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Descriptive Epidemiology of Typhoid Fever during an Epidemic in Harare, Zimbabwe, 2012

BACKGROUND: Typhoid fever remains a significant public health problem in developing countries. In October 2011, a typhoid fever epidemic was declared in Harare, Zimbabwe - the fourth enteric infection epidemic since 2008. To orient control activities, we described the epidemiology and spatiotemporal...

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Autores principales: Polonsky, Jonathan A., Martínez-Pino, Isabel, Nackers, Fabienne, Chonzi, Prosper, Manangazira, Portia, Van Herp, Michel, Maes, Peter, Porten, Klaudia, Luquero, Francisco J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4259398/
https://www.ncbi.nlm.nih.gov/pubmed/25486292
http://dx.doi.org/10.1371/journal.pone.0114702
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author Polonsky, Jonathan A.
Martínez-Pino, Isabel
Nackers, Fabienne
Chonzi, Prosper
Manangazira, Portia
Van Herp, Michel
Maes, Peter
Porten, Klaudia
Luquero, Francisco J.
author_facet Polonsky, Jonathan A.
Martínez-Pino, Isabel
Nackers, Fabienne
Chonzi, Prosper
Manangazira, Portia
Van Herp, Michel
Maes, Peter
Porten, Klaudia
Luquero, Francisco J.
author_sort Polonsky, Jonathan A.
collection PubMed
description BACKGROUND: Typhoid fever remains a significant public health problem in developing countries. In October 2011, a typhoid fever epidemic was declared in Harare, Zimbabwe - the fourth enteric infection epidemic since 2008. To orient control activities, we described the epidemiology and spatiotemporal clustering of the epidemic in Dzivaresekwa and Kuwadzana, the two most affected suburbs of Harare. METHODS: A typhoid fever case-patient register was analysed to describe the epidemic. To explore clustering, we constructed a dataset comprising GPS coordinates of case-patient residences and randomly sampled residential locations (spatial controls). The scale and significance of clustering was explored with Ripley K functions. Cluster locations were determined by a random labelling technique and confirmed using Kulldorff's spatial scan statistic. PRINCIPAL FINDINGS: We analysed data from 2570 confirmed and suspected case-patients, and found significant spatiotemporal clustering of typhoid fever in two non-overlapping areas, which appeared to be linked to environmental sources. Peak relative risk was more than six times greater than in areas lying outside the cluster ranges. Clusters were identified in similar geographical ranges by both random labelling and Kulldorff's spatial scan statistic. The spatial scale at which typhoid fever clustered was highly localised, with significant clustering at distances up to 4.5 km and peak levels at approximately 3.5 km. The epicentre of infection transmission shifted from one cluster to the other during the course of the epidemic. CONCLUSIONS: This study demonstrated highly localised clustering of typhoid fever during an epidemic in an urban African setting, and highlights the importance of spatiotemporal analysis for making timely decisions about targetting prevention and control activities and reinforcing treatment during epidemics. This approach should be integrated into existing surveillance systems to facilitate early detection of epidemics and identify their spatial range.
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spelling pubmed-42593982014-12-15 Descriptive Epidemiology of Typhoid Fever during an Epidemic in Harare, Zimbabwe, 2012 Polonsky, Jonathan A. Martínez-Pino, Isabel Nackers, Fabienne Chonzi, Prosper Manangazira, Portia Van Herp, Michel Maes, Peter Porten, Klaudia Luquero, Francisco J. PLoS One Research Article BACKGROUND: Typhoid fever remains a significant public health problem in developing countries. In October 2011, a typhoid fever epidemic was declared in Harare, Zimbabwe - the fourth enteric infection epidemic since 2008. To orient control activities, we described the epidemiology and spatiotemporal clustering of the epidemic in Dzivaresekwa and Kuwadzana, the two most affected suburbs of Harare. METHODS: A typhoid fever case-patient register was analysed to describe the epidemic. To explore clustering, we constructed a dataset comprising GPS coordinates of case-patient residences and randomly sampled residential locations (spatial controls). The scale and significance of clustering was explored with Ripley K functions. Cluster locations were determined by a random labelling technique and confirmed using Kulldorff's spatial scan statistic. PRINCIPAL FINDINGS: We analysed data from 2570 confirmed and suspected case-patients, and found significant spatiotemporal clustering of typhoid fever in two non-overlapping areas, which appeared to be linked to environmental sources. Peak relative risk was more than six times greater than in areas lying outside the cluster ranges. Clusters were identified in similar geographical ranges by both random labelling and Kulldorff's spatial scan statistic. The spatial scale at which typhoid fever clustered was highly localised, with significant clustering at distances up to 4.5 km and peak levels at approximately 3.5 km. The epicentre of infection transmission shifted from one cluster to the other during the course of the epidemic. CONCLUSIONS: This study demonstrated highly localised clustering of typhoid fever during an epidemic in an urban African setting, and highlights the importance of spatiotemporal analysis for making timely decisions about targetting prevention and control activities and reinforcing treatment during epidemics. This approach should be integrated into existing surveillance systems to facilitate early detection of epidemics and identify their spatial range. Public Library of Science 2014-12-08 /pmc/articles/PMC4259398/ /pubmed/25486292 http://dx.doi.org/10.1371/journal.pone.0114702 Text en © 2014 Polonsky et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Polonsky, Jonathan A.
Martínez-Pino, Isabel
Nackers, Fabienne
Chonzi, Prosper
Manangazira, Portia
Van Herp, Michel
Maes, Peter
Porten, Klaudia
Luquero, Francisco J.
Descriptive Epidemiology of Typhoid Fever during an Epidemic in Harare, Zimbabwe, 2012
title Descriptive Epidemiology of Typhoid Fever during an Epidemic in Harare, Zimbabwe, 2012
title_full Descriptive Epidemiology of Typhoid Fever during an Epidemic in Harare, Zimbabwe, 2012
title_fullStr Descriptive Epidemiology of Typhoid Fever during an Epidemic in Harare, Zimbabwe, 2012
title_full_unstemmed Descriptive Epidemiology of Typhoid Fever during an Epidemic in Harare, Zimbabwe, 2012
title_short Descriptive Epidemiology of Typhoid Fever during an Epidemic in Harare, Zimbabwe, 2012
title_sort descriptive epidemiology of typhoid fever during an epidemic in harare, zimbabwe, 2012
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4259398/
https://www.ncbi.nlm.nih.gov/pubmed/25486292
http://dx.doi.org/10.1371/journal.pone.0114702
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