Spatial and temporal dynamics of superspreading events in the 2014–2015 West Africa Ebola epidemic
Open Access
- 13 February 2017
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 114 (9), 2337-2342
- https://doi.org/10.1073/pnas.1614595114
Abstract
The unprecedented scale of the Ebola outbreak in Western Africa (2014–2015) has prompted an explosion of efforts to understand the transmission dynamics of the virus and to analyze the performance of possible containment strategies. Models have focused primarily on the reproductive numbers of the disease that represent the average number of secondary infections produced by a random infectious individual. However, these population-level estimates may conflate important systematic variation in the number of cases generated by infected individuals, particularly found in spatially localized transmission and superspreading events. Although superspreading features prominently in first-hand narratives of Ebola transmission, its dynamics have not been systematically characterized, hindering refinements of future epidemic predictions and explorations of targeted interventions. We used Bayesian model inference to integrate individual-level spatial information with other epidemiological data of community-based (undetected within clinical-care systems) cases and to explicitly infer distribution of the cases generated by each infected individual. Our results show that superspreaders play a key role in sustaining onward transmission of the epidemic, and they are responsible for a significant proportion ( 61%) of the infections. Our results also suggest age as a key demographic predictor for superspreading. We also show that community-based cases may have progressed more rapidly than those notified within clinical-care systems, and most transmission events occurred in a relatively short distance (with median value of 2.51 km). Our results stress the importance of characterizing superspreading of Ebola, enhance our current understanding of its spatiotemporal dynamics, and highlight the potential importance of targeted control measures.
Keywords
This publication has 35 references indexed in Scilit:
- A Bayesian Inference Framework to Reconstruct Transmission Trees Using Epidemiological and Genetic DataPLoS Computational Biology, 2012
- Inferring Epidemic Contact Structure from Phylogenetic TreesPLoS Computational Biology, 2012
- Integrating genetic and epidemiological data to determine transmission pathways of foot-and-mouth disease virusProceedings. Biological sciences, 2008
- Under-reporting of notifiable infectious disease hospitalizations in a health board region in Ireland: room for improvement?Epidemiology and Infection, 2007
- Synchrony, Waves, and Spatial Hierarchies in the Spread of InfluenzaScience, 2006
- Measles Metapopulation Dynamics: A Gravity Model for Epidemiological Coupling and DynamicsThe American Naturalist, 2004
- The construction and analysis of epidemic trees with reference to the 2001 UK foot–and–mouth outbreakProceedings. Biological sciences, 2003
- Understanding the Metropolis-Hastings AlgorithmThe American Statistician, 1995
- Spatial Interaction and Spatial Autocorrelation: A Cross-Product ApproachEnvironment and Planning A: Economy and Space, 1991
- Age-related changes in the rate of disease transmission: implications for the design of vaccination programmesEpidemiology and Infection, 1985