The Fever: How Malaria Has Ruled Humankind for 500,000 Years (13 page)

Having thus extended the local mosquitoes’ already capacious territory, the soldiers offered up their flesh, with the tents they retired to each night providing little barrier to the insects’ entry. One soldier counted one hundred mosquitoes in his tent alone.
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The introduction of just a handful of malaria parasites could easily have launched an epidemic, but, in fact, the bodies of the troops and the locals together housed scores of parasites from all over the globe. Each tent sheltered three soldiers, many of whom had arrived direct from other malarious fronts of the war. Local mosquitoes could pick up malaria parasites from India, East Africa, or Palestine, not to mention the already extensive range of local strains.
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“Malaria struck our men down like a scythe cutting grass,” remembered one survivor. “In every battalion men went down by
the hundred, and there were several cases of one or two officers and two or three score men . . . left out of a whole battalion up to full strength.” The victims had to be dragged through the valley’s still-trackless mud to the Greek city of Thessaloniki—which they called Salonika—on makeshift carts pulled by mules. Every afternoon, convoys of dozens of ambulances rumbled through the streets of Salonika to the general hospitals. “As they rolled silently along the busy, hot streets, one saw from behind each ambulance the feet of the four recumbent men within,” wrote the British journalist H. Collinson Owen in 1919. Malaria sent nearly thirty thousand soldiers into Salonika’s hospitals that summer, a flood of patients that outstripped the number of available beds by nearly three to one.
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Unaware of the epidemic, Allied leaders ordered General Sarrail to mobilize his forces for battle. Sarrail replied by telegram: “Regret that my army is in hospital with malaria.”
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While the Bulgarians cut the railway line through Demir Hisar in Macedonia and captured the Greek port of Kavala,
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the Allied soldiers fevered uselessly. Those who stayed out of hospital were not much better. The Salonika Army “was full of listless, anaemic, unhappy, sallow men whose lives were a physical burden to them and a material burden to the Army,” wrote Owen. By 1917, Salonika’s hospitals hosted more than sixty-five thousand troops sick with malaria,
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the armies of three of Europe’s most powerful nations “virtually paralysed,” the malariologist Lewis Hackett later remarked, “before they could strike a blow.”
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And the sick soldiers were stuck there. With German submarines threatening to bomb hospital ships, a planned evacuation to Malta was scuttled.
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The mosquitoes continued to bite. After the extent of the malaria problem became apparent, the military organized anti-mosquito patrols to oil puddles and clear vegetation, but the Struma Valley’s streams and marshes were under constant enemy surveillance and fire, and there was plenty of mosquito habitat beyond the patrols’ reach, just over the front line.
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And so when Greek hospital administrators rejected military health officers’ suggestion that they install screens
on the hospital windows, infected soldiers in hospital continued to reinfect others, and themselves.
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In the closing months of the war, an overland evacuation route safe from the German U-boats finally opened up. The officers at Salonika sent the sickest, most heavily infected soldiers back home, effectively relocating the Macedonian epidemic to the rest of Europe.
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Five thousand fell ill as far north as the German coast, and in Archangel, Russia, in the Arctic Circle.
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The old malarious counties of Kent and Essex in England suffered around five hundred cases.
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But malaria’s First World War rampage did not stick in anyone’s mind for long, overshadowed by the flu pandemic that struck in 1918. Only the neat rows of white crosses dotting the cemeteries of Salonika, marking the graves of Allied soldiers, bear testimony to malaria’s World War I toll. The Salonika Campaign Society, dedicated to remembrance of the Salonika soldiers, still visits the graves annually.

Modern ships no longer ferry cholera vibrio from port to port. Or yellow fever. Physicians don’t regularly infect patients with deadly bacteria. In most societies with sufficient resources, food preparation no longer spreads the pathogens of waste products. Public buildings do not broadcast tubercular bacteria.

But our mining, logging, and farming projects continue to disrupt environmental conditions in ways that create and spread malaria to this day. As late as the early 1990s, the World Health Organization complained that “economic development in agriculture and mining” continued to be a prime vector for the spread of malaria.
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Part of the problem is that some of the most desirable natural resources rest under prime malaria stomping grounds. Take the copper deposits buried under the Luanshya River, nestled between the Congo and Zambezi rivers in Central Africa. For years, fear of malaria kept both locals and outsiders away. Locals called the area “The Snake,” for the seasonal wetlands that covered the area. Tall
grasses, sedges, and rushes obscured their shallow, winding waterways, and the pathogen-carrying insects they harbored.
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But as the industrial revolution boomed, extracting the copper became increasingly alluring, despite the formidable microbes. The mining magnate Alfred Chester Beatty resolved to extract ten thousand tons of copper ore from Luanshya in the 1920s. The colonial government of Northern Rhodesia started building huts all along the Snake, most within half a mile of the feared wetlands.
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Despite the offers of free room and board, Beatty’s mining company had trouble recruiting sufficient workers. Some fled as soon as they arrived at the mine. Others worked for a week and then disappeared, not bothering to pick up their paychecks. When one worker, Joseph Zgambo, fell into the roiling river while assisting a surveyor, his fellow workers refused to work any longer. “They sat in a group muttering that the Snake had taken their fellow workman,” the company’s recruiter C. F. Spearpoint recalled, and the next morning they were gone. “The people are afraid that if they remain here they will certainly die,” Spearpoint wrote. Within a few months, of the eleven hundred recruited workers, four hundred had fled.
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Those who stayed suffered the consequences. The construction of the mine and the township created new larval habitats for local mosquitoes daily, the malariologist Sir Malcolm Watson wrote,
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and the mining company actively discouraged the use of local healers, who might have had some experience with the diseases common to the area.
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People were advised not to waste their money on round-trip tickets to the mines. To add insult to injury, of the 500 cattle imported to help with transport, 498 died of sleeping sickness. Nearly every last dog died, too.
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More recent examples are not hard to find. Between 1970 and 1996, the Brazilian government, supported by the World Bank, engineered widescale development projects in the untouched jungles of the Amazon. Their agriculture and mineral extraction projects disrupted the jungle environment, creating new habitats for malarial
mosquitoes. Migrant workers and others flooded into the region, residing in crude dwellings, where they were vulnerable to mosquito bites.
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Soon, parasites from a sparse population of rubber tappers (unrecognized by the government), who traditionally lived in the jungle, started to infect the newcomers.
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Between 1970 and 1999, the malaria caseload in the Amazon region of Brazil zoomed from around 30,000 to 600,000.
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Between 1983 and 1995, road builders, farmers, and others denuded more than four thousand hectares of Peruvian rain forest. Their new roads and fish farms extended the habitat of local
Anopheles
and brought them into close proximity to new, malaria-naïve settlers. More than 120,000 fell prey to
P. falciparum
in Peru in the late 1990s, compared to under 150 cases a year earlier in the decade.
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In the mid-1990s, encouraged by local government and international nongovernmental organizations, Ethiopian farmers replaced traditional crops with higher-yielding hybrid maize. Planting the maize required deep furrows in the ground, in which water collected and
Anopheles
larvae squirmed. Feeding on the pollen of the maize that fell into the water-filled furrows, the larvae grew larger than usual, increasing their likely longevity, and with it their reliability as malaria vectors. At the same time, the high-yielding maize negated the need for the fenced home gardens that farmers traditionally kept between their residences and the fields. Instead, they planted their crops right next to their homes, bringing their bodies within easy flying distance of the
Anopheles
-infested maize. It was this altered agro-ecology, researchers speculate, that triggered the unprecedented malaria epidemic that hit the traditionally malaria-free Ethiopian highlands in 1998–1999.
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In the first decade of the new millennium, the rapidly growing Indian economy led to a building boom in Mumbai. Stagnant water collected amid the rubble of construction, while construction workers from across the region introduced new parasites into the area, and malaria began to spread. The city’s annual monsoon-related
malaria spiked.
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Over the course of 2006, malaria cases in the city rose by 50 percent.
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Between June and August 2008, more than fourteen thousand cases of malaria were recorded. “The numbers are huge,” the epidemiologist Kishor Harugoli said. He places the blame squarely on the construction boom.
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It is not as if all environmental disruptions will set in motion developments that will trigger malaria epidemics. The ecology that sustains the disease varies from place to place. But at least with the building of dams and the logging of forests, the actual transformation itself is obvious: Waters go still. Trees fall down. In the case of what may well turn out to be our biggest environmental disruption of all—the changing global climate due to excess carbon in the atmosphere—the contours of the possible disruptions that will strike are more obscure, and thus their impact on malaria even harder to predict.

Nevertheless, climate-change-induced malaria—unlike the malaria caused by routine industrial practices—has already inspired great alarm in the public mind. “It bites, it kills, it’s coming to Essex,” read a recent headline in the London newspaper
The Independent
. “Malaria . . . Many researchers believe global warming could bring the disease back.”
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“Climate change brings back malaria,” a dispatch from the Italian website ANSA warned. “Italy in firing line.”
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“Malaria goes global as the world gets warmer,” Singapore’s
Straits Times
headline writers added.
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And yet, for all the sensation, climate change is expected to be nothing if not variable: hotter in some places, cooler in others, wetter here and drier there. There is no easy equation between any one factor and malaria transmission. The right climate doesn’t mean there’ll be the right mosquitoes, or the right parasites, or the right human population.

Even when a global warming–induced change is predictable, its impacts may not be. More rain
could
mean more malaria. Or not, if
the rain washes away mosquito larvae, say, or deepens water bodies, allowing them to sustain fish, which would eat the mosquito larvae. More warmth
could
mean more malaria. At higher temperatures, malarial mosquitoes bite more and grow faster. The parasite develops more rapidly inside the mosquito, making it more likely that the mosquito will survive long enough to infect people. But then again, England was at its most malarious during the Little Ice Age, and malaria receded from Europe during a warming period. Other factors outweighed the weather.
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Climate experts do widely agree on certain effects of global warming. El Niño, a warm ocean current named after the baby Jesus, usually makes annual visits to the shores of Peru for three to six years in a row, after which cool currents rush in, in an opposite phenomenon named La Niña. The alternating currents influence trade winds, the jet stream, and storm tracks that shape the planet’s climate. In northeast Brazil, southern Africa, South Asia, Indonesia, and northern Australia, El Niño years result in droughts; in Peru, Colombia, Ecuador, and Bolivia, intense rain.
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We know that El Niño years are correlated with a spike in malaria cases and deaths. In the Kenyan highlands, people have long enjoyed malaria-free lives thousands of feet above sea level, where malarial mosquitoes can scarcely survive. But after heavy, El Niño–induced rains in 1998, mosquitoes invaded the region. To the nonimmune villagers, the ravages of malaria that followed the mosquito bites were inexplicable. “In a crowd of perhaps two dozen people,” recounts a
New York Times
reporter who visited the area, “no one could say exactly how malaria was spread or how to prevent it.” “If you have experience, maybe you can explain it,” one girl said to the reporter.
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Hundreds perished. The following year, a three-month outbreak took even more lives. Malaria experts were conflicted over what precisely triggered the violent resurgence of malaria, but for the local clinicians, the answer was obvious. “When you think it will disappear, then it rains again,” one said. “There will be more stagnant
water, the mosquitoes will hatch, and there will be problems again.”
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Today, fifteen districts in the highlands of Kenya are under constant threat of malaria epidemics, compared to just three in 1988.
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In Venezuela, El Niño is correlated with a 36 percent increase in malaria’s death toll. In Sri Lanka, the risk of malaria epidemics grows by 400 percent when El Niño is in play. In northeast Punjab in India, the risk increases by 500 percent.
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