Environment &Indoor Residual Spraying Bill Brieger | 23 May 2007 07:29 am
DDT – an emotional or an epidemiological response?
The issue of DDT for malaria control continues to raise emotions. Even though the World Health Organization has endorsed the use of DDT for indoor residual spraying (IRS), people make emotional claims that the banning of DDT has causes millions of deaths, because of political wrangling over its safety. A common response to the situation is to blame Rachel Carson.
The WHO position paper on IRS traces the history of its use in malaria control dating back to the 1950s, a time of optimism for eradicating malaria. While acknowledging that changing opinion about DDT safety was involved in its discontinued use, the position paper points out other serious constraints including “lack of government commitment and financing to susÂtain these efforts over the long term and to concerns about insecticide reÂsistance and community acceptance.” A major reason why malaria eradication efforts of the 1950s and 1960 failed in Africa was the lack of health system infrastructure to maintain continued IRS.
The early success of IRS was not just a matter of health infrastructure, but also of epidemiology. Greater success was recorded in areas where malaria was seasonal/epidemic – areas where IRS did not have to be maintained year round.
Issues of epidemiology and entomology, not emotion are leading groups like the Malaria Consortium to encourage dialogue on appropriate use of IRS, especially in highly endemic areas with year round transmission. In particular, Kolaczinski et al. note “In high transmission settings, IRS must be implemented indefinitely and at high quality to achieve control. As current infrastructure limitations and unpredictable funding make this unlikely, each country must carefully consider the role of IRS.” In short each country must examine its own financial and epidemiological situation and make a rational choice. A combination of strategies, including ITNs, is available as no one intervention fits all circumstances. Kolaczinski and colleagues also point to the need for better costing data to aid national malaria programs in making such hard decisions.
There are donors who can help make the financial decisions easier in the short run. PMI is pledging to make IRS available in all 15 of its countries in an appropriate manner based on “environmental assessments.” The Global Fund also acknowledges the use of IRS. The GFATM malaria grant to Liberia is an example of a grant proposal that includes IRS, and IRS is being implemented in Yemen. Now that IRS has been added to the current arsenal of anti-malaria weapons, it is time to stop complaining and start fundraising to guarantee adequate supplies as well as well trained and equipped malaria control staff who will apply IRS in a safe and epidemiologically sound manner.