Insecticide Spraying Reduces
Blindness And Diarrhea
In Third World
NEW YORK (Reuters Health) - Spraying insecticide to control fly populations can reduce rates of blindness and diarrhea in the developing world, concludes a study published in the April 24th issue of The Lancet.
According to researchers, "fly control resulted in 75% fewer new cases" of trachoma, an eye infection estimated to be the leading cause of preventable blindness in the world.
Flies are a prime means of transmission for a number of infections prevalent throughout the developing world, including trachoma (caused by Chlamydia trachomatis bacteria) and diarrhea, which kills more than 3.3 million children each year.
Researchers led by Dr. Paul Emerson of the Medical Research Council in Banjul, The Gambia, sought to determine the impact of fly-control insecticide programs on rates of fly-borne infection. They sprayed two Gambian villages with insecticide during the wet or dry season, and compared subsequent rates of trachoma and diarrhea rates to those of villages without these interventions.
"Fly control resulted in 75% fewer new cases of trachoma in intervention villages than in (unsprayed) villages," the authors report, as well as up to a 26% decline in cases of childhood diarrhea.
However, the researchers believe that rural spray programs are "unlikely to be a sustainable routine public-health measure" for resource-poor nations in Africa and elsewhere in the developing world.
The study findings do point out the importance of fly control in reducing risks for trachoma and diarrhea. In a commentary, Dr. Chandler Dawson of the University of California, San Francisco, points out that "other measures of integrated pest management, such as the availability of covered latrines to limit fly breeding sites, can substantially reduce the population of eye-seeking flies."
The Lancet 1999;353:1376-1377,1401-1403.