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Spatiotemporal variability in case fatality ratios for the 2013–2016 Ebola epidemic in West Africa

BACKGROUND: For the 2013–2016 Ebola epidemic in West Africa, the largest Ebola virus disease (EVD) epidemic to date, we aim to analyse the patient mix in detail to characterise key sources of spatiotemporal heterogeneity in the case fatality ratios (CFR). METHODS: We applied a non-parametric Boosted...

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Autores principales: Forna, Alpha, Dorigatti, Ilaria, Nouvellet, Pierre, Donnelly, Christl A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7191269/
https://www.ncbi.nlm.nih.gov/pubmed/32004692
http://dx.doi.org/10.1016/j.ijid.2020.01.046
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author Forna, Alpha
Dorigatti, Ilaria
Nouvellet, Pierre
Donnelly, Christl A.
author_facet Forna, Alpha
Dorigatti, Ilaria
Nouvellet, Pierre
Donnelly, Christl A.
author_sort Forna, Alpha
collection PubMed
description BACKGROUND: For the 2013–2016 Ebola epidemic in West Africa, the largest Ebola virus disease (EVD) epidemic to date, we aim to analyse the patient mix in detail to characterise key sources of spatiotemporal heterogeneity in the case fatality ratios (CFR). METHODS: We applied a non-parametric Boosted Regression Trees (BRT) imputation approach for patients with missing survival outcomes and adjusted for model imperfection. Semivariogram analysis and kriging were used to investigate spatiotemporal heterogeneities. RESULTS: CFR estimates varied significantly between districts and over time over the course of the epidemic. BRT modelling accounted for most of the spatiotemporal variation and interactions in CFR, but moderate spatial autocorrelation remained for distances up to approximately 90 km. Combining district-level CFR estimates and kriged district-level residuals provided the best linear unbiased predicted map of CFR accounting for the both explained and unexplained spatial variation. Temporal autocorrelation was not observed in the district-level residuals from the BRT estimates. CONCLUSIONS: This study provides new insight into the epidemiology of the 2013–2016 West African Ebola epidemic with a view of informing future public health contingency planning, resource allocation and impact assessment. The analytical framework developed in this analysis, coupled with key domain knowledge, could be deployed in real time to support the response to ongoing and future outbreaks.
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spelling pubmed-71912692020-05-05 Spatiotemporal variability in case fatality ratios for the 2013–2016 Ebola epidemic in West Africa Forna, Alpha Dorigatti, Ilaria Nouvellet, Pierre Donnelly, Christl A. Int J Infect Dis Article BACKGROUND: For the 2013–2016 Ebola epidemic in West Africa, the largest Ebola virus disease (EVD) epidemic to date, we aim to analyse the patient mix in detail to characterise key sources of spatiotemporal heterogeneity in the case fatality ratios (CFR). METHODS: We applied a non-parametric Boosted Regression Trees (BRT) imputation approach for patients with missing survival outcomes and adjusted for model imperfection. Semivariogram analysis and kriging were used to investigate spatiotemporal heterogeneities. RESULTS: CFR estimates varied significantly between districts and over time over the course of the epidemic. BRT modelling accounted for most of the spatiotemporal variation and interactions in CFR, but moderate spatial autocorrelation remained for distances up to approximately 90 km. Combining district-level CFR estimates and kriged district-level residuals provided the best linear unbiased predicted map of CFR accounting for the both explained and unexplained spatial variation. Temporal autocorrelation was not observed in the district-level residuals from the BRT estimates. CONCLUSIONS: This study provides new insight into the epidemiology of the 2013–2016 West African Ebola epidemic with a view of informing future public health contingency planning, resource allocation and impact assessment. The analytical framework developed in this analysis, coupled with key domain knowledge, could be deployed in real time to support the response to ongoing and future outbreaks. Elsevier 2020-04 /pmc/articles/PMC7191269/ /pubmed/32004692 http://dx.doi.org/10.1016/j.ijid.2020.01.046 Text en © 2020 The Author(s) http://creativecommons.org/licenses/by/4.0/ This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Forna, Alpha
Dorigatti, Ilaria
Nouvellet, Pierre
Donnelly, Christl A.
Spatiotemporal variability in case fatality ratios for the 2013–2016 Ebola epidemic in West Africa
title Spatiotemporal variability in case fatality ratios for the 2013–2016 Ebola epidemic in West Africa
title_full Spatiotemporal variability in case fatality ratios for the 2013–2016 Ebola epidemic in West Africa
title_fullStr Spatiotemporal variability in case fatality ratios for the 2013–2016 Ebola epidemic in West Africa
title_full_unstemmed Spatiotemporal variability in case fatality ratios for the 2013–2016 Ebola epidemic in West Africa
title_short Spatiotemporal variability in case fatality ratios for the 2013–2016 Ebola epidemic in West Africa
title_sort spatiotemporal variability in case fatality ratios for the 2013–2016 ebola epidemic in west africa
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7191269/
https://www.ncbi.nlm.nih.gov/pubmed/32004692
http://dx.doi.org/10.1016/j.ijid.2020.01.046
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