Every year, 250 million people are infected with malaria, resulting in 880,000 deaths, primarily to African children under age five. Many malaria-endemic countries use Indoor Residual Spraying (IRS), the application of dichlorodiphenyl trichloroethane (DDT) or pyrethroid insecticides to interior walls of homes, to control malaria. Concerns regarding the unintended consequences of chronic, high-level DDT exposure have resulted in considerable international debate. For example, the Stockholm Convention on Persistent Organic Pollutants aims to ban DDT, while the World Health Organization and the U.S. Agency for International Development promote and/or fund IRS, including with DDT. DDT and pyrethroids are neurotoxicants in insects and animals. Human studies, primarily conducted in Western populations with low to moderate levels of exposure, suggest that prenatal exposure to DDT and its breakdown product, DDE, may adversely affect children's neurodevelopment. DDT/E exposure has also been related to adverse effects on thyroid function, gestational duration and birth weight, and changes in global DNA methylation, which could serve as pathways for compromised neurodevelopment. Although there is virtually no research in humans on the health effects of pyrethroids, research in rodents has shown detrimental effects on neurodevelopment both independently and synergistically with DDT. No study has evaluated the impact of human exposure to DDT and/or pyrethroids on neurodevelopment in the context of IRS We propose to address these important knowledge gaps by examining relationships between exposure to IRS insecticides and neurodevelopment, and possible mediators in a birth cohort study.
We aim to enroll 750 rural South African mothers and to follow their children for 24 months, assessing exposures and neurodevelopment prospectively. We take advantage of a natural experiment where gradations in altitude impact mosquito survival and, by extension, use of IRS, but sprayed and unsprayed villages are otherwise similar, e.g, demographically. Our proposed study will be the first to: 1) assess levels and determinants of IRS insecticide exposure to pregnant women and infants in IRS-treated homes;2) study the effects of very high DDT/E and pyrethroid exposures on human neurodevelopment;3) assess the relative and synergistic health impacts of alternative IRS insecticides;and 4) evaluate whether poverty, malnutrition and poor health potentiate the health effects of these exposures. We will introduce two techniques with wider implications for environmental health science: the use of PBPK models to quantify the relative contributions of in utero, breast milk, and other postnatal environmental exposures in infants, and the use of state-of-the-art epigenetic methods to determine whether environmental exposures can alter DNA methylation in fetal tissue. This study aims to provide data to evaluate the risk/benefit of different methods of malaria control and for the development of appropriate interventions to reduce exposure to pregnant women and children.

Public Health Relevance

DDT and pyrethroids are sprayed inside homes in many countries to control malaria. This method, called Indoor Residual Spraying (IRS), results in very high exposure to human populations. We propose the first study to examine the potential effects of these exposures on child neurodevelopment in these communities.

National Institute of Health (NIH)
National Institute of Environmental Health Sciences (NIEHS)
Research Project (R01)
Project #
Application #
Study Section
Neurological, Aging and Musculoskeletal Epidemiology (NAME)
Program Officer
Gray, Kimberly A
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of California Berkeley
Schools of Public Health
United States
Zip Code
Huang, Jonathan; Eskenazi, Brenda; Bornman, Riana et al. (2018) Maternal Peripartum Serum DDT/E and Urinary Pyrethroid Metabolite Concentrations and Child Infections at 2 Years in the VHEMBE Birth Cohort. Environ Health Perspect 126:067006
Murray, Jennifer; Eskenazi, Brenda; Bornman, Riana et al. (2018) Exposure to DDT and hypertensive disorders of pregnancy among South African women from an indoor residual spraying region: The VHEMBE study. Environ Res 162:49-54
Eskenazi, Brenda; An, Sookee; Rauch, Stephen A et al. (2018) Prenatal Exposure to DDT and Pyrethroids for Malaria Control and Child Neurodevelopment: The VHEMBE Cohort, South Africa. Environ Health Perspect 126:047004
Coker, Eric; Chevrier, Jonathan; Rauch, Stephen et al. (2018) Association between prenatal exposure to multiple insecticides and child body weight and body composition in the VHEMBE South African birth cohort. Environ Int 113:122-132
Verner, Marc-André; Chevrier, Jonathan; Ngueta, Gérard et al. (2018) Early-life exposure to p,p'-DDT and p,p'-DDE in South African children participating in the VHEMBE study: An assessment using repeated serum measurements and pharmacokinetic modeling. Environ Int 119:478-484
Gaspar, Fraser W; Chevrier, Jonathan; Quirós-Alcalá, Lesliam et al. (2017) Levels and Determinants of DDT and DDE Exposure in the VHEMBE Cohort. Environ Health Perspect 125:077006
Bornman, M S; Chevrier, J; Rauch, S et al. (2016) Dichlorodiphenyltrichloroethane exposure and anogenital distance in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) birth cohort study, South Africa. Andrology 4:608-15
Gaspar, Fraser W; Chevrier, Jonathan; Bornman, Riana et al. (2015) Undisturbed dust as a metric of long-term indoor insecticide exposure: Residential DDT contamination from indoor residual spraying and its association with serum levels in the VHEMBE cohort. Environ Int 85:163-7
Eskenazi, Brenda; Quirós-Alcalá, Lesliam; Lipsitt, Jonah M et al. (2014) mSpray: a mobile phone technology to improve malaria control efforts and monitor human exposure to malaria control pesticides in Limpopo, South Africa. Environ Int 68:219-26