Global determinants of vector-targeted insecticide use in public health: a modeling and mapping analysis

Background. Insecticides are the cornerstone of control for vectors of human pathogens, yet global patterns of deployment and their socioeconomic and environmental drivers are poorly characterized. Understanding where and why insecticides are used is essential for optimizing control efforts. Methods. We analyzed annual national vector-targeted insecticide-use data spanning 123 countries (1990-2019) for insecticide-treated nets (ITNs), residual spraying (RS), space spraying (SS), and larviciding (LA). Generalized linear mixed models and hurdle models quantified associations between deployment and mosquito-borne disease incidence, human development index (HDI), population, temperature, and precipitation. Models were evaluated using repeated cross-validation and applied to generate downscaled predictions of insecticide use at subnational administrative regions globally. Findings. Insecticide deployment increased with mosquito-borne disease incidence, but this response was stronger in higher-HDI countries, indicating that deployment depends on socioeconomic capacity as well as disease burden. Intervention types each exhibited distinct patterns. ITN and RS tracked Anopheles-borne disease incidence, whereas SS and LA tracked Aedes-borne disease incidence. ITN use increased with precipitation and temperature, whereas SS use decreased with precipitation. Mapping uncovered substantial within-country heterogeneity, highlighting regions where predicted deployment remains low relative to disease risk. Interpretation. Insecticide deployment reflects epidemiological need and economic capacity, creating mismatches between risk and control. High-resolution mapping can support more equitable intervention allocation, guide insecticide resistance stewardship, and improve strategic planning as climate and urbanization reshape vector-borne disease risk. Funding. JRR acknowledges support from NSF (DEB-2109293, ITE-2333795, BCS-2307944, CISE-2435758), Notre Dame Poverty Initiative, Berthiaume Institute for Precision Health, IL-IN Sea Grant, Frontier Research Foundation.