Integration of vector and human behavior in residual malaria in rural communities in the Peruvian Amazon
6 affiliations
- 1Laboratorio ICEMR-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias e Ingeniería, Universidad Peruana Cayetano Heredia, Lima, Peru
- 2Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, United States of America
- 3Department of Biomedical Sciences, School of Public Health, State University of New York-Albany, Albany, New York, United States of America
- 4Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
- 5Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias e Ingeniería, Universidad Peruana Cayetano Heredia, Lima, Peru
- 6Laboratorio de Malaria: Parásitos y Vectores, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias e Ingeniería, Universidad Peruana Cayetano Heredia, Lima, Peru
Abstract
Background: Malaria persists as a leading cause of morbidity in the Amazon Basin, where the Loreto region of Peru contributes over 90% of the national burden. Despite widespread deployment of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) under Peru’s Malaria Elimination Plan 2022–2030, residual transmission continues in rural riverine communities. This transmission is driven by the interplay between vector ecology and human behavior. This study quantified residual human exposure to Nyssorhynchus darlingi by integrating hourly entomological indices with real-time human behavioral data across two seasons in three communities in Mazán, Loreto. Methodology/principal findings: Entomological (HLC) and epidemiological (HBS) data were collected during the wet and dry seasons of 2022. Plasmodium infections were detected in 619 participants by microscopy and qPCR. Molecular surveillance revealed a 13% infection prevalence over seven times higher than routine microscopy (2%) indicating a substantial submicroscopic reservoir. Infection burden was heterogeneous, with Gamitanacocha showing the highest prevalence (33%). LLIN usage was high (>97%), yet nets prevented only 63.3%–80.3% of potential mosquito bites. Residual exposure occurred mainly indoors during early evening (18:00–21:00) while individuals were awake and unprotected, particularly in the dry season when domestic routines coincided with peak vector biting. Outdoor exposure increased during the wet season due to evening recreational activities. Multivariate analysis identified age as the only significant predictor of infection (p < 0.05), with individuals over five years showing consistently higher odds of infection than children under five (OR range: 3.62–5.46). Conclusions/significance: A critical protection gap exists during early evening and dawn, when human activity overlaps with peak vectors biting outside the protection of bed nets. The high submicroscopic burden and persistent indoor exposure while awake demonstrate that current interventions are insufficient for elimination. These findings highlight that Loreto’s elimination strategies must complement intradomiciliary tools with peri-domestic and behavioral interventions—such as full house screening and spatial repellents—specifically targeting the exposure windows identified here. Author summary: Malaria persists in the Peruvian Amazon despite high coverage of bed nets and indoor spraying. This “residual transmission” occurs because mosquitoes bite at times and places where current tools offer little protection. We conducted this study in the Mazán district to pinpoint when and where residents are exposed to bites by combining hourly mosquito activity records with real-time surveys of community daily routines.
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BibTeX
@article{acosta2026integration,
title = {{Integration of vector and human behavior in residual malaria in rural communities in the Peruvian Amazon}},
author = {Carlos Acosta and Diana Cubas-Montecino and Joaquin Gomez and Marlon Saavedra and Mitchel Guzman-Guzman and Sara A. Bickersmith and Jan E. Conn and Dionicia Gamboa and Joseph M. Vinetz},
journal = {PLOS Neglected Tropical Diseases},
year = {2026},
month = sep,
doi = {10.1371/journal.pntd.0014261},
url = {https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014261},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Integration of vector and human behavior in residual malaria in rural communities in the Peruvian Amazon
AU - Carlos Acosta
AU - Diana Cubas-Montecino
AU - Joaquin Gomez
AU - Marlon Saavedra
AU - Mitchel Guzman-Guzman
AU - Sara A. Bickersmith
AU - Jan E. Conn
AU - Dionicia Gamboa
AU - Joseph M. Vinetz
PY - 2026
DA - 2026/09/25
JO - PLOS Neglected Tropical Diseases
DO - 10.1371/journal.pntd.0014261
UR - https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014261
AB - Background: Malaria persists as a leading cause of morbidity in the Amazon Basin, where the Loreto region of Peru contributes over 90% of the national burden. Despite widespread deployment of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) under Peru’s Malaria Elimination Plan 2022–2030, residual transmission continues in rural riverine communities. This transmission is driven by the interplay between vector ecology and human behavior. This study quantified residual human exposure to Nyssorhynchus darlingi by integrating hourly entomological indices with real-time human behavioral data across two seasons in three communities in Mazán, Loreto. Methodology/principal findings: Entomological (HLC) and epidemiological (HBS) data were collected during the wet and dry seasons of 2022. Plasmodium infections were detected in 619 participants by microscopy and qPCR. Molecular surveillance revealed a 13% infection prevalence over seven times higher than routine microscopy (2%) indicating a substantial submicroscopic reservoir. Infection burden was heterogeneous, with Gamitanacocha showing the highest prevalence (33%). LLIN usage was high (>97%), yet nets prevented only 63.3%–80.3% of potential mosquito bites. Residual exposure occurred mainly indoors during early evening (18:00–21:00) while individuals were awake and unprotected, particularly in the dry season when domestic routines coincided with peak vector biting. Outdoor exposure increased during the wet season due to evening recreational activities. Multivariate analysis identified age as the only significant predictor of infection (p < 0.05), with individuals over five years showing consistently higher odds of infection than children under five (OR range: 3.62–5.46). Conclusions/significance: A critical protection gap exists during early evening and dawn, when human activity overlaps with peak vectors biting outside the protection of bed nets. The high submicroscopic burden and persistent indoor exposure while awake demonstrate that current interventions are insufficient for elimination. These findings highlight that Loreto’s elimination strategies must complement intradomiciliary tools with peri-domestic and behavioral interventions—such as full house screening and spatial repellents—specifically targeting the exposure windows identified here. Author summary: Malaria persists in the Peruvian Amazon despite high coverage of bed nets and indoor spraying. This “residual transmission” occurs because mosquitoes bite at times and places where current tools offer little protection. We conducted this study in the Mazán district to pinpoint when and where residents are exposed to bites by combining hourly mosquito activity records with real-time surveys of community daily routines.
SN - 1935-2735
ER -