A Canadian promotes a strategy to eradicate the carrier of sleeping sickness
TARGETING THE TSETSE FLY
A Canadian promotes a strategy to eradicate the carrier of sleeping sickness
THE TREK to see Talib All’s goat takes nine perspiring strangers along a dirt path that parts the lush, steaming bush on the edge of Zanzibar’s Jozani Forest Reserve. Perched demurely on a throne of bound poles, shaded by coconut palms and mango trees, a butter-coloured Irish dairy goat holds court. Six years ago, Ali would not have dreamed of owning such an exotic animal— it would have been assured of an untimely death in this fertile, steamy island on Tanzania’s Indian Ocean coast. But leading the delegation of strangers is the man who made Ali’s goat ownership possible: a bespectacled, Vienna-based Canadian entomologist named Arnold Dyck.
From 1994 to 1997, Dyck oversaw a bugcontrol program that successfully rid Zanzibar of a yellow-bellied foe known as the tsetse fly—an insect that’s the bane of
humans and livestock. Now Dyck, the scion of Saskatchewan Mennonites, is promoting a plan to eradicate the pest from 37 other sub-Saharan African countries—a project that has the support of the African Union (formerly the Organization of African Unity), but lacks the billions of dollars needed to make it happen.
Like the former lay preacher he is, the energetic 61-year-old doesn’t waste an opportunity to repeat his central message: that foreign aid of food will never be more than a stop-gap measure for rural Africa, while a productive cow or a goat is a family’s insurance against future hunger. As if on cue, Ali beams as he holds up a happy, milk-fed infant, the youngest of his nine offspring. “The children are stronger,” he says proudly.
Pronounced “say-say” by most Africans, the tsetse fly is the only creature in the world known to host and transmit trypanosomes, parasites that attack the blood and nervous system and lead to a deadly wasting disease in livestock called nagana. While many varieties attack farm animals, only two types of trypanosomes infect humans and produce sleeping sickness.
That disease causes a detectable brain fever or lies dormant for years before its deadly symptoms appear. Monitoring of sleeping sickness has been haphazard, but the World Health organization estimates that as many as 500,000 Africans could be suffering from it.
In Uganda, the Namungalwe treatment facility about 175 km west of Kampala is filled with the bone-thin and weary who receive a painful arsenic-based medicine for the acute stages of their illness. Julius Dhabangi, a 35-year-old farmer, has been at the treatment centre for three weeks. He is listless and stares into space like an automaton. Nearby, 65-year-old James Ikaba writhes wildly in his bed. Still, these men, whose relatives brought them long distances to the spare cement clinic buildings, are the lucky ones for receiving any treatment at all. Others infected with the disease will simply stay in their remote villages and work until their life ebbs away.
Meanwhile, it is not just humans in need of testing and expensive medication. Every year, tsetse flies kill three million cows and results in more than $6 billion in lost productivity in sub-Saharan Africa. Nagana makes them anemic, infertile and sluggish before it kills them. And the people get hungrier. Keder Umer is a gaunt father of nine daughters and four sons, and a member of Ethiopia’s Gurage people, known for their hard work and smarts as traders. When a tsetse invasion hit his village of Cheha in 1976, Umer gradually lost all 70 of his cattle.
The children were sent to town to work in restaurants or as housekeepers. The youngsters who stayed behind developed symptoms of malnutrition. There was little milk or meat, and Umer’s fields of teff, the staple grain used to make the tangy Ethiopian bread, injera, had to be cultivated by hand. Umer’s voice breaks as he talks about tracking down his older children in the city so he could get some money. “We are proud people,” he says, “and I can’t say enough about the problem of tsetse and how we have suffered.”
Dyck’s mission is to spread the word about a technology called the sterile insect technique, which he used to rid Zanzibar’s 1,650 sq. km of the tsetse fly. It’s a controversial method that involves no spraying, kills no other insects, but requires an enormous investment and is unproven in wide-
open spaces. In Zanzibar, Dyck raised eight million male tsetse flies, gave them a strong enough blast of Cobalt-60 gamma radiation to render them infertile, then dropped them in biodegradable boxes over the island at a ratio of 10 sterilized males for every wild tsetse fly. As female tsetse flies mated with sterile males and produced no viable offspring, Dyck upped the ratio of sterile males. The entire species was wiped out in three years.
The bill came to $9 million, footed by Dyck’s employer, the United Nations International Atomic Energy Agency, based in Vienna. That, critics calculate, worked out to about $500 per dead fly. Now seeking international donors for tsetse eradication, Dyck insists it won’t have to cost so much in other countries. Still, he doesn’t deny it’s a leap of faith to believe that what worked on a small island surrounded by ocean could be as successful on mainland Africa with its lack of barriers to prevent tsetse migration. “The poten-
Critics say there’s no reason to think a costly program that worked on an island will be as effective on the African mainland
tial is great but it is a technology on the edge,” he says.
In Ethiopia, they’re getting ready to take that leap. A few hours’ drive south of the capital, Addis Ababa, the Great Rift Valley opens into a wet, green landscape beaded with the glint of rivers and lakes. And not a single farm in sight. According to Ethiopia’s department of animal health, the population density in the dusty highlands is as high as 600 people per square kilometre; in the fertile lowlands it’s two. The tsetse fly keeps hungry farmers from grazing cattle there. Nor can they raise crops, says Dyck, because cultivation without draft-animal power is back-breaking and ineffective.
The regional coordinator of the eradication program, John Kabayo, is watching over the first stage of an ambitious project to reclaim 25,000 sq. km of the jewelgreen valley for farmers. Results in Ethiopia will undoubtedly colour international donors’ willingness to invest in projects elsewhere. Kabayo, a Ugandan biochemist whose father raised cattle, understands the urgency. “Ninety per cent of what some farmers pay out in costs is for tsetse fly insecticide or medicine,” he says. Meanwhile, the disease has developed resistance to current drugs. “Up to 50 per cent of animals treated are not protected,” he says, “and there are no new drugs being developed.”
But for all its worth, critics cite several reasons why sterile-insect eradication may not work, and perhaps shouldn’t be funded. Some scientists insist that the technique has not produced results that would justify its price tag. Critics also note that the tsetse fly now keeps cattle ranchers from letting their livestock loose on bush and grasslands that sustain the wild game that attracts lucrative tourism. Some bristle at the hubris of wiping out an entire bug species.
But then there is Zanzibar. Four years after the tsetse fly’s eradication, the dairy cow population has more than tripled, average milk production is up and farmers report higher incomes, according to Kassim Juma, director of livestock development. As Dyck sees it, if a fly is standing in the way of healthier animals and people and a better crack at prosperity, get rid of the fly. “Human beings,” he says, “are more important than insects.” lïl
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