When it comes to defeating malaria, the most promising techniques may involve neither genetic engineering nor biological control. In several studies in Africa, plain, ol' mosquito netting (treated with insecticide) has protected large numbers of people.
Clive Shiff, a malaria expert at the Johns Hopkins School of Public Health, was part of a project that sold the treated nets to parents of 20,000 children in Tanzania. (By selling the nets, the researchers hoped to give the technique more staying power with the families, Shiff explains. He adds that the money went into village operating funds.)
All children received anti-malarial drugs when the six-month study began, and whenever they showed signs of the disease. The treatment group slept under treated nets, but the control group did not. Otherwise, there was no difference among them.
The technique was effective: at
the end, anemia -- the primary symptom
of malaria -- was 50 percent less
common in the treatment group than
in the control group.
These and other new
approaches in preventing malaria
are proving very productive and
Do you take a nap after dinner?
So does the average mosquito... a fact that, surprisingly enough, explains how the scheme worked. What happens, Shiff says, is that the engorged insect (a polite term for a bug that's too heavy with human blood to move) needs a place to rest to digest its nutritious repast. (Does it like to read a magazine -- perhaps the Mosquito Monthly -- after dinner, too?)
If that resting place happens to be an insecticide-treated net, it can become the bloodsucker's final resting place. And since malaria can only spread if a mosquito feeds on an infected person and then on a healthy person, the chain of infection is broken.
The technique was certainly cheap: the nylon nets are very inexpensive and the pyrethroid insecticide costs even less. The insecticide must be reapplied about every six months.
Economy is important, even in the control of an epidemic disease like malaria, Shiff says. While international agencies no longer regularly fund malaria control, several African countries are considering using treated mosquito nets to alleviate the enormous toll malaria exacts from their populations. (According to the World Health Report (published in 1996 by the World Health Organization), the estimated direct and indirect cost of malaria in Africa was US $1.8 billion in 1995.) "I think these low-tech, community-based interactions are the way to go," Shiff says. "These results must be widely publicized so the ministers of health can see them."
As for the families in his study, he says 50 to 60 percent continue using the nets (that's down somewhat from 75 to 80 percent who used them during the study). There is no question that africa is being offered a new hope to fight malaria.