I have resided here 33 years," a lumber merchant explained to a newspaper reporter, "and was never compelled to take a dose of [anti-malarial remedy] quinine, or use it in my family, until 1878. Now we all take it in pretty large quantities, and have had touches of the malaria in some form." His neighbor took massive doses of antimalarial meds every day, just "in order to keep well."  Across New England, the story was the same, chills and fevers reported in epidemic form all the way up to the foot of the Berkshire hills. 

Pioneers brought malaria from the coasts into the interior of the country after the civil war, creating a disease barrier so fierce many felt the west would never be settled. The 19th-century American physician Daniel Drake called malaria "the great cause of mortality or infirmity of constitution" in the Mississippi valley. Malaria took 80 percent of settlers in Pike County, Illinois in the 1820s, and 80 of 600 Norwegian settlers in Wisconsin in 1841. It destroyed an 1830s effort to build a canal between the Great Lakes and the Mississippi river. Cruising down the Mississippi river, Northern passengers ogled the "sallow faced...pitiable looking objects" that emerged from mud huts, sod houses and dugouts along the river's banks. Their malaria-bloated spleens expanded their bellies by nearly a foot. It was the "swamp devil," one boat captain explained. "I'm feared you will see plenty of it if you stay long in these parts," he said to a passenger. "It will take the roses out of the cheeks of those plump little ones of yours mighty quick."  Popular ditties warned outsiders of Michigan's malaria. "Don't go to Michigan, that land of ills," one song advised, "the word means ague, fever and chills." Commentators considered anti-malarial quinine pills as crucial to survival as food.  "Had our bread failed, our wells and the river dried up, we could have endured it," wrote one typical 19th century enthusiast from Michigan. "But to be without cathartic pills and quinine...was worse than a bread and water famine."