Epidemiological impact of a dual-action insecticidal coating applied to Aedes aegypti breeding sites on dengue transmission in Colombia: a cluster-randomised trial.

Authors

Rocio Cardenas, Axel Kroeger, Max Petzold, Winfried V Kern, Marcus Panning, Susana Koo, Tatiana Rivera-Ramirez, Yohana Yañez-Montaño, Maria Angelica Carrillo

Published in

The Lancet. Infectious diseases. Aug 19, 2026. Epub Aug 19, 2026.

Abstract

Cost-effective, socially acceptable, and sustainable strategies for dengue vector control are urgently needed, particularly in settings with low resources for prevention measures. Following preliminary entomological and safety studies, we evaluated a novel dual-action insecticidal protective coating targeting domestic water containers.
We conducted a cluster-randomised trial in 20 community clusters (each consisting of about 2000 households) in metropolitan Cúcuta, Colombia. Ten matched pairs of clusters were defined on the basis of sociodemographic, environmental, and epidemiological characteristics; within each pair, clusters were randomly assigned (1:1) to intervention or control by simple lottery. The control group received no study-specific treatment, but households in both study groups remained subject to standard routine municipal vector control activities. Entomological and sociodemographic surveys were conducted at baseline in 250 households per cluster. The intervention consisted of applying the protective coating (containing microencapsulated pyriproxyfen and alpha-cypermethrin) to indoor ground-level water containers (used for cleaning and washing) with support from trained community health volunteers. Follow-up over 12 months included two interim entomological surveys (40 households per cluster) and a final survey (250 households per cluster). Dengue incidence was obtained from the national surveillance system (SIVIGILA). Intervention effects were estimated using a difference-in-differences approach with Poisson regression accounting for clustering. The primary outcome was the change in annual dengue incidence across all clusters. Secondary outcomes included Aedes infestation indices. Direct intervention costs were also estimated. This study is registered with ClinicalTrials.gov (NCT06268691) and is complete.
Between Dec 3, 2019, and Feb 27, 2020, 20 clusters (ten matched pairs) were enrolled and randomly assigned to the study groups. Ten clusters were allocated to the control group (18 410 households) and ten to the intervention group (20 029 households). In the intervention group, 15 580 households were eligible for treatment, of which 13 803 (88·6%) received the protective coating on water tanks. In the control group, 15 594 households were eligible and received no treatment. At follow-up in 2022, pooled annual dengue incidence was 337·1 cases per 100 000 population (95% CI 299·3-378·4) in the intervention clusters and 528·5 cases per 100 000 population (478·9-581·9) in the control clusters. The incidence rate ratio comparing changes between 2022 and 2021 for intervention versus control clusters was 0·55 (95% CI 0·45-0·68; p<0·0001). The absolute difference-in-differences was 352·7 cases per 100 000 population (95% CI 31·0-674·4; p=0·033). Aedes infestation indices decreased significantly, including the house index (difference-in-differences effect 31·7 percentage points, 95% CI 28·4-35·0; p<0·0001) and the pupae per person index (0·8 pupae per person, 95% CI 0·2-1·4; p=0·0090). The estimated direct cost of the intervention was US$2 per household per year.
The intervention reduced dengue incidence and Aedes aegypti infestation over 12 months. A single application of a dual-action insecticidal coating to domestic water containers represents a scalable and affordable complementary strategy for dengue control in endemic urban settings.
Colombian Ministry of Science, Technology and Innovation (Minciencias), Government of Norte de Santander, Colombia, and the Centre for Planetary Health, University of Freiburg.
For the Spanish translation of the abstract see Supplementary Materials section.

PMID:
42617628
Bibliographic data and abstract were imported from PubMed on 20 Aug 2026.

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