Saturday, August 18, 2007

Important step 45 years after Silent Spring

nile tilapia
Rachel Carson, one of the greatest environmentalists of all times, would have loved what I report here: In search of a better way to fight malaria, scientists in a region of Kenya have turned away from DDT and used a fish called tilapia instead. Tilapia feeds on mosquito larvae. As a test, tilapias have been introduced in one pond, and a second pond has been left without fish as a control. During half a year, both ponds have been observed. The results are encouraging: The tilapias have eliminated 94 percent of the malaria mosquitoes in the test pond.

And even better: Tilapia is edible, already a popular food in Kenya, and offers an important source of protein for the people and a source of income from fish farming.

Resistance: An old problem must be solved today

Rachel CarsonRachel Carson, with her landmark book Silent Spring, has initiated a shift in awareness that, within ten years, led to a ban of DDT in the United States. But she never has claimed a ban of DDT against malaria. She only warned against the drawbacks of resistant insects and suggested a well-dosed approach:

«No responsible person contends that insect-borne disease should be ignored. The question that has now urgently presented itself is whether it is either wise or responsible to attack the problem by methods that are rapidly making it worse. (...) Malaria programmes are threatened by resistance among mosquitoes. (...) Practical advice should be 'Spray as little as you possibly can' rather than 'Spray to the limit of your capacity' (...) Pressure on the pest population should always be as slight as possible.» (Source: Wikipedia)
As predicted by Rachel Carson, resistance in malaria mosquitoes against DDT and other pesticides has grown so strong today that only biological control methods can offer sustainable solutions. If the Kenyan tilapia research will be put into practice in rural Africa, this could be one of the rare good news from this continent.

Photo credits: Niall Crotty and U.S. Government

No comments: