We understand that
If Malaria's the Problem, DDT's Not the Only Answer...
the continued presence of the insecticide, susceptible populations can be rapidly replaced by resistant ones. Though widespread use of DDT didn't begin until WWII, there were resistant houseflies in Europe by 1947, and by 1949, DDT-resistant mosquitoes were documented on two continents.
By 1972, when the U.S. DDT ban went into effect, 19 species of mosquitoes capable of transmitting malaria, including some in Africa, were resistant to DDT. Genes for DDT resistance can persist in populations for decades. Spraying DDT on the interior walls of houses -- the form of chemical use advocated as the solution to Africa's malaria problem -- led to the evolution of resistance 40 years ago and will almost certainly lead to it again in many places unless resistance monitoring and management strategies are put into place
In fact, pockets of resistance to DDT in some mosquito species in Africa are already well documented. There are strains of mosquitoes that can metabolize DDT into harmless byproducts and mosquitoes whose nervous systems are immune to DDT. There are even mosquitoes who avoid the toxic effects of DDT by resting between meals not on the interior walls of houses, where chemicals are sprayed, but on the exterior walls, where they don't encounter the chemical at all.
washingtonpost.com
but thanks for yer concern. Why not Help to Eliminate Malaria in Botswana clintonfoundation.org |
