Bad Blood

(Page 4 of 5)

Kennedy Agwanda makes at least 100 mud bricks a day. He accomplishes this backbreaking task with his hands and just a few crude tools. Barefoot and shirtless, he bends at the waist and applies a mold to the muck, transforming a tiny slice of floodplain, brick by brick, into an income for him and his family. Agwanda is 23 years old, with a wife and a child. His daily output can fetch between 300 and 400 Kenya shillings ($4.50 to $6), more if he bakes the bricks, but in that case he has to shell out a percentage to kiln operators and other middlemen.

I asked Agwanda if he'd ever had malaria. He interrupted the rhythm of his work to look at me. "Yes," he said. "A few times. When I was younger." These days he worries about his baby boy, who has not yet contracted the disease.

Every brick Agwanda extracts from the saturated earth leaves a negative image of itself that quickly fills with seeping groundwater. One by one, as he stacks the bricks into pyramids to dry, each brick-shaped puddle forms a ready-made larva nursery for local mosquitoes. These miniature sun-warmed pools are consummate breeding sites for Anopheles gambiae, a species that likes to lay its eggs in shallow, placid, temporary reservoirs, undisturbed by plant or predator. Here was a man laboring to sustain his family, while a by-product of that labor perpetuated a breeding cycle that could destroy his family. The awful symmetry was not lost on Agwanda.  

From where we stood, on a 12-square-mile floodplain at the base of the first swell in Kenya's western highlands, I could see other brickmaking sites and a kiln belching smoke. These features appeared randomly distributed on the flat expanse, but upon closer inspection I could see that they were linked by a network of trenches. These had been put in to drain the puddles and ditches, thus drying up the mosquito nurseries, and to generate a current. If water is flowing or even trickling, Anopheles gambiae won't deposit its eggs. The mosquito's demand for tranquility is an exploitable weakness.

In Nyabondo, a town perched on a rise overlooking the plain, a group is working under the auspices of ICIPE to press that advantage. Operating on a shoestring budget out of an annex in a convent hospital, Swiss entomologist François Omlin and his team of field-workers and educators are trying to bridge the gap between what's necessary and what's possible, focusing on the interface among vector, parasite, and community. It's the kind of work that can get lost in plain sight. Some 90 percent of local mosquitoes breed in man-made environments, and a civic initiative to raise awareness and control breeding sites would seem elementary. Be that as it may, Africa's scarce resources have a way of obscuring the most obvious and compelling ideas.

A parable can be found in the events that finally routed malaria in the United States. By the early twentieth century, the disease had been eliminated everywhere except in the deep South, where the climate was warm and wet and many of the people were poor. Cash-strapped local governments had been unwilling or unable to fund malaria programs, but during World War I heads were turned by the army's successful mosquito-elimination campaigns at arsenals and bases in the South. When the war was over, and with assistance from the Rockefeller Foundation, municipal governments revved up their own programs. Two essential tactics were to drain swamps and to install screens in windows and doors. Even through the Depression, FDR's Works Progress Administration dug thousands of miles of ditches and drained hundreds of thousands of swampy acres. Quinine (the drug of choice back then), combined with greater prosperity and education, delivered the final blow. Some historians assert that DDT rescued the American South from malaria, but the spraying campaigns of the 1950s merely ran up the score on a game that had already been decided.

No one is spraying DDT in Kenya's western highlands. Nor is anyone installing screens in the doors and windows of the houses built from Kennedy Agwanda's bricks. But the Ministry of Health and NGOs are distributing bed nets treated with deltamethrin and other insecticides that are harmless to humans; Omlin's team is spraying Bti (a naturally occurring microbial larvicide, see page 34); and the Ministry of Roads is excavating trenches to link the arteries dug at brickmaking sites to larger watercourses. Africa has long been deemed a less than ideal setting for environmental management programs of this sort: too much unpredictable rain; too many potential breeding sites, from big swamps to small hoofprints; no safe or effective larvicide to target those breeding sites (Bti is only now beginning to catch on); and, perhaps most significant, a lack of political and institutional will to overcome the obstacles.

"When larva counts go down, so do queues at the clinic for malaria treatment," Simon Osire Owuor told me as we stood watching kiln operators fire up a load of bricks. In his sixties (he couldn't precisely give his age) and an ex-brickmaker himself, Owuor now conducts barasas, community meetings in which he lays out the ABCs of malaria transmission and larva control and hammers home to brickmakers the importance of filling puddles and maintaining irrigation sluices at the end of a day's work. Owuor was among the first wave of brickmakers in the area, trained by a Dutch missionary who introduced the technology, along with the teachings of Christ, to select members of his flock. Not so long ago, Owuor said, popular belief held that disease-carrying mosquitoes came in from Lake Victoria, some 25 miles away. It's this kind of inertia-inducing misinformation that he works to eliminate. Wearing a threadbare suit and a beat-up felt fedora, the retired laborer gestured grandly across the floodplain. "There used to be thousands of breeding sites here. Not anymore. But there are still too many. We want none."

A long, man-made stream led away from the kiln, past some brickmaking sites and through an undisturbed field, as far as the eye could see. It snaked by a school that now has a soccer pitch in its backyard rather than a mosquito-infested swamp. We sat in on a class where the kids were being drilled on all matters malaria. The session included a primer on how to recognize potential breeding sites at home and what to do about them, a show-and-tell Bti pump demonstration, a refresher on the importance of sleeping under bed nets, and some basic vector/parasite science.

The charismatic instructor, Elijah Nyarangi, explained that a mosquito was like a matatu, the customized, tricked-out minivans that careen heedlessly around Kenyan cities and towns, crammed to bursting with humanity. Like the matatu, the mosquito is a transport vehicle. It must pick up a parasite from an infected individual before it can unload it elsewhere, into another person, causing another infection. Nyarangi turned sideways and slapped one elbow flat against his ribs, as if slamming shut a door, then revved up a whining engine in his throat before peeling out in wobbly matatu circles before the class. When he stopped and hinged his elbow open, he modulated the throaty whine to a mosquito buzz. The kids were laughing but the message could not have been clearer: bed nets keep uninfected people from receiving a fateful mosquito bite and passing the parasite along to others.

"That silver bullet thing is an idea of the past," François Omlin said to me in his office after a long day in the field. Hunched and sweating and coughing, Omlin was recovering from his own bout of malaria. No one really believes any longer that a single, monolithic solution will one day vanquish the disease, with the exception perhaps of vaccine researchers. But even if a malaria vaccine is one day formulated -- by no means a sure thing -- the challenge of inoculating millions in remote locations all over Africa may be insurmountable. Quinine, DDT, chloroquine, past vaccine quests, bed nets -- each, to one degree or another, has held out passing hope that it might singlehandedly save the day. But today most experts embrace the concept of integrated malaria management, along with its subset, integrated vector management.

Resistance, even to our most cleverly designed weapons, is malaria's ace in the hole. This is why policy makers in Geneva and field-workers in Nyabondo tend to agree: the best strategy for outmaneuvering the wily disease is to hit it and the mosquito it rode in on with as wide a range of ammo as possible.

Omlin is convinced that an integrated approach must include environmental management and local participation. Take fishponds. About 1,500 concrete ponds for fish-farming were installed years ago in the western highlands, but due to lack of money and training in their use they are now defunct, serving as de facto mosquito breeding sites. Omlin has conducted studies showing that restocking the ponds with Nile tilapia, a tasty local fish that happens to be a mosquito-vacuum, would vastly reduce the malaria burden as well as provide jobs and add a vital protein source to nearby markets. But the cash, education, and maintenance infrastructure the project would need to get off the ground are all still in short supply -- a scarcity that is hard to square with a world spending billions on malaria.

Burton Singer is a tropical disease specialist, a professor at Princeton's Woodrow Wilson School of Public and International Affairs, and author of numerous studies on both the history and contemporary challenges of environmental management in fighting malaria. He would like to see more money channeled into IVM, convinced that it can work in Africa. After all, it's worked there before -- when there has been sufficient motivation and funding. In Northern Rhodesia (now Zambia), from 1930 to 1950, colonial copper mines were located in a malaria-endemic region. The British owners could not have turned a profit with a sick and dying labor force, so they cleared vegetation, drained swamps, screened houses, and distributed bed nets and quinine. Within a few years malaria had ceased to threaten the economic stability of the enterprise.

Scientists are accustomed to tracking specific links between an individual method and its outcome, Singer says, but by definition environmental management programs pool approaches and look at aggregate results. Omlin told me that over the course of two years the effort in the brickmaking area, comprising water management, bed net distribution, larvicides, and community education, reduced malaria infections in children under the age of 5 by more than 50 percent. But, Omlin said, "It's impossible to discern the effect of an individual intervention since the whole approach is integrated."

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