Association between entomological indices and malaria test positivity rates in Western Kenya: implications for surveillance
4 affiliations
- 1Pwani University Bioscience Research Centre (PUBReC), Pwani University
- 2Center for Global Health Research, Kenya Medical Research Institute
- 3Division of Parasitic Diseases and Malaria, Centre for Global Health, Centre for Disease Control and Prevention
- 4Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame
Abstract
The relationship between malaria entomological indices and epidemiological outcomes remains poorly understood at local scales in western Kenya, limiting evidence-based surveillance strategies. This study evaluated associations between malaria test positivity rates and vector densities, human biting rates, and entomological inoculation rates (EIR) in a high-transmission setting. The study was conducted in five villages within Teso South sub-County, Busia County, Kenya, from March to June 2021. Village-level entomological indices including vector densities, human biting rates (HBR), and entomological inoculation rates (EIR) were calculated for Anopheles funestus and An. gambiae s.l. Concurrent malaria test positivity rates were obtained from outpatient department registers in the health facilities serving the five villages (n = 2377 cases). The relationship between entomological indices and malaria test positivity was analyzed using multilevel logistic regression models, accounting for individual- and village-level factors. During this period 1950 female anopheline mosquitoes, predominantly An. gambiae s.l (89.0%) and An. funestus (11.0%) were collected. Malaria test positivity rates varied significantly across villages (range: 23.6%-68.7%). Multilevel analysis revealed significant associations between malaria test positivity and both anopheline mean density (OR 1.11, 95% CI 1.08–1.15, p < 0.0001) and HBR (OR 1.35, 95% CI 1.17–1.57, p < 0.0001). However, an association between EIR and malaria test positivity was not observed (OR 1.04, 95% CI 0.96–1.13, p = 0.316). These findings suggest that one solution to address foci with higher malaria cases is to target transmission through vector control based on health facility surveillance. This information could be valuable for national malaria control programs in optimizing surveillance strategies and evaluating intervention effectiveness.
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BibTeX
@article{omala2026association,
title = {{Association between entomological indices and malaria test positivity rates in Western Kenya: implications for surveillance}},
author = {Brenda Omala and David Mburu and Maurice Ombok and Vincent Moshi and John Gimnig and Nicole L. Achee and John P. Grieco and Bernard Abong’o and Eric Ochomo},
journal = {Malaria Journal},
year = {2026},
month = aug,
doi = {10.1186/s12936-026-06073-x},
url = {https://doi.org/10.1186/s12936-026-06073-x},
note = {CC BY},
}
RIS
TY - JOUR
TI - Association between entomological indices and malaria test positivity rates in Western Kenya: implications for surveillance
AU - Brenda Omala
AU - David Mburu
AU - Maurice Ombok
AU - Vincent Moshi
AU - John Gimnig
AU - Nicole L. Achee
AU - John P. Grieco
AU - Bernard Abong’o
AU - Eric Ochomo
PY - 2026
DA - 2026/08/01
JO - Malaria Journal
DO - 10.1186/s12936-026-06073-x
UR - https://doi.org/10.1186/s12936-026-06073-x
AB - The relationship between malaria entomological indices and epidemiological outcomes remains poorly understood at local scales in western Kenya, limiting evidence-based surveillance strategies. This study evaluated associations between malaria test positivity rates and vector densities, human biting rates, and entomological inoculation rates (EIR) in a high-transmission setting. The study was conducted in five villages within Teso South sub-County, Busia County, Kenya, from March to June 2021. Village-level entomological indices including vector densities, human biting rates (HBR), and entomological inoculation rates (EIR) were calculated for Anopheles funestus and An. gambiae s.l. Concurrent malaria test positivity rates were obtained from outpatient department registers in the health facilities serving the five villages (n = 2377 cases). The relationship between entomological indices and malaria test positivity was analyzed using multilevel logistic regression models, accounting for individual- and village-level factors. During this period 1950 female anopheline mosquitoes, predominantly An. gambiae s.l (89.0%) and An. funestus (11.0%) were collected. Malaria test positivity rates varied significantly across villages (range: 23.6%-68.7%). Multilevel analysis revealed significant associations between malaria test positivity and both anopheline mean density (OR 1.11, 95% CI 1.08–1.15, p < 0.0001) and HBR (OR 1.35, 95% CI 1.17–1.57, p < 0.0001). However, an association between EIR and malaria test positivity was not observed (OR 1.04, 95% CI 0.96–1.13, p = 0.316). These findings suggest that one solution to address foci with higher malaria cases is to target transmission through vector control based on health facility surveillance. This information could be valuable for national malaria control programs in optimizing surveillance strategies and evaluating intervention effectiveness.
SN - 1475-2875
ER -