Why not encourage Africans to use the 'meen' tree to fight malaria rather than toxic pesticides like DDT?

Publié le par hort

WHO Urges DDT for Malaria Control Strategies

Jim Lobe
WASHINGTON, Sep 15 (IPS) - In an important policy shift, the World Health Organisation (WHO) Friday announced that it is urging the use of the pesticide DDT to control the spread of malaria, a mosquito-borne disease that kills about one million people a year, most of whom are infants and young children in Africa.
The announcement by the director of the WHO's Global Malaria Department, Dr. Arata Kochi, stressed that the use of the controversial pesticide, which was banned in the United States in 1972 due to concerns about its impact on animal and human health, should be confined to what is called indoor residual spraying.

"We must take a position based on the science and the data," Kochi told reporters here. "One of the best tools we have against malaria is indoor residual house spraying. Of the dozen insecticides WHO has approved as safe for house spraying, the most effective is DDT."

"Extensive research and testing has... demonstrated that well-managed indoor residual spraying programmes using DDT pose no harm to wildlife or to humans," he added.

Some public-interest and health groups, however, immediately challenged that assessment.

"This approach takes us in exactly the wrong direction," said Dr. Paul Saoke, director of Physicians for Social Responsibility in Kenya. "DDT is a short-sighted response with long-term consequences, and WHO should be helping countries fight malaria with safer and more effective alternatives."

"Reliance on pesticides, especially DDT, as a silver-bullet solution for malaria protection is extremely dangerous," according to Jay Feldman, executive director of Beyond Pesticides, a Washington-based public interest group.

He noted that government agencies both here and in other countries have classified DDT as an agent that may cause cancer and nerve damage and disrupt the human and animal endocrine systems.

Indeed, DDT is one of 12 chemicals to be phased out globally under the Stockholm Convention on Persistent Organic Pollutants (POPs), substances that are both toxic and persist in the environment -- in plants, water, and animal tissue -- for many years.

In 2001, the same year that the Convention was concluded, WHO itself published a plan of action for reducing reliance on DDT to control malaria in countries where it was used.

Developed during World War II, DDT, the abbreviation for dicholoro-diphenyl-trichloroethane, was hailed as a "miracle" for its effectiveness in combating malaria, typhus, and other insect-born diseases. In 1955, WHO launched a worldwide programme to eradicate the disease, primarily through the use of the pesticide.

While the effort proved spectacularly successful in reducing mortality, particularly in parts of Asia and Latin America, resistance emerged in many mosquito populations over time, reducing its impact.

At the same time, environmentalists -- notably Rachel Carson, whose 1962 best-selling book, "Silent Spring", about DDT's effects on the health of birds and their offspring, created a national sensation -- began documenting how DDT entered and persisted in the food chain, wreaking havoc on animal populations in the wild. Led by Scandinavia, most industrialised countries had banned DDT by the late 1970s.

While DDT was still being used in many developing countries, global agencies, including WHO, and foreign-aid donors over the next two decades promoted alternatives, including pesticides that were considered safer than DDT, insecticide-treated bed nets, and drugs designed to prevent or treat malaria.

But progress in reducing the spread of the disease, which infects some 500 million people a year, has been limited, particularly in Africa, due to a variety of problems ranging from weakness of the region's health-care systems to the costs and maintenance of bed nets and the speed with which the most deadly malaria parasite, particularly Plasmodium falciparum, develops resistance to drugs.

As a result, the pressure to rehabilitate DDT as a major component of the effort to curb the disease has been rising steadily in recent years, particularly given evidence, cited by WHO Friday, that DDT is the most effective of the pesticides used in indoor residual spraying, or IRS.

Indoor spraying is the application of long-acting insecticides on the walls and roofs of houses and animal shelters in order to kill malaria-carrying mosquitoes that land there. One application may last as a long as a year.

Fourteen sub-Saharan countries are currently using IRS, and ten of those, including South Africa, are using DDT, according to WHO. In addition, the Global Fund to Fight Tuberculosis, AIDS and Malaria, has endorsed the strategy and is currently financing its use in some 41 countries.

The United States also stands poised to devote increased resources to IRS. Last year, President George W. Bush announced his President's Malaria Initiative, a five-year, 1.2-billion-dollar plan to reduce malaria-caused mortality by 50 percent in 14 sub-Saharan African countries. The initiative, which is administered by the U.S. Agency for International Development (USAID), has earmarked 20 million dollars for IRS programmes in 2007, up from only one million dollars last year.

"Under the leadership of President Bush," the U.S. has begun to support indoor spraying for malaria control in Africa, including programmes using DDT," said Senator Tom Coburn (Republican of Oklahoma), who hailed WHO's decision to endorse the use of DDT as "bold" and "revolutionary". "I hope that these strong new policies on spraying and DDT from the WHO will encourage more donors to do the same."

In endorsing the use of DDT, WHO's Kochi stressed that it should be applied only as recommended and, under no circumstances, used outdoors or for agricultural purposes, as was done in the United States before the 1972 ban.

"DDT presents no health risk when used properly indoors," he said, adding in an appeal to the environmental community, "Help save African babies as you are helping to save the environment."

That argument, however, is not accepted by many activists. "DDT is not a harmless chemical," says Kristin Schafer, programme coordinator for the North American section of the Pesticide Action Network (PAN), "despite the claims of its aggressive promoters" who, she added, received support from the pesticide industry.

"While we agree that short-term DDT use may be appropriate in limited cases, we are very concerned that WHO appears to be bowing to pressure from these advocates and backtracking from their commitments to help countries fight malaria without DDT," she said.

She noted that Vietnam reduced malaria deaths by 97 percent and malaria cases by 59 percent when it switched in 1991 to a DDT-free malaria control programme based on drug distribution, bed nets, and local health-education projects.
Malaria and how to beat it
Jan 31st 2008

A remarkable study on fighting malaria

“FREE goods are worth what you pay for them” is the cynic’s approach to the world, shared by hard-headed poverty-busters. Charging even a nominal price for things such as mosquito nets and condoms makes people take them more seriously, it is argued. Given away free, the nets may end up being used to catch fish rather than protecting sleeping people.
That does happen. Even so, a recent study in Kenya suggested providing malarial areas with large numbers of free bed nets brought better results than selling them. Now a new survey carried out by the World Health Organisation (WHO) on behalf of the Global Fund to Fight AIDS, Malaria and Tuberculosis, which is to be published on Friday February 1st, has shown that the approach works well in other countries, too.
Unlike most big do-gooding outfits, the Global Fund is flexible and iconoclastic. It was one of the first international aid organisations to come up with the radical idea of seeing whether its interventions actually work. Since it consists of a small secretariat in Geneva and a few local offices, it lacks the scientific and managerial infrastructure to do this itself. So it subcontracts the job—in this case to Arata Kochi, the head of WHO’s anti-malaria operation.
Dr Kochi and his team reviewed antimalaria operations in Ethiopia, Ghana, Rwanda and Zambia, looking mainly at under-fives, who are most threatened by the disease. WHO says that over 1m people die each year of malaria, mostly in Africa. In Ethiopia, the amount of childhood malaria reported at clinics fell by 60% and the death rate halved within two years of the beginning of the mass-distribution programme. In Rwanda, things were even more spectacular: both cases and deaths dropped by two-thirds within a single year. In Zambia the fall in both was around a third. Only in Ghana were the data equivocal. Cases fell by an eighth and deaths by a third, but that was against a background of generally improving health in which the amelioration rates for malaria were worse than those for non-malarial illness and death. In other countries, the rate of malaria tracked the general disease rate until the programmes began, and then fell suddenly
Giving away insecticide-impregnated nets free to anyone visiting a clinic (the nets stay potent for about five years) was not the only new thing about the operations. In all cases, the countries rolled out nationwide campaigns instead of relying on local ones. In many cases, they also gave away drugs based on artemisinin, a substance to which the malarial parasite has yet to develop widespread resistance.
Nets and artemisinin are two planks of malaria control. The third is to spray the inside of people’s houses with DDT, to kill female mosquitoes when they settle to digest their blood meals. The objective is to achieve 80% take-up in each village. At that point, the cycle of transmission from mosquito to human to mosquito is broken in a way similar to the action of a vaccine; this stops the spread of the disease, and thus protects everyone.
Based on the new results, Dr Kochi reckons that a five-year campaign costing about $10 billion would be enough to bring malaria under control in most of Africa, reducing the death rate to a matter of thousands a year. Eliminating malaria altogether, though, would be a far harder task, involving destroying mosquitoes in the remaining pockets of infection. That is controversial: some—not least Dr Kochi—see it as a dangerous distraction until the easier job of bringing the disease under control is completed. Others want to aim straight away for elimination. In the long run, that should surely be the objective. But, as the old saying has it, the best can often turn out to be the enemy of the good. And the good now looks to be in sight

Publié dans health-sante

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