OBJECTIVE
Indoor residual spraying (IRS) using pyrethroids insecticides to control malaria results in high exposure to local populations. Pyrethroids are immunosuppressant and prenatal exposure has been associated with higher rates of infection-related symptoms such as fever and colds among preschool children. Whether associations persist at older ages is unclear. Furthermore, prior studies assessed symptoms based on recall periods of ≥1 year, which may introduce misclassification. The aim of this study was thus to estimate associations between prenatal exposure to pyrethroids and infections among early school-aged children from an IRS area using shorter recall periods.
METHODS
We measured urinary concentrations of four pyrethroid metabolites in peripartum samples collected from mothers enrolled in the Venda Health Examination of Mothers, Babies, and their Environment (VHEMBE), a birth cohort study situated in Limpopo, South Africa, where IRS with pyrethroids is conducted annually. From age 5, we collected data on infection symptoms using up to 4 questionnaires each encompassing a three-month recall period. We used Poisson marginal structural models for repeated outcomes to estimate associations between maternal exposure to pyrethroids and infection symptoms.
RESULTS
A 10-fold increase in maternal cis-DCCA, trans-DCCA and 3-PBA was associated with a doubling in the rates of persistent fever (cis-DCCA: Incidence Rate Ratio [IRR] = 1.9, 95% CI = 1.2, 3.2; trans-DCCA: IRR = 2.2, 95% CI = 1.4, 3.5; 3-PBA: IRR = 1.9, 95% CI = 1.0, 3.4). Higher trans-DCCA was also related to a 70% increase in diarrhea rates (IRR = 1.7, 95% CI = 1.0, 2.8).
CONCLUSION
Maternal pyrethroid exposure may be related to elevated infection rates among early school-aged children from an IRS area. In addition to IRS, pyrethroids are widely used in agriculture and retail products. Results may thus have global implications.
Basant Elsiwi, Brenda Eskenazi, R. Bornman et al.· Chemosphere· 0 citations
BACKGROUND
The widespread use of pesticides in agriculture raises concerns about exposure among populations living near treated fields. Environmental contamination may lead to prolonged pesticide exposure, with potential health effects, yet significant knowledge gaps remain regarding exposure levels and pathways in agricultural communities.
OBJECTIVE
The Exposure to Pesticides Used in Regions of Agriculture (EPURA) study aims to characterize pesticide exposure patterns and identify their key sources and determinants through an integrated approach combining biological and environmental measurements.
METHODS
We recruited 400 participants from agricultural communities living within 1500 meters of vegetable production fields in Quebec, Canada, throughout the 2 years of data collection. Over 4 summer months and 3 winter months, participants provided monthly urine samples and floor wipes and completed questionnaires on diet, water consumption, household characteristics, pesticide use, and lifestyles. Summer and winter urine samples were pooled for each participant, and summer and winter wipe samples were pooled for each household. At the end of the summer, we collected additional samples, including indoor dust, yard soil, and tap water. Environmental and biological samples will be analyzed for 51 pesticides and their metabolites. Pesticide applications near residences will be estimated using agricultural land use data integrated into a geographic information system. Pesticide intake from food and water will be assessed by combining consumption data with pesticide residues measured in water and in food monitoring programs. Residential contamination will be estimated by measuring pesticides in indoor dust and yard soil. Urinary pesticide concentrations will be used to estimate exposure doses. Urinary concentrations will be compared across population subgroups and seasons and with available Canadian biomonitoring data. Associations between exposure doses and dietary and water intake, indoor and outdoor contamination, proximity to treated fields, and household-level determinants will be examined using mixed models. Variable selection will be performed using high-dimensional methods.
RESULTS
As of June 1, 2026, participant recruitment and data collection are complete. A total of 173 households (372 participants) were included in the study, with 1049 wipe samples, 170 sealed petri dishes, 157 water samples, 170 yard soil samples, and 2257 urine samples collected. Completion of all laboratory analyses is expected in 2027, after which the statistical analyses will be conducted in accordance with the study objectives.
CONCLUSIONS
This study will generate crucial data on pesticide exposure in agricultural communities. Its findings will help identify major determinants of household contamination and key risk factors contributing to residents' pesticide exposure. Ultimately, the EPURA study will support the development of targeted strategies to reduce pesticide-related health risks and inform public health policies.
INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)
DERR1-10.2196/94740.
Raphael Teysseire, Jonathan Chevrier, Pedro A. Segura et al.· JMIR Research Protocols· 0 citations
