quinta-feira, 14 de setembro de 2006

DDT e Malária

A Organização Mundial de Saúde está propondo a volta do DDT para controle do mosquito vetor da malária com pulverização em paredes e outras superfícies de casa, mas em doses menores. O uso fora de casa continua sendo não recomendado. The Wall Street Journal (14/09/06) noticia: DDT already is on a list of WHO-approved chemicals for indoor spraying. But until now, the agency hadn't strongly endorsed its use, and donors funding malaria programs were reluctant to finance purchases of it. As a result, countries hit hardest by malaria generally have been unable to afford substantial supplies.
The WHO's new stance is aimed partly at encouraging even countries that ban the pesticide to help finance its use in areas ravaged by the disease.

The spraying of DDT has led to a sharp reduction in malaria cases in the few countries where it has been used, such as South Africa. Malaria experts say it is one of the cheapest and most effective forms of prevention. But it must be sprayed in more than 70% of the homes in targeted areas, and nearby regions also must be sprayed to halt mosquitoes there from reintroducing the disease.
Some environmentalists link DDT with cancer and disruptions of the endocrine system, but scientists disagree about DDT's effects on human health. The fear is that spraying DDT in high-risk areas would increase other health risks without eliminating breeding grounds of mosquitoes that spread the disease.

Wider use of DDT "is shortsighted and doesn't recognize the long-term problems and hazards," said Jay Feldman, executive director of Beyond Pesticides, a Washington group pushing for the elimination of toxic pesticides. "It behooves us to advocate the phase-out of this chemical around the world and find solutions to malaria that go to the cause of infestation."
He says officials need to focus more on eliminating mosquito breeding grounds, such as standing pools of water.
Some African government officials have expressed concern that increased use of DDT could hurt exports of agricultural products to the European Union, where the pesticide has been widely banned for more than 20 years. The EU is the main trading partner for most African countries, with EU imports from developing African, Caribbean, and Pacific countries totaling some $36.04 billion (28.4 billion euros) in 2004.
The malaria parasite, borne by infected mosquitoes, clogs a patient's circulatory system, impeding blood flow to the brain and other vital organs. There are drugs for the disease, but some of the cheapest and most commonly used aren't very effective because the parasite has developed resistance. Other pesticides and malaria-fighting methods have often proved to be less-effective and more costly than DDT. Insecticide-treated mosquito nets hung in sleeping areas are successful, but cost, distribution problems and varying usage make them less effective than they could be. Malaria experts say deployment of a malaria vaccine that is now in development could still be years away.

Por outro lado, há o apoio decisivo do Global Fund:
Pressure has been growing in the past few years for the WHO to support DDT more aggressively. Jon Liden, a spokesman for the Global Fund, which pays for indoor DDT spraying in 41 countries, says the organization welcomes the WHO's move. "The Global Fund ... is ready to finance increased use of the strategy if affected countries request it," he says.
In 2004, Africa Fighting Malaria, a not-for-profit health-advocacy group, accused the agency of ignoring advice and research from malaria-control scientists who advocate indoor spraying of DDT.
The U.S. government has stepped up support for indoor pesticide spraying of homes in Africa. While it spent less than $1 million on such programs in 2005, it plans to spend $20 million in fiscal 2007, according to Admiral R. Timothy Ziemer, coordinator of the President's Malaria Initiative and the U.S. Agency for International Development's malaria programs. This year, the U.S. government purchased DDT for a spraying program in Zambia

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