Analysing dengue fever spread in Kenya using the Zero-Inflated Poisson model

Background: Dengue fever (DF), transmitted by Aedes mosquitoes, remains a major public health concern in tropical and subtropical regions. Understanding the influence of climatic variables on DF incidence is essential for improving outbreak prediction and control measures. Aim: This study analysed...

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Main Authors: Lameck Ondieki Agasa, Faith Thuita, Thomas Achia, Antony Karanja
Format: Article
Language:English
Published: AOSIS 2025-02-01
Series:Journal of Public Health in Africa
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Online Access:https://publichealthinafrica.org/index.php/jphia/article/view/781
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author Lameck Ondieki Agasa
Faith Thuita
Thomas Achia
Antony Karanja
author_facet Lameck Ondieki Agasa
Faith Thuita
Thomas Achia
Antony Karanja
author_sort Lameck Ondieki Agasa
collection DOAJ
description Background: Dengue fever (DF), transmitted by Aedes mosquitoes, remains a major public health concern in tropical and subtropical regions. Understanding the influence of climatic variables on DF incidence is essential for improving outbreak prediction and control measures. Aim: This study analysed the impact of climatic factors on DF incidence in Kenya using a Zero-Inflated Poisson (ZIP) model. Setting: The study focused on DF cases in Kenya from 2019 to 2021. Methods: A ZIP model was applied to monthly dengue case data and associated climatic variables, such as temperature, rainfall, and humidity. The model addresses over-dispersion and excess zeros in the data, providing a more accurate depiction of DF dynamics. Results: The ZIP model revealed significant associations between climatic variables and DF incidence. Humidity (β = 0.0578, standard error [s.e.] = 0.0024, z = 24.157, p  2e-16) and temperature (β = 0.0558, s.e. = 0.0053, z = 10.497, p  0.01) showed a positive relationship with dengue cases, while rainfall (β = –0.0045, s.e. = 0.0003, z = –16.523, p  0.01) had a significant negative effect. The over-dispersion test confirmed excess variability in the data (O statistic = 456.3, p = 0.004), and the Vuong test supported the use of the ZIP model over a standard Poisson model. Model comparison indicated superior fit for the ZIP model (akaike information criterion [AIC] = 5230.959 vs. 27061.367 for Poisson), effectively accounting for zero-inflation. Conclusion: The results suggest that higher humidity and temperature favor dengue transmission, while heavy rainfall may disrupt mosquito breeding, reducing cases. These findings provide a basis for targeted public health interventions. Contribution: This study enhances understanding of DF-climate interactions in Kenya, supporting the application of ZIP modelling for improved disease surveillance and control strategies.
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spelling doaj-art-b7421bfab547459ea8840fe5d9a4c73c2025-08-20T02:27:39ZengAOSISJournal of Public Health in Africa2038-99222038-99302025-02-01161e1e810.4102/jphia.v16i1.781813Analysing dengue fever spread in Kenya using the Zero-Inflated Poisson modelLameck Ondieki Agasa0Faith Thuita1Thomas Achia2Antony Karanja3Department of Public and Global Health, Faculty of Health Sciences, University of Nairobi, Nairobi, Kenya; and, Department of Community Health and Behavioral Sciences, School of Health Sciences, Kisii University, KisiiDepartment of Public and Global Health, Faculty of Health Sciences, University of Nairobi, NairobiInstitute of Mathematical Sciences, Strathmore University, NairobiDepartment of Mathematics, Faculty of Science and Technology, Multimedia University, NairobiBackground: Dengue fever (DF), transmitted by Aedes mosquitoes, remains a major public health concern in tropical and subtropical regions. Understanding the influence of climatic variables on DF incidence is essential for improving outbreak prediction and control measures. Aim: This study analysed the impact of climatic factors on DF incidence in Kenya using a Zero-Inflated Poisson (ZIP) model. Setting: The study focused on DF cases in Kenya from 2019 to 2021. Methods: A ZIP model was applied to monthly dengue case data and associated climatic variables, such as temperature, rainfall, and humidity. The model addresses over-dispersion and excess zeros in the data, providing a more accurate depiction of DF dynamics. Results: The ZIP model revealed significant associations between climatic variables and DF incidence. Humidity (β = 0.0578, standard error [s.e.] = 0.0024, z = 24.157, p  2e-16) and temperature (β = 0.0558, s.e. = 0.0053, z = 10.497, p  0.01) showed a positive relationship with dengue cases, while rainfall (β = –0.0045, s.e. = 0.0003, z = –16.523, p  0.01) had a significant negative effect. The over-dispersion test confirmed excess variability in the data (O statistic = 456.3, p = 0.004), and the Vuong test supported the use of the ZIP model over a standard Poisson model. Model comparison indicated superior fit for the ZIP model (akaike information criterion [AIC] = 5230.959 vs. 27061.367 for Poisson), effectively accounting for zero-inflation. Conclusion: The results suggest that higher humidity and temperature favor dengue transmission, while heavy rainfall may disrupt mosquito breeding, reducing cases. These findings provide a basis for targeted public health interventions. Contribution: This study enhances understanding of DF-climate interactions in Kenya, supporting the application of ZIP modelling for improved disease surveillance and control strategies.https://publichealthinafrica.org/index.php/jphia/article/view/781dengue feverzero-inflated poisson modelclimatic factorsepidemiologykenya.
spellingShingle Lameck Ondieki Agasa
Faith Thuita
Thomas Achia
Antony Karanja
Analysing dengue fever spread in Kenya using the Zero-Inflated Poisson model
Journal of Public Health in Africa
dengue fever
zero-inflated poisson model
climatic factors
epidemiology
kenya.
title Analysing dengue fever spread in Kenya using the Zero-Inflated Poisson model
title_full Analysing dengue fever spread in Kenya using the Zero-Inflated Poisson model
title_fullStr Analysing dengue fever spread in Kenya using the Zero-Inflated Poisson model
title_full_unstemmed Analysing dengue fever spread in Kenya using the Zero-Inflated Poisson model
title_short Analysing dengue fever spread in Kenya using the Zero-Inflated Poisson model
title_sort analysing dengue fever spread in kenya using the zero inflated poisson model
topic dengue fever
zero-inflated poisson model
climatic factors
epidemiology
kenya.
url https://publichealthinafrica.org/index.php/jphia/article/view/781
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