Daily News Archive
Weighs Risks and Benefits of DDT
(Beyond Pesticides, August 14, 2003) A new study finds that benefits of DDT in controlling malaria may not be worth the risk the chemical poses to infants. A. Chen and W.J. Rogan researched the increase of infant mortality due to DDT toxicity and compared it with the decrease in infant mortality due to mosquito control because of DDT use. In their report "Nonmalarial infant deaths and DDT use for malaria control," published in 2003 in Emerging Infectious Diseases, they conclude that "debates over the value of using DDT for malaria control should incorporate consideration of the unintended consequences of exposure."
Chen and Rogan studied a history of scientific literature and correlated an expected rise in infant mortality due to pre-term birth and shortened lactation with use of DDT. The National Institute of Environmental Health Sciences and the US Centers for Disease Control released a study in 2001, "Association between maternal serum concentration of the DDT metabolite DDE and preterm and small-for-gestational-age babies at birth," which found a three-fold increase in pre-term birth associated with high levels of DDE in the mother's serum. Pre-term birth is strongly linked to increased infant mortality. The American Journal of Public Health published "DDE and shortened duration of lactation in a northern Mexican town" in 1995, as well as the 1987 study "Polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE) in human milk: effects on growth, morbidity, and duration of lactation," which showed that duration of lactation deceases with an increase in DDE in mother's serum. These mothers with elevated levels of DDE nursed their babies 40 to 50% less than mothers without DDE in their serum. Overall, they found that infant mortality increased 9% with pre-term births and 20% with shortened lactation. Considering this past research, Chen and Rogan calculated an overall increase of 20.5 deaths per 1000 infants because of DDT. Data from Africa indicates that malaria itself causes 20% of infant deaths in Africa. While the number of deaths from maternal exposure to DDT is smaller than from malaria, it is still comparable. According to Chen and Rogan, "the side effects of DDT spraying might reduce or abolish its benefits from the control of malaria in infants."
There are several factors to consider regarding this study. Firstly, Chen and Rogan used conservative assumptions on the effects of DDT, since the historical data they studied was not generated in Africa. Pre-term births and shortened lactation could be much worse than assumed. Additionally, since DDT does not prevent all cases of childhood malaria, comparing infant deaths caused by malaria to infant deaths caused by DDT is not quite accurate - the number of deaths DDT prevents is actually lower. Furthermore, DDT has other effects on the population not examined in this report that would further decrease its net benefit. For example, prenatal exposure to DDT has been associated with decreased fertility in women 30 years later. However, the prevention of deaths from individuals other than infants is also not studied.
Recently, an op-ed was published in the NY Times by Henry I. Miller, which toted DDT as a viable option for use in the U.S. to control mosquitoes carrying West Nile Virus. Chen and Rogan's research does not specifically address West Nile, but it is certainly relevant. As stated on OurStolenFuture.org, "The increases in infant mortality due to DDT use would dramatically outweigh any possible benefits that might result from using DDT to fight West Nile Virus, because the number of deaths due to WNV is so low."
See Beyond Pesticides' West Nile Virus/Mosquito Management Program Page for more information on West Nile Virus and alternatives for mosquito management.