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Report on the encounter “DDT controversy in the face of safe and effective malaria vector control”

December 20, 2010 - 13:25 -- Stefanie Keller

On November 12, an encounter on “DDT controversy in the face of safe and effective malaria vector control” was held in Geneva, organized by Media 21 and hosted by Biovision, icipe and the Millennium Institute with the support of the Secretariat of the Stockholm Convention. Representatives from the Governments (Ministry of Health of Uganda), international organizations (UNEP), research institutions (icipe), the industry (Croplife) and NGOs (Africa Fighting Malaria, Biovision, Physicians for Social Responsibility) debated on the pros and cons of DDT and alternatives for effective malaria control. This blog summarizes the most important arguments and statements made by the panellists and the audience regarding the use of DDT in malaria vector control.

Health effects of DDT
Two panellists of the encounter, Dr. Myers Lugemwa, Health Ministry of Uganda and Mr. Richard Tren, co-founder and chairman of Africa Fighting Malaria, insisted that DDT has no serious health impacts on people exposed to DDT used in Indoor Residual Spraying (IRS). According to Mr. Tren, scientific studies that find associations between DDT and negative human health impacts are often weak, unreplicated and contradictory. This statement was commented from the audience by Ms. Brenda Eskenazi, professor in epidemiology and leading author of the widely known report “Pine River Statement” which reviews almost 500 papers on the potential health risks of DDT exposure. According to Ms. Eskenazi, studies indicate that communities using IRS are exposed to much higher levels of DDT measured in blood and breast milk than studies showed in the USA. Furthermore, she pointed out the paucity of information available about health effects related to DDT used for malaria vector control. Also Dr. Paul Saoke, public health specialist and Executive Director of Physicians for Social Responsibility, emphasised the negative impacts of DDT on human and environmental health. He referred to a global consensus about the danger of DDT and the global commitment of banning the insecticide in near future.

Cost-effectiveness of DDT
Richard Tren and also Dr. Myers Lugemwa, ministry of health of Uganda, argue that DDT is cheap and effective. Furthermore, they stress that DDT primarily works through repellence and irritating modes of actions, thus resistances do not decrease the efficacy. In contradiction to these statements highlighting the cheap price of DDT, Mr. Konrad Meyer, representative of the NGO Biovision, insisted on integrating the full-costs of using DDT. According to Mr. Meyer, it is essential to integrate unintended side effects on human health in order to comprehensively evaluate the cost-effectiveness of DDT. This statement was supported by Mr. Baur and Jan Betlem of UNEP who stated that cost-effectiveness of DDT can only be assessed by integrating the associated costs such as costs of transport, waste management, training of communities and health consequences.

Alternatives to DDT
Dr. Charles Mbogo, consultant scientist at the International Centre of Insect Physiology and Ecology (ICIPE) in Nairobi, is convinced that the essential way forward in the fight against malaria is using Integrated Vector Management (IVM) and targeting the problem at the local level with its causes. According to Dr. Mbogo, using DDT will decrease the effectiveness of IRS and will compromise the effectiveness of all bed nets distributed in Africa. “We can achieve a more effective, efficient and ecological sound vector control through a combination of approaches having decisions based on local evidence, local knowledge and local resources”. Furthermore, Dr. Mbogo insisted on enhancing the capacity building process at the grassroots in order to strengthen and empower local communities in malaria vector control. Dr. Paul Saoke promoted the use of non-chemical interventions such as botanicals for treating mosquito breeding sites.

DDT and the Industry
According to Mr. Frédéric Baur, Vice-Chair of Vector Control of Croplife, the industry association, the industry is also committed to the promotion of alternatives to DDT. There is no large-scale commercial interest in the production of DDT, as the production companies are very few: from 3 factories two years ago only one has remained and still produces DDT today. This state-owned company, Hindustan Insecticides Ltd. in India, has now been reported to give up DDT production, after China and North Korea had also stopped production earlier on. This news is highly relevant since India is known as both the biggest user of DDT (3,000 to 3,500 tons/year) and the only producer left. Already now 12 insecticides that may be used for Indoor Residual Spraying are in the market. Mr. Baur stresses that “rotation between DDT and other insecticides is essential to properly manage and delay resistances to these products.” He also confirms that new products by BASF, Bayer, and Syngenta, will hit the market in late 2011.

Conclusion
The debate on DDT use in malaria vector control held in Geneva on 12th November was an interesting exchange between experts from various fields and different backgrounds. The encounter gave new insights such as the global commitment to use already available non-chemical alternatives that replace the need for DDT in malaria vector control and the effort of the industry in pushing alternatives to DDT. Contradicting the opinion of needed alternatives to DDT, the two panelists emphasised DDT’s efficacy and questioned that DDT has negative health impacts. However, most panellists highlighted the prime importance of enhancing the application of available sustainable alternatives to DDT and pushing forward Integrated Vector Management (IVM) in the fight against malaria.