DDT cleared for fighting malaria
DDT, the long-banned insecticide blamed for killing birds and other wildlife, is now approved for use indoors to fight malaria, says the World Health Organization.
"One of the best tools we have against malaria is indoor residual house spraying," says Dr Arata Kochi, director of the WHO malaria department.
"Of the dozen pesticides WHO has approved as safe for house spraying, the most effective is DDT."
For about US$5 per house, indoor spraying with DDT is a cost-effective response to malaria, says the WHO.
Malaria kills about a million people annually, most of them children under five.
In parts of Africa and Asia where malaria-carrying mosquitoes spread the disease, 85% of home dwellers approached by health workers allow their houses to be sprayed, say global health officials.
DDT came into common use in the 1930s as an agricultural insecticide. It became notorious after biologist and ecologist Rachel Carson's 1962 book Silent Spring exposed how DDT entered the food chain, killing wildlife and threatening humans.
In 1969, the US National Cancer Institute announced findings that DDT could cause cancer, and a US federal ban was imposed in 1972.
Richard Tren, director of the group Africa Fighting Malaria, stresses the difference between agricultural DDT sprayed outdoors and the residual spraying means to act like a giant mosquito net over individual houses.
"The environmental impact associated with spraying insecticides, whether it's DDT or other insecticides, indoors is minimal, it's negligible ... This is as unrelated to Silent Spring as anything," Tren says. "The science is very clear that there are no harmful human effects."
Tren says environmental groups in Africa support its use.
In Washington, the director of the Sierra Club's environmental quality program gives muted backing to the plan.
"Reluctantly, we do support it," says the group's Ed Hopkins. "Malaria kills millions of people and when there are no other alternatives to indoor use of DDT, and where that use will be well-monitored and controlled, we support it."
Hopkins stresses the need for safer alternatives to DDT, "because DDT is not a silver bullet to solve this problem".