The Fly That Blinds

In the fertile valley of French Equatorial Africa's Mayo-Kebbi River the cotton fields lay untended, and the sun beat down upon hundreds of deserted huts. Where some 40,000 Africans had once lived and worked, only a handful were to be seen, and they were mostly blind. Nearly everyone had fled the valley before the terror of the "Nbwa," the fly that blinds.

The Nbwa fly (Simulium damnosum) has long been the scourge of French Equatorial Africa, where it breeds along the rivers. When it bites, the fly injects a microorganism that causes onchocerciasis, a disease characterized by nodules under the skin and lesions of the eye that often cause blindness. French officials estimate that 200,000 natives in the territory are affected by the disease, and that 5,000 of them are totally blind.

Air Attack. Because some 60% of the population of the Mayo-Kebbi valley had been stricken with onchocerciasis, the French colonial government decided some four months ago to choose this well-limited area (250,000 acres) to fight the disease to a standstill. Into the valley rushed a team of eight French scientists (led by Tropical Diseases Expert Dr. Raymond Campana), 20 native nurses and two helicopter crews.

The Africans were so terrified by fear of the epidemic that they swallowed their traditional fear of white doctors. The team examined 34,000 in 40 days, found that 24,000 had onchocerciasis in some stage.

Working in makeshift tents or native huts from dawn to dusk--and often later by the headlights of the expedition's only truck--the doctors performed 3,700 operations in an effort to prevent blindness, gave injections and pills to the other thousands who showed symptoms of the disease.

Meanwhile, the helicopter crews fought the fly itself, flew more than 300 missions in their U.S.-made Bell 47Gs. Repeatedly, they sprayed breeding sites with two powerful insecticides: lindamul, to coat the river and kill the larvae; lindane, to coat the foliage and kill the adult flies. The trick was to hedgehop the dense areas so closely that the insecticide would be blasted to the ground by the downwash from the rotors, would then boil up to saturate the underside of the foliage.

Bare Leg. To keep check on the density of the flies during the 40-day spraying period, the expedition resorted to a makeshift method: a member of the rescue team exposed an arm or leg for a specified time, then counted the fly bites on it. Swift treatment prevented infection. At first, as many as 400 bites a day were being counted; at the end of 40 days, a man could bare his arm or leg without getting a single bite. Even mosquitoes and other pests had been wiped out by the helicopters' relentless spraying.

Last week the Mayo-Kebbi valley was free of the Nbwa fly for the first time in memory, and natives were returning to their homes. It would be several months--at least until the disease incubation period had passed--before authorities could say for sure that the scourge had been banished from the valley. The immediate results of the mission were so encouraging, however, that the French colonial government was planning a big campaign next year against the Nbwa fly in other densely infected areas of the territory.

This file is automatically generated by a robot program, so reader's discretion is required.