The Fever: How Malaria Has Ruled Humankind for 500,000 Years (11 page)

Just as malaria immunity helped the Bantu spread and restrained European intrusion into malarious Africa, so Rome’s cultural and biological adaptation to chronic vivax malaria helped strengthen the city’s ability to repel outsiders. To enter the capital, the armies of malaria-free Northern Europe would have to spend days in the malarious swamps around the city, exposed to the bites of infected
Anopheles
. Unlike the regularly exposed Romans, the Northern Europeans had no tricks to help them minimize malarial feasts on their bodies. Time and again foreign armies fell prey to Rome’s malaria. “When
unable to defend herself by the sword,” the poet Godfrey of Viterbo noted, “Rome could defend herself by means of the fever.”
¹⁷

And so, even as Julius Caesar lay in bed with malaria, his armies conquered lands far and wide, bringing booty and slaves to enrich Rome.
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Having forsaken its best farmland to malaria, ancient Rome could not feed itself, but the riches of conquest paid for grain, olives, fish sauce, and oil imported from North Africa. It paid for elaborate aqueducts, allowing wealthy Romans to move away from the most mosquito-ridden water’s edge.
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Until the environmental conditions that underlay Rome’s stable malarial ecology shifted, the malarious Roman Empire thrived.

But building an empire required natural resources, and Rome’s oak forests suffered the brunt. As the peninsula was deforested, the usual changes occurred. Erosion intensified. As sheets of rainwater washed off the shorn hills and into the valleys below, the water table rose. Rivers flooded more easily. The plains grew marshy.
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What this meant is that Rome increasingly harbored a new, uncolonized mosquito habitat, and at some point, stowaway
A. labranchiae
from North Africa must have found amenable spots unharassed by
A. atroparvus
and quietly laid their eggs.
²¹
Adapting to Rome’s cool winters required a simple adjustment for the nonhibernating insects—spending the winter indoors, say, inside warm, dimly lit Roman homes, where they could continue to bite year-round.
²²
It wasn’t a big stretch. The behavior of
Anopheles
mosquitoes is not that rigid. We don’t know precisely when
A. labranchiae
made itself at home in Rome, but we do know that it did. In time, the mosquito established a foothold on the peninsula as well as on the islands of Sicily and Sardinia, which
A. atroparvus
had failed to colonize.
²³

By the fifth century
AD
, Roman villagers were suffering horribly from
P. falciparum
outbreaks. The disease terrified them in a way that suggests the scourge had been previously unknown. Between 1988 and 1992, the archaeologist David Soren and his team from the University
of Arizona excavated the remains of nearly fifty infant corpses from a fifth-century village near Rome called Lugnano. The infants had died in rapid succession and been buried hastily, in an ad hoc trash heap, entombed with mysterious offerings to pagan gods. Along with the bodies of their dead babies, the villagers had buried the torn-off jaw of a six-month-old puppy and the carcass of a dog split straight down the middle. They’d included the claws of ravens and singed honeysuckle branches. The hands and feet of the body of a two-year-old child had been weighed down with giant stones and tiles.
²⁴

The carnage started to make sense when molecular biologists discovered the DNA of falciparum parasites inside the excavated bones.
²⁵
P. falciparum
preys most prolifically on babies and young children, which would explain the predominance of dead babies at the site. After the first few infections, falciparum malaria spreads quickly—a single victim can infect one hundred others. Thus the quick succession of hasty burials. Honeysuckle was a known Roman salve for malarial symptoms. As for the mutilated dogs—well, if it was
P. falciparum
that killed the babies, the outbreak would probably have occurred in the heat of summer, when the waters of the Tiber running alongside the village receded, leaving behind a mess of puddle and marsh. Those long summer days were known in Roman times as the
caniculares dies
, the dog days, when the dog star Sirius disappears in the glow of the sun. And the keeper of infants’ souls, according to Roman mythology, was the goddess Hecate, who sailed through the heavens on a chariot pulled by the hounds of hell.
²⁶

Making offerings to appease an enraged Hecate made sense in the face of a summer outbreak of an infant-slaughtering pathogen. Early medieval Romans had no other explanation for an illness that suddenly struck so many people at once. Their medical authorities considered sickness to be the result of idiosyncratic imbalances in the body. They had no concept for contagion. A curse cast by the pagan gods of their ancestors must have seemed the most reasonable explanation, the goddess Hecate the most likely culprit.
²⁷

But the canine sacrifices also point to the terror the villagers must have felt. Practicing pagan rituals in that period risked serious political consequences. By the fifth century, Christianity had been the official religion of the Roman Empire for some two hundred years.
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The Church reserved special venom for the followers of Febris, and anyone caught wearing an amulet was to be executed.
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It wouldn’t have been the fact of child deaths that scared the Romans. Generally speaking, fewer than half of the infants in early medieval Roman villages such as Lugnano survived childhood, and even the adults wouldn’t have expected to live past twenty years.
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More likely, the deadly epidemic was something novel, something they’d never seen before. As falciparum infection progresses, the symptoms of fever and chills become much more pronounced, and divergent from the usual vivax malaria to which the villagers were undoubtedly inured. Some victims would have fallen into open-eyed comas and gone into convulsions. Such symptoms might well have struck the villagers as otherworldly, which would explain why they weighed down the body of one dead child with stones and tiles, as if to prevent the evil spirit that seemed to possess her from rising again.

If the fifth-century falciparum outbreak in Lugnano was indeed new, its emergence in Rome coincided with a broader dissipation of the empire’s power. The fifth century found the empire weakened, under attack, and wasted by famine. In
AD
401, for the first time in eight centuries, the city of Rome’s famous defenses were breached by Alaric and his Visigoth army.
³¹
Fifth-century Romans had to survive on shipments of food from North Africa, a thin thread that northern armies severed simply by holding up the grain ships at sea, plunging Rome into famine.
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The elaborate villas that sat above villages such as Lugnano lay in ruins; villagers squatted in the rubble.
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Historians still debate what triggered Rome’s decline. Was it the empire’s internal contradictions, the superior technology of its rivals, its trade deficits, its plagues and pestilences? Clearly, many
things went awry. But the transformation of malaria from the fever that protected Rome to one that killed, occurring just around the time of Rome’s decline, surely exerted a demoralizing and destabilizing effect.

As falciparum transmission became established, the troublesome but mild malaria season would have yielded to a year-round scourge, which struck foreigners and Romans with equal severity.
P. falciparum
would have laid bare the inadequacies of Roman medicine and mythology. Amulets and prayers might have seemed effective in the face of self-limiting vivax infections, for by probability alone, their use would have sometimes coincided with
P. vivax
’s natural cessation. Not so with
P. falciparum
infection. Its arrival, thanks to slow-moving ecological disruptions, shattered all the old certainties.

By
AD
476, the Roman Empire was no more, its canals filled with rubble and its aqueducts crumbled.
³⁴

Foreign powers took control of Naples, Sicily, and Sardinia. Only the northern city-states, beyond
A. labranchiae
’s reach, prospered. Elsewhere,
P. falciparum
took so many lives that the deadly compromise forged in Africa—the sickle-cell gene—emerged and spread along the shores of the Mediterranean.
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Even the most celebrated Romans, such as the poet Dante Alighieri, suffered the “shivering of the quartan.”
³⁶
Dante died of malaria in 1321.
³⁷

The Vatican founded a vast hospital, Santo Spirito, along the banks of the Tiber, which overflowed, generally to at least three times capacity, with fever patients.
³⁸
But there wasn’t much that could be done to save the sufferers. The parasite took the life of Pope Innocent VIII in 1492, Pope Alexander VI in 1503, Pope Adrian VI in 1523, and Pope Sixtus V in 1590.
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The people of Rome no longer could understand their fevers. They seemed to have something to do with bad air, they said: the
mal’aria
.
⁴⁰
The demons of air, water, and earth were locked in battle with the demon of cold, the sixth-century historian John Lydus speculated.
⁴¹
No, a foul dragon lurked in a cave beneath the city, others said, breathing out the bad air.
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It was a vengeful Febris, the poet Poliziano said, flying through the air in her lion-drawn chariot, followed by a train of monsters. She injected flames from her torch and icy snow mixed with venom into the bones of her victims.
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Rome’s unknowable malaria inspired images of horror still potent today. There’s nothing intrinsically sepulchral about mists and wetlands. And yet, then and now, writers describe these environments as deathly. “The rising of the sparkling Dog Star at the morbid foot of Orion was imminent,” one medieval bishop wrote, in anticipation of a deadly malarial summer in Rome.

All the air in the vicinity became dense with misty vapours arising from the neighbouring swamps and caverns and the ruined places around the city, air that was pestilential and lethal for mortals to breathe . . . the rage of the Dog Star . . . grew even hotter, and there were hardly any men left who were not debilitated by the seething heat and bad air.
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Healthful northerners visited the malarious Vatican and the ruins of Rome and professed disgust. “There is a horrid thing called the malaria, that comes to Rome every summer, and kills one,” Horace Walpole wrote in a 1740 letter, introducing, at long last, the word
malaria
into the English language.
⁴⁵
There was “a strange horror lying over the whole city,” wrote the English critic John Ruskin in 1840. “It is a shadow of death, possessing and penetrating all things . . . you feel like an artist in a fever, haunted by every dream of beauty . . . but all mixed with the fever fear.”
⁴⁶

“The Valley of the Shadow of Death”—that’s how Florence Nightingale, in 1847, described the silent, thyme-covered Roman Campagna into which nonimmune villagers from the surrounding hills descended during the summer to harvest wheat.
⁴⁷
The wheat ripened at the height of the malaria season, and the impoverished peasants who worked the fields spent their nights in caves, stables,
and under the stars, easy prey for mosquitoes.
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They were “the most unhappy, most resigned” people in Italy, the French writer Stendhal wrote in 1829. “They visited Rome on Sundays, dressed in their primitive costumes, their faces showing traces of malaria.”
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They were “pale, yellow, sickly,” wrote Hans Christian Andersen in 1845.
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In the first half of the twentieth century, it wasn’t unusual for the women who stayed behind in the mountain villages to lose three or more husbands to the Campagna’s fever.
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As a result, two million hectares of arable land remained fallow, and two million more were “cultivated badly,” writes historian Frank Snowden.
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The earth’s axis wobbles about one degree every seventy-one years, so the dog star and the sun no longer rise as one in the summer sky. The dog days are technically over. But the plague of
P. falciparum
that befell Rome during the end of the empire and those early medieval
caniculares dies
lingered for more than a thousand years.

Of course, the kinds of environmental disruptions that allow more malignant malarial mosquitoes to extend their territory vary from locale to locale. In the northeastern United States, the troubles began when people started building dams.

Colonial New England’s myriad brooks and creeks provided plentiful habitat for populations of
Anopheles punctipennis
, a little forest mosquito that thrives in shaded, running waters.
A. punctipennis
has a predilection for animals, and so it wasn’t a particularly potent vector for the few malaria parasites it picked up here and there. Despite hot summers and the repeated introduction of vivax parasites from farther south, malaria’s grip on the Northeast was weak and sporadic.
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But by the late eighteenth century, industrious New Englanders started to realize they could harness the power of the region’s rocky, tumbling rivers to card wool, grind grain, and cut logs. All they had to do was build some dams so they could draw down the water power as their mills required.
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