WHO follows SA’s lead on DDT

20 September 2006

The World Health Organization (WHO) has done an about-turn on the use of Dichloro-Diphenyl-Trichloroethane (DDT) to fight malaria, citing South Africa’s successful anti-malaria programme as evidence that controlled indoor spraying of the insecticide is not only safe, but “one of the best tools we have” against the killer disease.

Nearly 30 years after phasing out the widespread use of indoor spraying with DDT and other insecticides to control malaria, the WHO announced on Monday that this intervention would once again play a major role in its efforts to fight the disease.

The WHO said in a statement that it “is now recommending the use of indoor residual spraying not only in epidemic areas but also in areas with constant and high malaria transmission, including throughout Africa.”

According to SA Health Ministry spokesperson Sibani Mngadi, South Africa has been playing a leading international role in advocating the use of DDT as a critical element in eliminating malaria, particularly in Africa, which carries more than 80% of the world’s malaria cases.

South Africa country is one of the few countries that – despite strong lobbying in some quarters against the decision – continued to use DDT after the early 1980s, when environmental concerns led the WHO to stop promoting the pesticide.

Evidence from South Africa
In its press statement on Monday, the WHO cited South Africa and India as offering “programmatic evidence … that correct and timely use of indoor residual spraying can reduce malaria transmission by up to 90%.

“In the past, India was able to use DDT effectively in indoor residual spraying to cut dramatically the number of malaria cases and fatalities,” the WHO said.

“South Africa has again re-introduced DDT for indoor residual spraying to keep malaria case and fatality numbers at all-time low levels and move towards malaria elimination. Today, 14 countries in sub-Saharan Africa are using indoor residual spraying and 10 of those are using DDT.”

According to the Health Ministry, malaria cases in South Africa were reduced from 64 868 (15 out of every 10 000 people) in 2000 to 7 754 (2 per 10 000) in 2005.

Indoor residual spraying with DDT has also been the main element in a cross-border malaria control collaboration involving South Africa, Swaziland and Mozambique.

Mngadi said the three countries had worked together through the Lubombo Spatial Development Initiative, leading to a dramatic decrease in malaria cases in the Lubombo region.

While most of South Africa is malaria-free, certain areas – the Kruger National Park, the lower-lying areas of the Mpumalanga and Limpopo provinces, and the northern parts of KwaZulu-Natal – do pose a malaria risk in the summer months.

‘One of our best weapons’
Indoor residual spraying is the application of long-acting insecticides on the walls and roofs of houses and domestic animal shelters in order to kill malaria-carrying mosquitoes that land on these surfaces.

According to the WHO’s reassessment, the evidence shows that correct and timely use of indoor residual spraying can reduce malaria transmission by up to 90%.

“We must take a position based on the science and the data,” said Dr Arata Kochi, the director of the WHO’s global malaria programme. “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.”

Indoor residual spraying “has proven to be just as cost-effective as other malaria prevention measures,” the WHO said, “and DDT presents no health risk when used properly.”

“Indoor spraying is like providing a huge mosquito net over an entire household for around-the-clock protection,” said US Senator Tom Coburn, a leading advocate for global malaria control efforts.

“Finally, with WHO’s unambiguous leadership on the issue, we can put to rest the junk science and myths that have provided aid and comfort to the real enemy – mosquitoes – which threaten the lives of more than 300 million children each year.”

Insecticide-treated mosquito nets
While indoor residual spraying is now one of the main anti-malaria interventions being promoted by the WHO, a second is the use of insecticide-treated mosquito nets – particulary the recently developed “long-lasting insecticidal nets,” which remain effective for up to five years without retreatment.

For those who contract malaria, more effective medicines – including the WHO-recommended Artemisinin Combination Therapies – are increasingly becoming available throughout the world.

In January, the WHO banned the use of “malaria monotherapy” to help prevent future resistance to antimalarial medicines.

Malaria is endemic in 107 countries around the world. Each year, according to the WHO, more than 500 million people suffer from acute malaria, resulting in more than 1 million deaths – at least 86% of these in sub-Saharan Africa.

“Malaria disproportionately affects poor people, with almost 60% of malaria cases occurring among the poorest 20% of the world’s population,” the WHO says.

SouthAfrica.info reporter and BuaNews

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