Africa Fighting Malaria Responds To Berkeley University Study Into DDT And Neurodevelopment In Children

Africa Fighting Malaria | 18 Jul 2006
Medical News Today
Once again media attention has been given to research that links DDT exposure to human harm. The latest study by Eskenazi et al.[1] found a limited, perhaps transient association between DDT and neurodevelopment in children at 6, 12 and 24 months born to Mexican women who lived in California following exposure to agricultural uses of DDT in Mexico. The findings, based on a small sample population in one location, prompted the researchers to recommend that countries considering the use of DDT in malaria control should "weigh its benefit in eradicating malaria against the negative associations" found in their study. Africa Fighting Malaria rejects this conclusion and finds it both irresponsible and misleading.

During WWII, soldiers and civilians were covered in DDT to protect them from lice-born typhus, a strategy which rapidly brought epidemics under control. DDT was also used to control malarial mosquitoes in the Pacific theatre of war where it was sprayed on tents and housing. Due to these resounding successes, DDT was employed widely for malaria control after 1945 through indoor residual spraying (IRS) programs. In IRS programs, DDT is sprayed in tiny quantities on the inside walls of houses where it protects residents from mosquito bites for up to a year by repelling the insects and killing the few that enter the home. This limited, indoor spraying has saved millions of people from malaria. The use of DDT in this way is entirely different to the widespread and indiscriminate spraying of DDT in agriculture, which is now outlawed.

The research by Eskenazi et al. is the latest in a long line of studies that have attempted to find associations between DDT and its metabolite DDE and harm to human health. In the past several decades, innumerable studies have examined DDT's toxicity and claimed "links" between DDT and human cancers, reduced maternal lactation, pre-term births, low birth weight and endocrine disruption. The overwhelming majority of these studies has not been successfully replicated and ultimately failed to demonstrate any actual human harm. DDT is known to be minimally toxic to humans, and is classified as a "possible human carcinogen" - along with coffee, beer, peanut butter and a host of everyday comestibles - by the International Agency for Research on Cancer. DDT is exempted for public health use in the Stockholm Treaty on Persistent Organic Pollutants.

Allegations that maternal lactation is affected by DDT have little substance and seem contradicted by Eskenazi's research. Equally the claims that DDT causes pre-term births and endocrine disruption were not confirmed by Eskenazi's research. Moreover, in spite of the flurry of media activity surrounding this study, the real-world implications for the current use of DDT are very limited.

Richard Tren, Director of Africa Fighting Malaria notes, "These studies amount to little more than momentary scare stories designed to direct popular attention to unknown, hypothetical risks from DDT and to ignore the considerable and ongoing benefits of using DDT in malaria control in conjunction with mosquito nets and effective drugs. The findings of Eskenazi et al. are neither conclusive nor relevant to the use of DDT with IRS programs for malaria control."

DDT has saved millions of lives from malaria and continues to protect millions more from a disease that causes pain, suffering, childhood impairment, economic loss ($12 billion annually on the African continent) and the deaths of over a million people globally each year. This continued failure to balance the real risks that children in malarial areas face with hypothetical risks from DDT reveals a startling lack of scientific integrity, as well as ill-conceived ideas about the economics of public health policy. The media coverage of this singular, un-replicated study begs the question of how many more children and pregnant women will die from a preventable disease as a result of yet another unconfirmed scare story?

Africa Fighting Malaria welcomes research and studies that help us to understand DDT better. However, AFM urges malaria control programs, malaria scientists and public health experts to base anti-malaria interventions on sound science and scientific evidence. Limited, un-replicated studies should have no place in decision making on DDT.

[1] Brenda Eskenazi PhD et al. "In Utero Exposure to Dichlorodiphenyltrichloroethane (DDT) and Dichlorodiphenyldicholorethylene (DDE) and Neurodevelopment Among Young Mexican American Children" Pediatrics Vol 118, No. 1, July 2006.