DDT pesticide risk and danger
May 28 2015
Malaria remains a significant public health problem in endemic regions of the world, most especially in sub-Saharan Africa. As part of the global efforts to control malaria, dichlorodiphenyltrichloroethane (DDT), a cheap and effective chemical, was endorsed by the World Health Organization for use in indoor residual spraying (IRS). However, in the light of evidence on the acute toxicity of DDT, concerns have grown about the safety or the possible chronic health effects from the continued use of this persistent chemical, generating much debate and research efforts over the years.
Controlled indoor spraying of the pesticide DDT is poised to make a comeback in countries that have tried and failed to do without it in the battle against malaria. DDT -- short for dichlorodiphenyl-trichloro ethane -- is known to be very effective against malaria and helped rid the United States of the disease in the late 1940s. In the 1950s and 1960s, the Global Malaria Eradication Campaign relied heavily on DDT to control malaria globally. It was used not only in the US but also in Europe, India, Africa and South America, where it dramatically cut malaria rates and saved millions of lives. Beginning in the 1970s however, the US and several European countries banned DDT, fearing it may harm the environment and get into the food chain, leading perhaps to illness. African governments were also pressured to abandon DDT for malaria control and most did. On May 2, the United States Agency for International Development (USAID), endorsed indoor spraying of DDT to rid homes of malaria-carrying mosquitoes. "The World Health Organization is set to follow. Controlled spraying a small amount of DDT on the inside walls and eaves of houses where mosquitoes rest -- as opposed to aerial spraying on crops and villages as was done in the past -- can have a big impact in the fight against malaria with a low risk of harmful effects on the environment and on human health. Nature Medicine, 2006.
Environ Health Perspect. 2014 Feb 21. Predictors of Plasma DDT and DDE Concentrations among Women Exposed to Indoor Residual Spraying for Malaria Control in the South African Study of Women and Babies (SOWB). Few studies have examined predictors of DDT (dichlorodiphenyltrichloroethane) and DDE (dichlorodiphenyldichloroethylene) levels among residents in homes sprayed with DDT for malaria control, to identify exposure reduction strategies. This analysis includes 381 women enrolled in The Study of Women and Babies (SOWB) from 2010-2011, from eight South African villages in the Limpopo Province. Indoor residual spraying (IRS) occurred in half of the villages. Questionnaires regarding various demographic and medical factors were administered and blood samples were obtained. Women were classified into three exposure groups by type of residence: unsprayed village (n=175), IRS village in household with a low likelihood of DDT use (non-DDT IRS Household, n=106), IRS village in household with a high likelihood of DDT use (DDT IRS Household, n=100). Multivariable models of natural log-transformed DDT (µg/L) and DDE (µg/L) plasma levels were used to identify predictors for each group. Median levels of DDT and DDE among women in unsprayed villages were 0.3 (IQR: 0.1, 0.9) and 1.7 (IQR: 0.7, 5.5), respectively. Median levels of DDT and DDE among women in DDT IRS households were 2.6 (IQR: 1.1, 6.6) and 8.5 (IQR: 4.7, 18.0), respectively. In unsprayed villages, women with water piped to the yard, rather than a public tap, had 73% lower DDT (95% CI: -83, -57%) and 61% lower DDE levels. In DDT IRS households, women who reported taking > 6 actions to prepare their home before IRS (e.g. covering water and food) had 40% lower DDT levels (95% CI: -63, -0.3%) than women who took < 4 actions. The predictors of DDT and DDE plasma levels identified in this study may inform interventions aimed at decreasing exposure. Among households where DDT is likely used for IRS, education regarding home preparations may provide an interventional target.